fs: introduce __getname_gfp()

The purpose of this change is to allow __getname() users to pass a
custom GFP mask to kmem_cache_alloc(). This is needed for annotating
a certain kmemcheck false positive.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

include/linux/fs.h

@@ -1919,8 +1919,9 @@ extern void __init vfs_caches_init(unsigned long);
 
 extern struct kmem_cache *names_cachep;
 
-#define __getname()	kmem_cache_alloc(names_cachep, GFP_KERNEL)
-#define __putname(name) kmem_cache_free(names_cachep, (void *)(name))
+#define __getname_gfp(gfp)	kmem_cache_alloc(names_cachep, (gfp))
+#define __getname()		__getname_gfp(GFP_KERNEL)
+#define __putname(name)		kmem_cache_free(names_cachep, (void *)(name))
 #ifndef CONFIG_AUDITSYSCALL
 #define putname(name)   __putname(name)
 #else