slub: Add dummy functions for the !SLUB_DEBUG case

On Wed, 25 Aug 2010, Randy Dunlap wrote:
> mm/slub.c:1732: error: implicit declaration of function 'slab_pre_alloc_hook'
> mm/slub.c:1751: error: implicit declaration of function 'slab_post_alloc_hook'
> mm/slub.c:1881: error: implicit declaration of function 'slab_free_hook'
> mm/slub.c:1886: error: implicit declaration of function 'slab_free_hook_irq'

Empty functions are missing if the runtime debuggability option is compiled
out.

Provide the fall back functions to empty hooks if SLUB_DEBUG is not set.
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

mm/slub.c

@@ -1098,6 +1098,18 @@ static inline void inc_slabs_node(struct kmem_cache *s, int node,
 							int objects) {}
 static inline void dec_slabs_node(struct kmem_cache *s, int node,
 							int objects) {}
+
+static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
+							{ return 0; }
+
+static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
+		void *object) {}
+
+static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
+
+static inline void slab_free_hook_irq(struct kmem_cache *s,
+		void *object) {}
+
 #endif
 
 /*