Introduced by 
5a5f79b57069 ("Btrfs: allow unaligned DIO") and never
used. The buffered fallback from unaligned DIO works as expected.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Timofey Titovets <nefelim4ag@gmail.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
 }
 
 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
-                              struct kiocb *iocb,
                               const struct iov_iter *iter, loff_t offset)
 {
        int seg;
        bool relock = false;
        ssize_t ret;
 
-       if (check_direct_IO(fs_info, iocb, iter, offset))
+       if (check_direct_IO(fs_info, iter, offset))
                return 0;
 
        inode_dio_begin(inode);