pass iov_iter to ->direct_IO()

unmodified, for now

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

30 files changed, 117 insertions, 126 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index eba79013425..9b0d5a33c8b 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -196,8 +196,7 @@ prototypes:
 	void (*invalidatepage) (struct page *, unsigned int, unsigned int);
 	int (*releasepage) (struct page *, int);
 	void (*freepage)(struct page *);
-	int (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
-			loff_t offset, unsigned long nr_segs);
+	int (*direct_IO)(int, struct kiocb *, struct iov_iter *iter, loff_t offset);
 	int (*get_xip_mem)(struct address_space *, pgoff_t, int, void **,
 				unsigned long *);
 	int (*migratepage)(struct address_space *, struct page *, struct page *);
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 617f6d70c07..1846374a5ad 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -589,8 +589,7 @@ struct address_space_operations {
 	void (*invalidatepage) (struct page *, unsigned int, unsigned int);
 	int (*releasepage) (struct page *, int);
 	void (*freepage)(struct page *);
-	ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
-			loff_t offset, unsigned long nr_segs);
+	ssize_t (*direct_IO)(int, struct kiocb *, struct iov_iter *iter, loff_t offset);
 	struct page* (*get_xip_page)(struct address_space *, sector_t,
 			int);
 	/* migrate the contents of a page to the specified target */
diff --git a/drivers/staging/lustre/lustre/llite/rw26.c b/drivers/staging/lustre/lustre/llite/rw26.c
index 7e3e0967993..66e05c6f4d2 100644
--- a/drivers/staging/lustre/lustre/llite/rw26.c
+++ b/drivers/staging/lustre/lustre/llite/rw26.c
@@ -363,15 +363,14 @@ static ssize_t ll_direct_IO_26_seg(const struct lu_env *env, struct cl_io *io,
 #define MAX_DIO_SIZE ((MAX_MALLOC / sizeof(struct brw_page) * PAGE_CACHE_SIZE) & \
 		      ~(DT_MAX_BRW_SIZE - 1))
 static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
-			       const struct iovec *iov, loff_t file_offset,
-			       unsigned long nr_segs)
+			       struct iov_iter *iter, loff_t file_offset)
 {
 	struct lu_env *env;
 	struct cl_io *io;
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	struct ccc_object *obj = cl_inode2ccc(inode);
-	long count = iov_length(iov, nr_segs);
+	long count = iov_length(iter->iov, iter->nr_segs);
 	long tot_bytes = 0, result = 0;
 	struct ll_inode_info *lli = ll_i2info(inode);
 	unsigned long seg = 0;
@@ -392,9 +391,9 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
 	       MAX_DIO_SIZE >> PAGE_CACHE_SHIFT);
 
 	/* Check that all user buffers are aligned as well */
-	for (seg = 0; seg < nr_segs; seg++) {
-		if (((unsigned long)iov[seg].iov_base & ~CFS_PAGE_MASK) ||
-		    (iov[seg].iov_len & ~CFS_PAGE_MASK))
+	for (seg = 0; seg < iter->nr_segs; seg++) {
+		if (((unsigned long)iter->iov[seg].iov_base & ~CFS_PAGE_MASK) ||
+		    (iter->iov[seg].iov_len & ~CFS_PAGE_MASK))
 			return -EINVAL;
 	}
 
@@ -411,9 +410,9 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
 		mutex_lock(&inode->i_mutex);
 
 	LASSERT(obj->cob_transient_pages == 0);
-	for (seg = 0; seg < nr_segs; seg++) {
-		long iov_left = iov[seg].iov_len;
-		unsigned long user_addr = (unsigned long)iov[seg].iov_base;
+	for (seg = 0; seg < iter->nr_segs; seg++) {
+		long iov_left = iter->iov[seg].iov_len;
+		unsigned long user_addr = (unsigned long)iter->iov[seg].iov_base;
 
 		if (rw == READ) {
 			if (file_offset >= i_size_read(inode))
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index c71e88602ff..cc1cfae726b 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -259,8 +259,7 @@ static int v9fs_launder_page(struct page *page)
  *
  */
 static ssize_t
-v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
-	       loff_t pos, unsigned long nr_segs)
+v9fs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
 {
 	/*
 	 * FIXME
@@ -269,7 +268,7 @@ v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 	 */
 	p9_debug(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) off/no(%lld/%lu) EINVAL\n",
 		 iocb->ki_filp->f_path.dentry->d_name.name,
-		 (long long)pos, nr_segs);
+		 (long long)pos, iter->nr_segs);
 
 	return -EINVAL;
 }
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 552a8d13bc3..938fc707d76 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -165,14 +165,15 @@ blkdev_get_block(struct inode *inode, sector_t iblock,
 }
 
 static ssize_t
-blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
-			loff_t offset, unsigned long nr_segs)
+blkdev_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
+			loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 
-	return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iov, offset,
-				    nr_segs, blkdev_get_block, NULL, NULL, 0);
+	return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iter->iov,
+				    offset, iter->nr_segs, blkdev_get_block,
+				    NULL, NULL, 0);
 }
 
 int __sync_blockdev(struct block_device *bdev, int wait)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5f805bc944f..30a6cc51f32 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7433,8 +7433,7 @@ out:
 }
 
 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
-			const struct iovec *iov, loff_t offset,
-			unsigned long nr_segs)
+			struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -7444,8 +7443,8 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
 	bool relock = false;
 	ssize_t ret;
 
-	if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iov,
-			    offset, nr_segs))
+	if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iter->iov,
+			    offset, iter->nr_segs))
 		return 0;
 
 	atomic_inc(&inode->i_dio_count);
@@ -7457,7 +7456,7 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
 	 * we need to flush the dirty pages again to make absolutely sure
 	 * that any outstanding dirty pages are on disk.
 	 */
-	count = iov_length(iov, nr_segs);
+	count = iov_length(iter->iov, iter->nr_segs);
 	if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
 		     &BTRFS_I(inode)->runtime_flags))
 		filemap_fdatawrite_range(inode->i_mapping, offset, count);
@@ -7484,7 +7483,8 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
 
 	ret = __blockdev_direct_IO(rw, iocb, inode,
 			BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
-			iov, offset, nr_segs, btrfs_get_blocks_direct, NULL,
+			iter->iov, offset, iter->nr_segs,
+			btrfs_get_blocks_direct, NULL,
 			btrfs_submit_direct, flags);
 	if (rw & WRITE) {
 		if (ret < 0 && ret != -EIOCBQUEUED)
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index b53278c9fd9..342ca5e423f 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1187,8 +1187,8 @@ static int ceph_write_end(struct file *file, struct address_space *mapping,
  * never get called.
  */
 static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
-			      const struct iovec *iov,
-			      loff_t pos, unsigned long nr_segs)
+			      struct iov_iter *iter,
+			      loff_t pos)
 {
 	WARN_ON(1);
 	return -EINVAL;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 2900d150654..a4ccc39e6c1 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3702,8 +3702,8 @@ void cifs_oplock_break(struct work_struct *work)
  * Direct IO is not yet supported in the cached mode. 
  */
 static ssize_t
-cifs_direct_io(int rw, struct kiocb *iocb, const struct iovec *iov,
-               loff_t pos, unsigned long nr_segs)
+cifs_direct_io(int rw, struct kiocb *iocb, struct iov_iter *iter,
+               loff_t pos)
 {
         /*
          * FIXME
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index d1c244d6766..3f9cafd7393 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -964,7 +964,7 @@ static void exofs_invalidatepage(struct page *page, unsigned int offset,
 
  /* TODO: Should be easy enough to do proprly */
 static ssize_t exofs_direct_IO(int rw, struct kiocb *iocb,
-		const struct iovec *iov, loff_t offset, unsigned long nr_segs)
+		struct iov_iter *iter, loff_t offset)
 {
 	return 0;
 }
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index b1d2a4675d4..47fbe760a7f 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -850,18 +850,19 @@ static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
 }
 
 static ssize_t
-ext2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
-			loff_t offset, unsigned long nr_segs)
+ext2_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
+			loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = mapping->host;
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
-				 ext2_get_block);
+	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
+				 iter->nr_segs, ext2_get_block);
 	if (ret < 0 && (rw & WRITE))
-		ext2_write_failed(mapping, offset + iov_length(iov, nr_segs));
+		ext2_write_failed(mapping, offset +
+				  iov_length(iter->iov, iter->nr_segs));
 	return ret;
 }
 
diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index f5157d0d1b4..7a5c501dc31 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1820,8 +1820,7 @@ static int ext3_releasepage(struct page *page, gfp_t wait)
  * VFS code falls back into buffered path in that case so we are safe.
  */
 static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
-			const struct iovec *iov, loff_t offset,
-			unsigned long nr_segs)
+			struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -1829,10 +1828,10 @@ static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
 	handle_t *handle;
 	ssize_t ret;
 	int orphan = 0;
-	size_t count = iov_length(iov, nr_segs);
+	size_t count = iov_length(iter->iov, iter->nr_segs);
 	int retries = 0;
 
-	trace_ext3_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
+	trace_ext3_direct_IO_enter(inode, offset, count, rw);
 
 	if (rw == WRITE) {
 		loff_t final_size = offset + count;
@@ -1856,15 +1855,15 @@ static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
 	}
 
 retry:
-	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
-				 ext3_get_block);
+	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
+				 iter->nr_segs, ext3_get_block);
 	/*
 	 * In case of error extending write may have instantiated a few
 	 * blocks outside i_size. Trim these off again.
 	 */
 	if (unlikely((rw & WRITE) && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iov, nr_segs);
+		loff_t end = offset + count;
 
 		if (end > isize)
 			ext3_truncate_failed_direct_write(inode);
@@ -1909,8 +1908,7 @@ retry:
 			ret = err;
 	}
 out:
-	trace_ext3_direct_IO_exit(inode, offset,
-				iov_length(iov, nr_segs), rw, ret);
+	trace_ext3_direct_IO_exit(inode, offset, count, rw, ret);
 	return ret;
 }
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d7b7462a0e1..f51db730da3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3222,8 +3222,7 @@ retake_lock:
 }
 
 static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
-			      const struct iovec *iov, loff_t offset,
-			      unsigned long nr_segs)
+			      struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -3239,13 +3238,13 @@ static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
 	if (ext4_has_inline_data(inode))
 		return 0;
 
-	trace_ext4_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
+	trace_ext4_direct_IO_enter(inode, offset, iov_length(iter->iov, iter->nr_segs), rw);
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
-		ret = ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
+		ret = ext4_ext_direct_IO(rw, iocb, iter->iov, offset, iter->nr_segs);
 	else
-		ret = ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
+		ret = ext4_ind_direct_IO(rw, iocb, iter->iov, offset, iter->nr_segs);
 	trace_ext4_direct_IO_exit(inode, offset,
-				iov_length(iov, nr_segs), rw, ret);
+				iov_length(iter->iov, iter->nr_segs), rw, ret);
 	return ret;
 }
 
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 45abd60e2bf..3a6ef121c09 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1010,7 +1010,7 @@ static int check_direct_IO(struct inode *inode, int rw,
 }
 
 static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
-		const struct iovec *iov, loff_t offset, unsigned long nr_segs)
+		struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -1019,11 +1019,11 @@ static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
 	if (f2fs_has_inline_data(inode))
 		return 0;
 
-	if (check_direct_IO(inode, rw, iov, offset, nr_segs))
+	if (check_direct_IO(inode, rw, iter->iov, offset, iter->nr_segs))
 		return 0;
 
-	return blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
-							get_data_block);
+	return blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
+				  iter->nr_segs, get_data_block);
 }
 
 static void f2fs_invalidate_data_page(struct page *page, unsigned int offset,
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index b3361fe2bcb..d5237a19905 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -185,8 +185,8 @@ static int fat_write_end(struct file *file, struct address_space *mapping,
 }
 
 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
-			     const struct iovec *iov,
-			     loff_t offset, unsigned long nr_segs)
+			     struct iov_iter *iter,
+			     loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -203,7 +203,7 @@ static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
 		 *
 		 * Return 0, and fallback to normal buffered write.
 		 */
-		loff_t size = offset + iov_length(iov, nr_segs);
+		loff_t size = offset + iov_length(iter->iov, iter->nr_segs);
 		if (MSDOS_I(inode)->mmu_private < size)
 			return 0;
 	}
@@ -212,10 +212,11 @@ static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
 	 * FAT need to use the DIO_LOCKING for avoiding the race
 	 * condition of fat_get_block() and ->truncate().
 	 */
-	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
-				 fat_get_block);
+	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
+				 iter->nr_segs, fat_get_block);
 	if (ret < 0 && (rw & WRITE))
-		fat_write_failed(mapping, offset + iov_length(iov, nr_segs));
+		fat_write_failed(mapping, offset +
+			         iov_length(iter->iov, iter->nr_segs));
 
 	return ret;
 }
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 9c7f346879e..17d96f36df1 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2890,8 +2890,8 @@ static inline loff_t fuse_round_up(loff_t off)
 }
 
 static ssize_t
-fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
-			loff_t offset, unsigned long nr_segs)
+fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
+			loff_t offset)
 {
 	ssize_t ret = 0;
 	struct file *file = iocb->ki_filp;
@@ -2900,7 +2900,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 	loff_t pos = 0;
 	struct inode *inode;
 	loff_t i_size;
-	size_t count = iov_length(iov, nr_segs);
+	size_t count = iov_length(iter->iov, iter->nr_segs);
 	struct fuse_io_priv *io;
 
 	pos = offset;
@@ -2944,9 +2944,9 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 		io->async = false;
 
 	if (rw == WRITE)
-		ret = __fuse_direct_write(io, iov, nr_segs, &pos);
+		ret = __fuse_direct_write(io, iter->iov, iter->nr_segs, &pos);
 	else
-		ret = __fuse_direct_read(io, iov, nr_segs, &pos, count);
+		ret = __fuse_direct_read(io, iter->iov, iter->nr_segs, &pos, count);
 
 	if (io->async) {
 		fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index ce62dcac90b..e84ddaa4210 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -1041,8 +1041,7 @@ static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
 
 
 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
-			      const struct iovec *iov, loff_t offset,
-			      unsigned long nr_segs)
+			      struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -1082,7 +1081,7 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 	 */
 	if (mapping->nrpages) {
 		loff_t lstart = offset & (PAGE_CACHE_SIZE - 1);
-		loff_t len = iov_length(iov, nr_segs);
+		loff_t len = iov_length(iter->iov, iter->nr_segs);
 		loff_t end = PAGE_ALIGN(offset + len) - 1;
 
 		rv = 0;
@@ -1097,9 +1096,9 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 			truncate_inode_pages_range(mapping, lstart, end);
 	}
 
-	rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
-				  offset, nr_segs, gfs2_get_block_direct,
-				  NULL, NULL, 0);
+	rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev,
+				  iter->iov, offset, iter->nr_segs,
+				  gfs2_get_block_direct, NULL, NULL, 0);
 out:
 	gfs2_glock_dq(&gh);
 	gfs2_holder_uninit(&gh);
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 9e2fecd62f6..09cff13528c 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -125,15 +125,15 @@ static int hfs_releasepage(struct page *page, gfp_t mask)
 }
 
 static ssize_t hfs_direct_IO(int rw, struct kiocb *iocb,
-		const struct iovec *iov, loff_t offset, unsigned long nr_segs)
+		struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = file_inode(file)->i_mapping->host;
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
-				 hfs_get_block);
+	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
+				 iter->nr_segs, hfs_get_block);
 
 	/*
 	 * In case of error extending write may have instantiated a few
@@ -141,7 +141,7 @@ static ssize_t hfs_direct_IO(int rw, struct kiocb *iocb,
 	 */
 	if (unlikely((rw & WRITE) && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iov, nr_segs);
+		loff_t end = offset + iov_length(iter->iov, iter->nr_segs);
 
 		if (end > isize)
 			hfs_write_failed(mapping, end);
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index a4f45bd88a6..7f894a5b5ea 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -123,14 +123,14 @@ static int hfsplus_releasepage(struct page *page, gfp_t mask)
 }
 
 static ssize_t hfsplus_direct_IO(int rw, struct kiocb *iocb,
-		const struct iovec *iov, loff_t offset, unsigned long nr_segs)
+		struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = file_inode(file)->i_mapping->host;
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
+	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset, iter->nr_segs,
 				 hfsplus_get_block);
 
 	/*
@@ -139,7 +139,7 @@ static ssize_t hfsplus_direct_IO(int rw, struct kiocb *iocb,
 	 */
 	if (unlikely((rw & WRITE) && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iov, nr_segs);
+		loff_t end = offset + iov_length(iter->iov, iter->nr_segs);
 
 		if (end > isize)
 			hfsplus_write_failed(mapping, end);
diff --git a/fs/jfs/inode.c b/fs/jfs/inode.c
index 6f8fe72c2a7..7052744d510 100644
--- a/fs/jfs/inode.c
+++ b/fs/jfs/inode.c
@@ -331,15 +331,15 @@ static sector_t jfs_bmap(struct address_space *mapping, sector_t block)
 }
 
 static ssize_t jfs_direct_IO(int rw, struct kiocb *iocb,
-	const struct iovec *iov, loff_t offset, unsigned long nr_segs)
+	struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = file->f_mapping->host;
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
-				 jfs_get_block);
+	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
+				 iter->nr_segs, jfs_get_block);
 
 	/*
 	 * In case of error extending write may have instantiated a few
@@ -347,7 +347,7 @@ static ssize_t jfs_direct_IO(int rw, struct kiocb *iocb,
 	 */
 	if (unlikely((rw & WRITE) && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iov, nr_segs);
+		loff_t end = offset + iov_length(iter->iov, iter->nr_segs);
 
 		if (end > isize)
 			jfs_write_failed(mapping, end);
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index b8797ae6831..e9cde393500 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -121,20 +121,20 @@ static inline int put_dreq(struct nfs_direct_req *dreq)
  * shunt off direct read and write requests before the VFS gets them,
  * so this method is only ever called for swap.
  */
-ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs)
+ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
 {
 #ifndef CONFIG_NFS_SWAP
 	dprintk("NFS: nfs_direct_IO (%pD) off/no(%Ld/%lu) EINVAL\n",
-			iocb->ki_filp, (long long) pos, nr_segs);
+			iocb->ki_filp, (long long) pos, iter->nr_segs);
 
 	return -EINVAL;
 #else
 	VM_BUG_ON(iocb->ki_nbytes != PAGE_SIZE);
 
 	if (rw == READ || rw == KERNEL_READ)
-		return nfs_file_direct_read(iocb, iov, nr_segs, pos,
+		return nfs_file_direct_read(iocb, iter->iov, iter->nr_segs, pos,
 				rw == READ ? true : false);
-	return nfs_file_direct_write(iocb, iov, nr_segs, pos,
+	return nfs_file_direct_write(iocb, iter->iov, iter->nr_segs, pos,
 				rw == WRITE ? true : false);
 #endif /* CONFIG_NFS_SWAP */
 }
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index b9c5726120e..1c0e8fedc09 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -298,8 +298,8 @@ static int nilfs_write_end(struct file *file, struct address_space *mapping,
 }
 
 static ssize_t
-nilfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
-		loff_t offset, unsigned long nr_segs)
+nilfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
+		loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -310,8 +310,8 @@ nilfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 		return 0;
 
 	/* Needs synchronization with the cleaner */
-	size = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
-				  nilfs_get_block);
+	size = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
+				  iter->nr_segs, nilfs_get_block);
 
 	/*
 	 * In case of error extending write may have instantiated a few
@@ -319,7 +319,7 @@ nilfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 	 */
 	if (unlikely((rw & WRITE) && size < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iov, nr_segs);
+		loff_t end = offset + iov_length(iter->iov, iter->nr_segs);
 
 		if (end > isize)
 			nilfs_write_failed(mapping, end);
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index d310d12a9ad..799fd0afcb3 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -599,9 +599,8 @@ static int ocfs2_releasepage(struct page *page, gfp_t wait)
 
 static ssize_t ocfs2_direct_IO(int rw,
 			       struct kiocb *iocb,
-			       const struct iovec *iov,
-			       loff_t offset,
-			       unsigned long nr_segs)
+			       struct iov_iter *iter,
+			       loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file)->i_mapping->host;
@@ -618,7 +617,7 @@ static ssize_t ocfs2_direct_IO(int rw,
 		return 0;
 
 	return __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev,
-				    iov, offset, nr_segs,
+				    iter->iov, offset, iter->nr_segs,
 				    ocfs2_direct_IO_get_blocks,
 				    ocfs2_dio_end_io, NULL, 0);
 }
diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index bc8b8009897..17bf4c41a50 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -3083,15 +3083,14 @@ static int reiserfs_releasepage(struct page *page, gfp_t unused_gfp_flags)
 /* We thank Mingming Cao for helping us understand in great detail what
    to do in this section of the code. */
 static ssize_t reiserfs_direct_IO(int rw, struct kiocb *iocb,
-				  const struct iovec *iov, loff_t offset,
-				  unsigned long nr_segs)
+				  struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
-				  reiserfs_get_blocks_direct_io);
+	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
+				 iter->nr_segs, reiserfs_get_blocks_direct_io);
 
 	/*
 	 * In case of error extending write may have instantiated a few
@@ -3099,7 +3098,7 @@ static ssize_t reiserfs_direct_IO(int rw, struct kiocb *iocb,
 	 */
 	if (unlikely((rw & WRITE) && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iov, nr_segs);
+		loff_t end = offset + iov_length(iter->iov, iter->nr_segs);
 
 		if ((end > isize) && inode_newsize_ok(inode, isize) == 0) {
 			truncate_setsize(inode, isize);
diff --git a/fs/udf/file.c b/fs/udf/file.c
index d2c170f8b03..ade88640165 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -119,8 +119,8 @@ static int udf_adinicb_write_end(struct file *file,
 }
 
 static ssize_t udf_adinicb_direct_IO(int rw, struct kiocb *iocb,
-				     const struct iovec *iov,
-				     loff_t offset, unsigned long nr_segs)
+				     struct iov_iter *iter,
+				     loff_t offset)
 {
 	/* Fallback to buffered I/O. */
 	return 0;
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 5d643706212..5b184c7f7dc 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -217,18 +217,18 @@ static int udf_write_begin(struct file *file, struct address_space *mapping,
 }
 
 static ssize_t udf_direct_IO(int rw, struct kiocb *iocb,
-			     const struct iovec *iov,
-			     loff_t offset, unsigned long nr_segs)
+			     struct iov_iter *iter,
+			     loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = mapping->host;
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
+	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset, iter->nr_segs,
 				  udf_get_block);
 	if (unlikely(ret < 0 && (rw & WRITE)))
-		udf_write_failed(mapping, offset + iov_length(iov, nr_segs));
+		udf_write_failed(mapping, offset + iov_length(iter->iov, iter->nr_segs));
 	return ret;
 }
 
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 0479c32c5eb..330d7b1c4be 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1449,9 +1449,8 @@ STATIC ssize_t
 xfs_vm_direct_IO(
 	int			rw,
 	struct kiocb		*iocb,
-	const struct iovec	*iov,
-	loff_t			offset,
-	unsigned long		nr_segs)
+	struct iov_iter		*iter,
+	loff_t			offset)
 {
 	struct inode		*inode = iocb->ki_filp->f_mapping->host;
 	struct block_device	*bdev = xfs_find_bdev_for_inode(inode);
@@ -1459,7 +1458,7 @@ xfs_vm_direct_IO(
 	ssize_t			ret;
 
 	if (rw & WRITE) {
-		size_t size = iov_length(iov, nr_segs);
+		size_t size = iov_length(iter->iov, iter->nr_segs);
 
 		/*
 		 * We cannot preallocate a size update transaction here as we
@@ -1471,16 +1470,16 @@ xfs_vm_direct_IO(
 		if (offset + size > XFS_I(inode)->i_d.di_size)
 			ioend->io_isdirect = 1;
 
-		ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
-					    offset, nr_segs,
+		ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iter->iov,
+					    offset, iter->nr_segs,
 					    xfs_get_blocks_direct,
 					    xfs_end_io_direct_write, NULL,
 					    DIO_ASYNC_EXTEND);
 		if (ret != -EIOCBQUEUED && iocb->private)
 			goto out_destroy_ioend;
 	} else {
-		ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
-					    offset, nr_segs,
+		ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iter->iov,
+					    offset, iter->nr_segs,
 					    xfs_get_blocks_direct,
 					    NULL, NULL, 0);
 	}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 796de742fe4..399a338c92b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -343,8 +343,7 @@ struct address_space_operations {
 	void (*invalidatepage) (struct page *, unsigned int, unsigned int);
 	int (*releasepage) (struct page *, gfp_t);
 	void (*freepage)(struct page *);
-	ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
-			loff_t offset, unsigned long nr_segs);
+	ssize_t (*direct_IO)(int, struct kiocb *, struct iov_iter *iter, loff_t offset);
 	int (*get_xip_mem)(struct address_space *, pgoff_t, int,
 						void **, unsigned long *);
 	/*
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index fa6918b0f82..5a0d78ec739 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -459,8 +459,7 @@ extern int nfs3_removexattr (struct dentry *, const char *name);
 /*
  * linux/fs/nfs/direct.c
  */
-extern ssize_t nfs_direct_IO(int, struct kiocb *, const struct iovec *, loff_t,
-			unsigned long);
+extern ssize_t nfs_direct_IO(int, struct kiocb *, struct iov_iter *, loff_t);
 extern ssize_t nfs_file_direct_read(struct kiocb *iocb,
 			const struct iovec *iov, unsigned long nr_segs,
 			loff_t pos, bool uio);
diff --git a/mm/filemap.c b/mm/filemap.c
index 7c1417b0bd7..139641274f1 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1699,10 +1699,9 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
 		size = i_size_read(inode);
 		retval = filemap_write_and_wait_range(mapping, pos,
 					pos + iov_length(iov, nr_segs) - 1);
-		if (!retval) {
-			retval = mapping->a_ops->direct_IO(READ, iocb,
-							   iov, pos, nr_segs);
-		}
+		if (!retval)
+			retval = mapping->a_ops->direct_IO(READ, iocb, &i, pos);
+
 		if (retval > 0) {
 			*ppos = pos + retval;
 			count -= retval;
@@ -2383,7 +2382,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
 		}
 	}
 
-	written = mapping->a_ops->direct_IO(WRITE, iocb, from->iov, pos, from->nr_segs);
+	written = mapping->a_ops->direct_IO(WRITE, iocb, from, pos);
 
 	/*
 	 * Finally, try again to invalidate clean pages which might have been
diff --git a/mm/page_io.c b/mm/page_io.c
index 7c59ef68138..0ed0644c73d 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -263,16 +263,18 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
 			.iov_base = kmap(page),
 			.iov_len  = PAGE_SIZE,
 		};
+		struct iov_iter from;
 
 		init_sync_kiocb(&kiocb, swap_file);
 		kiocb.ki_pos = page_file_offset(page);
 		kiocb.ki_nbytes = PAGE_SIZE;
+		iov_iter_init(&from, &iov, 1, PAGE_SIZE, 0);
 
 		set_page_writeback(page);
 		unlock_page(page);
 		ret = mapping->a_ops->direct_IO(KERNEL_WRITE,
-						&kiocb, &iov,
-						kiocb.ki_pos, 1);
+						&kiocb, &from,
+						kiocb.ki_pos);
 		kunmap(page);
 		if (ret == PAGE_SIZE) {
 			count_vm_event(PSWPOUT);