ext4: switch the guts of ->direct_IO() to iov_iter

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

fs/ext4/ext4.h

@@ -2150,8 +2150,7 @@ extern void ext4_da_update_reserve_space(struct inode *inode,
 extern int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
 				struct ext4_map_blocks *map, int flags);
 extern ssize_t ext4_ind_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);
 extern int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock);
 extern int ext4_ind_trans_blocks(struct inode *inode, int nrblocks);
 extern void ext4_ind_truncate(handle_t *, struct inode *inode);

fs/ext4/indirect.c

@@ -639,8 +639,7 @@ int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
  * VFS code falls back into buffered path in that case so we are safe.
  */
 ssize_t ext4_ind_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;
@@ -648,7 +647,7 @@ ssize_t ext4_ind_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;
 
 	if (rw == WRITE) {
@@ -687,18 +686,18 @@ ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
 			goto locked;
 		}
 		ret = __blockdev_direct_IO(rw, iocb, inode,
-				 inode->i_sb->s_bdev, iov,
-				 offset, nr_segs,
+				 inode->i_sb->s_bdev, iter->iov,
+				 offset, iter->nr_segs,
 				 ext4_get_block, NULL, NULL, 0);
 		inode_dio_done(inode);
 	} else {
 locked:
-		ret = blockdev_direct_IO(rw, iocb, inode, iov,
-				 offset, nr_segs, ext4_get_block);
+		ret = blockdev_direct_IO(rw, iocb, inode, iter->iov,
+				 offset, iter->nr_segs, ext4_get_block);
 
 		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)
 				ext4_truncate_failed_write(inode);

fs/ext4/inode.c

@@ -3085,13 +3085,12 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
  *
  */
 static ssize_t ext4_ext_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;
-	size_t count = iov_length(iov, nr_segs);
+	size_t count = iov_length(iter->iov, iter->nr_segs);
 	int overwrite = 0;
 	get_block_t *get_block_func = NULL;
 	int dio_flags = 0;
@@ -3100,7 +3099,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 
 	/* Use the old path for reads and writes beyond i_size. */
 	if (rw != WRITE || final_size > inode->i_size)
-		return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
+		return ext4_ind_direct_IO(rw, iocb, iter, offset);
 
 	BUG_ON(iocb->private == NULL);
 
@@ -3167,8 +3166,8 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 		dio_flags = DIO_LOCKING;
 	}
 	ret = __blockdev_direct_IO(rw, iocb, inode,
-				   inode->i_sb->s_bdev, iov,
-				   offset, nr_segs,
+				   inode->i_sb->s_bdev, iter->iov,
+				   offset, iter->nr_segs,
 				   get_block_func,
 				   ext4_end_io_dio,
 				   NULL,
@@ -3240,9 +3239,9 @@ static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
 
 	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, iter->iov, offset, iter->nr_segs);
+		ret = ext4_ext_direct_IO(rw, iocb, iter, offset);
 	else
-		ret = ext4_ind_direct_IO(rw, iocb, iter->iov, offset, iter->nr_segs);
+		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);
 	return ret;