slab: use slab_post_alloc_hook in SLAB allocator shared with SLUB

Reviewers notice that the order in slab_post_alloc_hook() of
kmemcheck_slab_alloc() and kmemleak_alloc_recursive() gets swapped
compared to slab.c / SLAB allocator.

Also notice memset now occurs before calling kmemcheck_slab_alloc() and
kmemleak_alloc_recursive().

I assume this reordering of kmemcheck, kmemleak and memset is okay
because this is the order they are used by the SLUB allocator.

This patch completes the sharing of alloc_hook's between SLUB and SLAB.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.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: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slab.c

@@ -3176,16 +3176,11 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
   out:
 	local_irq_restore(save_flags);
 	ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
-	kmemleak_alloc_recursive(ptr, cachep->object_size, 1, cachep->flags,
-				 flags);
 
-	if (likely(ptr)) {
-		kmemcheck_slab_alloc(cachep, flags, ptr, cachep->object_size);
-		if (unlikely(flags & __GFP_ZERO))
-			memset(ptr, 0, cachep->object_size);
-	}
+	if (unlikely(flags & __GFP_ZERO) && ptr)
+		memset(ptr, 0, cachep->object_size);
 
-	memcg_kmem_put_cache(cachep);
+	slab_post_alloc_hook(cachep, flags, 1, &ptr);
 	return ptr;
 }
 
@@ -3237,17 +3232,12 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
 	objp = __do_cache_alloc(cachep, flags);
 	local_irq_restore(save_flags);
 	objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
-	kmemleak_alloc_recursive(objp, cachep->object_size, 1, cachep->flags,
-				 flags);
 	prefetchw(objp);
 
-	if (likely(objp)) {
-		kmemcheck_slab_alloc(cachep, flags, objp, cachep->object_size);
-		if (unlikely(flags & __GFP_ZERO))
-			memset(objp, 0, cachep->object_size);
-	}
+	if (unlikely(flags & __GFP_ZERO) && objp)
+		memset(objp, 0, cachep->object_size);
 
-	memcg_kmem_put_cache(cachep);
+	slab_post_alloc_hook(cachep, flags, 1, &objp);
 	return objp;
 }