[PATCH 1/5] btrfs: extent_io: Add comment about the return value of alloc_extent_buffer()

[Qu Wenruo <wqu@suse.com>]

To inform later developers how to check the return value of it.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/extent_io.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 52abe4082680..b28a75546700 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4890,6 +4890,13 @@ struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
 }
 #endif
 
+/*
+ * Allocate an extent buffer structure, with all its pages attached and locked.
+ *
+ * Return valid pointer if nothing goes wrong.
+ * Return PTR_ERR() if failed.
+ * Will never return NULL.
+ */
 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 					  u64 start)
 {
-- 
2.20.1