SLUB: Replace __builtin_return_address(0) with _RET_IP_.

This patch replaces __builtin_return_address(0) with _RET_IP_, since a
previous patch moved _RET_IP_ and _THIS_IP_ to include/linux/kernel.h and
they're widely available now. This makes for shorter and easier to read
code.

[penberg@cs.helsinki.fi: remove _RET_IP_ casts to void pointer]
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 000da12..c97ed28 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -253,9 +253,9 @@
  * request comes from.
  */
 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
-extern void *__kmalloc_track_caller(size_t, gfp_t, void*);
+extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
 #define kmalloc_track_caller(size, flags) \
-	__kmalloc_track_caller(size, flags, __builtin_return_address(0))
+	__kmalloc_track_caller(size, flags, _RET_IP_)
 #else
 #define kmalloc_track_caller(size, flags) \
 	__kmalloc(size, flags)
@@ -271,10 +271,10 @@
  * allocation request comes from.
  */
 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
-extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, void *);
+extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
 #define kmalloc_node_track_caller(size, flags, node) \
 	__kmalloc_node_track_caller(size, flags, node, \
-			__builtin_return_address(0))
+			_RET_IP_)
 #else
 #define kmalloc_node_track_caller(size, flags, node) \
 	__kmalloc_node(size, flags, node)