mm, slab: Remove silly function slab_buffer_size()

This function is seldom used, and can be simply replaced with cachep->size.
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

include/linux/slab_def.h

@@ -113,17 +113,12 @@ void *__kmalloc(size_t size, gfp_t flags);
 #ifdef CONFIG_TRACING
 extern void *kmem_cache_alloc_trace(size_t size,
 				    struct kmem_cache *cachep, gfp_t flags);
-extern size_t slab_buffer_size(struct kmem_cache *cachep);
 #else
 static __always_inline void *
 kmem_cache_alloc_trace(size_t size, struct kmem_cache *cachep, gfp_t flags)
 {
 	return kmem_cache_alloc(cachep, flags);
 }
-static inline size_t slab_buffer_size(struct kmem_cache *cachep)
-{
-	return 0;
-}
 #endif
 
 static __always_inline void *kmalloc(size_t size, gfp_t flags)

mm/slab.c

@@ -498,14 +498,6 @@ static void **dbg_userword(struct kmem_cache *cachep, void *objp)
 
 #endif
 
-#ifdef CONFIG_TRACING
-size_t slab_buffer_size(struct kmem_cache *cachep)
-{
-	return cachep->size;
-}
-EXPORT_SYMBOL(slab_buffer_size);
-#endif
-
 /*
  * Do not go above this order unless 0 objects fit into the slab or
  * overridden on the command line.
@@ -3850,7 +3842,7 @@ kmem_cache_alloc_trace(size_t size, struct kmem_cache *cachep, gfp_t flags)
 	ret = __cache_alloc(cachep, flags, __builtin_return_address(0));
 
 	trace_kmalloc(_RET_IP_, ret,
-		      size, slab_buffer_size(cachep), flags);
+		      size, cachep->size, flags);
 	return ret;
 }
 EXPORT_SYMBOL(kmem_cache_alloc_trace);
@@ -3881,7 +3873,7 @@ void *kmem_cache_alloc_node_trace(size_t size,
 	ret = __cache_alloc_node(cachep, flags, nodeid,
 				  __builtin_return_address(0));
 	trace_kmalloc_node(_RET_IP_, ret,
-			   size, slab_buffer_size(cachep),
+			   size, cachep->size,
 			   flags, nodeid);
 	return ret;
 }