Re: [PATCH 14/17] cifs: Change the I/O paths to use an iterator rather than a page list

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This had various checkpatch warnings - some are probably worth
cleaning up.  Do you want to spin a v2 of this patch?

0014-cifs-Change-the-I-O-paths-to-use-an-iterator-rather-.patch
---------------------------------------------------------------
WARNING: ENOTSUPP is not a SUSV4 error code, prefer EOPNOTSUPP
#465: FILE: fs/cifs/file.c:2444:
+ rc = -ENOTSUPP;

WARNING: Consider removing the code enclosed by this #if 0 and its #endif
#627: FILE: fs/cifs/file.c:2609:
+#if 0 // TODO: Remove for iov_iter support

WARNING: Missing a blank line after declarations
#657: FILE: fs/cifs/file.c:2937:
+ XA_STATE(xas, &mapping->i_pages, index);
+ folio_batch_init(&batch);

WARNING: Consider removing the code enclosed by this #if 0 and its #endif
#1040: FILE: fs/cifs/file.c:3512:
+#if 0 // TODO: Remove for iov_iter support

WARNING: Consider removing the code enclosed by this #if 0 and its #endif
#1067: FILE: fs/cifs/file.c:3587:
+#if 0 // TODO: Remove for iov_iter support

WARNING: Consider removing the code enclosed by this #if 0 and its #endif
#1530: FILE: fs/cifs/file.c:4217:
+#if 0 // TODO: Remove for iov_iter support

WARNING: Consider removing the code enclosed by this #if 0 and its #endif
#1837: FILE: fs/cifs/file.c:4903:
+#if 0 // TODO: Remove for iov_iter support

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
#2190: FILE: fs/cifs/misc.c:975:
+ unsigned i;

WARNING: nested (un)?likely() calls, IS_ERR already uses unlikely() internally
#2453: FILE: fs/cifs/smb2ops.c:4409:
+ if (unlikely(IS_ERR(creq)))

total: 0 errors, 9 warnings, 3271 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

0014-cifs-Change-the-I-O-paths-to-use-an-iterator-rather-.patch has
style problems, please review.

On Thu, Feb 16, 2023 at 3:48 PM David Howells <dhowells@xxxxxxxxxx> wrote:
>
> Currently, the cifs I/O paths hand lists of pages from the VM interface
> routines at the top all the way through the intervening layers to the
> socket interface at the bottom.
>
> This is a problem, however, for interfacing with netfslib which passes an
> iterator through to the ->issue_read() method (and will pass an iterator
> through to the ->issue_write() method in future).  Netfslib takes over
> bounce buffering for direct I/O, async I/O and encrypted content, so cifs
> doesn't need to do that.  Netfslib also converts IOVEC-type iterators into
> BVEC-type iterators if necessary.
>
> Further, cifs needs foliating - and folios may come in a variety of sizes,
> so a page list pointing to an array of heterogeneous pages may cause
> problems in places such as where crypto is done.
>
> Change the cifs I/O paths to hand iov_iter iterators all the way through
> instead.
>
> Notes:
>
>  (1) Some old routines are #if'd out to be removed in a follow up patch so
>      as to avoid confusing diff, thereby making the diff output easier to
>      follow.  I've removed functions that don't overlap with anything
>      added.
>
>  (2) struct smb_rqst loses rq_pages, rq_offset, rq_npages, rq_pagesz and
>      rq_tailsz which describe the pages forming the buffer; instead there's
>      an rq_iter describing the source buffer and an rq_buffer which is used
>      to hold the buffer for encryption.
>
>  (3) struct cifs_readdata and cifs_writedata are similarly modified to
>      smb_rqst.  The ->read_into_pages() and ->copy_into_pages() are then
>      replaced with passing the iterator directly to the socket.
>
>      The iterators are stored in these structs so that they are persistent
>      and don't get deallocated when the function returns (unlike if they
>      were stack variables).
>
>  (4) Buffered writeback is overhauled, borrowing the code from the afs
>      filesystem to gather up contiguous runs of folios.  The XARRAY-type
>      iterator is then used to refer directly to the pagecache and can be
>      passed to the socket to transmit data directly from there.
>
>      This includes:
>
>         cifs_extend_writeback()
>         cifs_write_back_from_locked_folio()
>         cifs_writepages_region()
>         cifs_writepages()
>
>  (5) Pages are converted to folios.
>
>  (6) Direct I/O uses netfs_extract_user_iter() to create a BVEC-type
>      iterator from an IOBUF/UBUF-type source iterator.
>
>  (7) smb2_get_aead_req() uses netfs_extract_iter_to_sg() to extract page
>      fragments from the iterator into the scatterlists that the crypto
>      layer prefers.
>
>  (8) smb2_init_transform_rq() attached pages to smb_rqst::rq_buffer, an
>      xarray, to use as a bounce buffer for encryption.  An XARRAY-type
>      iterator can then be used to pass the bounce buffer to lower layers.
>
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> cc: Steve French <sfrench@xxxxxxxxx>
> cc: Shyam Prasad N <nspmangalore@xxxxxxxxx>
> cc: Rohith Surabattula <rohiths.msft@xxxxxxxxx>
> cc: Paulo Alcantara <pc@xxxxxx>
> cc: Jeff Layton <jlayton@xxxxxxxxxx>
> cc: linux-cifs@xxxxxxxxxxxxxxx
>
> Link: https://lore.kernel.org/r/164311907995.2806745.400147335497304099.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # rfc
> Link: https://lore.kernel.org/r/164928620163.457102.11602306234438271112.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v1
> Link: https://lore.kernel.org/r/165211420279.3154751.15923591172438186144.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v1
> Link: https://lore.kernel.org/r/165348880385.2106726.3220789453472800240.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v1
> Link: https://lore.kernel.org/r/165364827111.3334034.934805882842932881.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v3
> Link: https://lore.kernel.org/r/166126396180.708021.271013668175370826.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v1
> Link: https://lore.kernel.org/r/166697259595.61150.5982032408321852414.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # rfc
> Link: https://lore.kernel.org/r/166732031756.3186319.12528413619888902872.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # rfc
> ---
>  fs/cifs/Kconfig       |    1 +
>  fs/cifs/cifsencrypt.c |   28 +-
>  fs/cifs/cifsglob.h    |   66 +--
>  fs/cifs/cifsproto.h   |    8 +-
>  fs/cifs/cifssmb.c     |   15 +-
>  fs/cifs/file.c        | 1197 ++++++++++++++++++++++++++---------------
>  fs/cifs/fscache.c     |   22 +-
>  fs/cifs/fscache.h     |   10 +-
>  fs/cifs/misc.c        |  128 +----
>  fs/cifs/smb2ops.c     |  362 ++++++-------
>  fs/cifs/smb2pdu.c     |   53 +-
>  fs/cifs/smbdirect.c   |  262 ++++-----
>  fs/cifs/smbdirect.h   |    4 +-
>  fs/cifs/transport.c   |   54 +-
>  14 files changed, 1122 insertions(+), 1088 deletions(-)
>
> diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
> index bbf63a9eb927..4c0d53bf931a 100644
> --- a/fs/cifs/Kconfig
> +++ b/fs/cifs/Kconfig
> @@ -18,6 +18,7 @@ config CIFS
>         select DNS_RESOLVER
>         select ASN1
>         select OID_REGISTRY
> +       select NETFS_SUPPORT
>         help
>           This is the client VFS module for the SMB3 family of network file
>           protocols (including the most recent, most secure dialect SMB3.1.1).
> diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
> index 7be589aeb520..357bd27a7fd1 100644
> --- a/fs/cifs/cifsencrypt.c
> +++ b/fs/cifs/cifsencrypt.c
> @@ -169,11 +169,11 @@ static int cifs_shash_iter(const struct iov_iter *iter, size_t maxsize,
>  }
>
>  int __cifs_calc_signature(struct smb_rqst *rqst,
> -                       struct TCP_Server_Info *server, char *signature,
> -                       struct shash_desc *shash)
> +                         struct TCP_Server_Info *server, char *signature,
> +                         struct shash_desc *shash)
>  {
>         int i;
> -       int rc;
> +       ssize_t rc;
>         struct kvec *iov = rqst->rq_iov;
>         int n_vec = rqst->rq_nvec;
>
> @@ -205,25 +205,9 @@ int __cifs_calc_signature(struct smb_rqst *rqst,
>                 }
>         }
>
> -       /* now hash over the rq_pages array */
> -       for (i = 0; i < rqst->rq_npages; i++) {
> -               void *kaddr;
> -               unsigned int len, offset;
> -
> -               rqst_page_get_length(rqst, i, &len, &offset);
> -
> -               kaddr = (char *) kmap(rqst->rq_pages[i]) + offset;
> -
> -               rc = crypto_shash_update(shash, kaddr, len);
> -               if (rc) {
> -                       cifs_dbg(VFS, "%s: Could not update with payload\n",
> -                                __func__);
> -                       kunmap(rqst->rq_pages[i]);
> -                       return rc;
> -               }
> -
> -               kunmap(rqst->rq_pages[i]);
> -       }
> +       rc = cifs_shash_iter(&rqst->rq_iter, iov_iter_count(&rqst->rq_iter), shash);
> +       if (rc < 0)
> +               return rc;
>
>         rc = crypto_shash_final(shash, signature);
>         if (rc)
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 1d893bea4723..893c2e21eb8e 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -216,11 +216,9 @@ static inline void cifs_free_open_info(struct cifs_open_info_data *data)
>  struct smb_rqst {
>         struct kvec     *rq_iov;        /* array of kvecs */
>         unsigned int    rq_nvec;        /* number of kvecs in array */
> -       struct page     **rq_pages;     /* pointer to array of page ptrs */
> -       unsigned int    rq_offset;      /* the offset to the 1st page */
> -       unsigned int    rq_npages;      /* number pages in array */
> -       unsigned int    rq_pagesz;      /* page size to use */
> -       unsigned int    rq_tailsz;      /* length of last page */
> +       size_t          rq_iter_size;   /* Amount of data in ->rq_iter */
> +       struct iov_iter rq_iter;        /* Data iterator */
> +       struct xarray   rq_buffer;      /* Page buffer for encryption */
>  };
>
>  struct mid_q_entry;
> @@ -1428,10 +1426,11 @@ struct cifs_aio_ctx {
>         struct cifsFileInfo     *cfile;
>         struct bio_vec          *bv;
>         loff_t                  pos;
> -       unsigned int            npages;
> +       unsigned int            nr_pinned_pages;
>         ssize_t                 rc;
>         unsigned int            len;
>         unsigned int            total_len;
> +       unsigned int            bv_need_unpin;  /* If ->bv[] needs unpinning */
>         bool                    should_dirty;
>         /*
>          * Indicates if this aio_ctx is for direct_io,
> @@ -1449,28 +1448,18 @@ struct cifs_readdata {
>         struct address_space            *mapping;
>         struct cifs_aio_ctx             *ctx;
>         __u64                           offset;
> +       ssize_t                         got_bytes;
>         unsigned int                    bytes;
> -       unsigned int                    got_bytes;
>         pid_t                           pid;
>         int                             result;
>         struct work_struct              work;
> -       int (*read_into_pages)(struct TCP_Server_Info *server,
> -                               struct cifs_readdata *rdata,
> -                               unsigned int len);
> -       int (*copy_into_pages)(struct TCP_Server_Info *server,
> -                               struct cifs_readdata *rdata,
> -                               struct iov_iter *iter);
> +       struct iov_iter                 iter;
>         struct kvec                     iov[2];
>         struct TCP_Server_Info          *server;
>  #ifdef CONFIG_CIFS_SMB_DIRECT
>         struct smbd_mr                  *mr;
>  #endif
> -       unsigned int                    pagesz;
> -       unsigned int                    page_offset;
> -       unsigned int                    tailsz;
>         struct cifs_credits             credits;
> -       unsigned int                    nr_pages;
> -       struct page                     **pages;
>  };
>
>  /* asynchronous write support */
> @@ -1482,6 +1471,8 @@ struct cifs_writedata {
>         struct work_struct              work;
>         struct cifsFileInfo             *cfile;
>         struct cifs_aio_ctx             *ctx;
> +       struct iov_iter                 iter;
> +       struct bio_vec                  *bv;
>         __u64                           offset;
>         pid_t                           pid;
>         unsigned int                    bytes;
> @@ -1490,12 +1481,7 @@ struct cifs_writedata {
>  #ifdef CONFIG_CIFS_SMB_DIRECT
>         struct smbd_mr                  *mr;
>  #endif
> -       unsigned int                    pagesz;
> -       unsigned int                    page_offset;
> -       unsigned int                    tailsz;
>         struct cifs_credits             credits;
> -       unsigned int                    nr_pages;
> -       struct page                     **pages;
>  };
>
>  /*
> @@ -2155,9 +2141,9 @@ static inline void move_cifs_info_to_smb2(struct smb2_file_all_info *dst, const
>         dst->FileNameLength = src->FileNameLength;
>  }
>
> -static inline unsigned int cifs_get_num_sgs(const struct smb_rqst *rqst,
> -                                           int num_rqst,
> -                                           const u8 *sig)
> +static inline int cifs_get_num_sgs(const struct smb_rqst *rqst,
> +                                  int num_rqst,
> +                                  const u8 *sig)
>  {
>         unsigned int len, skip;
>         unsigned int nents = 0;
> @@ -2177,6 +2163,19 @@ static inline unsigned int cifs_get_num_sgs(const struct smb_rqst *rqst,
>          * rqst[1+].rq_iov[0+] data to be encrypted/decrypted
>          */
>         for (i = 0; i < num_rqst; i++) {
> +               /* We really don't want a mixture of pinned and unpinned pages
> +                * in the sglist.  It's hard to keep track of which is what.
> +                * Instead, we convert to a BVEC-type iterator higher up.
> +                */
> +               if (WARN_ON_ONCE(user_backed_iter(&rqst[i].rq_iter)))
> +                       return -EIO;
> +
> +               /* We also don't want to have any extra refs or pins to clean
> +                * up in the sglist.
> +                */
> +               if (WARN_ON_ONCE(iov_iter_extract_will_pin(&rqst[i].rq_iter)))
> +                       return -EIO;
> +
>                 for (j = 0; j < rqst[i].rq_nvec; j++) {
>                         struct kvec *iov = &rqst[i].rq_iov[j];
>
> @@ -2190,7 +2189,7 @@ static inline unsigned int cifs_get_num_sgs(const struct smb_rqst *rqst,
>                         }
>                         skip = 0;
>                 }
> -               nents += rqst[i].rq_npages;
> +               nents += iov_iter_npages(&rqst[i].rq_iter, INT_MAX);
>         }
>         nents += DIV_ROUND_UP(offset_in_page(sig) + SMB2_SIGNATURE_SIZE, PAGE_SIZE);
>         return nents;
> @@ -2199,9 +2198,9 @@ static inline unsigned int cifs_get_num_sgs(const struct smb_rqst *rqst,
>  /* We can not use the normal sg_set_buf() as we will sometimes pass a
>   * stack object as buf.
>   */
> -static inline struct scatterlist *cifs_sg_set_buf(struct scatterlist *sg,
> -                                                 const void *buf,
> -                                                 unsigned int buflen)
> +static inline void cifs_sg_set_buf(struct sg_table *sgtable,
> +                                  const void *buf,
> +                                  unsigned int buflen)
>  {
>         unsigned long addr = (unsigned long)buf;
>         unsigned int off = offset_in_page(addr);
> @@ -2211,16 +2210,17 @@ static inline struct scatterlist *cifs_sg_set_buf(struct scatterlist *sg,
>                 do {
>                         unsigned int len = min_t(unsigned int, buflen, PAGE_SIZE - off);
>
> -                       sg_set_page(sg++, vmalloc_to_page((void *)addr), len, off);
> +                       sg_set_page(&sgtable->sgl[sgtable->nents++],
> +                                   vmalloc_to_page((void *)addr), len, off);
>
>                         off = 0;
>                         addr += PAGE_SIZE;
>                         buflen -= len;
>                 } while (buflen);
>         } else {
> -               sg_set_page(sg++, virt_to_page(addr), buflen, off);
> +               sg_set_page(&sgtable->sgl[sgtable->nents++],
> +                           virt_to_page(addr), buflen, off);
>         }
> -       return sg;
>  }
>
>  #endif /* _CIFS_GLOB_H */
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index cb7a3fe89278..2873f68a051c 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -584,10 +584,7 @@ int cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid);
>  int cifs_async_writev(struct cifs_writedata *wdata,
>                       void (*release)(struct kref *kref));
>  void cifs_writev_complete(struct work_struct *work);
> -struct cifs_writedata *cifs_writedata_alloc(unsigned int nr_pages,
> -                                               work_func_t complete);
> -struct cifs_writedata *cifs_writedata_direct_alloc(struct page **pages,
> -                                               work_func_t complete);
> +struct cifs_writedata *cifs_writedata_alloc(work_func_t complete);
>  void cifs_writedata_release(struct kref *refcount);
>  int cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
>                           struct cifs_sb_info *cifs_sb,
> @@ -604,13 +601,10 @@ enum securityEnum cifs_select_sectype(struct TCP_Server_Info *,
>                                         enum securityEnum);
>  struct cifs_aio_ctx *cifs_aio_ctx_alloc(void);
>  void cifs_aio_ctx_release(struct kref *refcount);
> -int setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw);
>
>  int cifs_alloc_hash(const char *name, struct shash_desc **sdesc);
>  void cifs_free_hash(struct shash_desc **sdesc);
>
> -void rqst_page_get_length(const struct smb_rqst *rqst, unsigned int page,
> -                         unsigned int *len, unsigned int *offset);
>  struct cifs_chan *
>  cifs_ses_find_chan(struct cifs_ses *ses, struct TCP_Server_Info *server);
>  int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses);
> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> index 8c014a3ff9e0..730ae3273698 100644
> --- a/fs/cifs/cifssmb.c
> +++ b/fs/cifs/cifssmb.c
> @@ -24,6 +24,7 @@
>  #include <linux/task_io_accounting_ops.h>
>  #include <linux/uaccess.h>
>  #include "cifspdu.h"
> +#include "cifsfs.h"
>  #include "cifsglob.h"
>  #include "cifsacl.h"
>  #include "cifsproto.h"
> @@ -1294,11 +1295,8 @@ cifs_readv_callback(struct mid_q_entry *mid)
>         struct TCP_Server_Info *server = tcon->ses->server;
>         struct smb_rqst rqst = { .rq_iov = rdata->iov,
>                                  .rq_nvec = 2,
> -                                .rq_pages = rdata->pages,
> -                                .rq_offset = rdata->page_offset,
> -                                .rq_npages = rdata->nr_pages,
> -                                .rq_pagesz = rdata->pagesz,
> -                                .rq_tailsz = rdata->tailsz };
> +                                .rq_iter_size = iov_iter_count(&rdata->iter),
> +                                .rq_iter = rdata->iter };
>         struct cifs_credits credits = { .value = 1, .instance = 0 };
>
>         cifs_dbg(FYI, "%s: mid=%llu state=%d result=%d bytes=%u\n",
> @@ -1737,11 +1735,8 @@ cifs_async_writev(struct cifs_writedata *wdata,
>
>         rqst.rq_iov = iov;
>         rqst.rq_nvec = 2;
> -       rqst.rq_pages = wdata->pages;
> -       rqst.rq_offset = wdata->page_offset;
> -       rqst.rq_npages = wdata->nr_pages;
> -       rqst.rq_pagesz = wdata->pagesz;
> -       rqst.rq_tailsz = wdata->tailsz;
> +       rqst.rq_iter = wdata->iter;
> +       rqst.rq_iter_size = iov_iter_count(&wdata->iter);
>
>         cifs_dbg(FYI, "async write at %llu %u bytes\n",
>                  wdata->offset, wdata->bytes);
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 09240b8b018a..33779d184692 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -36,6 +36,32 @@
>  #include "cifs_ioctl.h"
>  #include "cached_dir.h"
>
> +/*
> + * Remove the dirty flags from a span of pages.
> + */
> +static void cifs_undirty_folios(struct inode *inode, loff_t start, unsigned int len)
> +{
> +       struct address_space *mapping = inode->i_mapping;
> +       struct folio *folio;
> +       pgoff_t end;
> +
> +       XA_STATE(xas, &mapping->i_pages, start / PAGE_SIZE);
> +
> +       rcu_read_lock();
> +
> +       end = (start + len - 1) / PAGE_SIZE;
> +       xas_for_each_marked(&xas, folio, end, PAGECACHE_TAG_DIRTY) {
> +               xas_pause(&xas);
> +               rcu_read_unlock();
> +               folio_lock(folio);
> +               folio_clear_dirty_for_io(folio);
> +               folio_unlock(folio);
> +               rcu_read_lock();
> +       }
> +
> +       rcu_read_unlock();
> +}
> +
>  /*
>   * Completion of write to server.
>   */
> @@ -2391,7 +2417,6 @@ cifs_writedata_release(struct kref *refcount)
>         if (wdata->cfile)
>                 cifsFileInfo_put(wdata->cfile);
>
> -       kvfree(wdata->pages);
>         kfree(wdata);
>  }
>
> @@ -2402,51 +2427,49 @@ cifs_writedata_release(struct kref *refcount)
>  static void
>  cifs_writev_requeue(struct cifs_writedata *wdata)
>  {
> -       int i, rc = 0;
> +       int rc = 0;
>         struct inode *inode = d_inode(wdata->cfile->dentry);
>         struct TCP_Server_Info *server;
> -       unsigned int rest_len;
> +       unsigned int rest_len = wdata->bytes;
> +       loff_t fpos = wdata->offset;
>
>         server = tlink_tcon(wdata->cfile->tlink)->ses->server;
> -       i = 0;
> -       rest_len = wdata->bytes;
>         do {
>                 struct cifs_writedata *wdata2;
> -               unsigned int j, nr_pages, wsize, tailsz, cur_len;
> +               unsigned int wsize, cur_len;
>
>                 wsize = server->ops->wp_retry_size(inode);
>                 if (wsize < rest_len) {
> -                       nr_pages = wsize / PAGE_SIZE;
> -                       if (!nr_pages) {
> -                               rc = -EOPNOTSUPP;
> +                       if (wsize < PAGE_SIZE) {
> +                               rc = -ENOTSUPP;
>                                 break;
>                         }
> -                       cur_len = nr_pages * PAGE_SIZE;
> -                       tailsz = PAGE_SIZE;
> +                       cur_len = min(round_down(wsize, PAGE_SIZE), rest_len);
>                 } else {
> -                       nr_pages = DIV_ROUND_UP(rest_len, PAGE_SIZE);
>                         cur_len = rest_len;
> -                       tailsz = rest_len - (nr_pages - 1) * PAGE_SIZE;
>                 }
>
> -               wdata2 = cifs_writedata_alloc(nr_pages, cifs_writev_complete);
> +               wdata2 = cifs_writedata_alloc(cifs_writev_complete);
>                 if (!wdata2) {
>                         rc = -ENOMEM;
>                         break;
>                 }
>
> -               for (j = 0; j < nr_pages; j++) {
> -                       wdata2->pages[j] = wdata->pages[i + j];
> -                       lock_page(wdata2->pages[j]);
> -                       clear_page_dirty_for_io(wdata2->pages[j]);
> -               }
> -
>                 wdata2->sync_mode = wdata->sync_mode;
> -               wdata2->nr_pages = nr_pages;
> -               wdata2->offset = page_offset(wdata2->pages[0]);
> -               wdata2->pagesz = PAGE_SIZE;
> -               wdata2->tailsz = tailsz;
> -               wdata2->bytes = cur_len;
> +               wdata2->offset  = fpos;
> +               wdata2->bytes   = cur_len;
> +               wdata2->iter    = wdata->iter;
> +
> +               iov_iter_advance(&wdata2->iter, fpos - wdata->offset);
> +               iov_iter_truncate(&wdata2->iter, wdata2->bytes);
> +
> +               if (iov_iter_is_xarray(&wdata2->iter))
> +                       /* Check for pages having been redirtied and clean
> +                        * them.  We can do this by walking the xarray.  If
> +                        * it's not an xarray, then it's a DIO and we shouldn't
> +                        * be mucking around with the page bits.
> +                        */
> +                       cifs_undirty_folios(inode, fpos, cur_len);
>
>                 rc = cifs_get_writable_file(CIFS_I(inode), FIND_WR_ANY,
>                                             &wdata2->cfile);
> @@ -2461,33 +2484,22 @@ cifs_writev_requeue(struct cifs_writedata *wdata)
>                                                        cifs_writedata_release);
>                 }
>
> -               for (j = 0; j < nr_pages; j++) {
> -                       unlock_page(wdata2->pages[j]);
> -                       if (rc != 0 && !is_retryable_error(rc)) {
> -                               SetPageError(wdata2->pages[j]);
> -                               end_page_writeback(wdata2->pages[j]);
> -                               put_page(wdata2->pages[j]);
> -                       }
> -               }
> -
>                 kref_put(&wdata2->refcount, cifs_writedata_release);
>                 if (rc) {
>                         if (is_retryable_error(rc))
>                                 continue;
> -                       i += nr_pages;
> +                       fpos += cur_len;
> +                       rest_len -= cur_len;
>                         break;
>                 }
>
> +               fpos += cur_len;
>                 rest_len -= cur_len;
> -               i += nr_pages;
> -       } while (i < wdata->nr_pages);
> +       } while (rest_len > 0);
>
> -       /* cleanup remaining pages from the original wdata */
> -       for (; i < wdata->nr_pages; i++) {
> -               SetPageError(wdata->pages[i]);
> -               end_page_writeback(wdata->pages[i]);
> -               put_page(wdata->pages[i]);
> -       }
> +       /* Clean up remaining pages from the original wdata */
> +       if (iov_iter_is_xarray(&wdata->iter))
> +               cifs_pages_write_failed(inode, fpos, rest_len);
>
>         if (rc != 0 && !is_retryable_error(rc))
>                 mapping_set_error(inode->i_mapping, rc);
> @@ -2500,7 +2512,6 @@ cifs_writev_complete(struct work_struct *work)
>         struct cifs_writedata *wdata = container_of(work,
>                                                 struct cifs_writedata, work);
>         struct inode *inode = d_inode(wdata->cfile->dentry);
> -       int i = 0;
>
>         if (wdata->result == 0) {
>                 spin_lock(&inode->i_lock);
> @@ -2511,45 +2522,24 @@ cifs_writev_complete(struct work_struct *work)
>         } else if (wdata->sync_mode == WB_SYNC_ALL && wdata->result == -EAGAIN)
>                 return cifs_writev_requeue(wdata);
>
> -       for (i = 0; i < wdata->nr_pages; i++) {
> -               struct page *page = wdata->pages[i];
> +       if (wdata->result == -EAGAIN)
> +               cifs_pages_write_redirty(inode, wdata->offset, wdata->bytes);
> +       else if (wdata->result < 0)
> +               cifs_pages_write_failed(inode, wdata->offset, wdata->bytes);
> +       else
> +               cifs_pages_written_back(inode, wdata->offset, wdata->bytes);
>
> -               if (wdata->result == -EAGAIN)
> -                       __set_page_dirty_nobuffers(page);
> -               else if (wdata->result < 0)
> -                       SetPageError(page);
> -               end_page_writeback(page);
> -               cifs_readpage_to_fscache(inode, page);
> -               put_page(page);
> -       }
>         if (wdata->result != -EAGAIN)
>                 mapping_set_error(inode->i_mapping, wdata->result);
>         kref_put(&wdata->refcount, cifs_writedata_release);
>  }
>
> -struct cifs_writedata *
> -cifs_writedata_alloc(unsigned int nr_pages, work_func_t complete)
> -{
> -       struct cifs_writedata *writedata = NULL;
> -       struct page **pages =
> -               kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
> -       if (pages) {
> -               writedata = cifs_writedata_direct_alloc(pages, complete);
> -               if (!writedata)
> -                       kvfree(pages);
> -       }
> -
> -       return writedata;
> -}
> -
> -struct cifs_writedata *
> -cifs_writedata_direct_alloc(struct page **pages, work_func_t complete)
> +struct cifs_writedata *cifs_writedata_alloc(work_func_t complete)
>  {
>         struct cifs_writedata *wdata;
>
>         wdata = kzalloc(sizeof(*wdata), GFP_NOFS);
>         if (wdata != NULL) {
> -               wdata->pages = pages;
>                 kref_init(&wdata->refcount);
>                 INIT_LIST_HEAD(&wdata->list);
>                 init_completion(&wdata->done);
> @@ -2558,7 +2548,6 @@ cifs_writedata_direct_alloc(struct page **pages, work_func_t complete)
>         return wdata;
>  }
>
> -
>  static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
>  {
>         struct address_space *mapping = page->mapping;
> @@ -2617,6 +2606,7 @@ static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
>         return rc;
>  }
>
> +#if 0 // TODO: Remove for iov_iter support
>  static struct cifs_writedata *
>  wdata_alloc_and_fillpages(pgoff_t tofind, struct address_space *mapping,
>                           pgoff_t end, pgoff_t *index,
> @@ -2922,6 +2912,375 @@ static int cifs_writepages(struct address_space *mapping,
>         set_bit(CIFS_INO_MODIFIED_ATTR, &CIFS_I(inode)->flags);
>         return rc;
>  }
> +#endif
> +
> +/*
> + * Extend the region to be written back to include subsequent contiguously
> + * dirty pages if possible, but don't sleep while doing so.
> + */
> +static void cifs_extend_writeback(struct address_space *mapping,
> +                                 long *_count,
> +                                 loff_t start,
> +                                 int max_pages,
> +                                 size_t max_len,
> +                                 unsigned int *_len)
> +{
> +       struct folio_batch batch;
> +       struct folio *folio;
> +       unsigned int psize, nr_pages;
> +       size_t len = *_len;
> +       pgoff_t index = (start + len) / PAGE_SIZE;
> +       bool stop = true;
> +       unsigned int i;
> +
> +       XA_STATE(xas, &mapping->i_pages, index);
> +       folio_batch_init(&batch);
> +
> +       do {
> +               /* Firstly, we gather up a batch of contiguous dirty pages
> +                * under the RCU read lock - but we can't clear the dirty flags
> +                * there if any of those pages are mapped.
> +                */
> +               rcu_read_lock();
> +
> +               xas_for_each(&xas, folio, ULONG_MAX) {
> +                       stop = true;
> +                       if (xas_retry(&xas, folio))
> +                               continue;
> +                       if (xa_is_value(folio))
> +                               break;
> +                       if (folio_index(folio) != index)
> +                               break;
> +                       if (!folio_try_get_rcu(folio)) {
> +                               xas_reset(&xas);
> +                               continue;
> +                       }
> +                       nr_pages = folio_nr_pages(folio);
> +                       if (nr_pages > max_pages)
> +                               break;
> +
> +                       /* Has the page moved or been split? */
> +                       if (unlikely(folio != xas_reload(&xas))) {
> +                               folio_put(folio);
> +                               break;
> +                       }
> +
> +                       if (!folio_trylock(folio)) {
> +                               folio_put(folio);
> +                               break;
> +                       }
> +                       if (!folio_test_dirty(folio) || folio_test_writeback(folio)) {
> +                               folio_unlock(folio);
> +                               folio_put(folio);
> +                               break;
> +                       }
> +
> +                       max_pages -= nr_pages;
> +                       psize = folio_size(folio);
> +                       len += psize;
> +                       stop = false;
> +                       if (max_pages <= 0 || len >= max_len || *_count <= 0)
> +                               stop = true;
> +
> +                       index += nr_pages;
> +                       if (!folio_batch_add(&batch, folio))
> +                               break;
> +                       if (stop)
> +                               break;
> +               }
> +
> +               if (!stop)
> +                       xas_pause(&xas);
> +               rcu_read_unlock();
> +
> +               /* Now, if we obtained any pages, we can shift them to being
> +                * writable and mark them for caching.
> +                */
> +               if (!folio_batch_count(&batch))
> +                       break;
> +
> +               for (i = 0; i < folio_batch_count(&batch); i++) {
> +                       folio = batch.folios[i];
> +                       /* The folio should be locked, dirty and not undergoing
> +                        * writeback from the loop above.
> +                        */
> +                       if (!folio_clear_dirty_for_io(folio))
> +                               WARN_ON(1);
> +                       if (folio_start_writeback(folio))
> +                               WARN_ON(1);
> +
> +                       *_count -= folio_nr_pages(folio);
> +                       folio_unlock(folio);
> +               }
> +
> +               folio_batch_release(&batch);
> +               cond_resched();
> +       } while (!stop);
> +
> +       *_len = len;
> +}
> +
> +/*
> + * Write back the locked page and any subsequent non-locked dirty pages.
> + */
> +static ssize_t cifs_write_back_from_locked_folio(struct address_space *mapping,
> +                                                struct writeback_control *wbc,
> +                                                struct folio *folio,
> +                                                loff_t start, loff_t end)
> +{
> +       struct inode *inode = mapping->host;
> +       struct TCP_Server_Info *server;
> +       struct cifs_writedata *wdata;
> +       struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
> +       struct cifs_credits credits_on_stack;
> +       struct cifs_credits *credits = &credits_on_stack;
> +       struct cifsFileInfo *cfile = NULL;
> +       unsigned int xid, wsize, len;
> +       loff_t i_size = i_size_read(inode);
> +       size_t max_len;
> +       long count = wbc->nr_to_write;
> +       int rc;
> +
> +       /* The folio should be locked, dirty and not undergoing writeback. */
> +       if (folio_start_writeback(folio))
> +               WARN_ON(1);
> +
> +       count -= folio_nr_pages(folio);
> +       len = folio_size(folio);
> +
> +       xid = get_xid();
> +       server = cifs_pick_channel(cifs_sb_master_tcon(cifs_sb)->ses);
> +
> +       rc = cifs_get_writable_file(CIFS_I(inode), FIND_WR_ANY, &cfile);
> +       if (rc) {
> +               cifs_dbg(VFS, "No writable handle in writepages rc=%d\n", rc);
> +               goto err_xid;
> +       }
> +
> +       rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->wsize,
> +                                          &wsize, credits);
> +       if (rc != 0)
> +               goto err_close;
> +
> +       wdata = cifs_writedata_alloc(cifs_writev_complete);
> +       if (!wdata) {
> +               rc = -ENOMEM;
> +               goto err_uncredit;
> +       }
> +
> +       wdata->sync_mode = wbc->sync_mode;
> +       wdata->offset = folio_pos(folio);
> +       wdata->pid = cfile->pid;
> +       wdata->credits = credits_on_stack;
> +       wdata->cfile = cfile;
> +       wdata->server = server;
> +       cfile = NULL;
> +
> +       /* Find all consecutive lockable dirty pages, stopping when we find a
> +        * page that is not immediately lockable, is not dirty or is missing,
> +        * or we reach the end of the range.
> +        */
> +       if (start < i_size) {
> +               /* Trim the write to the EOF; the extra data is ignored.  Also
> +                * put an upper limit on the size of a single storedata op.
> +                */
> +               max_len = wsize;
> +               max_len = min_t(unsigned long long, max_len, end - start + 1);
> +               max_len = min_t(unsigned long long, max_len, i_size - start);
> +
> +               if (len < max_len) {
> +                       int max_pages = INT_MAX;
> +
> +#ifdef CONFIG_CIFS_SMB_DIRECT
> +                       if (server->smbd_conn)
> +                               max_pages = server->smbd_conn->max_frmr_depth;
> +#endif
> +                       max_pages -= folio_nr_pages(folio);
> +
> +                       if (max_pages > 0)
> +                               cifs_extend_writeback(mapping, &count, start,
> +                                                     max_pages, max_len, &len);
> +               }
> +               len = min_t(loff_t, len, max_len);
> +       }
> +
> +       wdata->bytes = len;
> +
> +       /* We now have a contiguous set of dirty pages, each with writeback
> +        * set; the first page is still locked at this point, but all the rest
> +        * have been unlocked.
> +        */
> +       folio_unlock(folio);
> +
> +       if (start < i_size) {
> +               iov_iter_xarray(&wdata->iter, ITER_SOURCE, &mapping->i_pages,
> +                               start, len);
> +
> +               rc = adjust_credits(wdata->server, &wdata->credits, wdata->bytes);
> +               if (rc)
> +                       goto err_wdata;
> +
> +               if (wdata->cfile->invalidHandle)
> +                       rc = -EAGAIN;
> +               else
> +                       rc = wdata->server->ops->async_writev(wdata,
> +                                                             cifs_writedata_release);
> +               if (rc >= 0) {
> +                       kref_put(&wdata->refcount, cifs_writedata_release);
> +                       goto err_close;
> +               }
> +       } else {
> +               /* The dirty region was entirely beyond the EOF. */
> +               cifs_pages_written_back(inode, start, len);
> +               rc = 0;
> +       }
> +
> +err_wdata:
> +       kref_put(&wdata->refcount, cifs_writedata_release);
> +err_uncredit:
> +       add_credits_and_wake_if(server, credits, 0);
> +err_close:
> +       if (cfile)
> +               cifsFileInfo_put(cfile);
> +err_xid:
> +       free_xid(xid);
> +       if (rc == 0) {
> +               wbc->nr_to_write = count;
> +       } else if (is_retryable_error(rc)) {
> +               cifs_pages_write_redirty(inode, start, len);
> +       } else {
> +               cifs_pages_write_failed(inode, start, len);
> +               mapping_set_error(mapping, rc);
> +       }
> +       /* Indication to update ctime and mtime as close is deferred */
> +       set_bit(CIFS_INO_MODIFIED_ATTR, &CIFS_I(inode)->flags);
> +       return rc;
> +}
> +
> +/*
> + * write a region of pages back to the server
> + */
> +static int cifs_writepages_region(struct address_space *mapping,
> +                                 struct writeback_control *wbc,
> +                                 loff_t start, loff_t end, loff_t *_next)
> +{
> +       struct folio *folio;
> +       struct page *head_page;
> +       ssize_t ret;
> +       int n, skips = 0;
> +
> +       do {
> +               pgoff_t index = start / PAGE_SIZE;
> +
> +               n = find_get_pages_range_tag(mapping, &index, end / PAGE_SIZE,
> +                                            PAGECACHE_TAG_DIRTY, 1, &head_page);
> +               if (!n)
> +                       break;
> +
> +               folio = page_folio(head_page);
> +               start = folio_pos(folio); /* May regress with THPs */
> +
> +               /* At this point we hold neither the i_pages lock nor the
> +                * page lock: the page may be truncated or invalidated
> +                * (changing page->mapping to NULL), or even swizzled
> +                * back from swapper_space to tmpfs file mapping
> +                */
> +               if (wbc->sync_mode != WB_SYNC_NONE) {
> +                       ret = folio_lock_killable(folio);
> +                       if (ret < 0) {
> +                               folio_put(folio);
> +                               return ret;
> +                       }
> +               } else {
> +                       if (!folio_trylock(folio)) {
> +                               folio_put(folio);
> +                               return 0;
> +                       }
> +               }
> +
> +               if (folio_mapping(folio) != mapping ||
> +                   !folio_test_dirty(folio)) {
> +                       start += folio_size(folio);
> +                       folio_unlock(folio);
> +                       folio_put(folio);
> +                       continue;
> +               }
> +
> +               if (folio_test_writeback(folio) ||
> +                   folio_test_fscache(folio)) {
> +                       folio_unlock(folio);
> +                       if (wbc->sync_mode != WB_SYNC_NONE) {
> +                               folio_wait_writeback(folio);
> +#ifdef CONFIG_CIFS_FSCACHE
> +                               folio_wait_fscache(folio);
> +#endif
> +                       } else {
> +                               start += folio_size(folio);
> +                       }
> +                       folio_put(folio);
> +                       if (wbc->sync_mode == WB_SYNC_NONE) {
> +                               if (skips >= 5 || need_resched())
> +                                       break;
> +                               skips++;
> +                       }
> +                       continue;
> +               }
> +
> +               if (!folio_clear_dirty_for_io(folio))
> +                       /* We hold the page lock - it should've been dirty. */
> +                       WARN_ON(1);
> +
> +               ret = cifs_write_back_from_locked_folio(mapping, wbc, folio, start, end);
> +               folio_put(folio);
> +               if (ret < 0)
> +                       return ret;
> +
> +               start += ret;
> +               cond_resched();
> +       } while (wbc->nr_to_write > 0);
> +
> +       *_next = start;
> +       return 0;
> +}
> +
> +/*
> + * Write some of the pending data back to the server
> + */
> +static int cifs_writepages(struct address_space *mapping,
> +                          struct writeback_control *wbc)
> +{
> +       loff_t start, next;
> +       int ret;
> +
> +       /* We have to be careful as we can end up racing with setattr()
> +        * truncating the pagecache since the caller doesn't take a lock here
> +        * to prevent it.
> +        */
> +
> +       if (wbc->range_cyclic) {
> +               start = mapping->writeback_index * PAGE_SIZE;
> +               ret = cifs_writepages_region(mapping, wbc, start, LLONG_MAX, &next);
> +               if (ret == 0) {
> +                       mapping->writeback_index = next / PAGE_SIZE;
> +                       if (start > 0 && wbc->nr_to_write > 0) {
> +                               ret = cifs_writepages_region(mapping, wbc, 0,
> +                                                            start, &next);
> +                               if (ret == 0)
> +                                       mapping->writeback_index =
> +                                               next / PAGE_SIZE;
> +                       }
> +               }
> +       } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
> +               ret = cifs_writepages_region(mapping, wbc, 0, LLONG_MAX, &next);
> +               if (wbc->nr_to_write > 0 && ret == 0)
> +                       mapping->writeback_index = next / PAGE_SIZE;
> +       } else {
> +               ret = cifs_writepages_region(mapping, wbc,
> +                                            wbc->range_start, wbc->range_end, &next);
> +       }
> +
> +       return ret;
> +}
>
>  static int
>  cifs_writepage_locked(struct page *page, struct writeback_control *wbc)
> @@ -2972,6 +3331,7 @@ static int cifs_write_end(struct file *file, struct address_space *mapping,
>         struct inode *inode = mapping->host;
>         struct cifsFileInfo *cfile = file->private_data;
>         struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->dentry->d_sb);
> +       struct folio *folio = page_folio(page);
>         __u32 pid;
>
>         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
> @@ -2982,14 +3342,14 @@ static int cifs_write_end(struct file *file, struct address_space *mapping,
>         cifs_dbg(FYI, "write_end for page %p from pos %lld with %d bytes\n",
>                  page, pos, copied);
>
> -       if (PageChecked(page)) {
> +       if (folio_test_checked(folio)) {
>                 if (copied == len)
> -                       SetPageUptodate(page);
> -               ClearPageChecked(page);
> -       } else if (!PageUptodate(page) && copied == PAGE_SIZE)
> -               SetPageUptodate(page);
> +                       folio_mark_uptodate(folio);
> +               folio_clear_checked(folio);
> +       } else if (!folio_test_uptodate(folio) && copied == PAGE_SIZE)
> +               folio_mark_uptodate(folio);
>
> -       if (!PageUptodate(page)) {
> +       if (!folio_test_uptodate(folio)) {
>                 char *page_data;
>                 unsigned offset = pos & (PAGE_SIZE - 1);
>                 unsigned int xid;
> @@ -3149,6 +3509,7 @@ int cifs_flush(struct file *file, fl_owner_t id)
>         return rc;
>  }
>
> +#if 0 // TODO: Remove for iov_iter support
>  static int
>  cifs_write_allocate_pages(struct page **pages, unsigned long num_pages)
>  {
> @@ -3189,17 +3550,15 @@ size_t get_numpages(const size_t wsize, const size_t len, size_t *cur_len)
>
>         return num_pages;
>  }
> +#endif
>
>  static void
>  cifs_uncached_writedata_release(struct kref *refcount)
>  {
> -       int i;
>         struct cifs_writedata *wdata = container_of(refcount,
>                                         struct cifs_writedata, refcount);
>
>         kref_put(&wdata->ctx->refcount, cifs_aio_ctx_release);
> -       for (i = 0; i < wdata->nr_pages; i++)
> -               put_page(wdata->pages[i]);
>         cifs_writedata_release(refcount);
>  }
>
> @@ -3225,6 +3584,7 @@ cifs_uncached_writev_complete(struct work_struct *work)
>         kref_put(&wdata->refcount, cifs_uncached_writedata_release);
>  }
>
> +#if 0 // TODO: Remove for iov_iter support
>  static int
>  wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from,
>                       size_t *len, unsigned long *num_pages)
> @@ -3266,6 +3626,7 @@ wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from,
>         *num_pages = i + 1;
>         return 0;
>  }
> +#endif
>
>  static int
>  cifs_resend_wdata(struct cifs_writedata *wdata, struct list_head *wdata_list,
> @@ -3337,23 +3698,57 @@ cifs_resend_wdata(struct cifs_writedata *wdata, struct list_head *wdata_list,
>         return rc;
>  }
>
> +/*
> + * Select span of a bvec iterator we're going to use.  Limit it by both maximum
> + * size and maximum number of segments.
> + */
> +static size_t cifs_limit_bvec_subset(const struct iov_iter *iter, size_t max_size,
> +                                    size_t max_segs, unsigned int *_nsegs)
> +{
> +       const struct bio_vec *bvecs = iter->bvec;
> +       unsigned int nbv = iter->nr_segs, ix = 0, nsegs = 0;
> +       size_t len, span = 0, n = iter->count;
> +       size_t skip = iter->iov_offset;
> +
> +       if (WARN_ON(!iov_iter_is_bvec(iter)) || n == 0)
> +               return 0;
> +
> +       while (n && ix < nbv && skip) {
> +               len = bvecs[ix].bv_len;
> +               if (skip < len)
> +                       break;
> +               skip -= len;
> +               n -= len;
> +               ix++;
> +       }
> +
> +       while (n && ix < nbv) {
> +               len = min3(n, bvecs[ix].bv_len - skip, max_size);
> +               span += len;
> +               nsegs++;
> +               ix++;
> +               if (span >= max_size || nsegs >= max_segs)
> +                       break;
> +               skip = 0;
> +               n -= len;
> +       }
> +
> +       *_nsegs = nsegs;
> +       return span;
> +}
> +
>  static int
> -cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
> +cifs_write_from_iter(loff_t fpos, size_t len, struct iov_iter *from,
>                      struct cifsFileInfo *open_file,
>                      struct cifs_sb_info *cifs_sb, struct list_head *wdata_list,
>                      struct cifs_aio_ctx *ctx)
>  {
>         int rc = 0;
> -       size_t cur_len;
> -       unsigned long nr_pages, num_pages, i;
> +       size_t cur_len, max_len;
>         struct cifs_writedata *wdata;
> -       struct iov_iter saved_from = *from;
> -       loff_t saved_offset = offset;
>         pid_t pid;
>         struct TCP_Server_Info *server;
> -       struct page **pagevec;
> -       size_t start;
> -       unsigned int xid;
> +       unsigned int xid, max_segs = INT_MAX;
>
>         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
>                 pid = open_file->pid;
> @@ -3363,10 +3758,20 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
>         server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
>         xid = get_xid();
>
> +#ifdef CONFIG_CIFS_SMB_DIRECT
> +       if (server->smbd_conn)
> +               max_segs = server->smbd_conn->max_frmr_depth;
> +#endif
> +
>         do {
> -               unsigned int wsize;
>                 struct cifs_credits credits_on_stack;
>                 struct cifs_credits *credits = &credits_on_stack;
> +               unsigned int wsize, nsegs = 0;
> +
> +               if (signal_pending(current)) {
> +                       rc = -EINTR;
> +                       break;
> +               }
>
>                 if (open_file->invalidHandle) {
>                         rc = cifs_reopen_file(open_file, false);
> @@ -3381,99 +3786,42 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
>                 if (rc)
>                         break;
>
> -               cur_len = min_t(const size_t, len, wsize);
> -
> -               if (ctx->direct_io) {
> -                       ssize_t result;
> -
> -                       result = iov_iter_get_pages_alloc2(
> -                               from, &pagevec, cur_len, &start);
> -                       if (result < 0) {
> -                               cifs_dbg(VFS,
> -                                        "direct_writev couldn't get user pages (rc=%zd) iter type %d iov_offset %zd count %zd\n",
> -                                        result, iov_iter_type(from),
> -                                        from->iov_offset, from->count);
> -                               dump_stack();
> -
> -                               rc = result;
> -                               add_credits_and_wake_if(server, credits, 0);
> -                               break;
> -                       }
> -                       cur_len = (size_t)result;
> -
> -                       nr_pages =
> -                               (cur_len + start + PAGE_SIZE - 1) / PAGE_SIZE;
> -
> -                       wdata = cifs_writedata_direct_alloc(pagevec,
> -                                            cifs_uncached_writev_complete);
> -                       if (!wdata) {
> -                               rc = -ENOMEM;
> -                               for (i = 0; i < nr_pages; i++)
> -                                       put_page(pagevec[i]);
> -                               kvfree(pagevec);
> -                               add_credits_and_wake_if(server, credits, 0);
> -                               break;
> -                       }
> -
> -
> -                       wdata->page_offset = start;
> -                       wdata->tailsz =
> -                               nr_pages > 1 ?
> -                                       cur_len - (PAGE_SIZE - start) -
> -                                       (nr_pages - 2) * PAGE_SIZE :
> -                                       cur_len;
> -               } else {
> -                       nr_pages = get_numpages(wsize, len, &cur_len);
> -                       wdata = cifs_writedata_alloc(nr_pages,
> -                                            cifs_uncached_writev_complete);
> -                       if (!wdata) {
> -                               rc = -ENOMEM;
> -                               add_credits_and_wake_if(server, credits, 0);
> -                               break;
> -                       }
> -
> -                       rc = cifs_write_allocate_pages(wdata->pages, nr_pages);
> -                       if (rc) {
> -                               kvfree(wdata->pages);
> -                               kfree(wdata);
> -                               add_credits_and_wake_if(server, credits, 0);
> -                               break;
> -                       }
> -
> -                       num_pages = nr_pages;
> -                       rc = wdata_fill_from_iovec(
> -                               wdata, from, &cur_len, &num_pages);
> -                       if (rc) {
> -                               for (i = 0; i < nr_pages; i++)
> -                                       put_page(wdata->pages[i]);
> -                               kvfree(wdata->pages);
> -                               kfree(wdata);
> -                               add_credits_and_wake_if(server, credits, 0);
> -                               break;
> -                       }
> +               max_len = min_t(const size_t, len, wsize);
> +               if (!max_len) {
> +                       rc = -EAGAIN;
> +                       add_credits_and_wake_if(server, credits, 0);
> +                       break;
> +               }
>
> -                       /*
> -                        * Bring nr_pages down to the number of pages we
> -                        * actually used, and free any pages that we didn't use.
> -                        */
> -                       for ( ; nr_pages > num_pages; nr_pages--)
> -                               put_page(wdata->pages[nr_pages - 1]);
> +               cur_len = cifs_limit_bvec_subset(from, max_len, max_segs, &nsegs);
> +               cifs_dbg(FYI, "write_from_iter len=%zx/%zx nsegs=%u/%lu/%u\n",
> +                        cur_len, max_len, nsegs, from->nr_segs, max_segs);
> +               if (cur_len == 0) {
> +                       rc = -EIO;
> +                       add_credits_and_wake_if(server, credits, 0);
> +                       break;
> +               }
>
> -                       wdata->tailsz = cur_len - ((nr_pages - 1) * PAGE_SIZE);
> +               wdata = cifs_writedata_alloc(cifs_uncached_writev_complete);
> +               if (!wdata) {
> +                       rc = -ENOMEM;
> +                       add_credits_and_wake_if(server, credits, 0);
> +                       break;
>                 }
>
>                 wdata->sync_mode = WB_SYNC_ALL;
> -               wdata->nr_pages = nr_pages;
> -               wdata->offset = (__u64)offset;
> -               wdata->cfile = cifsFileInfo_get(open_file);
> -               wdata->server = server;
> -               wdata->pid = pid;
> -               wdata->bytes = cur_len;
> -               wdata->pagesz = PAGE_SIZE;
> -               wdata->credits = credits_on_stack;
> -               wdata->ctx = ctx;
> +               wdata->offset   = (__u64)fpos;
> +               wdata->cfile    = cifsFileInfo_get(open_file);
> +               wdata->server   = server;
> +               wdata->pid      = pid;
> +               wdata->bytes    = cur_len;
> +               wdata->credits  = credits_on_stack;
> +               wdata->iter     = *from;
> +               wdata->ctx      = ctx;
>                 kref_get(&ctx->refcount);
>
> +               iov_iter_truncate(&wdata->iter, cur_len);
> +
>                 rc = adjust_credits(server, &wdata->credits, wdata->bytes);
>
>                 if (!rc) {
> @@ -3488,16 +3836,14 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
>                         add_credits_and_wake_if(server, &wdata->credits, 0);
>                         kref_put(&wdata->refcount,
>                                  cifs_uncached_writedata_release);
> -                       if (rc == -EAGAIN) {
> -                               *from = saved_from;
> -                               iov_iter_advance(from, offset - saved_offset);
> +                       if (rc == -EAGAIN)
>                                 continue;
> -                       }
>                         break;
>                 }
>
>                 list_add_tail(&wdata->list, wdata_list);
> -               offset += cur_len;
> +               iov_iter_advance(from, cur_len);
> +               fpos += cur_len;
>                 len -= cur_len;
>         } while (len > 0);
>
> @@ -3596,8 +3942,6 @@ static ssize_t __cifs_writev(
>         struct cifs_tcon *tcon;
>         struct cifs_sb_info *cifs_sb;
>         struct cifs_aio_ctx *ctx;
> -       struct iov_iter saved_from = *from;
> -       size_t len = iov_iter_count(from);
>         int rc;
>
>         /*
> @@ -3631,23 +3975,54 @@ static ssize_t __cifs_writev(
>                 ctx->iocb = iocb;
>
>         ctx->pos = iocb->ki_pos;
> +       ctx->direct_io = direct;
> +       ctx->nr_pinned_pages = 0;
>
> -       if (direct) {
> -               ctx->direct_io = true;
> -               ctx->iter = *from;
> -               ctx->len = len;
> -       } else {
> -               rc = setup_aio_ctx_iter(ctx, from, ITER_SOURCE);
> -               if (rc) {
> +       if (user_backed_iter(from)) {
> +               /*
> +                * Extract IOVEC/UBUF-type iterators to a BVEC-type iterator as
> +                * they contain references to the calling process's virtual
> +                * memory layout which won't be available in an async worker
> +                * thread.  This also takes a pin on every folio involved.
> +                */
> +               rc = netfs_extract_user_iter(from, iov_iter_count(from),
> +                                            &ctx->iter, 0);
> +               if (rc < 0) {
>                         kref_put(&ctx->refcount, cifs_aio_ctx_release);
>                         return rc;
>                 }
> +
> +               ctx->nr_pinned_pages = rc;
> +               ctx->bv = (void *)ctx->iter.bvec;
> +               ctx->bv_need_unpin = iov_iter_extract_will_pin(&ctx->iter);
> +       } else if ((iov_iter_is_bvec(from) || iov_iter_is_kvec(from)) &&
> +                  !is_sync_kiocb(iocb)) {
> +               /*
> +                * If the op is asynchronous, we need to copy the list attached
> +                * to a BVEC/KVEC-type iterator, but we assume that the storage
> +                * will be pinned by the caller; in any case, we may or may not
> +                * be able to pin the pages, so we don't try.
> +                */
> +               ctx->bv = (void *)dup_iter(&ctx->iter, from, GFP_KERNEL);
> +               if (!ctx->bv) {
> +                       kref_put(&ctx->refcount, cifs_aio_ctx_release);
> +                       return -ENOMEM;
> +               }
> +       } else {
> +               /*
> +                * Otherwise, we just pass the iterator down as-is and rely on
> +                * the caller to make sure the pages referred to by the
> +                * iterator don't evaporate.
> +                */
> +               ctx->iter = *from;
>         }
>
> +       ctx->len = iov_iter_count(&ctx->iter);
> +
>         /* grab a lock here due to read response handlers can access ctx */
>         mutex_lock(&ctx->aio_mutex);
>
> -       rc = cifs_write_from_iter(iocb->ki_pos, ctx->len, &saved_from,
> +       rc = cifs_write_from_iter(iocb->ki_pos, ctx->len, &ctx->iter,
>                                   cfile, cifs_sb, &ctx->list, ctx);
>
>         /*
> @@ -3790,14 +4165,12 @@ cifs_strict_writev(struct kiocb *iocb, struct iov_iter *from)
>         return written;
>  }
>
> -static struct cifs_readdata *
> -cifs_readdata_direct_alloc(struct page **pages, work_func_t complete)
> +static struct cifs_readdata *cifs_readdata_alloc(work_func_t complete)
>  {
>         struct cifs_readdata *rdata;
>
>         rdata = kzalloc(sizeof(*rdata), GFP_KERNEL);
> -       if (rdata != NULL) {
> -               rdata->pages = pages;
> +       if (rdata) {
>                 kref_init(&rdata->refcount);
>                 INIT_LIST_HEAD(&rdata->list);
>                 init_completion(&rdata->done);
> @@ -3807,27 +4180,14 @@ cifs_readdata_direct_alloc(struct page **pages, work_func_t complete)
>         return rdata;
>  }
>
> -static struct cifs_readdata *
> -cifs_readdata_alloc(unsigned int nr_pages, work_func_t complete)
> -{
> -       struct page **pages =
> -               kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
> -       struct cifs_readdata *ret = NULL;
> -
> -       if (pages) {
> -               ret = cifs_readdata_direct_alloc(pages, complete);
> -               if (!ret)
> -                       kfree(pages);
> -       }
> -
> -       return ret;
> -}
> -
>  void
>  cifs_readdata_release(struct kref *refcount)
>  {
>         struct cifs_readdata *rdata = container_of(refcount,
>                                         struct cifs_readdata, refcount);
> +
> +       if (rdata->ctx)
> +               kref_put(&rdata->ctx->refcount, cifs_aio_ctx_release);
>  #ifdef CONFIG_CIFS_SMB_DIRECT
>         if (rdata->mr) {
>                 smbd_deregister_mr(rdata->mr);
> @@ -3837,85 +4197,9 @@ cifs_readdata_release(struct kref *refcount)
>         if (rdata->cfile)
>                 cifsFileInfo_put(rdata->cfile);
>
> -       kvfree(rdata->pages);
>         kfree(rdata);
>  }
>
> -static int
> -cifs_read_allocate_pages(struct cifs_readdata *rdata, unsigned int nr_pages)
> -{
> -       int rc = 0;
> -       struct page *page;
> -       unsigned int i;
> -
> -       for (i = 0; i < nr_pages; i++) {
> -               page = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
> -               if (!page) {
> -                       rc = -ENOMEM;
> -                       break;
> -               }
> -               rdata->pages[i] = page;
> -       }
> -
> -       if (rc) {
> -               unsigned int nr_page_failed = i;
> -
> -               for (i = 0; i < nr_page_failed; i++) {
> -                       put_page(rdata->pages[i]);
> -                       rdata->pages[i] = NULL;
> -               }
> -       }
> -       return rc;
> -}
> -
> -static void
> -cifs_uncached_readdata_release(struct kref *refcount)
> -{
> -       struct cifs_readdata *rdata = container_of(refcount,
> -                                       struct cifs_readdata, refcount);
> -       unsigned int i;
> -
> -       kref_put(&rdata->ctx->refcount, cifs_aio_ctx_release);
> -       for (i = 0; i < rdata->nr_pages; i++) {
> -               put_page(rdata->pages[i]);
> -       }
> -       cifs_readdata_release(refcount);
> -}
> -
> -/**
> - * cifs_readdata_to_iov - copy data from pages in response to an iovec
> - * @rdata:     the readdata response with list of pages holding data
> - * @iter:      destination for our data
> - *
> - * This function copies data from a list of pages in a readdata response into
> - * an array of iovecs. It will first calculate where the data should go
> - * based on the info in the readdata and then copy the data into that spot.
> - */
> -static int
> -cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter)
> -{
> -       size_t remaining = rdata->got_bytes;
> -       unsigned int i;
> -
> -       for (i = 0; i < rdata->nr_pages; i++) {
> -               struct page *page = rdata->pages[i];
> -               size_t copy = min_t(size_t, remaining, PAGE_SIZE);
> -               size_t written;
> -
> -               if (unlikely(iov_iter_is_pipe(iter))) {
> -                       void *addr = kmap_atomic(page);
> -
> -                       written = copy_to_iter(addr, copy, iter);
> -                       kunmap_atomic(addr);
> -               } else
> -                       written = copy_page_to_iter(page, 0, copy, iter);
> -               remaining -= written;
> -               if (written < copy && iov_iter_count(iter) > 0)
> -                       break;
> -       }
> -       return remaining ? -EFAULT : 0;
> -}
> -
>  static void collect_uncached_read_data(struct cifs_aio_ctx *ctx);
>
>  static void
> @@ -3927,9 +4211,11 @@ cifs_uncached_readv_complete(struct work_struct *work)
>         complete(&rdata->done);
>         collect_uncached_read_data(rdata->ctx);
>         /* the below call can possibly free the last ref to aio ctx */
> -       kref_put(&rdata->refcount, cifs_uncached_readdata_release);
> +       kref_put(&rdata->refcount, cifs_readdata_release);
>  }
>
> +#if 0 // TODO: Remove for iov_iter support
> +
>  static int
>  uncached_fill_pages(struct TCP_Server_Info *server,
>                     struct cifs_readdata *rdata, struct iov_iter *iter,
> @@ -4003,6 +4289,7 @@ cifs_uncached_copy_into_pages(struct TCP_Server_Info *server,
>  {
>         return uncached_fill_pages(server, rdata, iter, iter->count);
>  }
> +#endif
>
>  static int cifs_resend_rdata(struct cifs_readdata *rdata,
>                         struct list_head *rdata_list,
> @@ -4072,37 +4359,36 @@ static int cifs_resend_rdata(struct cifs_readdata *rdata,
>         } while (rc == -EAGAIN);
>
>  fail:
> -       kref_put(&rdata->refcount, cifs_uncached_readdata_release);
> +       kref_put(&rdata->refcount, cifs_readdata_release);
>         return rc;
>  }
>
>  static int
> -cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
> +cifs_send_async_read(loff_t fpos, size_t len, struct cifsFileInfo *open_file,
>                      struct cifs_sb_info *cifs_sb, struct list_head *rdata_list,
>                      struct cifs_aio_ctx *ctx)
>  {
>         struct cifs_readdata *rdata;
> -       unsigned int npages, rsize;
> +       unsigned int rsize, nsegs, max_segs = INT_MAX;
>         struct cifs_credits credits_on_stack;
>         struct cifs_credits *credits = &credits_on_stack;
> -       size_t cur_len;
> +       size_t cur_len, max_len;
>         int rc;
>         pid_t pid;
>         struct TCP_Server_Info *server;
> -       struct page **pagevec;
> -       size_t start;
> -       struct iov_iter direct_iov = ctx->iter;
>
>         server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
>
> +#ifdef CONFIG_CIFS_SMB_DIRECT
> +       if (server->smbd_conn)
> +               max_segs = server->smbd_conn->max_frmr_depth;
> +#endif
> +
>         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
>                 pid = open_file->pid;
>         else
>                 pid = current->tgid;
>
> -       if (ctx->direct_io)
> -               iov_iter_advance(&direct_iov, offset - ctx->pos);
> -
>         do {
>                 if (open_file->invalidHandle) {
>                         rc = cifs_reopen_file(open_file, true);
> @@ -4122,78 +4408,37 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
>                 if (rc)
>                         break;
>
> -               cur_len = min_t(const size_t, len, rsize);
> -
> -               if (ctx->direct_io) {
> -                       ssize_t result;
> -
> -                       result = iov_iter_get_pages_alloc2(
> -                                       &direct_iov, &pagevec,
> -                                       cur_len, &start);
> -                       if (result < 0) {
> -                               cifs_dbg(VFS,
> -                                        "Couldn't get user pages (rc=%zd) iter type %d iov_offset %zd count %zd\n",
> -                                        result, iov_iter_type(&direct_iov),
> -                                        direct_iov.iov_offset,
> -                                        direct_iov.count);
> -                               dump_stack();
> -
> -                               rc = result;
> -                               add_credits_and_wake_if(server, credits, 0);
> -                               break;
> -                       }
> -                       cur_len = (size_t)result;
> -
> -                       rdata = cifs_readdata_direct_alloc(
> -                                       pagevec, cifs_uncached_readv_complete);
> -                       if (!rdata) {
> -                               add_credits_and_wake_if(server, credits, 0);
> -                               rc = -ENOMEM;
> -                               break;
> -                       }
> -
> -                       npages = (cur_len + start + PAGE_SIZE-1) / PAGE_SIZE;
> -                       rdata->page_offset = start;
> -                       rdata->tailsz = npages > 1 ?
> -                               cur_len-(PAGE_SIZE-start)-(npages-2)*PAGE_SIZE :
> -                               cur_len;
> -
> -               } else {
> -
> -                       npages = DIV_ROUND_UP(cur_len, PAGE_SIZE);
> -                       /* allocate a readdata struct */
> -                       rdata = cifs_readdata_alloc(npages,
> -                                           cifs_uncached_readv_complete);
> -                       if (!rdata) {
> -                               add_credits_and_wake_if(server, credits, 0);
> -                               rc = -ENOMEM;
> -                               break;
> -                       }
> +               max_len = min_t(size_t, len, rsize);
>
> -                       rc = cifs_read_allocate_pages(rdata, npages);
> -                       if (rc) {
> -                               kvfree(rdata->pages);
> -                               kfree(rdata);
> -                               add_credits_and_wake_if(server, credits, 0);
> -                               break;
> -                       }
> +               cur_len = cifs_limit_bvec_subset(&ctx->iter, max_len,
> +                                                max_segs, &nsegs);
> +               cifs_dbg(FYI, "read-to-iter len=%zx/%zx nsegs=%u/%lu/%u\n",
> +                        cur_len, max_len, nsegs, ctx->iter.nr_segs, max_segs);
> +               if (cur_len == 0) {
> +                       rc = -EIO;
> +                       add_credits_and_wake_if(server, credits, 0);
> +                       break;
> +               }
>
> -                       rdata->tailsz = PAGE_SIZE;
> +               rdata = cifs_readdata_alloc(cifs_uncached_readv_complete);
> +               if (!rdata) {
> +                       add_credits_and_wake_if(server, credits, 0);
> +                       rc = -ENOMEM;
> +                       break;
>                 }
>
> -               rdata->server = server;
> -               rdata->cfile = cifsFileInfo_get(open_file);
> -               rdata->nr_pages = npages;
> -               rdata->offset = offset;
> -               rdata->bytes = cur_len;
> -               rdata->pid = pid;
> -               rdata->pagesz = PAGE_SIZE;
> -               rdata->read_into_pages = cifs_uncached_read_into_pages;
> -               rdata->copy_into_pages = cifs_uncached_copy_into_pages;
> -               rdata->credits = credits_on_stack;
> -               rdata->ctx = ctx;
> +               rdata->server   = server;
> +               rdata->cfile    = cifsFileInfo_get(open_file);
> +               rdata->offset   = fpos;
> +               rdata->bytes    = cur_len;
> +               rdata->pid      = pid;
> +               rdata->credits  = credits_on_stack;
> +               rdata->ctx      = ctx;
>                 kref_get(&ctx->refcount);
>
> +               rdata->iter     = ctx->iter;
> +               iov_iter_truncate(&rdata->iter, cur_len);
> +
>                 rc = adjust_credits(server, &rdata->credits, rdata->bytes);
>
>                 if (!rc) {
> @@ -4205,17 +4450,15 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
>
>                 if (rc) {
>                         add_credits_and_wake_if(server, &rdata->credits, 0);
> -                       kref_put(&rdata->refcount,
> -                               cifs_uncached_readdata_release);
> -                       if (rc == -EAGAIN) {
> -                               iov_iter_revert(&direct_iov, cur_len);
> +                       kref_put(&rdata->refcount, cifs_readdata_release);
> +                       if (rc == -EAGAIN)
>                                 continue;
> -                       }
>                         break;
>                 }
>
>                 list_add_tail(&rdata->list, rdata_list);
> -               offset += cur_len;
> +               iov_iter_advance(&ctx->iter, cur_len);
> +               fpos += cur_len;
>                 len -= cur_len;
>         } while (len > 0);
>
> @@ -4257,22 +4500,6 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx)
>                                 list_del_init(&rdata->list);
>                                 INIT_LIST_HEAD(&tmp_list);
>
> -                               /*
> -                                * Got a part of data and then reconnect has
> -                                * happened -- fill the buffer and continue
> -                                * reading.
> -                                */
> -                               if (got_bytes && got_bytes < rdata->bytes) {
> -                                       rc = 0;
> -                                       if (!ctx->direct_io)
> -                                               rc = cifs_readdata_to_iov(rdata, to);
> -                                       if (rc) {
> -                                               kref_put(&rdata->refcount,
> -                                                       cifs_uncached_readdata_release);
> -                                               continue;
> -                                       }
> -                               }
> -
>                                 if (ctx->direct_io) {
>                                         /*
>                                          * Re-use rdata as this is a
> @@ -4289,7 +4516,7 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx)
>                                                 &tmp_list, ctx);
>
>                                         kref_put(&rdata->refcount,
> -                                               cifs_uncached_readdata_release);
> +                                               cifs_readdata_release);
>                                 }
>
>                                 list_splice(&tmp_list, &ctx->list);
> @@ -4297,8 +4524,6 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx)
>                                 goto again;
>                         } else if (rdata->result)
>                                 rc = rdata->result;
> -                       else if (!ctx->direct_io)
> -                               rc = cifs_readdata_to_iov(rdata, to);
>
>                         /* if there was a short read -- discard anything left */
>                         if (rdata->got_bytes && rdata->got_bytes < rdata->bytes)
> @@ -4307,7 +4532,7 @@ collect_uncached_read_data(struct cifs_aio_ctx *ctx)
>                         ctx->total_len += rdata->got_bytes;
>                 }
>                 list_del_init(&rdata->list);
> -               kref_put(&rdata->refcount, cifs_uncached_readdata_release);
> +               kref_put(&rdata->refcount, cifs_readdata_release);
>         }
>
>         if (!ctx->direct_io)
> @@ -4367,26 +4592,53 @@ static ssize_t __cifs_readv(
>         if (!ctx)
>                 return -ENOMEM;
>
> -       ctx->cfile = cifsFileInfo_get(cfile);
> +       ctx->pos        = offset;
> +       ctx->direct_io  = direct;
> +       ctx->len        = len;
> +       ctx->cfile      = cifsFileInfo_get(cfile);
> +       ctx->nr_pinned_pages = 0;
>
>         if (!is_sync_kiocb(iocb))
>                 ctx->iocb = iocb;
>
> -       if (user_backed_iter(to))
> -               ctx->should_dirty = true;
> -
> -       if (direct) {
> -               ctx->pos = offset;
> -               ctx->direct_io = true;
> -               ctx->iter = *to;
> -               ctx->len = len;
> -       } else {
> -               rc = setup_aio_ctx_iter(ctx, to, ITER_DEST);
> -               if (rc) {
> +       if (user_backed_iter(to)) {
> +               /*
> +                * Extract IOVEC/UBUF-type iterators to a BVEC-type iterator as
> +                * they contain references to the calling process's virtual
> +                * memory layout which won't be available in an async worker
> +                * thread.  This also takes a pin on every folio involved.
> +                */
> +               rc = netfs_extract_user_iter(to, iov_iter_count(to),
> +                                            &ctx->iter, 0);
> +               if (rc < 0) {
>                         kref_put(&ctx->refcount, cifs_aio_ctx_release);
>                         return rc;
>                 }
> -               len = ctx->len;
> +
> +               ctx->nr_pinned_pages = rc;
> +               ctx->bv = (void *)ctx->iter.bvec;
> +               ctx->bv_need_unpin = iov_iter_extract_will_pin(&ctx->iter);
> +               ctx->should_dirty = true;
> +       } else if ((iov_iter_is_bvec(to) || iov_iter_is_kvec(to)) &&
> +                  !is_sync_kiocb(iocb)) {
> +               /*
> +                * If the op is asynchronous, we need to copy the list attached
> +                * to a BVEC/KVEC-type iterator, but we assume that the storage
> +                * will be retained by the caller; in any case, we may or may
> +                * not be able to pin the pages, so we don't try.
> +                */
> +               ctx->bv = (void *)dup_iter(&ctx->iter, to, GFP_KERNEL);
> +               if (!ctx->bv) {
> +                       kref_put(&ctx->refcount, cifs_aio_ctx_release);
> +                       return -ENOMEM;
> +               }
> +       } else {
> +               /*
> +                * Otherwise, we just pass the iterator down as-is and rely on
> +                * the caller to make sure the pages referred to by the
> +                * iterator don't evaporate.
> +                */
> +               ctx->iter = *to;
>         }
>
>         if (direct) {
> @@ -4648,6 +4900,8 @@ int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
>         return rc;
>  }
>
> +#if 0 // TODO: Remove for iov_iter support
> +
>  static void
>  cifs_readv_complete(struct work_struct *work)
>  {
> @@ -4778,19 +5032,74 @@ cifs_readpages_copy_into_pages(struct TCP_Server_Info *server,
>  {
>         return readpages_fill_pages(server, rdata, iter, iter->count);
>  }
> +#endif
> +
> +/*
> + * Unlock a bunch of folios in the pagecache.
> + */
> +static void cifs_unlock_folios(struct address_space *mapping, pgoff_t first, pgoff_t last)
> +{
> +       struct folio *folio;
> +       XA_STATE(xas, &mapping->i_pages, first);
> +
> +       rcu_read_lock();
> +       xas_for_each(&xas, folio, last) {
> +               folio_unlock(folio);
> +       }
> +       rcu_read_unlock();
> +}
> +
> +static void cifs_readahead_complete(struct work_struct *work)
> +{
> +       struct cifs_readdata *rdata = container_of(work,
> +                                                  struct cifs_readdata, work);
> +       struct folio *folio;
> +       pgoff_t last;
> +       bool good = rdata->result == 0 || (rdata->result == -EAGAIN && rdata->got_bytes);
> +
> +       XA_STATE(xas, &rdata->mapping->i_pages, rdata->offset / PAGE_SIZE);
> +
> +       if (good)
> +               cifs_readahead_to_fscache(rdata->mapping->host,
> +                                         rdata->offset, rdata->bytes);
> +
> +       if (iov_iter_count(&rdata->iter) > 0)
> +               iov_iter_zero(iov_iter_count(&rdata->iter), &rdata->iter);
> +
> +       last = (rdata->offset + rdata->bytes - 1) / PAGE_SIZE;
> +
> +       rcu_read_lock();
> +       xas_for_each(&xas, folio, last) {
> +               if (good) {
> +                       flush_dcache_folio(folio);
> +                       folio_mark_uptodate(folio);
> +               }
> +               folio_unlock(folio);
> +       }
> +       rcu_read_unlock();
> +
> +       kref_put(&rdata->refcount, cifs_readdata_release);
> +}
>
>  static void cifs_readahead(struct readahead_control *ractl)
>  {
> -       int rc;
>         struct cifsFileInfo *open_file = ractl->file->private_data;
>         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(ractl->file);
>         struct TCP_Server_Info *server;
> -       pid_t pid;
> -       unsigned int xid, nr_pages, last_batch_size = 0, cache_nr_pages = 0;
> -       pgoff_t next_cached = ULONG_MAX;
> +       unsigned int xid, nr_pages, cache_nr_pages = 0;
> +       unsigned int ra_pages;
> +       pgoff_t next_cached = ULONG_MAX, ra_index;
>         bool caching = fscache_cookie_enabled(cifs_inode_cookie(ractl->mapping->host)) &&
>                 cifs_inode_cookie(ractl->mapping->host)->cache_priv;
>         bool check_cache = caching;
> +       pid_t pid;
> +       int rc = 0;
> +
> +       /* Note that readahead_count() lags behind our dequeuing of pages from
> +        * the ractl, wo we have to keep track for ourselves.
> +        */
> +       ra_pages = readahead_count(ractl);
> +       ra_index = readahead_index(ractl);
>
>         xid = get_xid();
>
> @@ -4799,22 +5108,21 @@ static void cifs_readahead(struct readahead_control *ractl)
>         else
>                 pid = current->tgid;
>
> -       rc = 0;
>         server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
>
>         cifs_dbg(FYI, "%s: file=%p mapping=%p num_pages=%u\n",
> -                __func__, ractl->file, ractl->mapping, readahead_count(ractl));
> +                __func__, ractl->file, ractl->mapping, ra_pages);
>
>         /*
>          * Chop the readahead request up into rsize-sized read requests.
>          */
> -       while ((nr_pages = readahead_count(ractl) - last_batch_size)) {
> -               unsigned int i, got, rsize;
> -               struct page *page;
> +       while ((nr_pages = ra_pages)) {
> +               unsigned int i, rsize;
>                 struct cifs_readdata *rdata;
>                 struct cifs_credits credits_on_stack;
>                 struct cifs_credits *credits = &credits_on_stack;
> -               pgoff_t index = readahead_index(ractl) + last_batch_size;
> +               struct folio *folio;
> +               pgoff_t fsize;
>
>                 /*
>                  * Find out if we have anything cached in the range of
> @@ -4823,21 +5131,22 @@ static void cifs_readahead(struct readahead_control *ractl)
>                 if (caching) {
>                         if (check_cache) {
>                                 rc = cifs_fscache_query_occupancy(
> -                                       ractl->mapping->host, index, nr_pages,
> +                                       ractl->mapping->host, ra_index, nr_pages,
>                                         &next_cached, &cache_nr_pages);
>                                 if (rc < 0)
>                                         caching = false;
>                                 check_cache = false;
>                         }
>
> -                       if (index == next_cached) {
> +                       if (ra_index == next_cached) {
>                                 /*
>                                  * TODO: Send a whole batch of pages to be read
>                                  * by the cache.
>                                  */
> -                               struct folio *folio = readahead_folio(ractl);
> -
> -                               last_batch_size = folio_nr_pages(folio);
> +                               folio = readahead_folio(ractl);
> +                               fsize = folio_nr_pages(folio);
> +                               ra_pages -= fsize;
> +                               ra_index += fsize;
>                                 if (cifs_readpage_from_fscache(ractl->mapping->host,
>                                                                &folio->page) < 0) {
>                                         /*
> @@ -4848,8 +5157,8 @@ static void cifs_readahead(struct readahead_control *ractl)
>                                         caching = false;
>                                 }
>                                 folio_unlock(folio);
> -                               next_cached++;
> -                               cache_nr_pages--;
> +                               next_cached += fsize;
> +                               cache_nr_pages -= fsize;
>                                 if (cache_nr_pages == 0)
>                                         check_cache = true;
>                                 continue;
> @@ -4874,8 +5183,9 @@ static void cifs_readahead(struct readahead_control *ractl)
>                                                    &rsize, credits);
>                 if (rc)
>                         break;
> -               nr_pages = min_t(size_t, rsize / PAGE_SIZE, readahead_count(ractl));
> -               nr_pages = min_t(size_t, nr_pages, next_cached - index);
> +               nr_pages = min_t(size_t, rsize / PAGE_SIZE, ra_pages);
> +               if (next_cached != ULONG_MAX)
> +                       nr_pages = min_t(size_t, nr_pages, next_cached - ra_index);
>
>                 /*
>                  * Give up immediately if rsize is too small to read an entire
> @@ -4888,33 +5198,31 @@ static void cifs_readahead(struct readahead_control *ractl)
>                         break;
>                 }
>
> -               rdata = cifs_readdata_alloc(nr_pages, cifs_readv_complete);
> +               rdata = cifs_readdata_alloc(cifs_readahead_complete);
>                 if (!rdata) {
>                         /* best to give up if we're out of mem */
>                         add_credits_and_wake_if(server, credits, 0);
>                         break;
>                 }
>
> -               got = __readahead_batch(ractl, rdata->pages, nr_pages);
> -               if (got != nr_pages) {
> -                       pr_warn("__readahead_batch() returned %u/%u\n",
> -                               got, nr_pages);
> -                       nr_pages = got;
> -               }
> -
> -               rdata->nr_pages = nr_pages;
> -               rdata->bytes    = readahead_batch_length(ractl);
> +               rdata->offset   = ra_index * PAGE_SIZE;
> +               rdata->bytes    = nr_pages * PAGE_SIZE;
>                 rdata->cfile    = cifsFileInfo_get(open_file);
>                 rdata->server   = server;
>                 rdata->mapping  = ractl->mapping;
> -               rdata->offset   = readahead_pos(ractl);
>                 rdata->pid      = pid;
> -               rdata->pagesz   = PAGE_SIZE;
> -               rdata->tailsz   = PAGE_SIZE;
> -               rdata->read_into_pages = cifs_readpages_read_into_pages;
> -               rdata->copy_into_pages = cifs_readpages_copy_into_pages;
>                 rdata->credits  = credits_on_stack;
>
> +               for (i = 0; i < nr_pages; i++) {
> +                       if (!readahead_folio(ractl))
> +                               WARN_ON(1);
> +               }
> +               ra_pages -= nr_pages;
> +               ra_index += nr_pages;
> +
> +               iov_iter_xarray(&rdata->iter, ITER_DEST, &rdata->mapping->i_pages,
> +                               rdata->offset, rdata->bytes);
> +
>                 rc = adjust_credits(server, &rdata->credits, rdata->bytes);
>                 if (!rc) {
>                         if (rdata->cfile->invalidHandle)
> @@ -4925,18 +5233,15 @@ static void cifs_readahead(struct readahead_control *ractl)
>
>                 if (rc) {
>                         add_credits_and_wake_if(server, &rdata->credits, 0);
> -                       for (i = 0; i < rdata->nr_pages; i++) {
> -                               page = rdata->pages[i];
> -                               unlock_page(page);
> -                               put_page(page);
> -                       }
> +                       cifs_unlock_folios(rdata->mapping,
> +                                          rdata->offset / PAGE_SIZE,
> +                                          (rdata->offset + rdata->bytes - 1) / PAGE_SIZE);
>                         /* Fallback to the readpage in error/reconnect cases */
>                         kref_put(&rdata->refcount, cifs_readdata_release);
>                         break;
>                 }
>
>                 kref_put(&rdata->refcount, cifs_readdata_release);
> -               last_batch_size = nr_pages;
>         }
>
>         free_xid(xid);
> @@ -4978,10 +5283,6 @@ static int cifs_readpage_worker(struct file *file, struct page *page,
>
>         flush_dcache_page(page);
>         SetPageUptodate(page);
> -
> -       /* send this page to the cache */
> -       cifs_readpage_to_fscache(file_inode(file), page);
> -
>         rc = 0;
>
>  io_error:
> diff --git a/fs/cifs/fscache.c b/fs/cifs/fscache.c
> index f6f3a6b75601..47c9f36c11fb 100644
> --- a/fs/cifs/fscache.c
> +++ b/fs/cifs/fscache.c
> @@ -165,22 +165,16 @@ static int fscache_fallback_read_page(struct inode *inode, struct page *page)
>  /*
>   * Fallback page writing interface.
>   */
> -static int fscache_fallback_write_page(struct inode *inode, struct page *page,
> -                                      bool no_space_allocated_yet)
> +static int fscache_fallback_write_pages(struct inode *inode, loff_t start, size_t len,
> +                                       bool no_space_allocated_yet)
>  {
>         struct netfs_cache_resources cres;
>         struct fscache_cookie *cookie = cifs_inode_cookie(inode);
>         struct iov_iter iter;
> -       struct bio_vec bvec[1];
> -       loff_t start = page_offset(page);
> -       size_t len = PAGE_SIZE;
>         int ret;
>
>         memset(&cres, 0, sizeof(cres));
> -       bvec[0].bv_page         = page;
> -       bvec[0].bv_offset       = 0;
> -       bvec[0].bv_len          = PAGE_SIZE;
> -       iov_iter_bvec(&iter, ITER_SOURCE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
> +       iov_iter_xarray(&iter, ITER_SOURCE, &inode->i_mapping->i_pages, start, len);
>
>         ret = fscache_begin_write_operation(&cres, cookie);
>         if (ret < 0)
> @@ -189,7 +183,7 @@ static int fscache_fallback_write_page(struct inode *inode, struct page *page,
>         ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode),
>                                       no_space_allocated_yet);
>         if (ret == 0)
> -               ret = fscache_write(&cres, page_offset(page), &iter, NULL, NULL);
> +               ret = fscache_write(&cres, start, &iter, NULL, NULL);
>         fscache_end_operation(&cres);
>         return ret;
>  }
> @@ -213,12 +207,12 @@ int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
>         return 0;
>  }
>
> -void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
> +void __cifs_readahead_to_fscache(struct inode *inode, loff_t pos, size_t len)
>  {
> -       cifs_dbg(FYI, "%s: (fsc: %p, p: %p, i: %p)\n",
> -                __func__, cifs_inode_cookie(inode), page, inode);
> +       cifs_dbg(FYI, "%s: (fsc: %p, p: %llx, l: %zx, i: %p)\n",
> +                __func__, cifs_inode_cookie(inode), pos, len, inode);
>
> -       fscache_fallback_write_page(inode, page, true);
> +       fscache_fallback_write_pages(inode, pos, len, true);
>  }
>
>  /*
> diff --git a/fs/cifs/fscache.h b/fs/cifs/fscache.h
> index 67b601041f0a..173999610997 100644
> --- a/fs/cifs/fscache.h
> +++ b/fs/cifs/fscache.h
> @@ -90,7 +90,7 @@ static inline int cifs_fscache_query_occupancy(struct inode *inode,
>  }
>
>  extern int __cifs_readpage_from_fscache(struct inode *pinode, struct page *ppage);
> -extern void __cifs_readpage_to_fscache(struct inode *pinode, struct page *ppage);
> +extern void __cifs_readahead_to_fscache(struct inode *pinode, loff_t pos, size_t len);
>
>
>  static inline int cifs_readpage_from_fscache(struct inode *inode,
> @@ -101,11 +101,11 @@ static inline int cifs_readpage_from_fscache(struct inode *inode,
>         return -ENOBUFS;
>  }
>
> -static inline void cifs_readpage_to_fscache(struct inode *inode,
> -                                           struct page *page)
> +static inline void cifs_readahead_to_fscache(struct inode *inode,
> +                                            loff_t pos, size_t len)
>  {
>         if (cifs_inode_cookie(inode))
> -               __cifs_readpage_to_fscache(inode, page);
> +               __cifs_readahead_to_fscache(inode, pos, len);
>  }
>
>  #else /* CONFIG_CIFS_FSCACHE */
> @@ -141,7 +141,7 @@ cifs_readpage_from_fscache(struct inode *inode, struct page *page)
>  }
>
>  static inline
> -void cifs_readpage_to_fscache(struct inode *inode, struct page *page) {}
> +void cifs_readahead_to_fscache(struct inode *inode, loff_t pos, size_t len) {}
>
>  #endif /* CONFIG_CIFS_FSCACHE */
>
> diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> index 2a19c7987c5b..967bc3b74def 100644
> --- a/fs/cifs/misc.c
> +++ b/fs/cifs/misc.c
> @@ -966,16 +966,22 @@ cifs_aio_ctx_release(struct kref *refcount)
>
>         /*
>          * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
> -        * which means that iov_iter_get_pages() was a success and thus that
> -        * we have taken reference on pages.
> +        * which means that iov_iter_extract_pages() was a success and thus
> +        * that we may have references or pins on pages that we need to
> +        * release.
>          */
>         if (ctx->bv) {
> -               unsigned i;
> +               if (ctx->should_dirty || ctx->bv_need_unpin) {
> +                       unsigned i;
>
> -               for (i = 0; i < ctx->npages; i++) {
> -                       if (ctx->should_dirty)
> -                               set_page_dirty(ctx->bv[i].bv_page);
> -                       put_page(ctx->bv[i].bv_page);
> +                       for (i = 0; i < ctx->nr_pinned_pages; i++) {
> +                               struct page *page = ctx->bv[i].bv_page;
> +
> +                               if (ctx->should_dirty)
> +                                       set_page_dirty(page);
> +                               if (ctx->bv_need_unpin)
> +                                       unpin_user_page(page);
> +                       }
>                 }
>                 kvfree(ctx->bv);
>         }
> @@ -983,95 +989,6 @@ cifs_aio_ctx_release(struct kref *refcount)
>         kfree(ctx);
>  }
>
> -#define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
> -
> -int
> -setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
> -{
> -       ssize_t rc;
> -       unsigned int cur_npages;
> -       unsigned int npages = 0;
> -       unsigned int i;
> -       size_t len;
> -       size_t count = iov_iter_count(iter);
> -       unsigned int saved_len;
> -       size_t start;
> -       unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
> -       struct page **pages = NULL;
> -       struct bio_vec *bv = NULL;
> -
> -       if (iov_iter_is_kvec(iter)) {
> -               memcpy(&ctx->iter, iter, sizeof(*iter));
> -               ctx->len = count;
> -               iov_iter_advance(iter, count);
> -               return 0;
> -       }
> -
> -       if (array_size(max_pages, sizeof(*bv)) <= CIFS_AIO_KMALLOC_LIMIT)
> -               bv = kmalloc_array(max_pages, sizeof(*bv), GFP_KERNEL);
> -
> -       if (!bv) {
> -               bv = vmalloc(array_size(max_pages, sizeof(*bv)));
> -               if (!bv)
> -                       return -ENOMEM;
> -       }
> -
> -       if (array_size(max_pages, sizeof(*pages)) <= CIFS_AIO_KMALLOC_LIMIT)
> -               pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
> -
> -       if (!pages) {
> -               pages = vmalloc(array_size(max_pages, sizeof(*pages)));
> -               if (!pages) {
> -                       kvfree(bv);
> -                       return -ENOMEM;
> -               }
> -       }
> -
> -       saved_len = count;
> -
> -       while (count && npages < max_pages) {
> -               rc = iov_iter_get_pages2(iter, pages, count, max_pages, &start);
> -               if (rc < 0) {
> -                       cifs_dbg(VFS, "Couldn't get user pages (rc=%zd)\n", rc);
> -                       break;
> -               }
> -
> -               if (rc > count) {
> -                       cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
> -                                count);
> -                       break;
> -               }
> -
> -               count -= rc;
> -               rc += start;
> -               cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
> -
> -               if (npages + cur_npages > max_pages) {
> -                       cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
> -                                npages + cur_npages, max_pages);
> -                       break;
> -               }
> -
> -               for (i = 0; i < cur_npages; i++) {
> -                       len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
> -                       bv[npages + i].bv_page = pages[i];
> -                       bv[npages + i].bv_offset = start;
> -                       bv[npages + i].bv_len = len - start;
> -                       rc -= len;
> -                       start = 0;
> -               }
> -
> -               npages += cur_npages;
> -       }
> -
> -       kvfree(pages);
> -       ctx->bv = bv;
> -       ctx->len = saved_len - count;
> -       ctx->npages = npages;
> -       iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
> -       return 0;
> -}
> -
>  /**
>   * cifs_alloc_hash - allocate hash and hash context together
>   * @name: The name of the crypto hash algo
> @@ -1129,25 +1046,6 @@ cifs_free_hash(struct shash_desc **sdesc)
>         *sdesc = NULL;
>  }
>
> -/**
> - * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
> - * @rqst: The request descriptor
> - * @page: The index of the page to query
> - * @len: Where to store the length for this page:
> - * @offset: Where to store the offset for this page
> - */
> -void rqst_page_get_length(const struct smb_rqst *rqst, unsigned int page,
> -                         unsigned int *len, unsigned int *offset)
> -{
> -       *len = rqst->rq_pagesz;
> -       *offset = (page == 0) ? rqst->rq_offset : 0;
> -
> -       if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
> -               *len = rqst->rq_tailsz;
> -       else if (page == 0)
> -               *len = rqst->rq_pagesz - rqst->rq_offset;
> -}
> -
>  void extract_unc_hostname(const char *unc, const char **h, size_t *len)
>  {
>         const char *end;
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 665ccf8d979d..121faf3b2900 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -4244,7 +4244,7 @@ fill_transform_hdr(struct smb2_transform_hdr *tr_hdr, unsigned int orig_len,
>
>  static void *smb2_aead_req_alloc(struct crypto_aead *tfm, const struct smb_rqst *rqst,
>                                  int num_rqst, const u8 *sig, u8 **iv,
> -                                struct aead_request **req, struct scatterlist **sgl,
> +                                struct aead_request **req, struct sg_table *sgt,
>                                  unsigned int *num_sgs)
>  {
>         unsigned int req_size = sizeof(**req) + crypto_aead_reqsize(tfm);
> @@ -4253,43 +4253,42 @@ static void *smb2_aead_req_alloc(struct crypto_aead *tfm, const struct smb_rqst
>         u8 *p;
>
>         *num_sgs = cifs_get_num_sgs(rqst, num_rqst, sig);
> +       if (IS_ERR_VALUE((long)(int)*num_sgs))
> +               return ERR_PTR(*num_sgs);
>
>         len = iv_size;
>         len += crypto_aead_alignmask(tfm) & ~(crypto_tfm_ctx_alignment() - 1);
>         len = ALIGN(len, crypto_tfm_ctx_alignment());
>         len += req_size;
>         len = ALIGN(len, __alignof__(struct scatterlist));
> -       len += *num_sgs * sizeof(**sgl);
> +       len += array_size(*num_sgs, sizeof(struct scatterlist));
>
> -       p = kmalloc(len, GFP_ATOMIC);
> +       p = kvzalloc(len, GFP_NOFS);
>         if (!p)
> -               return NULL;
> +               return ERR_PTR(-ENOMEM);
>
>         *iv = (u8 *)PTR_ALIGN(p, crypto_aead_alignmask(tfm) + 1);
>         *req = (struct aead_request *)PTR_ALIGN(*iv + iv_size,
>                                                 crypto_tfm_ctx_alignment());
> -       *sgl = (struct scatterlist *)PTR_ALIGN((u8 *)*req + req_size,
> -                                              __alignof__(struct scatterlist));
> +       sgt->sgl = (struct scatterlist *)PTR_ALIGN((u8 *)*req + req_size,
> +                                                  __alignof__(struct scatterlist));
>         return p;
>  }
>
> -static void *smb2_get_aead_req(struct crypto_aead *tfm, const struct smb_rqst *rqst,
> +static void *smb2_get_aead_req(struct crypto_aead *tfm, struct smb_rqst *rqst,
>                                int num_rqst, const u8 *sig, u8 **iv,
>                                struct aead_request **req, struct scatterlist **sgl)
>  {
> -       unsigned int off, len, skip;
> -       struct scatterlist *sg;
> -       unsigned int num_sgs;
> -       unsigned long addr;
> -       int i, j;
> +       struct sg_table sgtable = {};
> +       unsigned int skip, num_sgs, i, j;
> +       ssize_t rc;
>         void *p;
>
> -       p = smb2_aead_req_alloc(tfm, rqst, num_rqst, sig, iv, req, sgl, &num_sgs);
> -       if (!p)
> -               return NULL;
> +       p = smb2_aead_req_alloc(tfm, rqst, num_rqst, sig, iv, req, &sgtable, &num_sgs);
> +       if (IS_ERR(p))
> +               return ERR_CAST(p);
>
> -       sg_init_table(*sgl, num_sgs);
> -       sg = *sgl;
> +       sg_init_marker(sgtable.sgl, num_sgs);
>
>         /*
>          * The first rqst has a transform header where the
> @@ -4297,30 +4296,29 @@ static void *smb2_get_aead_req(struct crypto_aead *tfm, const struct smb_rqst *r
>          */
>         skip = 20;
>
> -       /* Assumes the first rqst has a transform header as the first iov.
> -        * I.e.
> -        * rqst[0].rq_iov[0]  is transform header
> -        * rqst[0].rq_iov[1+] data to be encrypted/decrypted
> -        * rqst[1+].rq_iov[0+] data to be encrypted/decrypted
> -        */
>         for (i = 0; i < num_rqst; i++) {
> -               for (j = 0; j < rqst[i].rq_nvec; j++) {
> -                       struct kvec *iov = &rqst[i].rq_iov[j];
> +               struct iov_iter *iter = &rqst[i].rq_iter;
> +               size_t count = iov_iter_count(iter);
>
> -                       addr = (unsigned long)iov->iov_base + skip;
> -                       len = iov->iov_len - skip;
> -                       sg = cifs_sg_set_buf(sg, (void *)addr, len);
> +               for (j = 0; j < rqst[i].rq_nvec; j++) {
> +                       cifs_sg_set_buf(&sgtable,
> +                                       rqst[i].rq_iov[j].iov_base + skip,
> +                                       rqst[i].rq_iov[j].iov_len - skip);
>
>                         /* See the above comment on the 'skip' assignment */
>                         skip = 0;
>                 }
> -               for (j = 0; j < rqst[i].rq_npages; j++) {
> -                       rqst_page_get_length(&rqst[i], j, &len, &off);
> -                       sg_set_page(sg++, rqst[i].rq_pages[j], len, off);
> -               }
> +               sgtable.orig_nents = sgtable.nents;
> +
> +               rc = netfs_extract_iter_to_sg(iter, count, &sgtable,
> +                                             num_sgs - sgtable.nents, 0);
> +               iov_iter_revert(iter, rc);
> +               sgtable.orig_nents = sgtable.nents;
>         }
> -       cifs_sg_set_buf(sg, sig, SMB2_SIGNATURE_SIZE);
>
> +       cifs_sg_set_buf(&sgtable, sig, SMB2_SIGNATURE_SIZE);
> +       sg_mark_end(&sgtable.sgl[sgtable.nents - 1]);
> +       *sgl = sgtable.sgl;
>         return p;
>  }
>
> @@ -4408,8 +4406,8 @@ crypt_message(struct TCP_Server_Info *server, int num_rqst,
>         }
>
>         creq = smb2_get_aead_req(tfm, rqst, num_rqst, sign, &iv, &req, &sg);
> -       if (unlikely(!creq))
> -               return -ENOMEM;
> +       if (unlikely(IS_ERR(creq)))
> +               return PTR_ERR(creq);
>
>         if (!enc) {
>                 memcpy(sign, &tr_hdr->Signature, SMB2_SIGNATURE_SIZE);
> @@ -4441,18 +4439,31 @@ crypt_message(struct TCP_Server_Info *server, int num_rqst,
>         return rc;
>  }
>
> +/*
> + * Clear a read buffer, discarding the folios which have XA_MARK_0 set.
> + */
> +static void cifs_clear_xarray_buffer(struct xarray *buffer)
> +{
> +       struct folio *folio;
> +
> +       XA_STATE(xas, buffer, 0);
> +
> +       rcu_read_lock();
> +       xas_for_each_marked(&xas, folio, ULONG_MAX, XA_MARK_0) {
> +               folio_put(folio);
> +       }
> +       rcu_read_unlock();
> +       xa_destroy(buffer);
> +}
> +
>  void
>  smb3_free_compound_rqst(int num_rqst, struct smb_rqst *rqst)
>  {
> -       int i, j;
> +       int i;
>
> -       for (i = 0; i < num_rqst; i++) {
> -               if (rqst[i].rq_pages) {
> -                       for (j = rqst[i].rq_npages - 1; j >= 0; j--)
> -                               put_page(rqst[i].rq_pages[j]);
> -                       kfree(rqst[i].rq_pages);
> -               }
> -       }
> +       for (i = 0; i < num_rqst; i++)
> +               if (!xa_empty(&rqst[i].rq_buffer))
> +                       cifs_clear_xarray_buffer(&rqst[i].rq_buffer);
>  }
>
>  /*
> @@ -4472,9 +4483,8 @@ static int
>  smb3_init_transform_rq(struct TCP_Server_Info *server, int num_rqst,
>                        struct smb_rqst *new_rq, struct smb_rqst *old_rq)
>  {
> -       struct page **pages;
>         struct smb2_transform_hdr *tr_hdr = new_rq[0].rq_iov[0].iov_base;
> -       unsigned int npages;
> +       struct page *page;
>         unsigned int orig_len = 0;
>         int i, j;
>         int rc = -ENOMEM;
> @@ -4482,40 +4492,43 @@ smb3_init_transform_rq(struct TCP_Server_Info *server, int num_rqst,
>         for (i = 1; i < num_rqst; i++) {
>                 struct smb_rqst *old = &old_rq[i - 1];
>                 struct smb_rqst *new = &new_rq[i];
> +               struct xarray *buffer = &new->rq_buffer;
> +               size_t size = iov_iter_count(&old->rq_iter), seg, copied = 0;
>
>                 orig_len += smb_rqst_len(server, old);
>                 new->rq_iov = old->rq_iov;
>                 new->rq_nvec = old->rq_nvec;
>
> -               npages = old->rq_npages;
> -               if (!npages)
> -                       continue;
> -
> -               pages = kmalloc_array(npages, sizeof(struct page *),
> -                                     GFP_KERNEL);
> -               if (!pages)
> -                       goto err_free;
> -
> -               new->rq_pages = pages;
> -               new->rq_npages = npages;
> -               new->rq_offset = old->rq_offset;
> -               new->rq_pagesz = old->rq_pagesz;
> -               new->rq_tailsz = old->rq_tailsz;
> -
> -               for (j = 0; j < npages; j++) {
> -                       pages[j] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
> -                       if (!pages[j])
> -                               goto err_free;
> -               }
> +               xa_init(buffer);
>
> -               /* copy pages form the old */
> -               for (j = 0; j < npages; j++) {
> -                       unsigned int offset, len;
> +               if (size > 0) {
> +                       unsigned int npages = DIV_ROUND_UP(size, PAGE_SIZE);
>
> -                       rqst_page_get_length(new, j, &len, &offset);
> +                       for (j = 0; j < npages; j++) {
> +                               void *o;
>
> -                       memcpy_page(new->rq_pages[j], offset,
> -                                   old->rq_pages[j], offset, len);
> +                               rc = -ENOMEM;
> +                               page = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
> +                               if (!page)
> +                                       goto err_free;
> +                               page->index = j;
> +                               o = xa_store(buffer, j, page, GFP_KERNEL);
> +                               if (xa_is_err(o)) {
> +                                       rc = xa_err(o);
> +                                       put_page(page);
> +                                       goto err_free;
> +                               }
> +
> +                               seg = min_t(size_t, size - copied, PAGE_SIZE);
> +                               if (copy_page_from_iter(page, 0, seg, &old->rq_iter) != seg) {
> +                                       rc = -EFAULT;
> +                                       goto err_free;
> +                               }
> +                               copied += seg;
> +                       }
> +                       iov_iter_xarray(&new->rq_iter, ITER_SOURCE,
> +                                       buffer, 0, size);
> +                       new->rq_iter_size = size;
>                 }
>         }
>
> @@ -4544,12 +4557,12 @@ smb3_is_transform_hdr(void *buf)
>
>  static int
>  decrypt_raw_data(struct TCP_Server_Info *server, char *buf,
> -                unsigned int buf_data_size, struct page **pages,
> -                unsigned int npages, unsigned int page_data_size,
> +                unsigned int buf_data_size, struct iov_iter *iter,
>                  bool is_offloaded)
>  {
>         struct kvec iov[2];
>         struct smb_rqst rqst = {NULL};
> +       size_t iter_size = 0;
>         int rc;
>
>         iov[0].iov_base = buf;
> @@ -4559,10 +4572,11 @@ decrypt_raw_data(struct TCP_Server_Info *server, char *buf,
>
>         rqst.rq_iov = iov;
>         rqst.rq_nvec = 2;
> -       rqst.rq_pages = pages;
> -       rqst.rq_npages = npages;
> -       rqst.rq_pagesz = PAGE_SIZE;
> -       rqst.rq_tailsz = (page_data_size % PAGE_SIZE) ? : PAGE_SIZE;
> +       if (iter) {
> +               rqst.rq_iter = *iter;
> +               rqst.rq_iter_size = iov_iter_count(iter);
> +               iter_size = iov_iter_count(iter);
> +       }
>
>         rc = crypt_message(server, 1, &rqst, 0);
>         cifs_dbg(FYI, "Decrypt message returned %d\n", rc);
> @@ -4573,73 +4587,37 @@ decrypt_raw_data(struct TCP_Server_Info *server, char *buf,
>         memmove(buf, iov[1].iov_base, buf_data_size);
>
>         if (!is_offloaded)
> -               server->total_read = buf_data_size + page_data_size;
> +               server->total_read = buf_data_size + iter_size;
>
>         return rc;
>  }
>
>  static int
> -read_data_into_pages(struct TCP_Server_Info *server, struct page **pages,
> -                    unsigned int npages, unsigned int len)
> +cifs_copy_pages_to_iter(struct xarray *pages, unsigned int data_size,
> +                       unsigned int skip, struct iov_iter *iter)
>  {
> -       int i;
> -       int length;
> +       struct page *page;
> +       unsigned long index;
>
> -       for (i = 0; i < npages; i++) {
> -               struct page *page = pages[i];
> -               size_t n;
> +       xa_for_each(pages, index, page) {
> +               size_t n, len = min_t(unsigned int, PAGE_SIZE - skip, data_size);
>
> -               n = len;
> -               if (len >= PAGE_SIZE) {
> -                       /* enough data to fill the page */
> -                       n = PAGE_SIZE;
> -                       len -= n;
> -               } else {
> -                       zero_user(page, len, PAGE_SIZE - len);
> -                       len = 0;
> +               n = copy_page_to_iter(page, skip, len, iter);
> +               if (n != len) {
> +                       cifs_dbg(VFS, "%s: something went wrong\n", __func__);
> +                       return -EIO;
>                 }
> -               length = cifs_read_page_from_socket(server, page, 0, n);
> -               if (length < 0)
> -                       return length;
> -               server->total_read += length;
> -       }
> -
> -       return 0;
> -}
> -
> -static int
> -init_read_bvec(struct page **pages, unsigned int npages, unsigned int data_size,
> -              unsigned int cur_off, struct bio_vec **page_vec)
> -{
> -       struct bio_vec *bvec;
> -       int i;
> -
> -       bvec = kcalloc(npages, sizeof(struct bio_vec), GFP_KERNEL);
> -       if (!bvec)
> -               return -ENOMEM;
> -
> -       for (i = 0; i < npages; i++) {
> -               bvec[i].bv_page = pages[i];
> -               bvec[i].bv_offset = (i == 0) ? cur_off : 0;
> -               bvec[i].bv_len = min_t(unsigned int, PAGE_SIZE, data_size);
> -               data_size -= bvec[i].bv_len;
> -       }
> -
> -       if (data_size != 0) {
> -               cifs_dbg(VFS, "%s: something went wrong\n", __func__);
> -               kfree(bvec);
> -               return -EIO;
> +               data_size -= n;
> +               skip = 0;
>         }
>
> -       *page_vec = bvec;
>         return 0;
>  }
>
>  static int
>  handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
> -                char *buf, unsigned int buf_len, struct page **pages,
> -                unsigned int npages, unsigned int page_data_size,
> -                bool is_offloaded)
> +                char *buf, unsigned int buf_len, struct xarray *pages,
> +                unsigned int pages_len, bool is_offloaded)
>  {
>         unsigned int data_offset;
>         unsigned int data_len;
> @@ -4648,9 +4626,6 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
>         unsigned int pad_len;
>         struct cifs_readdata *rdata = mid->callback_data;
>         struct smb2_hdr *shdr = (struct smb2_hdr *)buf;
> -       struct bio_vec *bvec = NULL;
> -       struct iov_iter iter;
> -       struct kvec iov;
>         int length;
>         bool use_rdma_mr = false;
>
> @@ -4739,7 +4714,7 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
>                         return 0;
>                 }
>
> -               if (data_len > page_data_size - pad_len) {
> +               if (data_len > pages_len - pad_len) {
>                         /* data_len is corrupt -- discard frame */
>                         rdata->result = -EIO;
>                         if (is_offloaded)
> @@ -4749,8 +4724,9 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
>                         return 0;
>                 }
>
> -               rdata->result = init_read_bvec(pages, npages, page_data_size,
> -                                              cur_off, &bvec);
> +               /* Copy the data to the output I/O iterator. */
> +               rdata->result = cifs_copy_pages_to_iter(pages, pages_len,
> +                                                       cur_off, &rdata->iter);
>                 if (rdata->result != 0) {
>                         if (is_offloaded)
>                                 mid->mid_state = MID_RESPONSE_MALFORMED;
> @@ -4758,14 +4734,16 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
>                                 dequeue_mid(mid, rdata->result);
>                         return 0;
>                 }
> +               rdata->got_bytes = pages_len;
>
> -               iov_iter_bvec(&iter, ITER_SOURCE, bvec, npages, data_len);
>         } else if (buf_len >= data_offset + data_len) {
>                 /* read response payload is in buf */
> -               WARN_ONCE(npages > 0, "read data can be either in buf or in pages");
> -               iov.iov_base = buf + data_offset;
> -               iov.iov_len = data_len;
> -               iov_iter_kvec(&iter, ITER_SOURCE, &iov, 1, data_len);
> +               WARN_ONCE(pages && !xa_empty(pages),
> +                         "read data can be either in buf or in pages");
> +               length = copy_to_iter(buf + data_offset, data_len, &rdata->iter);
> +               if (length < 0)
> +                       return length;
> +               rdata->got_bytes = data_len;
>         } else {
>                 /* read response payload cannot be in both buf and pages */
>                 WARN_ONCE(1, "buf can not contain only a part of read data");
> @@ -4777,26 +4755,18 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
>                 return 0;
>         }
>
> -       length = rdata->copy_into_pages(server, rdata, &iter);
> -
> -       kfree(bvec);
> -
> -       if (length < 0)
> -               return length;
> -
>         if (is_offloaded)
>                 mid->mid_state = MID_RESPONSE_RECEIVED;
>         else
>                 dequeue_mid(mid, false);
> -       return length;
> +       return 0;
>  }
>
>  struct smb2_decrypt_work {
>         struct work_struct decrypt;
>         struct TCP_Server_Info *server;
> -       struct page **ppages;
> +       struct xarray buffer;
>         char *buf;
> -       unsigned int npages;
>         unsigned int len;
>  };
>
> @@ -4805,11 +4775,13 @@ static void smb2_decrypt_offload(struct work_struct *work)
>  {
>         struct smb2_decrypt_work *dw = container_of(work,
>                                 struct smb2_decrypt_work, decrypt);
> -       int i, rc;
> +       int rc;
>         struct mid_q_entry *mid;
> +       struct iov_iter iter;
>
> +       iov_iter_xarray(&iter, ITER_DEST, &dw->buffer, 0, dw->len);
>         rc = decrypt_raw_data(dw->server, dw->buf, dw->server->vals->read_rsp_size,
> -                             dw->ppages, dw->npages, dw->len, true);
> +                             &iter, true);
>         if (rc) {
>                 cifs_dbg(VFS, "error decrypting rc=%d\n", rc);
>                 goto free_pages;
> @@ -4823,7 +4795,7 @@ static void smb2_decrypt_offload(struct work_struct *work)
>                 mid->decrypted = true;
>                 rc = handle_read_data(dw->server, mid, dw->buf,
>                                       dw->server->vals->read_rsp_size,
> -                                     dw->ppages, dw->npages, dw->len,
> +                                     &dw->buffer, dw->len,
>                                       true);
>                 if (rc >= 0) {
>  #ifdef CONFIG_CIFS_STATS2
> @@ -4856,10 +4828,7 @@ static void smb2_decrypt_offload(struct work_struct *work)
>         }
>
>  free_pages:
> -       for (i = dw->npages-1; i >= 0; i--)
> -               put_page(dw->ppages[i]);
> -
> -       kfree(dw->ppages);
> +       cifs_clear_xarray_buffer(&dw->buffer);
>         cifs_small_buf_release(dw->buf);
>         kfree(dw);
>  }
> @@ -4869,47 +4838,65 @@ static int
>  receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid,
>                        int *num_mids)
>  {
> +       struct page *page;
>         char *buf = server->smallbuf;
>         struct smb2_transform_hdr *tr_hdr = (struct smb2_transform_hdr *)buf;
> -       unsigned int npages;
> -       struct page **pages;
> -       unsigned int len;
> +       struct iov_iter iter;
> +       unsigned int len, npages;
>         unsigned int buflen = server->pdu_size;
>         int rc;
>         int i = 0;
>         struct smb2_decrypt_work *dw;
>
> +       dw = kzalloc(sizeof(struct smb2_decrypt_work), GFP_KERNEL);
> +       if (!dw)
> +               return -ENOMEM;
> +       xa_init(&dw->buffer);
> +       INIT_WORK(&dw->decrypt, smb2_decrypt_offload);
> +       dw->server = server;
> +
>         *num_mids = 1;
>         len = min_t(unsigned int, buflen, server->vals->read_rsp_size +
>                 sizeof(struct smb2_transform_hdr)) - HEADER_SIZE(server) + 1;
>
>         rc = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1, len);
>         if (rc < 0)
> -               return rc;
> +               goto free_dw;
>         server->total_read += rc;
>
>         len = le32_to_cpu(tr_hdr->OriginalMessageSize) -
>                 server->vals->read_rsp_size;
> +       dw->len = len;
>         npages = DIV_ROUND_UP(len, PAGE_SIZE);
>
> -       pages = kmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
> -       if (!pages) {
> -               rc = -ENOMEM;
> -               goto discard_data;
> -       }
> -
> +       rc = -ENOMEM;
>         for (; i < npages; i++) {
> -               pages[i] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
> -               if (!pages[i]) {
> -                       rc = -ENOMEM;
> +               void *old;
> +
> +               page = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
> +               if (!page)
> +                       goto discard_data;
> +               page->index = i;
> +               old = xa_store(&dw->buffer, i, page, GFP_KERNEL);
> +               if (xa_is_err(old)) {
> +                       rc = xa_err(old);
> +                       put_page(page);
>                         goto discard_data;
>                 }
>         }
>
> -       /* read read data into pages */
> -       rc = read_data_into_pages(server, pages, npages, len);
> -       if (rc)
> -               goto free_pages;
> +       iov_iter_xarray(&iter, ITER_DEST, &dw->buffer, 0, npages * PAGE_SIZE);
> +
> +       /* Read the data into the buffer and clear excess bufferage. */
> +       rc = cifs_read_iter_from_socket(server, &iter, dw->len);
> +       if (rc < 0)
> +               goto discard_data;
> +
> +       server->total_read += rc;
> +       if (rc < npages * PAGE_SIZE)
> +               iov_iter_zero(npages * PAGE_SIZE - rc, &iter);
> +       iov_iter_revert(&iter, npages * PAGE_SIZE);
> +       iov_iter_truncate(&iter, dw->len);
>
>         rc = cifs_discard_remaining_data(server);
>         if (rc)
> @@ -4922,39 +4909,28 @@ receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid,
>
>         if ((server->min_offload) && (server->in_flight > 1) &&
>             (server->pdu_size >= server->min_offload)) {
> -               dw = kmalloc(sizeof(struct smb2_decrypt_work), GFP_KERNEL);
> -               if (dw == NULL)
> -                       goto non_offloaded_decrypt;
> -
>                 dw->buf = server->smallbuf;
>                 server->smallbuf = (char *)cifs_small_buf_get();
>
> -               INIT_WORK(&dw->decrypt, smb2_decrypt_offload);
> -
> -               dw->npages = npages;
> -               dw->server = server;
> -               dw->ppages = pages;
> -               dw->len = len;
>                 queue_work(decrypt_wq, &dw->decrypt);
>                 *num_mids = 0; /* worker thread takes care of finding mid */
>                 return -1;
>         }
>
> -non_offloaded_decrypt:
>         rc = decrypt_raw_data(server, buf, server->vals->read_rsp_size,
> -                             pages, npages, len, false);
> +                             &iter, false);
>         if (rc)
>                 goto free_pages;
>
>         *mid = smb2_find_mid(server, buf);
> -       if (*mid == NULL)
> +       if (*mid == NULL) {
>                 cifs_dbg(FYI, "mid not found\n");
> -       else {
> +       } else {
>                 cifs_dbg(FYI, "mid found\n");
>                 (*mid)->decrypted = true;
>                 rc = handle_read_data(server, *mid, buf,
>                                       server->vals->read_rsp_size,
> -                                     pages, npages, len, false);
> +                                     &dw->buffer, dw->len, false);
>                 if (rc >= 0) {
>                         if (server->ops->is_network_name_deleted) {
>                                 server->ops->is_network_name_deleted(buf,
> @@ -4964,9 +4940,9 @@ receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid,
>         }
>
>  free_pages:
> -       for (i = i - 1; i >= 0; i--)
> -               put_page(pages[i]);
> -       kfree(pages);
> +       cifs_clear_xarray_buffer(&dw->buffer);
> +free_dw:
> +       kfree(dw);
>         return rc;
>  discard_data:
>         cifs_discard_remaining_data(server);
> @@ -5004,7 +4980,7 @@ receive_encrypted_standard(struct TCP_Server_Info *server,
>         server->total_read += length;
>
>         buf_size = pdu_length - sizeof(struct smb2_transform_hdr);
> -       length = decrypt_raw_data(server, buf, buf_size, NULL, 0, 0, false);
> +       length = decrypt_raw_data(server, buf, buf_size, NULL, false);
>         if (length)
>                 return length;
>
> @@ -5103,7 +5079,7 @@ smb3_handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid)
>         char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
>
>         return handle_read_data(server, mid, buf, server->pdu_size,
> -                               NULL, 0, 0, false);
> +                               NULL, 0, false);
>  }
>
>  static int
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index b16b41d35560..541d8174afb9 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -4140,10 +4140,8 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
>                 struct smbd_buffer_descriptor_v1 *v1;
>                 bool need_invalidate = server->dialect == SMB30_PROT_ID;
>
> -               rdata->mr = smbd_register_mr(
> -                               server->smbd_conn, rdata->pages,
> -                               rdata->nr_pages, rdata->page_offset,
> -                               rdata->tailsz, true, need_invalidate);
> +               rdata->mr = smbd_register_mr(server->smbd_conn, &rdata->iter,
> +                                            true, need_invalidate);
>                 if (!rdata->mr)
>                         return -EAGAIN;
>
> @@ -4200,15 +4198,9 @@ smb2_readv_callback(struct mid_q_entry *mid)
>                                 (struct smb2_hdr *)rdata->iov[0].iov_base;
>         struct cifs_credits credits = { .value = 0, .instance = 0 };
>         struct smb_rqst rqst = { .rq_iov = &rdata->iov[1],
> -                                .rq_nvec = 1, };
> -
> -       if (rdata->got_bytes) {
> -               rqst.rq_pages = rdata->pages;
> -               rqst.rq_offset = rdata->page_offset;
> -               rqst.rq_npages = rdata->nr_pages;
> -               rqst.rq_pagesz = rdata->pagesz;
> -               rqst.rq_tailsz = rdata->tailsz;
> -       }
> +                                .rq_nvec = 1,
> +                                .rq_iter = rdata->iter,
> +                                .rq_iter_size = iov_iter_count(&rdata->iter), };
>
>         WARN_ONCE(rdata->server != mid->server,
>                   "rdata server %p != mid server %p",
> @@ -4226,6 +4218,8 @@ smb2_readv_callback(struct mid_q_entry *mid)
>                 if (server->sign && !mid->decrypted) {
>                         int rc;
>
> +                       iov_iter_revert(&rqst.rq_iter, rdata->got_bytes);
> +                       iov_iter_truncate(&rqst.rq_iter, rdata->got_bytes);
>                         rc = smb2_verify_signature(&rqst, server);
>                         if (rc)
>                                 cifs_tcon_dbg(VFS, "SMB signature verification returned error = %d\n",
> @@ -4568,7 +4562,7 @@ smb2_async_writev(struct cifs_writedata *wdata,
>         req->VolatileFileId = io_parms->volatile_fid;
>         req->WriteChannelInfoOffset = 0;
>         req->WriteChannelInfoLength = 0;
> -       req->Channel = 0;
> +       req->Channel = SMB2_CHANNEL_NONE;
>         req->Offset = cpu_to_le64(io_parms->offset);
>         req->DataOffset = cpu_to_le16(
>                                 offsetof(struct smb2_write_req, Buffer));
> @@ -4588,26 +4582,18 @@ smb2_async_writev(struct cifs_writedata *wdata,
>          */
>         if (smb3_use_rdma_offload(io_parms)) {
>                 struct smbd_buffer_descriptor_v1 *v1;
> +               size_t data_size = iov_iter_count(&wdata->iter);
>                 bool need_invalidate = server->dialect == SMB30_PROT_ID;
>
> -               wdata->mr = smbd_register_mr(
> -                               server->smbd_conn, wdata->pages,
> -                               wdata->nr_pages, wdata->page_offset,
> -                               wdata->tailsz, false, need_invalidate);
> +               wdata->mr = smbd_register_mr(server->smbd_conn, &wdata->iter,
> +                                            false, need_invalidate);
>                 if (!wdata->mr) {
>                         rc = -EAGAIN;
>                         goto async_writev_out;
>                 }
>                 req->Length = 0;
>                 req->DataOffset = 0;
> -               if (wdata->nr_pages > 1)
> -                       req->RemainingBytes =
> -                               cpu_to_le32(
> -                                       (wdata->nr_pages - 1) * wdata->pagesz -
> -                                       wdata->page_offset + wdata->tailsz
> -                               );
> -               else
> -                       req->RemainingBytes = cpu_to_le32(wdata->tailsz);
> +               req->RemainingBytes = cpu_to_le32(data_size);
>                 req->Channel = SMB2_CHANNEL_RDMA_V1_INVALIDATE;
>                 if (need_invalidate)
>                         req->Channel = SMB2_CHANNEL_RDMA_V1;
> @@ -4626,19 +4612,14 @@ smb2_async_writev(struct cifs_writedata *wdata,
>
>         rqst.rq_iov = iov;
>         rqst.rq_nvec = 1;
> -       rqst.rq_pages = wdata->pages;
> -       rqst.rq_offset = wdata->page_offset;
> -       rqst.rq_npages = wdata->nr_pages;
> -       rqst.rq_pagesz = wdata->pagesz;
> -       rqst.rq_tailsz = wdata->tailsz;
> +       rqst.rq_iter = wdata->iter;
> +       rqst.rq_iter_size = iov_iter_count(&rqst.rq_iter);
>  #ifdef CONFIG_CIFS_SMB_DIRECT
> -       if (wdata->mr) {
> +       if (wdata->mr)
>                 iov[0].iov_len += sizeof(struct smbd_buffer_descriptor_v1);
> -               rqst.rq_npages = 0;
> -       }
>  #endif
> -       cifs_dbg(FYI, "async write at %llu %u bytes\n",
> -                io_parms->offset, io_parms->length);
> +       cifs_dbg(FYI, "async write at %llu %u bytes iter=%zx\n",
> +                io_parms->offset, io_parms->length, iov_iter_count(&rqst.rq_iter));
>
>  #ifdef CONFIG_CIFS_SMB_DIRECT
>         /* For RDMA read, I/O size is in RemainingBytes not in Length */
> diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
> index 3e0aacddc291..0eb32bbfc467 100644
> --- a/fs/cifs/smbdirect.c
> +++ b/fs/cifs/smbdirect.c
> @@ -34,12 +34,6 @@ static int smbd_post_recv(
>                 struct smbd_response *response);
>
>  static int smbd_post_send_empty(struct smbd_connection *info);
> -static int smbd_post_send_data(
> -               struct smbd_connection *info,
> -               struct kvec *iov, int n_vec, int remaining_data_length);
> -static int smbd_post_send_page(struct smbd_connection *info,
> -               struct page *page, unsigned long offset,
> -               size_t size, int remaining_data_length);
>
>  static void destroy_mr_list(struct smbd_connection *info);
>  static int allocate_mr_list(struct smbd_connection *info);
> @@ -986,24 +980,6 @@ static int smbd_post_send_sgl(struct smbd_connection *info,
>         return rc;
>  }
>
> -/*
> - * Send a page
> - * page: the page to send
> - * offset: offset in the page to send
> - * size: length in the page to send
> - * remaining_data_length: remaining data to send in this payload
> - */
> -static int smbd_post_send_page(struct smbd_connection *info, struct page *page,
> -               unsigned long offset, size_t size, int remaining_data_length)
> -{
> -       struct scatterlist sgl;
> -
> -       sg_init_table(&sgl, 1);
> -       sg_set_page(&sgl, page, size, offset);
> -
> -       return smbd_post_send_sgl(info, &sgl, size, remaining_data_length);
> -}
> -
>  /*
>   * Send an empty message
>   * Empty message is used to extend credits to peer to for keep live
> @@ -1015,35 +991,6 @@ static int smbd_post_send_empty(struct smbd_connection *info)
>         return smbd_post_send_sgl(info, NULL, 0, 0);
>  }
>
> -/*
> - * Send a data buffer
> - * iov: the iov array describing the data buffers
> - * n_vec: number of iov array
> - * remaining_data_length: remaining data to send following this packet
> - * in segmented SMBD packet
> - */
> -static int smbd_post_send_data(
> -       struct smbd_connection *info, struct kvec *iov, int n_vec,
> -       int remaining_data_length)
> -{
> -       int i;
> -       u32 data_length = 0;
> -       struct scatterlist sgl[SMBDIRECT_MAX_SEND_SGE - 1];
> -
> -       if (n_vec > SMBDIRECT_MAX_SEND_SGE - 1) {
> -               cifs_dbg(VFS, "Can't fit data to SGL, n_vec=%d\n", n_vec);
> -               return -EINVAL;
> -       }
> -
> -       sg_init_table(sgl, n_vec);
> -       for (i = 0; i < n_vec; i++) {
> -               data_length += iov[i].iov_len;
> -               sg_set_buf(&sgl[i], iov[i].iov_base, iov[i].iov_len);
> -       }
> -
> -       return smbd_post_send_sgl(info, sgl, data_length, remaining_data_length);
> -}
> -
>  /*
>   * Post a receive request to the transport
>   * The remote peer can only send data when a receive request is posted
> @@ -1986,6 +1933,42 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg)
>         return rc;
>  }
>
> +/*
> + * Send the contents of an iterator
> + * @iter: The iterator to send
> + * @_remaining_data_length: remaining data to send in this payload
> + */
> +static int smbd_post_send_iter(struct smbd_connection *info,
> +                              struct iov_iter *iter,
> +                              int *_remaining_data_length)
> +{
> +       struct scatterlist sgl[SMBDIRECT_MAX_SEND_SGE - 1];
> +       unsigned int max_payload = info->max_send_size - sizeof(struct smbd_data_transfer);
> +       ssize_t rc;
> +
> +       /* We're not expecting a user-backed iter */
> +       WARN_ON(iov_iter_extract_will_pin(iter));
> +
> +       do {
> +               struct sg_table sgtable = { .sgl = sgl };
> +               size_t maxlen = min_t(size_t, *_remaining_data_length, max_payload);
> +
> +               sg_init_table(sgtable.sgl, ARRAY_SIZE(sgl));
> +               rc = netfs_extract_iter_to_sg(iter, maxlen,
> +                                             &sgtable, ARRAY_SIZE(sgl), 0);
> +               if (rc < 0)
> +                       break;
> +               if (WARN_ON_ONCE(sgtable.nents == 0))
> +                       return -EIO;
> +
> +               sg_mark_end(&sgl[sgtable.nents - 1]);
> +               *_remaining_data_length -= rc;
> +               rc = smbd_post_send_sgl(info, sgl, rc, *_remaining_data_length);
> +       } while (rc == 0 && iov_iter_count(iter) > 0);
> +
> +       return rc;
> +}
> +
>  /*
>   * Send data to transport
>   * Each rqst is transported as a SMBDirect payload
> @@ -1996,18 +1979,10 @@ int smbd_send(struct TCP_Server_Info *server,
>         int num_rqst, struct smb_rqst *rqst_array)
>  {
>         struct smbd_connection *info = server->smbd_conn;
> -       struct kvec vecs[SMBDIRECT_MAX_SEND_SGE - 1];
> -       int nvecs;
> -       int size;
> -       unsigned int buflen, remaining_data_length;
> -       unsigned int offset, remaining_vec_data_length;
> -       int start, i, j;
> -       int max_iov_size =
> -               info->max_send_size - sizeof(struct smbd_data_transfer);
> -       struct kvec *iov;
> -       int rc;
>         struct smb_rqst *rqst;
> -       int rqst_idx;
> +       struct iov_iter iter;
> +       unsigned int remaining_data_length, klen;
> +       int rc, i, rqst_idx;
>
>         if (info->transport_status != SMBD_CONNECTED)
>                 return -EAGAIN;
> @@ -2034,84 +2009,36 @@ int smbd_send(struct TCP_Server_Info *server,
>         rqst_idx = 0;
>         do {
>                 rqst = &rqst_array[rqst_idx];
> -               iov = rqst->rq_iov;
>
>                 cifs_dbg(FYI, "Sending smb (RDMA): idx=%d smb_len=%lu\n",
> -                       rqst_idx, smb_rqst_len(server, rqst));
> -               remaining_vec_data_length = 0;
> -               for (i = 0; i < rqst->rq_nvec; i++) {
> -                       remaining_vec_data_length += iov[i].iov_len;
> -                       dump_smb(iov[i].iov_base, iov[i].iov_len);
> -               }
> -
> -               log_write(INFO, "rqst_idx=%d nvec=%d rqst->rq_npages=%d rq_pagesz=%d rq_tailsz=%d buflen=%lu\n",
> -                         rqst_idx, rqst->rq_nvec,
> -                         rqst->rq_npages, rqst->rq_pagesz,
> -                         rqst->rq_tailsz, smb_rqst_len(server, rqst));
> -
> -               start = 0;
> -               offset = 0;
> -               do {
> -                       buflen = 0;
> -                       i = start;
> -                       j = 0;
> -                       while (i < rqst->rq_nvec &&
> -                               j < SMBDIRECT_MAX_SEND_SGE - 1 &&
> -                               buflen < max_iov_size) {
> -
> -                               vecs[j].iov_base = iov[i].iov_base + offset;
> -                               if (buflen + iov[i].iov_len > max_iov_size) {
> -                                       vecs[j].iov_len =
> -                                               max_iov_size - iov[i].iov_len;
> -                                       buflen = max_iov_size;
> -                                       offset = vecs[j].iov_len;
> -                               } else {
> -                                       vecs[j].iov_len =
> -                                               iov[i].iov_len - offset;
> -                                       buflen += vecs[j].iov_len;
> -                                       offset = 0;
> -                                       ++i;
> -                               }
> -                               ++j;
> -                       }
> +                        rqst_idx, smb_rqst_len(server, rqst));
> +               for (i = 0; i < rqst->rq_nvec; i++)
> +                       dump_smb(rqst->rq_iov[i].iov_base, rqst->rq_iov[i].iov_len);
> +
> +               log_write(INFO, "RDMA-WR[%u] nvec=%d len=%u iter=%zu rqlen=%lu\n",
> +                         rqst_idx, rqst->rq_nvec, remaining_data_length,
> +                         iov_iter_count(&rqst->rq_iter), smb_rqst_len(server, rqst));
> +
> +               /* Send the metadata pages. */
> +               klen = 0;
> +               for (i = 0; i < rqst->rq_nvec; i++)
> +                       klen += rqst->rq_iov[i].iov_len;
> +               iov_iter_kvec(&iter, ITER_SOURCE, rqst->rq_iov, rqst->rq_nvec, klen);
> +
> +               rc = smbd_post_send_iter(info, &iter, &remaining_data_length);
> +               if (rc < 0)
> +                       break;
>
> -                       remaining_vec_data_length -= buflen;
> -                       remaining_data_length -= buflen;
> -                       log_write(INFO, "sending %s iov[%d] from start=%d nvecs=%d remaining_data_length=%d\n",
> -                                       remaining_vec_data_length > 0 ?
> -                                               "partial" : "complete",
> -                                       rqst->rq_nvec, start, j,
> -                                       remaining_data_length);
> -
> -                       start = i;
> -                       rc = smbd_post_send_data(info, vecs, j, remaining_data_length);
> -                       if (rc)
> -                               goto done;
> -               } while (remaining_vec_data_length > 0);
> -
> -               /* now sending pages if there are any */
> -               for (i = 0; i < rqst->rq_npages; i++) {
> -                       rqst_page_get_length(rqst, i, &buflen, &offset);
> -                       nvecs = (buflen + max_iov_size - 1) / max_iov_size;
> -                       log_write(INFO, "sending pages buflen=%d nvecs=%d\n",
> -                               buflen, nvecs);
> -                       for (j = 0; j < nvecs; j++) {
> -                               size = min_t(unsigned int, max_iov_size, remaining_data_length);
> -                               remaining_data_length -= size;
> -                               log_write(INFO, "sending pages i=%d offset=%d size=%d remaining_data_length=%d\n",
> -                                         i, j * max_iov_size + offset, size,
> -                                         remaining_data_length);
> -                               rc = smbd_post_send_page(
> -                                       info, rqst->rq_pages[i],
> -                                       j*max_iov_size + offset,
> -                                       size, remaining_data_length);
> -                               if (rc)
> -                                       goto done;
> -                       }
> +               if (iov_iter_count(&rqst->rq_iter) > 0) {
> +                       /* And then the data pages if there are any */
> +                       rc = smbd_post_send_iter(info, &rqst->rq_iter,
> +                                                &remaining_data_length);
> +                       if (rc < 0)
> +                               break;
>                 }
> +
>         } while (++rqst_idx < num_rqst);
>
> -done:
>         /*
>          * As an optimization, we don't wait for individual I/O to finish
>          * before sending the next one.
> @@ -2315,27 +2242,48 @@ static struct smbd_mr *get_mr(struct smbd_connection *info)
>         goto again;
>  }
>
> +/*
> + * Transcribe the pages from an iterator into an MR scatterlist.
> + * @iter: The iterator to transcribe
> + * @_remaining_data_length: remaining data to send in this payload
> + */
> +static int smbd_iter_to_mr(struct smbd_connection *info,
> +                          struct iov_iter *iter,
> +                          struct scatterlist *sgl,
> +                          unsigned int num_pages)
> +{
> +       struct sg_table sgtable = { .sgl = sgl };
> +       int ret;
> +
> +       sg_init_table(sgl, num_pages);
> +
> +       ret = netfs_extract_iter_to_sg(iter, iov_iter_count(iter),
> +                                      &sgtable, num_pages, 0);
> +       WARN_ON(ret < 0);
> +       return ret;
> +}
> +
>  /*
>   * Register memory for RDMA read/write
> - * pages[]: the list of pages to register memory with
> - * num_pages: the number of pages to register
> - * tailsz: if non-zero, the bytes to register in the last page
> + * iter: the buffer to register memory with
>   * writing: true if this is a RDMA write (SMB read), false for RDMA read
>   * need_invalidate: true if this MR needs to be locally invalidated after I/O
>   * return value: the MR registered, NULL if failed.
>   */
> -struct smbd_mr *smbd_register_mr(
> -       struct smbd_connection *info, struct page *pages[], int num_pages,
> -       int offset, int tailsz, bool writing, bool need_invalidate)
> +struct smbd_mr *smbd_register_mr(struct smbd_connection *info,
> +                                struct iov_iter *iter,
> +                                bool writing, bool need_invalidate)
>  {
>         struct smbd_mr *smbdirect_mr;
> -       int rc, i;
> +       int rc, num_pages;
>         enum dma_data_direction dir;
>         struct ib_reg_wr *reg_wr;
>
> +       num_pages = iov_iter_npages(iter, info->max_frmr_depth + 1);
>         if (num_pages > info->max_frmr_depth) {
>                 log_rdma_mr(ERR, "num_pages=%d max_frmr_depth=%d\n",
>                         num_pages, info->max_frmr_depth);
> +               WARN_ON_ONCE(1);
>                 return NULL;
>         }
>
> @@ -2344,32 +2292,16 @@ struct smbd_mr *smbd_register_mr(
>                 log_rdma_mr(ERR, "get_mr returning NULL\n");
>                 return NULL;
>         }
> +
> +       dir = writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
> +       smbdirect_mr->dir = dir;
>         smbdirect_mr->need_invalidate = need_invalidate;
>         smbdirect_mr->sgl_count = num_pages;
> -       sg_init_table(smbdirect_mr->sgl, num_pages);
> -
> -       log_rdma_mr(INFO, "num_pages=0x%x offset=0x%x tailsz=0x%x\n",
> -                       num_pages, offset, tailsz);
> -
> -       if (num_pages == 1) {
> -               sg_set_page(&smbdirect_mr->sgl[0], pages[0], tailsz, offset);
> -               goto skip_multiple_pages;
> -       }
>
> -       /* We have at least two pages to register */
> -       sg_set_page(
> -               &smbdirect_mr->sgl[0], pages[0], PAGE_SIZE - offset, offset);
> -       i = 1;
> -       while (i < num_pages - 1) {
> -               sg_set_page(&smbdirect_mr->sgl[i], pages[i], PAGE_SIZE, 0);
> -               i++;
> -       }
> -       sg_set_page(&smbdirect_mr->sgl[i], pages[i],
> -               tailsz ? tailsz : PAGE_SIZE, 0);
> +       log_rdma_mr(INFO, "num_pages=0x%x count=0x%zx\n",
> +                   num_pages, iov_iter_count(iter));
> +       smbd_iter_to_mr(info, iter, smbdirect_mr->sgl, num_pages);
>
> -skip_multiple_pages:
> -       dir = writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
> -       smbdirect_mr->dir = dir;
>         rc = ib_dma_map_sg(info->id->device, smbdirect_mr->sgl, num_pages, dir);
>         if (!rc) {
>                 log_rdma_mr(ERR, "ib_dma_map_sg num_pages=%x dir=%x rc=%x\n",
> diff --git a/fs/cifs/smbdirect.h b/fs/cifs/smbdirect.h
> index 207ef979cd51..be2cf18b7fec 100644
> --- a/fs/cifs/smbdirect.h
> +++ b/fs/cifs/smbdirect.h
> @@ -302,8 +302,8 @@ struct smbd_mr {
>
>  /* Interfaces to register and deregister MR for RDMA read/write */
>  struct smbd_mr *smbd_register_mr(
> -       struct smbd_connection *info, struct page *pages[], int num_pages,
> -       int offset, int tailsz, bool writing, bool need_invalidate);
> +       struct smbd_connection *info, struct iov_iter *iter,
> +       bool writing, bool need_invalidate);
>  int smbd_deregister_mr(struct smbd_mr *mr);
>
>  #else
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index 83e931824bf2..7ff67a27b361 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -270,26 +270,7 @@ smb_rqst_len(struct TCP_Server_Info *server, struct smb_rqst *rqst)
>         for (i = 0; i < nvec; i++)
>                 buflen += iov[i].iov_len;
>
> -       /*
> -        * Add in the page array if there is one. The caller needs to make
> -        * sure rq_offset and rq_tailsz are set correctly. If a buffer of
> -        * multiple pages ends at page boundary, rq_tailsz needs to be set to
> -        * PAGE_SIZE.
> -        */
> -       if (rqst->rq_npages) {
> -               if (rqst->rq_npages == 1)
> -                       buflen += rqst->rq_tailsz;
> -               else {
> -                       /*
> -                        * If there is more than one page, calculate the
> -                        * buffer length based on rq_offset and rq_tailsz
> -                        */
> -                       buflen += rqst->rq_pagesz * (rqst->rq_npages - 1) -
> -                                       rqst->rq_offset;
> -                       buflen += rqst->rq_tailsz;
> -               }
> -       }
> -
> +       buflen += iov_iter_count(&rqst->rq_iter);
>         return buflen;
>  }
>
> @@ -376,23 +357,15 @@ __smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
>
>                 total_len += sent;
>
> -               /* now walk the page array and send each page in it */
> -               for (i = 0; i < rqst[j].rq_npages; i++) {
> -                       struct bio_vec bvec;
> -
> -                       bvec.bv_page = rqst[j].rq_pages[i];
> -                       rqst_page_get_length(&rqst[j], i, &bvec.bv_len,
> -                                            &bvec.bv_offset);
> -
> -                       iov_iter_bvec(&smb_msg.msg_iter, ITER_SOURCE,
> -                                     &bvec, 1, bvec.bv_len);
> +               if (iov_iter_count(&rqst[j].rq_iter) > 0) {
> +                       smb_msg.msg_iter = rqst[j].rq_iter;
>                         rc = smb_send_kvec(server, &smb_msg, &sent);
>                         if (rc < 0)
>                                 break;
> -
>                         total_len += sent;
>                 }
> -       }
> +
> +}
>
>  unmask:
>         sigprocmask(SIG_SETMASK, &oldmask, NULL);
> @@ -1654,11 +1627,11 @@ int
>  cifs_discard_remaining_data(struct TCP_Server_Info *server)
>  {
>         unsigned int rfclen = server->pdu_size;
> -       int remaining = rfclen + HEADER_PREAMBLE_SIZE(server) -
> +       size_t remaining = rfclen + HEADER_PREAMBLE_SIZE(server) -
>                 server->total_read;
>
>         while (remaining > 0) {
> -               int length;
> +               ssize_t length;
>
>                 length = cifs_discard_from_socket(server,
>                                 min_t(size_t, remaining,
> @@ -1804,10 +1777,15 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
>                 return cifs_readv_discard(server, mid);
>         }
>
> -       length = rdata->read_into_pages(server, rdata, data_len);
> -       if (length < 0)
> -               return length;
> -
> +#ifdef CONFIG_CIFS_SMB_DIRECT
> +       if (rdata->mr)
> +               length = data_len; /* An RDMA read is already done. */
> +       else
> +#endif
> +               length = cifs_read_iter_from_socket(server, &rdata->iter,
> +                                                   data_len);
> +       if (length > 0)
> +               rdata->got_bytes += length;
>         server->total_read += length;
>
>         cifs_dbg(FYI, "total_read=%u buflen=%u remaining=%u\n",
>


-- 
Thanks,

Steve



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