From d8843922fba49e887874aa1f9e748d620c5092af Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Wed, 17 Oct 2012 15:36:51 +0400 Subject: slab: Ignore internal flags in cache creation Some flags are used internally by the allocators for management purposes. One example of that is the CFLGS_OFF_SLAB flag that slab uses to mark that the metadata for that cache is stored outside of the slab. No cache should ever pass those as a creation flags. We can just ignore this bit if it happens to be passed (such as when duplicating a cache in the kmem memcg patches). Because such flags can vary from allocator to allocator, we allow them to make their own decisions on that, defining SLAB_AVAILABLE_FLAGS with all flags that are valid at creation time. Allocators that doesn't have any specific flag requirement should define that to mean all flags. Common code will mask out all flags not belonging to that set. Acked-by: Christoph Lameter Acked-by: David Rientjes Signed-off-by: Glauber Costa Signed-off-by: Pekka Enberg --- mm/slab_common.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'mm/slab_common.c') diff --git a/mm/slab_common.c b/mm/slab_common.c index 5fb753da6cf..b705be7faa4 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -109,6 +109,13 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align if (!kmem_cache_sanity_check(name, size) == 0) goto out_locked; + /* + * Some allocators will constraint the set of valid flags to a subset + * of all flags. We expect them to define CACHE_CREATE_MASK in this + * case, and we'll just provide them with a sanitized version of the + * passed flags. + */ + flags &= CACHE_CREATE_MASK; s = __kmem_cache_alias(name, size, align, flags, ctor); if (s) -- cgit v1.2.3