btrfs: check NULL or not

Should check if functions returns NULL or not.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index f1d198128959..8b8d3d99ae68 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3075,6 +3075,8 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree,
 #endif
 
         eb = kmem_cache_zalloc(extent_buffer_cache, mask);
+        if (eb == NULL)
+                return NULL;
         eb->start = start;
         eb->len = len;
         spin_lock_init(&eb->lock);