btrfs: drop gfp parameter from alloc_extent_map

pass GFP_NOFS directly to kmem_cache_alloc

Signed-off-by: David Sterba <dsterba@suse.cz>
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 3c8f374..2d04103 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -40,16 +40,15 @@
 
 /**
  * alloc_extent_map - allocate new extent map structure
- * @mask:	memory allocation flags
  *
  * Allocate a new extent_map structure.  The new structure is
  * returned with a reference count of one and needs to be
  * freed using free_extent_map()
  */
-struct extent_map *alloc_extent_map(gfp_t mask)
+struct extent_map *alloc_extent_map(void)
 {
 	struct extent_map *em;
-	em = kmem_cache_alloc(extent_map_cache, mask);
+	em = kmem_cache_alloc(extent_map_cache, GFP_NOFS);
 	if (!em)
 		return NULL;
 	em->in_tree = 0;