btrfs: make btrfs_file_extent_inline_item_len take a slot

Instead of getting the btrfs_item for this, simply pass in the slot of
the item and then use the btrfs_item_size_nr() helper inside of
btrfs_file_extent_inline_item_len().
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -2534,9 +2534,9 @@ BTRFS_SETGET_FUNCS(file_extent_other_encoding, struct btrfs_file_extent_item,
  */
 static inline u32 btrfs_file_extent_inline_item_len(
 						const struct extent_buffer *eb,
-						struct btrfs_item *e)
+						int nr)
 {
-	return btrfs_item_size(eb, e) - BTRFS_FILE_EXTENT_INLINE_DATA_START;
+	return btrfs_item_size_nr(eb, nr) - BTRFS_FILE_EXTENT_INLINE_DATA_START;
 }
 
 /* btrfs_qgroup_status_item */

fs/btrfs/inode.c

@@ -6996,8 +6996,7 @@ static noinline int uncompress_inline(struct btrfs_path *path,
 	WARN_ON(pg_offset != 0);
 	compress_type = btrfs_file_extent_compression(leaf, item);
 	max_size = btrfs_file_extent_ram_bytes(leaf, item);
-	inline_size = btrfs_file_extent_inline_item_len(leaf,
-					btrfs_item_nr(path->slots[0]));
+	inline_size = btrfs_file_extent_inline_item_len(leaf, path->slots[0]);
 	tmp = kmalloc(inline_size, GFP_NOFS);
 	if (!tmp)
 		return -ENOMEM;