On Wed, 2022-06-22 at 05:15 +0100, Al Viro wrote:
> Most of the users immediately follow successful iov_iter_get_pages()
> with advancing by the amount it had returned.
>
> Provide inline wrappers doing that, convert trivial open-coded
> uses of those.
>
> BTW, iov_iter_get_pages() never returns more than it had been asked
> to; such checks in cifs ought to be removed someday...
>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/vhost/scsi.c | 4 +---
> fs/ceph/file.c | 3 +--
> fs/cifs/file.c | 6 ++----
> fs/cifs/misc.c | 3 +--
> fs/direct-io.c | 3 +--
> fs/fuse/dev.c | 3 +--
> fs/fuse/file.c | 3 +--
> fs/nfs/direct.c | 6 ++----
> include/linux/uio.h | 20 ++++++++++++++++++++
> net/core/datagram.c | 3 +--
> net/core/skmsg.c | 3 +--
> net/rds/message.c | 3 +--
> net/tls/tls_sw.c | 4 +---
> 13 files changed, 34 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index ffd9e6c2ffc1..9b65509424dc 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -643,14 +643,12 @@ vhost_scsi_map_to_sgl(struct vhost_scsi_cmd *cmd,
> size_t offset;
> unsigned int npages = 0;
>
> - bytes = iov_iter_get_pages(iter, pages, LONG_MAX,
> + bytes = iov_iter_get_pages2(iter, pages, LONG_MAX,
> VHOST_SCSI_PREALLOC_UPAGES, &offset);
> /* No pages were pinned */
> if (bytes <= 0)
> return bytes < 0 ? bytes : -EFAULT;
>
> - iov_iter_advance(iter, bytes);
> -
> while (bytes) {
> unsigned n = min_t(unsigned, PAGE_SIZE - offset, bytes);
> sg_set_page(sg++, pages[npages++], n, offset);
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index c535de5852bf..8fab5db16c73 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -95,12 +95,11 @@ static ssize_t __iter_get_bvecs(struct iov_iter *iter, size_t maxsize,
> size_t start;
> int idx = 0;
>
> - bytes = iov_iter_get_pages(iter, pages, maxsize - size,
> + bytes = iov_iter_get_pages2(iter, pages, maxsize - size,
> ITER_GET_BVECS_PAGES, &start);
> if (bytes < 0)
> return size ?: bytes;
>
> - iov_iter_advance(iter, bytes);
> size += bytes;
>
> for ( ; bytes; idx++, bvec_idx++) {
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index e1e05b253daa..3ba013e2987f 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -3022,7 +3022,7 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
> if (ctx->direct_io) {
> ssize_t result;
>
> - result = iov_iter_get_pages_alloc(
> + result = iov_iter_get_pages_alloc2(
> from, &pagevec, cur_len, &start);
> if (result < 0) {
> cifs_dbg(VFS,
> @@ -3036,7 +3036,6 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
> break;
> }
> cur_len = (size_t)result;
> - iov_iter_advance(from, cur_len);
>
> nr_pages =
> (cur_len + start + PAGE_SIZE - 1) / PAGE_SIZE;
> @@ -3758,7 +3757,7 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
> if (ctx->direct_io) {
> ssize_t result;
>
> - result = iov_iter_get_pages_alloc(
> + result = iov_iter_get_pages_alloc2(
> &direct_iov, &pagevec,
> cur_len, &start);
> if (result < 0) {
> @@ -3774,7 +3773,6 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
> break;
> }
> cur_len = (size_t)result;
> - iov_iter_advance(&direct_iov, cur_len);
>
> rdata = cifs_readdata_direct_alloc(
> pagevec, cifs_uncached_readv_complete);
> diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> index c69e1240d730..37493118fb72 100644
> --- a/fs/cifs/misc.c
> +++ b/fs/cifs/misc.c
> @@ -1022,7 +1022,7 @@ setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
> saved_len = count;
>
> while (count && npages < max_pages) {
> - rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
> + 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;
> @@ -1034,7 +1034,6 @@ setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
> break;
> }
>
> - iov_iter_advance(iter, rc);
> count -= rc;
> rc += start;
> cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
> diff --git a/fs/direct-io.c b/fs/direct-io.c
> index 72237f49ad94..9724244f12ce 100644
> --- a/fs/direct-io.c
> +++ b/fs/direct-io.c
> @@ -169,7 +169,7 @@ static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio)
> {
> ssize_t ret;
>
> - ret = iov_iter_get_pages(sdio->iter, dio->pages, LONG_MAX, DIO_PAGES,
> + ret = iov_iter_get_pages2(sdio->iter, dio->pages, LONG_MAX, DIO_PAGES,
> &sdio->from);
>
> if (ret < 0 && sdio->blocks_available && (dio->op == REQ_OP_WRITE)) {
> @@ -191,7 +191,6 @@ static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio)
> }
>
> if (ret >= 0) {
> - iov_iter_advance(sdio->iter, ret);
> ret += sdio->from;
> sdio->head = 0;
> sdio->tail = (ret + PAGE_SIZE - 1) / PAGE_SIZE;
> diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
> index 8d657c2cd6f7..51897427a534 100644
> --- a/fs/fuse/dev.c
> +++ b/fs/fuse/dev.c
> @@ -730,14 +730,13 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
> }
> } else {
> size_t off;
> - err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
> + err = iov_iter_get_pages2(cs->iter, &page, PAGE_SIZE, 1, &off);
> if (err < 0)
> return err;
> BUG_ON(!err);
> cs->len = err;
> cs->offset = off;
> cs->pg = page;
> - iov_iter_advance(cs->iter, err);
> }
>
> return lock_request(cs->req);
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index c982e3afe3b4..69e19fc0afc1 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -1401,14 +1401,13 @@ static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
> while (nbytes < *nbytesp && ap->num_pages < max_pages) {
> unsigned npages;
> size_t start;
> - ret = iov_iter_get_pages(ii, &ap->pages[ap->num_pages],
> + ret = iov_iter_get_pages2(ii, &ap->pages[ap->num_pages],
> *nbytesp - nbytes,
> max_pages - ap->num_pages,
> &start);
> if (ret < 0)
> break;
>
> - iov_iter_advance(ii, ret);
> nbytes += ret;
>
> ret += start;
> diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> index 022e1ce63e62..c275c83f0aef 100644
> --- a/fs/nfs/direct.c
> +++ b/fs/nfs/direct.c
> @@ -364,13 +364,12 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
> size_t pgbase;
> unsigned npages, i;
>
> - result = iov_iter_get_pages_alloc(iter, &pagevec,
> + result = iov_iter_get_pages_alloc2(iter, &pagevec,
> rsize, &pgbase);
> if (result < 0)
> break;
>
> bytes = result;
> - iov_iter_advance(iter, bytes);
> npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE;
> for (i = 0; i < npages; i++) {
> struct nfs_page *req;
> @@ -812,13 +811,12 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
> size_t pgbase;
> unsigned npages, i;
>
> - result = iov_iter_get_pages_alloc(iter, &pagevec,
> + result = iov_iter_get_pages_alloc2(iter, &pagevec,
> wsize, &pgbase);
> if (result < 0)
> break;
>
> bytes = result;
> - iov_iter_advance(iter, bytes);
> npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE;
> for (i = 0; i < npages; i++) {
> struct nfs_page *req;
> diff --git a/include/linux/uio.h b/include/linux/uio.h
> index d3e13b37ea72..ab1cc218b9de 100644
> --- a/include/linux/uio.h
> +++ b/include/linux/uio.h
> @@ -349,4 +349,24 @@ static inline void iov_iter_ubuf(struct iov_iter *i, unsigned int direction,
> };
> }
>
> +static inline ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
> + size_t maxsize, unsigned maxpages, size_t *start)
> +{
> + ssize_t res = iov_iter_get_pages(i, pages, maxsize, maxpages, start);
> +
> + if (res >= 0)
> + iov_iter_advance(i, res);
> + return res;
> +}
> +
> +static inline ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages,
> + size_t maxsize, size_t *start)
> +{
> + ssize_t res = iov_iter_get_pages_alloc(i, pages, maxsize, start);
> +
> + if (res >= 0)
> + iov_iter_advance(i, res);
> + return res;
> +}
> +
> #endif
> diff --git a/net/core/datagram.c b/net/core/datagram.c
> index 50f4faeea76c..344b4c5791ac 100644
> --- a/net/core/datagram.c
> +++ b/net/core/datagram.c
> @@ -629,12 +629,11 @@ int __zerocopy_sg_from_iter(struct sock *sk, struct sk_buff *skb,
> if (frag == MAX_SKB_FRAGS)
> return -EMSGSIZE;
>
> - copied = iov_iter_get_pages(from, pages, length,
> + copied = iov_iter_get_pages2(from, pages, length,
> MAX_SKB_FRAGS - frag, &start);
> if (copied < 0)
> return -EFAULT;
>
> - iov_iter_advance(from, copied);
> length -= copied;
>
> truesize = PAGE_ALIGN(copied + start);
> diff --git a/net/core/skmsg.c b/net/core/skmsg.c
> index 22b983ade0e7..662151678f20 100644
> --- a/net/core/skmsg.c
> +++ b/net/core/skmsg.c
> @@ -324,14 +324,13 @@ int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
> goto out;
> }
>
> - copied = iov_iter_get_pages(from, pages, bytes, maxpages,
> + copied = iov_iter_get_pages2(from, pages, bytes, maxpages,
> &offset);
> if (copied <= 0) {
> ret = -EFAULT;
> goto out;
> }
>
> - iov_iter_advance(from, copied);
> bytes -= copied;
> msg->sg.size += copied;
>
> diff --git a/net/rds/message.c b/net/rds/message.c
> index 799034e0f513..d74be4e3f3fa 100644
> --- a/net/rds/message.c
> +++ b/net/rds/message.c
> @@ -391,7 +391,7 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter *
> size_t start;
> ssize_t copied;
>
> - copied = iov_iter_get_pages(from, &pages, PAGE_SIZE,
> + copied = iov_iter_get_pages2(from, &pages, PAGE_SIZE,
> 1, &start);
> if (copied < 0) {
> struct mmpin *mmp;
> @@ -405,7 +405,6 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter *
> goto err;
> }
> total_copied += copied;
> - iov_iter_advance(from, copied);
> length -= copied;
> sg_set_page(sg, pages, copied, start);
> rm->data.op_nents++;
> diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
> index 0513f82b8537..b1406c60f8df 100644
> --- a/net/tls/tls_sw.c
> +++ b/net/tls/tls_sw.c
> @@ -1361,7 +1361,7 @@ static int tls_setup_from_iter(struct iov_iter *from,
> rc = -EFAULT;
> goto out;
> }
> - copied = iov_iter_get_pages(from, pages,
> + copied = iov_iter_get_pages2(from, pages,
> length,
> maxpages, &offset);
> if (copied <= 0) {
> @@ -1369,8 +1369,6 @@ static int tls_setup_from_iter(struct iov_iter *from,
> goto out;
> }
>
> - iov_iter_advance(from, copied);
> -
> length -= copied;
> size += copied;
> while (copied) {
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
