btrfs: remove extent_io_ops::readpage_end_io_hook

It's no longer used so let's remove it.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -4638,5 +4638,4 @@ static int btrfs_cleanup_transaction(struct btrfs_fs_info *fs_info)
 static const struct extent_io_ops btree_extent_io_ops = {
 	/* mandatory callbacks */
 	.submit_bio_hook = btree_submit_bio_hook,
-	.readpage_end_io_hook = NULL
 };

fs/btrfs/extent_io.h

@@ -76,13 +76,10 @@ typedef blk_status_t (extent_submit_bio_start_t)(void *private_data,
 
 struct extent_io_ops {
 	/*
-	 * The following callbacks must be always defined, the function
+	 * The following callback must be always defined, the function
 	 * pointer will be called unconditionally.
 	 */
 	submit_bio_hook_t *submit_bio_hook;
-	int (*readpage_end_io_hook)(struct btrfs_io_bio *io_bio, u64 phy_offset,
-				    struct page *page, u64 start, u64 end,
-				    int mirror);
 };
 
 

fs/btrfs/inode.c

@@ -10260,7 +10260,6 @@ static const struct file_operations btrfs_dir_file_operations = {
 static const struct extent_io_ops btrfs_extent_io_ops = {
 	/* mandatory callbacks */
 	.submit_bio_hook = btrfs_submit_bio_hook,
-	.readpage_end_io_hook = NULL
 };
 
 /*