[RFC PATCH 00/11] iov_iter: Use I/O direction from kiocb, iomap & request rather than iov_iter

[RFC PATCH 00/11] iov_iter: Use I/O direction from kiocb, iomap & request rather than iov_iter

[David Howells]

Hi Jens, Christoph,

Here are some patches to switch from using the I/O direction indication in the
iov_iter struct to using the I/O direction flags to be found in the kiocb
struct, the iomap_iter struct and the request struct.  The iterator's I/O
direction is then only used in some internal checks.

The patches also add direction flags into iov_iter_extract_pages() so that it
can perform some checks.  New constants are defined rather than using READ and
WRITE so that a check can be made that one of them is specified.  The problem
with the READ constant is that it is zero and is thus the same as no direction
being specified - but if we're modifying the buffer contents (ie. reading into
it), we need to know to set FOLL_WRITE.  Granted this would be the default if
unspecified, but it seems better that this case should be explicit.

There are also patches to make 9P and SCSI use iov_iter_extract_pages().

I've pushed the patches here also:

	https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=iov-extract

David


David Howells (11):
  iov_iter: Fix comment refs to iov_iter_get_pages/pages_alloc()
  vfs: Set IOCB_WRITE in iocbs that we're going to write from
  vfs: Use init_kiocb() to initialise new IOCBs
  iov_iter: Use IOCB_WRITE rather than iterator direction
  iov_iter: Use IOMAP_WRITE rather than iterator direction
  iov_iter: Use op_is_write() rather than iterator direction
  cifs: Drop the check using iov_iter_rw()
  iov_iter: Drop iov_iter_rw() and fold in last user
  iov_iter: Use I/O dir flags with iov_iter_extract_pages()
  9p: Pin pages rather than ref'ing if appropriate
  scsi: Use extract_iter_to_sg()

 block/bio.c                       |  6 ++
 block/blk-map.c                   |  5 +-
 block/fops.c                      |  8 +--
 crypto/af_alg.c                   |  5 +-
 crypto/algif_hash.c               |  3 +-
 drivers/block/loop.c              | 11 ++--
 drivers/nvme/target/io-cmd-file.c |  5 +-
 drivers/target/target_core_file.c |  2 +-
 drivers/vhost/scsi.c              | 79 ++++++++------------------
 fs/9p/vfs_addr.c                  |  2 +-
 fs/affs/file.c                    |  4 +-
 fs/aio.c                          |  9 ++-
 fs/btrfs/ioctl.c                  |  4 +-
 fs/cachefiles/io.c                | 10 ++--
 fs/ceph/file.c                    |  6 +-
 fs/dax.c                          |  6 +-
 fs/direct-io.c                    | 28 ++++++----
 fs/exfat/inode.c                  |  6 +-
 fs/ext2/inode.c                   |  2 +-
 fs/f2fs/file.c                    | 10 ++--
 fs/fat/inode.c                    |  4 +-
 fs/fuse/dax.c                     |  2 +-
 fs/fuse/file.c                    |  8 +--
 fs/hfs/inode.c                    |  2 +-
 fs/hfsplus/inode.c                |  2 +-
 fs/iomap/direct-io.c              |  4 +-
 fs/jfs/inode.c                    |  2 +-
 fs/nfs/direct.c                   |  2 +-
 fs/nilfs2/inode.c                 |  2 +-
 fs/ntfs3/inode.c                  |  2 +-
 fs/ocfs2/aops.c                   |  2 +-
 fs/orangefs/inode.c               |  2 +-
 fs/read_write.c                   | 10 ++--
 fs/reiserfs/inode.c               |  2 +-
 fs/seq_file.c                     |  2 +-
 fs/smb/client/smbdirect.c         |  9 ---
 fs/splice.c                       |  2 +-
 fs/udf/inode.c                    |  2 +-
 include/linux/bio.h               | 18 +++++-
 include/linux/fs.h                | 16 +++++-
 include/linux/mm_types.h          |  2 +-
 include/linux/uio.h               | 10 ++--
 io_uring/rw.c                     | 10 ++--
 lib/iov_iter.c                    | 14 ++++-
 lib/scatterlist.c                 | 12 +++-
 mm/filemap.c                      |  2 +-
 mm/page_io.c                      |  4 +-
 net/9p/trans_common.c             |  8 +--
 net/9p/trans_common.h             |  2 +-
 net/9p/trans_virtio.c             | 92 ++++++++++---------------------
 50 files changed, 221 insertions(+), 241 deletions(-)

[RFC PATCH 01/11] iov_iter: Fix comment refs to iov_iter_get_pages/pages_alloc()

[David Howells]

Fix references to iov_iter_get_pages/pages_alloc() in comments to refer to
the *2 interfaces instead.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christian Brauner <christian@brauner.io>
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---
 fs/ceph/file.c           | 4 ++--
 include/linux/mm_types.h | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index b1925232dc08..3bb27b9ce751 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -75,7 +75,7 @@ static __le32 ceph_flags_sys2wire(u32 flags)
  */
 
 /*
- * How many pages to get in one call to iov_iter_get_pages().  This
+ * How many pages to get in one call to iov_iter_get_pages2().  This
  * determines the size of the on-stack array used as a buffer.
  */
 #define ITER_GET_BVECS_PAGES	64
@@ -115,7 +115,7 @@ static ssize_t __iter_get_bvecs(struct iov_iter *iter, size_t maxsize,
 }
 
 /*
- * iov_iter_get_pages() only considers one iov_iter segment, no matter
+ * iov_iter_get_pages2() only considers one iov_iter segment, no matter
  * what maxsize or maxpages are given.  For ITER_BVEC that is a single
  * page.
  *
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index de10fc797c8e..f49029c943b0 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -1249,7 +1249,7 @@ enum {
 	/*
 	 * FOLL_LONGTERM indicates that the page will be held for an indefinite
 	 * time period _often_ under userspace control.  This is in contrast to
-	 * iov_iter_get_pages(), whose usages are transient.
+	 * iov_iter_get_pages2(), whose usages are transient.
 	 */
 	FOLL_LONGTERM = 1 << 8,
 	/* split huge pmd before returning */

[RFC PATCH 02/11] vfs: Set IOCB_WRITE in iocbs that we're going to write from

[David Howells]

IOCB_WRITE is set by aio, io_uring and cachefiles before submitting a write
operation to the VFS, but it isn't set by, say, the write() system call.

Fix this by adding an extra argument to init_sync_kiocb() to indicate the
direction and setting that to READ or WRITE, which will cause IOCB_WRITE to
be set as appropriate.

Whilst we're at it, rename init_sync_kiocb() to init_kiocb().

This will allow drivers to use IOCB_WRITE instead of the iterator data
source to determine the I/O direction.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christian Brauner <christian@brauner.io>
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---
 fs/btrfs/ioctl.c   |  4 ++--
 fs/read_write.c    | 10 +++++-----
 fs/seq_file.c      |  2 +-
 fs/splice.c        |  2 +-
 include/linux/fs.h |  6 +++++-
 mm/filemap.c       |  2 +-
 mm/page_io.c       |  4 ++--
 7 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index a895d105464b..15870337dd26 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4422,7 +4422,7 @@ static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp,
 	if (ret < 0)
 		goto out_iov;
 
-	init_sync_kiocb(&kiocb, file);
+	init_kiocb(&kiocb, file, READ);
 	kiocb.ki_pos = pos;
 
 	ret = btrfs_encoded_read(&kiocb, &iter, &args);
@@ -4523,7 +4523,7 @@ static int btrfs_ioctl_encoded_write(struct file *file, void __user *argp, bool
 	if (ret < 0)
 		goto out_end_write;
 
-	init_sync_kiocb(&kiocb, file);
+	init_kiocb(&kiocb, file, WRITE);
 	ret = kiocb_set_rw_flags(&kiocb, 0);
 	if (ret)
 		goto out_end_write;
diff --git a/fs/read_write.c b/fs/read_write.c
index b07de77ef126..6fe517047095 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -382,7 +382,7 @@ static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, lo
 	struct iov_iter iter;
 	ssize_t ret;
 
-	init_sync_kiocb(&kiocb, filp);
+	init_kiocb(&kiocb, filp, READ);
 	kiocb.ki_pos = (ppos ? *ppos : 0);
 	iov_iter_ubuf(&iter, ITER_DEST, buf, len);
 
@@ -422,7 +422,7 @@ ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
 	if (unlikely(!file->f_op->read_iter || file->f_op->read))
 		return warn_unsupported(file, "read");
 
-	init_sync_kiocb(&kiocb, file);
+	init_kiocb(&kiocb, file, READ);
 	kiocb.ki_pos = pos ? *pos : 0;
 	iov_iter_kvec(&iter, ITER_DEST, &iov, 1, iov.iov_len);
 	ret = file->f_op->read_iter(&kiocb, &iter);
@@ -484,7 +484,7 @@ static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t
 	struct iov_iter iter;
 	ssize_t ret;
 
-	init_sync_kiocb(&kiocb, filp);
+	init_kiocb(&kiocb, filp, WRITE);
 	kiocb.ki_pos = (ppos ? *ppos : 0);
 	iov_iter_ubuf(&iter, ITER_SOURCE, (void __user *)buf, len);
 
@@ -512,7 +512,7 @@ ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *po
 	if (unlikely(!file->f_op->write_iter || file->f_op->write))
 		return warn_unsupported(file, "write");
 
-	init_sync_kiocb(&kiocb, file);
+	init_kiocb(&kiocb, file, WRITE);
 	kiocb.ki_pos = pos ? *pos : 0;
 	ret = file->f_op->write_iter(&kiocb, from);
 	if (ret > 0) {
@@ -723,7 +723,7 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
 	struct kiocb kiocb;
 	ssize_t ret;
 
-	init_sync_kiocb(&kiocb, filp);
+	init_kiocb(&kiocb, filp, type);
 	ret = kiocb_set_rw_flags(&kiocb, flags);
 	if (ret)
 		return ret;
diff --git a/fs/seq_file.c b/fs/seq_file.c
index f5fdaf3b1572..1ee6ffc630da 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -155,7 +155,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 	struct iov_iter iter;
 	ssize_t ret;
 
-	init_sync_kiocb(&kiocb, file);
+	init_kiocb(&kiocb, file, READ);
 	iov_iter_init(&iter, ITER_DEST, &iov, 1, size);
 
 	kiocb.ki_pos = *ppos;
diff --git a/fs/splice.c b/fs/splice.c
index 004eb1c4ce31..867357ebb2c3 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -362,7 +362,7 @@ ssize_t copy_splice_read(struct file *in, loff_t *ppos,
 
 	/* Do the I/O */
 	iov_iter_bvec(&to, ITER_DEST, bv, npages, len);
-	init_sync_kiocb(&kiocb, in);
+	init_kiocb(&kiocb, in, READ);
 	kiocb.ki_pos = *ppos;
 	ret = call_read_iter(in, &kiocb, &to);
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d4b67bdeb53e..466eba253502 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2017,13 +2017,17 @@ static inline bool HAS_UNMAPPED_ID(struct mnt_idmap *idmap,
 	       !vfsgid_valid(i_gid_into_vfsgid(idmap, inode));
 }
 
-static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
+static inline void init_kiocb(struct kiocb *kiocb, struct file *filp,
+			      unsigned int rw)
 {
 	*kiocb = (struct kiocb) {
 		.ki_filp = filp,
 		.ki_flags = filp->f_iocb_flags,
 		.ki_ioprio = get_current_ioprio(),
 	};
+
+	if (rw == WRITE)
+		kiocb->ki_flags |= IOCB_WRITE;
 }
 
 static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
diff --git a/mm/filemap.c b/mm/filemap.c
index 9e44a49bbd74..cd763122d2a2 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2905,7 +2905,7 @@ ssize_t filemap_splice_read(struct file *in, loff_t *ppos,
 	if (unlikely(*ppos >= in->f_mapping->host->i_sb->s_maxbytes))
 		return 0;
 
-	init_sync_kiocb(&iocb, in);
+	init_kiocb(&iocb, in, READ);
 	iocb.ki_pos = *ppos;
 
 	/* Work out how much data we can actually add into the pipe */
diff --git a/mm/page_io.c b/mm/page_io.c
index 684cd3c7b59b..85cbadaf7395 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -312,7 +312,7 @@ static void swap_writepage_fs(struct page *page, struct writeback_control *wbc)
 	}
 	if (!sio) {
 		sio = mempool_alloc(sio_pool, GFP_NOIO);
-		init_sync_kiocb(&sio->iocb, swap_file);
+		init_kiocb(&sio->iocb, swap_file, WRITE);
 		sio->iocb.ki_complete = sio_write_complete;
 		sio->iocb.ki_pos = pos;
 		sio->pages = 0;
@@ -443,7 +443,7 @@ static void swap_readpage_fs(struct page *page,
 	}
 	if (!sio) {
 		sio = mempool_alloc(sio_pool, GFP_KERNEL);
-		init_sync_kiocb(&sio->iocb, sis->swap_file);
+		init_kiocb(&sio->iocb, sis->swap_file, READ);
 		sio->iocb.ki_pos = pos;
 		sio->iocb.ki_complete = sio_read_complete;
 		sio->pages = 0;

[RFC PATCH 00/11] iov_iter: Use I/O direction from kiocb, iomap & request rather than iov_iter

[David Howells]

Hi Jens, Christoph,

Here are some patches to switch from using the I/O direction indication in the
iov_iter struct to using the I/O direction flags to be found in the kiocb
struct, the iomap_iter struct and the request struct.  The iterator's I/O
direction is then only used in some internal checks.

The patches also add direction flags into iov_iter_extract_pages() so that it
can perform some checks.  New constants are defined rather than using READ and
WRITE so that a check can be made that one of them is specified.  The problem
with the READ constant is that it is zero and is thus the same as no direction
being specified - but if we're modifying the buffer contents (ie. reading into
it), we need to know to set FOLL_WRITE.  Granted this would be the default if
unspecified, but it seems better that this case should be explicit.

There are also patches to make 9P and SCSI use iov_iter_extract_pages().

I've pushed the patches here also:

	https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=iov-extract

David

David Howells (11):
  iov_iter: Fix comment refs to iov_iter_get_pages/pages_alloc()
  vfs: Set IOCB_WRITE in iocbs that we're going to write from
  vfs: Use init_kiocb() to initialise new IOCBs
  iov_iter: Use IOCB_WRITE rather than iterator direction
  iov_iter: Use IOMAP_WRITE rather than iterator direction
  iov_iter: Use op_is_write() rather than iterator direction
  cifs: Drop the check using iov_iter_rw()
  iov_iter: Drop iov_iter_rw() and fold in last user
  iov_iter: Use I/O dir flags with iov_iter_extract_pages()
  9p: Pin pages rather than ref'ing if appropriate
  scsi: Use extract_iter_to_sg()

 block/bio.c                       |  6 ++
 block/blk-map.c                   |  5 +-
 block/fops.c                      |  8 +--
 crypto/af_alg.c                   |  5 +-
 crypto/algif_hash.c               |  3 +-
 drivers/block/loop.c              | 11 ++--
 drivers/nvme/target/io-cmd-file.c |  5 +-
 drivers/target/target_core_file.c |  2 +-
 drivers/vhost/scsi.c              | 79 ++++++++------------------
 fs/9p/vfs_addr.c                  |  2 +-
 fs/affs/file.c                    |  4 +-
 fs/aio.c                          |  9 ++-
 fs/btrfs/ioctl.c                  |  4 +-
 fs/cachefiles/io.c                | 10 ++--
 fs/ceph/file.c                    |  6 +-
 fs/dax.c                          |  6 +-
 fs/direct-io.c                    | 28 ++++++----
 fs/exfat/inode.c                  |  6 +-
 fs/ext2/inode.c                   |  2 +-
 fs/f2fs/file.c                    | 10 ++--
 fs/fat/inode.c                    |  4 +-
 fs/fuse/dax.c                     |  2 +-
 fs/fuse/file.c                    |  8 +--
 fs/hfs/inode.c                    |  2 +-
 fs/hfsplus/inode.c                |  2 +-
 fs/iomap/direct-io.c              |  4 +-
 fs/jfs/inode.c                    |  2 +-
 fs/nfs/direct.c                   |  2 +-
 fs/nilfs2/inode.c                 |  2 +-
 fs/ntfs3/inode.c                  |  2 +-
 fs/ocfs2/aops.c                   |  2 +-
 fs/orangefs/inode.c               |  2 +-
 fs/read_write.c                   | 10 ++--
 fs/reiserfs/inode.c               |  2 +-
 fs/seq_file.c                     |  2 +-
 fs/smb/client/smbdirect.c         |  9 ---
 fs/splice.c                       |  2 +-
 fs/udf/inode.c                    |  2 +-
 include/linux/bio.h               | 18 +++++-
 include/linux/fs.h                | 16 +++++-
 include/linux/mm_types.h          |  2 +-
 include/linux/uio.h               | 10 ++--
 io_uring/rw.c                     | 10 ++--
 lib/iov_iter.c                    | 14 ++++-
 lib/scatterlist.c                 | 12 +++-
 mm/filemap.c                      |  2 +-
 mm/page_io.c                      |  4 +-
 net/9p/trans_common.c             |  8 +--
 net/9p/trans_common.h             |  2 +-
 net/9p/trans_virtio.c             | 92 ++++++++++---------------------
 50 files changed, 221 insertions(+), 241 deletions(-)

[RFC PATCH 02/11] vfs: Set IOCB_WRITE in iocbs that we're going to write from

[David Howells]

IOCB_WRITE is set by aio, io_uring and cachefiles before submitting a write
operation to the VFS, but it isn't set by, say, the write() system call.

Fix this by adding an extra argument to init_sync_kiocb() to indicate the
direction and setting that to READ or WRITE, which will cause IOCB_WRITE to
be set as appropriate.

Whilst we're at it, rename init_sync_kiocb() to init_kiocb().

This will allow drivers to use IOCB_WRITE instead of the iterator data
source to determine the I/O direction.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christian Brauner <christian@brauner.io>
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---
 fs/btrfs/ioctl.c   |  4 ++--
 fs/read_write.c    | 10 +++++-----
 fs/seq_file.c      |  2 +-
 fs/splice.c        |  2 +-
 include/linux/fs.h |  6 +++++-
 mm/filemap.c       |  2 +-
 mm/page_io.c       |  4 ++--
 7 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index a895d105464b..15870337dd26 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4422,7 +4422,7 @@ static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp,
 	if (ret < 0)
 		goto out_iov;
 
-	init_sync_kiocb(&kiocb, file);
+	init_kiocb(&kiocb, file, READ);
 	kiocb.ki_pos = pos;
 
 	ret = btrfs_encoded_read(&kiocb, &iter, &args);
@@ -4523,7 +4523,7 @@ static int btrfs_ioctl_encoded_write(struct file *file, void __user *argp, bool
 	if (ret < 0)
 		goto out_end_write;
 
-	init_sync_kiocb(&kiocb, file);
+	init_kiocb(&kiocb, file, WRITE);
 	ret = kiocb_set_rw_flags(&kiocb, 0);
 	if (ret)
 		goto out_end_write;
diff --git a/fs/read_write.c b/fs/read_write.c
index b07de77ef126..6fe517047095 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -382,7 +382,7 @@ static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, lo
 	struct iov_iter iter;
 	ssize_t ret;
 
-	init_sync_kiocb(&kiocb, filp);
+	init_kiocb(&kiocb, filp, READ);
 	kiocb.ki_pos = (ppos ? *ppos : 0);
 	iov_iter_ubuf(&iter, ITER_DEST, buf, len);
 
@@ -422,7 +422,7 @@ ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
 	if (unlikely(!file->f_op->read_iter || file->f_op->read))
 		return warn_unsupported(file, "read");
 
-	init_sync_kiocb(&kiocb, file);
+	init_kiocb(&kiocb, file, READ);
 	kiocb.ki_pos = pos ? *pos : 0;
 	iov_iter_kvec(&iter, ITER_DEST, &iov, 1, iov.iov_len);
 	ret = file->f_op->read_iter(&kiocb, &iter);
@@ -484,7 +484,7 @@ static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t
 	struct iov_iter iter;
 	ssize_t ret;
 
-	init_sync_kiocb(&kiocb, filp);
+	init_kiocb(&kiocb, filp, WRITE);
 	kiocb.ki_pos = (ppos ? *ppos : 0);
 	iov_iter_ubuf(&iter, ITER_SOURCE, (void __user *)buf, len);
 
@@ -512,7 +512,7 @@ ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *po
 	if (unlikely(!file->f_op->write_iter || file->f_op->write))
 		return warn_unsupported(file, "write");
 
-	init_sync_kiocb(&kiocb, file);
+	init_kiocb(&kiocb, file, WRITE);
 	kiocb.ki_pos = pos ? *pos : 0;
 	ret = file->f_op->write_iter(&kiocb, from);
 	if (ret > 0) {
@@ -723,7 +723,7 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
 	struct kiocb kiocb;
 	ssize_t ret;
 
-	init_sync_kiocb(&kiocb, filp);
+	init_kiocb(&kiocb, filp, type);
 	ret = kiocb_set_rw_flags(&kiocb, flags);
 	if (ret)
 		return ret;
diff --git a/fs/seq_file.c b/fs/seq_file.c
index f5fdaf3b1572..1ee6ffc630da 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -155,7 +155,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 	struct iov_iter iter;
 	ssize_t ret;
 
-	init_sync_kiocb(&kiocb, file);
+	init_kiocb(&kiocb, file, READ);
 	iov_iter_init(&iter, ITER_DEST, &iov, 1, size);
 
 	kiocb.ki_pos = *ppos;
diff --git a/fs/splice.c b/fs/splice.c
index 004eb1c4ce31..867357ebb2c3 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -362,7 +362,7 @@ ssize_t copy_splice_read(struct file *in, loff_t *ppos,
 
 	/* Do the I/O */
 	iov_iter_bvec(&to, ITER_DEST, bv, npages, len);
-	init_sync_kiocb(&kiocb, in);
+	init_kiocb(&kiocb, in, READ);
 	kiocb.ki_pos = *ppos;
 	ret = call_read_iter(in, &kiocb, &to);
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d4b67bdeb53e..466eba253502 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2017,13 +2017,17 @@ static inline bool HAS_UNMAPPED_ID(struct mnt_idmap *idmap,
 	       !vfsgid_valid(i_gid_into_vfsgid(idmap, inode));
 }
 
-static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
+static inline void init_kiocb(struct kiocb *kiocb, struct file *filp,
+			      unsigned int rw)
 {
 	*kiocb = (struct kiocb) {
 		.ki_filp = filp,
 		.ki_flags = filp->f_iocb_flags,
 		.ki_ioprio = get_current_ioprio(),
 	};
+
+	if (rw == WRITE)
+		kiocb->ki_flags |= IOCB_WRITE;
 }
 
 static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
diff --git a/mm/filemap.c b/mm/filemap.c
index 9e44a49bbd74..cd763122d2a2 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2905,7 +2905,7 @@ ssize_t filemap_splice_read(struct file *in, loff_t *ppos,
 	if (unlikely(*ppos >= in->f_mapping->host->i_sb->s_maxbytes))
 		return 0;
 
-	init_sync_kiocb(&iocb, in);
+	init_kiocb(&iocb, in, READ);
 	iocb.ki_pos = *ppos;
 
 	/* Work out how much data we can actually add into the pipe */
diff --git a/mm/page_io.c b/mm/page_io.c
index 684cd3c7b59b..85cbadaf7395 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -312,7 +312,7 @@ static void swap_writepage_fs(struct page *page, struct writeback_control *wbc)
 	}
 	if (!sio) {
 		sio = mempool_alloc(sio_pool, GFP_NOIO);
-		init_sync_kiocb(&sio->iocb, swap_file);
+		init_kiocb(&sio->iocb, swap_file, WRITE);
 		sio->iocb.ki_complete = sio_write_complete;
 		sio->iocb.ki_pos = pos;
 		sio->pages = 0;
@@ -443,7 +443,7 @@ static void swap_readpage_fs(struct page *page,
 	}
 	if (!sio) {
 		sio = mempool_alloc(sio_pool, GFP_KERNEL);
-		init_sync_kiocb(&sio->iocb, sis->swap_file);
+		init_kiocb(&sio->iocb, sis->swap_file, READ);
 		sio->iocb.ki_pos = pos;
 		sio->iocb.ki_complete = sio_read_complete;
 		sio->pages = 0;

Re: [RFC PATCH 02/11] vfs: Set IOCB_WRITE in iocbs that we're going to write from

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>