Define FOLL_SOURCE_BUF and FOLL_DEST_BUF to indicate to get_user_pages*() and iov_iter_get_pages*() how the buffer is intended to be used in an I/O operation. Don't use READ and WRITE as a read I/O writes to memory and vice versa - which causes confusion. The direction is checked against the iterator's data_source. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> --- block/bio.c | 6 ++++++ block/blk-map.c | 2 ++ crypto/af_alg.c | 9 ++++++--- crypto/algif_hash.c | 3 ++- drivers/vhost/scsi.c | 9 ++++++--- fs/ceph/addr.c | 2 +- fs/ceph/file.c | 14 ++++++++------ fs/cifs/file.c | 8 ++++---- fs/cifs/misc.c | 3 ++- fs/direct-io.c | 6 ++++-- fs/fuse/dev.c | 3 ++- fs/fuse/file.c | 8 ++++---- fs/nfs/direct.c | 10 ++++++---- fs/splice.c | 3 ++- include/crypto/if_alg.h | 3 ++- include/linux/bio.h | 18 ++++++++++++++++-- include/linux/mm.h | 10 ++++++++++ lib/iov_iter.c | 14 +++++++------- net/9p/trans_virtio.c | 12 ++++++++---- net/core/datagram.c | 5 +++-- net/core/skmsg.c | 4 ++-- net/rds/message.c | 4 ++-- net/tls/tls_sw.c | 5 ++--- 23 files changed, 107 insertions(+), 54 deletions(-) diff --git a/block/bio.c b/block/bio.c index 5f96fcae3f75..867cf4db87ea 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1242,6 +1242,8 @@ static int bio_iov_add_zone_append_page(struct bio *bio, struct page *page, * pages will have to be released using put_page() when done. * For multi-segment *iter, this function only adds pages from the * next non-empty segment of the iov iterator. + * + * The I/O direction is determined from the bio operation type. */ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) { @@ -1263,6 +1265,8 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2); pages += entries_left * (PAGE_PTRS_PER_BVEC - 1); + gup_flags |= bio_is_write(bio) ? FOLL_SOURCE_BUF : FOLL_DEST_BUF; + if (bio->bi_bdev && blk_queue_pci_p2pdma(bio->bi_bdev->bd_disk->queue)) gup_flags |= FOLL_PCI_P2PDMA; @@ -1332,6 +1336,8 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) * fit into the bio, or are requested in @iter, whatever is smaller. If * MM encounters an error pinning the requested pages, it stops. Error * is returned only if 0 pages could be pinned. + * + * The bio operation indicates the data direction. */ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) { diff --git a/block/blk-map.c b/block/blk-map.c index 08cbb7ff3b19..c30be529fb55 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -279,6 +279,8 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter, if (bio == NULL) return -ENOMEM; + gup_flags |= bio_is_write(bio) ? FOLL_SOURCE_BUF : FOLL_DEST_BUF; + if (blk_queue_pci_p2pdma(rq->q)) gup_flags |= FOLL_PCI_P2PDMA; diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 0a4fa2a429e2..7a68db157fae 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -531,13 +531,15 @@ static const struct net_proto_family alg_family = { .owner = THIS_MODULE, }; -int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len) +int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len, + unsigned int gup_flags) { size_t off; ssize_t n; int npages, i; - n = iov_iter_get_pages2(iter, sgl->pages, len, ALG_MAX_PAGES, &off); + n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off, + gup_flags); if (n < 0) return n; @@ -1310,7 +1312,8 @@ int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags, list_add_tail(&rsgl->list, &areq->rsgl_list); /* make one iovec available as scatterlist */ - err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen); + err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen, + FOLL_DEST_BUF); if (err < 0) { rsgl->sg_num_bytes = 0; return err; diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c index 1d017ec5c63c..fe3d2258145f 100644 --- a/crypto/algif_hash.c +++ b/crypto/algif_hash.c @@ -91,7 +91,8 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg, if (len > limit) len = limit; - len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len); + len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len, + FOLL_SOURCE_BUF); if (len < 0) { err = copied ? 0 : len; goto unlock; diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index dca6346d75b3..5d10837d19ec 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -646,10 +646,13 @@ vhost_scsi_map_to_sgl(struct vhost_scsi_cmd *cmd, struct scatterlist *sg = sgl; ssize_t bytes; size_t offset; - unsigned int npages = 0; + unsigned int npages = 0, gup_flags = 0; - bytes = iov_iter_get_pages2(iter, pages, LONG_MAX, - VHOST_SCSI_PREALLOC_UPAGES, &offset); + gup_flags |= write ? FOLL_SOURCE_BUF : FOLL_DEST_BUF; + + bytes = iov_iter_get_pages(iter, pages, LONG_MAX, + VHOST_SCSI_PREALLOC_UPAGES, &offset, + gup_flags); /* No pages were pinned */ if (bytes <= 0) return bytes < 0 ? bytes : -EFAULT; diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index 8c74871e37c9..cfc3353e5604 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -328,7 +328,7 @@ static void ceph_netfs_issue_read(struct netfs_io_subrequest *subreq) dout("%s: pos=%llu orig_len=%zu len=%llu\n", __func__, subreq->start, subreq->len, len); iov_iter_xarray(&iter, ITER_DEST, &rreq->mapping->i_pages, subreq->start, len); - err = iov_iter_get_pages_alloc2(&iter, &pages, len, &page_off); + err = iov_iter_get_pages_alloc(&iter, &pages, len, &page_off, FOLL_DEST_BUF); if (err < 0) { dout("%s: iov_ter_get_pages_alloc returned %d\n", __func__, err); goto out; diff --git a/fs/ceph/file.c b/fs/ceph/file.c index 27c72a2f6af5..ffd36eeea186 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -81,7 +81,7 @@ static __le32 ceph_flags_sys2wire(u32 flags) #define ITER_GET_BVECS_PAGES 64 static ssize_t __iter_get_bvecs(struct iov_iter *iter, size_t maxsize, - struct bio_vec *bvecs) + struct bio_vec *bvecs, bool write) { size_t size = 0; int bvec_idx = 0; @@ -95,8 +95,9 @@ static ssize_t __iter_get_bvecs(struct iov_iter *iter, size_t maxsize, size_t start; int idx = 0; - bytes = iov_iter_get_pages2(iter, pages, maxsize - size, - ITER_GET_BVECS_PAGES, &start); + bytes = iov_iter_get_pages(iter, pages, maxsize - size, + ITER_GET_BVECS_PAGES, &start, + write ? FOLL_SOURCE_BUF : FOLL_DEST_BUF); if (bytes < 0) return size ?: bytes; @@ -127,7 +128,8 @@ static ssize_t __iter_get_bvecs(struct iov_iter *iter, size_t maxsize, * Return the number of bytes in the created bio_vec array, or an error. */ static ssize_t iter_get_bvecs_alloc(struct iov_iter *iter, size_t maxsize, - struct bio_vec **bvecs, int *num_bvecs) + struct bio_vec **bvecs, int *num_bvecs, + bool write) { struct bio_vec *bv; size_t orig_count = iov_iter_count(iter); @@ -146,7 +148,7 @@ static ssize_t iter_get_bvecs_alloc(struct iov_iter *iter, size_t maxsize, if (!bv) return -ENOMEM; - bytes = __iter_get_bvecs(iter, maxsize, bv); + bytes = __iter_get_bvecs(iter, maxsize, bv, write); if (bytes < 0) { /* * No pages were pinned -- just free the array. @@ -1334,7 +1336,7 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter, break; } - len = iter_get_bvecs_alloc(iter, size, &bvecs, &num_pages); + len = iter_get_bvecs_alloc(iter, size, &bvecs, &num_pages, write); if (len < 0) { ceph_osdc_put_request(req); ret = len; diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 22dfc1f8b4f1..d100b9cb8682 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -3290,8 +3290,8 @@ 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_alloc2( - from, &pagevec, cur_len, &start); + result = iov_iter_get_pages_alloc( + from, &pagevec, cur_len, &start, FOLL_SOURCE_BUF); if (result < 0) { cifs_dbg(VFS, "direct_writev couldn't get user pages (rc=%zd) iter type %d iov_offset %zd count %zd\n", @@ -4031,9 +4031,9 @@ 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_alloc2( + result = iov_iter_get_pages_alloc( &direct_iov, &pagevec, - cur_len, &start); + cur_len, &start, FOLL_DEST_BUF); if (result < 0) { cifs_dbg(VFS, "Couldn't get user pages (rc=%zd) iter type %d iov_offset %zd count %zd\n", diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index 4d3c586785a5..9655cf359ab9 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -1030,7 +1030,8 @@ 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_pages2(iter, pages, count, max_pages, &start); + rc = iov_iter_get_pages(iter, pages, count, max_pages, &start, + rw == WRITE ? FOLL_SOURCE_BUF : FOLL_DEST_BUF); if (rc < 0) { cifs_dbg(VFS, "Couldn't get user pages (rc=%zd)\n", rc); break; diff --git a/fs/direct-io.c b/fs/direct-io.c index cf196f2a211e..b1e26a706e31 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -169,8 +169,10 @@ static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio) const enum req_op dio_op = dio->opf & REQ_OP_MASK; ssize_t ret; - ret = iov_iter_get_pages2(sdio->iter, dio->pages, LONG_MAX, DIO_PAGES, - &sdio->from); + ret = iov_iter_get_pages(sdio->iter, dio->pages, LONG_MAX, DIO_PAGES, + &sdio->from, + op_is_write(dio_op) ? + FOLL_SOURCE_BUF : FOLL_DEST_BUF); if (ret < 0 && sdio->blocks_available && dio_op == REQ_OP_WRITE) { struct page *page = ZERO_PAGE(0); diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index e8b60ce72c9a..e3d8443e24a6 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -730,7 +730,8 @@ static int fuse_copy_fill(struct fuse_copy_state *cs) } } else { size_t off; - err = iov_iter_get_pages2(cs->iter, &page, PAGE_SIZE, 1, &off); + err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off, + cs->write ? FOLL_SOURCE_BUF : FOLL_DEST_BUF); if (err < 0) return err; BUG_ON(!err); diff --git a/fs/fuse/file.c b/fs/fuse/file.c index d68b45f8b3ae..68c196437306 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -1414,10 +1414,10 @@ 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_pages2(ii, &ap->pages[ap->num_pages], - *nbytesp - nbytes, - max_pages - ap->num_pages, - &start); + ret = iov_iter_get_pages(ii, &ap->pages[ap->num_pages], + *nbytesp - nbytes, + max_pages - ap->num_pages, + &start, write ? FOLL_SOURCE_BUF : FOLL_DEST_BUF); if (ret < 0) break; diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index d865945f2a63..42af84685f20 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -332,8 +332,9 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, size_t pgbase; unsigned npages, i; - result = iov_iter_get_pages_alloc2(iter, &pagevec, - rsize, &pgbase); + result = iov_iter_get_pages_alloc(iter, &pagevec, + rsize, &pgbase, + FOLL_DEST_BUF); if (result < 0) break; @@ -791,8 +792,9 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, size_t pgbase; unsigned npages, i; - result = iov_iter_get_pages_alloc2(iter, &pagevec, - wsize, &pgbase); + result = iov_iter_get_pages_alloc(iter, &pagevec, + wsize, &pgbase, + FOLL_SOURCE_BUF); if (result < 0) break; diff --git a/fs/splice.c b/fs/splice.c index 5969b7a1d353..19c5b5adc548 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1165,7 +1165,8 @@ static int iter_to_pipe(struct iov_iter *from, size_t start; int i, n; - left = iov_iter_get_pages2(from, pages, ~0UL, 16, &start); + left = iov_iter_get_pages(from, pages, ~0UL, 16, &start, + FOLL_SOURCE_BUF); if (left <= 0) { ret = left; break; diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h index a5db86670bdf..12058ab6cad9 100644 --- a/include/crypto/if_alg.h +++ b/include/crypto/if_alg.h @@ -165,7 +165,8 @@ int af_alg_release(struct socket *sock); void af_alg_release_parent(struct sock *sk); int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern); -int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len); +int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len, + unsigned int gup_flags); void af_alg_free_sg(struct af_alg_sgl *sgl); static inline struct alg_sock *alg_sk(struct sock *sk) diff --git a/include/linux/bio.h b/include/linux/bio.h index 22078a28d7cb..3f7ba7fe48ac 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -40,11 +40,25 @@ static inline unsigned int bio_max_segs(unsigned int nr_segs) #define bio_sectors(bio) bvec_iter_sectors((bio)->bi_iter) #define bio_end_sector(bio) bvec_iter_end_sector((bio)->bi_iter) +/** + * bio_is_write - Query if the I/O direction is towards the disk + * @bio: The bio to query + * + * Return true if this is some sort of write operation - ie. the data is going + * towards the disk. + */ +static inline bool bio_is_write(const struct bio *bio) +{ + return op_is_write(bio_op(bio)); +} + /* * Return the data direction, READ or WRITE. */ -#define bio_data_dir(bio) \ - (op_is_write(bio_op(bio)) ? WRITE : READ) +static inline int bio_data_dir(const struct bio *bio) +{ + return bio_is_write(bio) ? WRITE : READ; +} /* * Check whether this bio carries any data or not. A NULL bio is allowed. diff --git a/include/linux/mm.h b/include/linux/mm.h index f3f196e4d66d..3af4ca8b1fe7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3090,6 +3090,10 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, #define FOLL_PCI_P2PDMA 0x100000 /* allow returning PCI P2PDMA pages */ #define FOLL_INTERRUPTIBLE 0x200000 /* allow interrupts from generic signals */ +#define FOLL_SOURCE_BUF 0 /* Memory will be read from by I/O */ +#define FOLL_DEST_BUF FOLL_WRITE /* Memory will be written to by I/O */ +#define FOLL_BUF_MASK FOLL_WRITE + /* * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each * other. Here is what they mean, and how to use them: @@ -3143,6 +3147,12 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, * releasing pages: get_user_pages*() pages must be released via put_page(), * while pin_user_pages*() pages must be released via unpin_user_page(). * + * FOLL_SOURCE_BUF and FOLL_DEST_BUF are indicators to get_user_pages*() and + * iov_iter_*_pages*() as to how the pages obtained are going to be used. + * FOLL_SOURCE_BUF indicates that I/O op is going to transfer from memory to + * device; FOLL_DEST_BUF that the op is going to transfer from device to + * memory. + * * Please see Documentation/core-api/pin_user_pages.rst for more information. */ diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 68497d9c1452..f53583836009 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1429,11 +1429,6 @@ static struct page *first_bvec_segment(const struct iov_iter *i, return page; } -static unsigned char iov_iter_rw(const struct iov_iter *i) -{ - return i->data_source ? WRITE : READ; -} - static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages, size_t maxsize, unsigned int maxpages, size_t *start, @@ -1448,12 +1443,17 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, if (maxsize > MAX_RW_COUNT) maxsize = MAX_RW_COUNT; + if (WARN_ON_ONCE((gup_flags & FOLL_BUF_MASK) == FOLL_SOURCE_BUF && + i->data_source == ITER_DEST)) + return -EIO; + if (WARN_ON_ONCE((gup_flags & FOLL_BUF_MASK) == FOLL_DEST_BUF && + i->data_source == ITER_SOURCE)) + return -EIO; + if (likely(user_backed_iter(i))) { unsigned long addr; int res; - if (iov_iter_rw(i) != WRITE) - gup_flags |= FOLL_WRITE; if (i->nofault) gup_flags |= FOLL_NOFAULT; diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index 3c27ffb781e3..eb28b54fe5f6 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -310,7 +310,8 @@ static int p9_get_mapped_pages(struct virtio_chan *chan, struct iov_iter *data, int count, size_t *offs, - int *need_drop) + int *need_drop, + unsigned int gup_flags) { int nr_pages; int err; @@ -330,7 +331,8 @@ static int p9_get_mapped_pages(struct virtio_chan *chan, if (err == -ERESTARTSYS) return err; } - n = iov_iter_get_pages_alloc2(data, pages, count, offs); + n = iov_iter_get_pages_alloc(data, pages, count, offs, + gup_flags); if (n < 0) return n; *need_drop = 1; @@ -437,7 +439,8 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req, if (uodata) { __le32 sz; int n = p9_get_mapped_pages(chan, &out_pages, uodata, - outlen, &offs, &need_drop); + outlen, &offs, &need_drop, + FOLL_DEST_BUF); if (n < 0) { err = n; goto err_out; @@ -456,7 +459,8 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req, memcpy(&req->tc.sdata[0], &sz, sizeof(sz)); } else if (uidata) { int n = p9_get_mapped_pages(chan, &in_pages, uidata, - inlen, &offs, &need_drop); + inlen, &offs, &need_drop, + FOLL_SOURCE_BUF); if (n < 0) { err = n; goto err_out; diff --git a/net/core/datagram.c b/net/core/datagram.c index e4ff2db40c98..9f0914b781ad 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -632,8 +632,9 @@ int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk, if (frag == MAX_SKB_FRAGS) return -EMSGSIZE; - copied = iov_iter_get_pages2(from, pages, length, - MAX_SKB_FRAGS - frag, &start); + copied = iov_iter_get_pages(from, pages, length, + MAX_SKB_FRAGS - frag, &start, + FOLL_SOURCE_BUF); if (copied < 0) return -EFAULT; diff --git a/net/core/skmsg.c b/net/core/skmsg.c index 53d0251788aa..f63a13690712 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -324,8 +324,8 @@ int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from, goto out; } - copied = iov_iter_get_pages2(from, pages, bytes, maxpages, - &offset); + copied = iov_iter_get_pages(from, pages, bytes, maxpages, + &offset, FOLL_SOURCE_BUF); if (copied <= 0) { ret = -EFAULT; goto out; diff --git a/net/rds/message.c b/net/rds/message.c index b47e4f0a1639..fcfd406b97af 100644 --- a/net/rds/message.c +++ b/net/rds/message.c @@ -390,8 +390,8 @@ static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter * size_t start; ssize_t copied; - copied = iov_iter_get_pages2(from, &pages, PAGE_SIZE, - 1, &start); + copied = iov_iter_get_pages(from, &pages, PAGE_SIZE, + 1, &start, FOLL_SOURCE_BUF); if (copied < 0) { struct mmpin *mmp; int i; diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index 9ed978634125..59acaeb24f54 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -1354,9 +1354,8 @@ static int tls_setup_from_iter(struct iov_iter *from, rc = -EFAULT; goto out; } - copied = iov_iter_get_pages2(from, pages, - length, - maxpages, &offset); + copied = iov_iter_get_pages(from, pages, length, + maxpages, &offset, FOLL_DEST_BUF); if (copied <= 0) { rc = -EFAULT; goto out;