Merge remote-tracking branch 'tip/auto-latest'

[deliverable/linux.git] / include / linux / compiler.h

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 0e0faff63bd2d7e98c5a0eead16f2aa445d9afd3..cf0fa5d86059b6672773025b625027f6301074c1 100644 (file)
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -554,13 +554,14 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
  * object's lifetime is managed by something other than RCU.  That
  * "something other" might be reference counting or simple immortality.
  *
- * The seemingly unused size_t variable is to validate @p is indeed a pointer
- * type by making sure it can be dereferenced.
+ * The seemingly unused variable ___typecheck_p validates that @p is
+ * indeed a pointer type by using a pointer to typeof(*p) as the type.
+ * Taking a pointer to typeof(*p) again is needed in case p is void *.
  */
 #define lockless_dereference(p) \
 ({ \
        typeof(p) _________p1 = READ_ONCE(p); \
-       size_t __maybe_unused __size_of_ptr = sizeof(*(p)); \
+       typeof(*(p)) *___typecheck_p __maybe_unused; \
        smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
        (_________p1); \
 })