mm, kasan: SLAB support

Add KASAN hooks to SLAB allocator.

This patch is based on the "mm: kasan: unified support for SLUB and SLAB
allocators" patch originally prepared by Dmitry Chernenkov.

Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index ac5143f95ee6..665cd0cd18b8 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -130,4 +130,15 @@ static inline void *virt_to_obj(struct kmem_cache *s,
 void object_err(struct kmem_cache *s, struct page *page,
                 u8 *object, char *reason);
 
+static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
+                                void *x) {
+        void *object = x - (x - page_address(page)) % cache->size;
+        void *last_object = page_address(page) +
+                (page->objects - 1) * cache->size;
+        if (unlikely(object > last_object))
+                return last_object;
+        else
+                return object;
+}
+
 #endif /* _LINUX_SLUB_DEF_H */