Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

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

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 86130cd..f1bfa15 100644 (file)
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -550,13 +550,14 @@ 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.
  *
  * object's lifetime is managed by something other than RCU.  That
  * "something other" might be reference counting or simple immortality.
  *

- * The seemingly unused void * variable is to validate @p is indeed a pointer
- * type. All pointer types silently cast to void *.
+ * 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); \
  */
 #define lockless_dereference(p) \
 ({ \
        typeof(p) _________p1 = READ_ONCE(p); \

-       __maybe_unused const void * const _________p2 = _________p1; \
+       typeof(*(p)) *___typecheck_p __maybe_unused; \

        smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
        (_________p1); \
 })
        smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
        (_________p1); \
 })