CacheFiles: Downgrade the requirements passed to the allocator

Downgrade the requirements passed to the allocator in the gfp flags parameter.
FS-Cache/CacheFiles can handle OOM conditions simply by aborting the attempt to
store an object or a page in the cache.

Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index bd6bc1b..4938251 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -23,6 +23,8 @@
 #define CACHEFILES_DEBUG_KLEAVE	2
 #define CACHEFILES_DEBUG_KDEBUG	4
 
+#define cachefiles_gfp (__GFP_WAIT | __GFP_NORETRY | __GFP_NOMEMALLOC)
+
 /*
  * node records
  */