Btrfs: check return value of alloc_extent_map()

I add the check on the return value of alloc_extent_map() to several places.
In addition, alloc_extent_map() returns only the address or NULL.
Therefore, check by IS_ERR() is unnecessary. So, I remove IS_ERR() checking.

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

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index b0e1fce12530..2b6c12e983b3 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -51,8 +51,8 @@ struct extent_map *alloc_extent_map(gfp_t mask)
 {
         struct extent_map *em;
         em = kmem_cache_alloc(extent_map_cache, mask);
-        if (!em || IS_ERR(em))
-                return em;
+        if (!em)
+                return NULL;
         em->in_tree = 0;
         em->flags = 0;
         em->compress_type = BTRFS_COMPRESS_NONE;