slub: fix ksize() build error

mm/slub.c: In function 'ksize':
mm/slub.c:2728: error: implicit declaration of function 'slab_ksize'

slab_ksize() needs to go out of CONFIG_SLUB_DEBUG section.
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Mariusz Kozlowski <mk@lab.zgora.pl>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

mm/slub.c

@@ -281,6 +281,30 @@ static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
 	return (p - addr) / s->size;
 }
 
+static inline size_t slab_ksize(const struct kmem_cache *s)
+{
+#ifdef CONFIG_SLUB_DEBUG
+	/*
+	 * Debugging requires use of the padding between object
+	 * and whatever may come after it.
+	 */
+	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
+		return s->objsize;
+
+#endif
+	/*
+	 * If we have the need to store the freelist pointer
+	 * back there or track user information then we can
+	 * only use the space before that information.
+	 */
+	if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
+		return s->inuse;
+	/*
+	 * Else we can use all the padding etc for the allocation
+	 */
+	return s->size;
+}
+
 static inline struct kmem_cache_order_objects oo_make(int order,
 						unsigned long size)
 {
@@ -797,30 +821,6 @@ static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
 	return should_failslab(s->objsize, flags, s->flags);
 }
 
-static inline size_t slab_ksize(const struct kmem_cache *s)
-{
-#ifdef CONFIG_SLUB_DEBUG
-	/*
-	 * Debugging requires use of the padding between object
-	 * and whatever may come after it.
-	 */
-	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
-		return s->objsize;
-
-#endif
-	/*
-	 * If we have the need to store the freelist pointer
-	 * back there or track user information then we can
-	 * only use the space before that information.
-	 */
-	if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
-		return s->inuse;
-	/*
-	 * Else we can use all the padding etc for the allocation
-	 */
-	return s->size;
-}
-
 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
 {
 	flags &= gfp_allowed_mask;