diff --git a/drivers/staging/lustre/lustre/llite/rw26.c b/drivers/staging/lustre/lustre/llite/rw26.c
index 66e05c6..38a5b58 100644
--- a/drivers/staging/lustre/lustre/llite/rw26.c
+++ b/drivers/staging/lustre/lustre/llite/rw26.c
@@ -370,7 +370,7 @@
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	struct ccc_object *obj = cl_inode2ccc(inode);
-	long count = iov_length(iter->iov, iter->nr_segs);
+	long count = iov_iter_count(iter);
 	long tot_bytes = 0, result = 0;
 	struct ll_inode_info *lli = ll_i2info(inode);
 	unsigned long seg = 0;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 30a6cc5..c46a025 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7456,7 +7456,7 @@
 	 * we need to flush the dirty pages again to make absolutely sure
 	 * that any outstanding dirty pages are on disk.
 	 */
-	count = iov_length(iter->iov, iter->nr_segs);
+	count = iov_iter_count(iter);
 	if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
 		     &BTRFS_I(inode)->runtime_flags))
 		filemap_fdatawrite_range(inode->i_mapping, offset, count);
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 47fbe76..116e809 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -856,13 +856,13 @@
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = mapping->host;
+	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
 	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(iter->iov, iter->nr_segs));
+		ext2_write_failed(mapping, offset + count);
 	return ret;
 }
 
diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index 7a5c501..8582ae2 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1828,7 +1828,7 @@
 	handle_t *handle;
 	ssize_t ret;
 	int orphan = 0;
-	size_t count = iov_length(iter->iov, iter->nr_segs);
+	size_t count = iov_iter_count(iter);
 	int retries = 0;
 
 	trace_ext3_direct_IO_enter(inode, offset, count, rw);
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index eb5ae16..123898a 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -647,7 +647,7 @@
 	handle_t *handle;
 	ssize_t ret;
 	int orphan = 0;
-	size_t count = iov_length(iter->iov, iter->nr_segs);
+	size_t count = iov_iter_count(iter);
 	int retries = 0;
 
 	if (rw == WRITE) {
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 29996c1..2b99357 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3090,7 +3090,7 @@
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	ssize_t ret;
-	size_t count = iov_length(iter->iov, iter->nr_segs);
+	size_t count = iov_iter_count(iter);
 	int overwrite = 0;
 	get_block_t *get_block_func = NULL;
 	int dio_flags = 0;
@@ -3225,6 +3225,7 @@
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
+	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
 	/*
@@ -3237,13 +3238,12 @@
 	if (ext4_has_inline_data(inode))
 		return 0;
 
-	trace_ext4_direct_IO_enter(inode, offset, iov_length(iter->iov, iter->nr_segs), rw);
+	trace_ext4_direct_IO_enter(inode, offset, count, rw);
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 		ret = ext4_ext_direct_IO(rw, iocb, iter, offset);
 	else
 		ret = ext4_ind_direct_IO(rw, iocb, iter, offset);
-	trace_ext4_direct_IO_exit(inode, offset,
-				iov_length(iter->iov, iter->nr_segs), rw, ret);
+	trace_ext4_direct_IO_exit(inode, offset, count, rw, ret);
 	return ret;
 }
 
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index d5237a1..154a6f9 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -191,6 +191,7 @@
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = mapping->host;
+	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
 	if (rw == WRITE) {
@@ -203,7 +204,7 @@
 		 *
 		 * Return 0, and fallback to normal buffered write.
 		 */
-		loff_t size = offset + iov_length(iter->iov, iter->nr_segs);
+		loff_t size = offset + count;
 		if (MSDOS_I(inode)->mmu_private < size)
 			return 0;
 	}
@@ -215,8 +216,7 @@
 	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(iter->iov, iter->nr_segs));
+		fat_write_failed(mapping, offset + count);
 
 	return ret;
 }
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 17d96f3..36f15f9 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2900,7 +2900,7 @@
 	loff_t pos = 0;
 	struct inode *inode;
 	loff_t i_size;
-	size_t count = iov_length(iter->iov, iter->nr_segs);
+	size_t count = iov_iter_count(iter);
 	struct fuse_io_priv *io;
 
 	pos = offset;
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index e84ddaa..228a12d 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -1081,7 +1081,7 @@
 	 */
 	if (mapping->nrpages) {
 		loff_t lstart = offset & (PAGE_CACHE_SIZE - 1);
-		loff_t len = iov_length(iter->iov, iter->nr_segs);
+		loff_t len = iov_iter_count(iter);
 		loff_t end = PAGE_ALIGN(offset + len) - 1;
 
 		rv = 0;
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 09cff13..dc69e8f 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -130,6 +130,7 @@
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = file_inode(file)->i_mapping->host;
+	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
 	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
@@ -141,7 +142,7 @@
 	 */
 	if (unlikely((rw & WRITE) && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iter->iov, iter->nr_segs);
+		loff_t end = offset + count;
 
 		if (end > isize)
 			hfs_write_failed(mapping, end);
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index 7f894a5..e6b1251 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -128,6 +128,7 @@
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = file_inode(file)->i_mapping->host;
+	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
 	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset, iter->nr_segs,
@@ -139,7 +140,7 @@
 	 */
 	if (unlikely((rw & WRITE) && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iter->iov, iter->nr_segs);
+		loff_t end = offset + count;
 
 		if (end > isize)
 			hfsplus_write_failed(mapping, end);
diff --git a/fs/jfs/inode.c b/fs/jfs/inode.c
index 7052744..6cde592 100644
--- a/fs/jfs/inode.c
+++ b/fs/jfs/inode.c
@@ -336,6 +336,7 @@
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = file->f_mapping->host;
+	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
 	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
@@ -347,7 +348,7 @@
 	 */
 	if (unlikely((rw & WRITE) && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iter->iov, iter->nr_segs);
+		loff_t end = offset + count;
 
 		if (end > isize)
 			jfs_write_failed(mapping, end);
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 2172314..1d34f45 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -486,9 +486,7 @@
 	struct nfs_direct_req *dreq;
 	struct nfs_lock_context *l_ctx;
 	ssize_t result = -EINVAL;
-	size_t count;
-
-	count = iov_length(iter->iov, iter->nr_segs);
+	size_t count = iov_iter_count(iter);
 	nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);
 
 	dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n",
@@ -877,7 +875,7 @@
 	get_dreq(dreq);
 	atomic_inc(&inode->i_dio_count);
 
-	NFS_I(dreq->inode)->write_io += iov_length(iter->iov, iter->nr_segs);
+	NFS_I(dreq->inode)->write_io += iov_iter_count(iter);
 	for (seg = 0; seg < iter->nr_segs; seg++) {
 		const struct iovec *vec = &iter->iov[seg];
 		result = nfs_direct_write_schedule_segment(&desc, vec, pos, uio);
@@ -936,9 +934,7 @@
 	struct nfs_direct_req *dreq;
 	struct nfs_lock_context *l_ctx;
 	loff_t end;
-	size_t count;
-
-	count = iov_length(iter->iov, iter->nr_segs);
+	size_t count = iov_iter_count(iter);
 	end = (pos + count - 1) >> PAGE_CACHE_SHIFT;
 
 	nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count);
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 1c0e8fe..7aaf913 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -304,6 +304,7 @@
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = file->f_mapping->host;
+	size_t count = iov_iter_count(iter);
 	ssize_t size;
 
 	if (rw == WRITE)
@@ -319,7 +320,7 @@
 	 */
 	if (unlikely((rw & WRITE) && size < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iter->iov, iter->nr_segs);
+		loff_t end = offset + count;
 
 		if (end > isize)
 			nilfs_write_failed(mapping, end);
diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index 17bf4c4..723affe 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -3087,6 +3087,7 @@
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
+	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
 	ret = blockdev_direct_IO(rw, iocb, inode, iter->iov, offset,
@@ -3098,7 +3099,7 @@
 	 */
 	if (unlikely((rw & WRITE) && ret < 0)) {
 		loff_t isize = i_size_read(inode);
-		loff_t end = offset + iov_length(iter->iov, iter->nr_segs);
+		loff_t end = offset + count;
 
 		if ((end > isize) && inode_newsize_ok(inode, isize) == 0) {
 			truncate_setsize(inode, isize);
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 5b184c7..28984ba 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -223,12 +223,13 @@
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = mapping->host;
+	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
 	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(iter->iov, iter->nr_segs));
+		udf_write_failed(mapping, offset + count);
 	return ret;
 }
 
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 330d7b1..6462b31 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1458,7 +1458,7 @@
 	ssize_t			ret;
 
 	if (rw & WRITE) {
-		size_t size = iov_length(iter->iov, iter->nr_segs);
+		size_t size = iov_iter_count(iter);
 
 		/*
 		 * We cannot preallocate a size update transaction here as we
diff --git a/mm/filemap.c b/mm/filemap.c
index 1396412..70c048e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1698,7 +1698,7 @@
 			goto out; /* skip atime */
 		size = i_size_read(inode);
 		retval = filemap_write_and_wait_range(mapping, pos,
-					pos + iov_length(iov, nr_segs) - 1);
+					pos + count - 1);
 		if (!retval)
 			retval = mapping->a_ops->direct_IO(READ, iocb, &i, pos);