aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/compiler.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/linux/compiler.h')
-rw-r--r--include/linux/compiler.h7
1 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 1bb954842725..668569844d37 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -527,13 +527,14 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
527 * object's lifetime is managed by something other than RCU. That 527 * object's lifetime is managed by something other than RCU. That
528 * "something other" might be reference counting or simple immortality. 528 * "something other" might be reference counting or simple immortality.
529 * 529 *
530 * The seemingly unused void * variable is to validate @p is indeed a pointer 530 * The seemingly unused variable ___typecheck_p validates that @p is
531 * type. All pointer types silently cast to void *. 531 * indeed a pointer type by using a pointer to typeof(*p) as the type.
532 * Taking a pointer to typeof(*p) again is needed in case p is void *.
532 */ 533 */
533#define lockless_dereference(p) \ 534#define lockless_dereference(p) \
534({ \ 535({ \
535 typeof(p) _________p1 = READ_ONCE(p); \ 536 typeof(p) _________p1 = READ_ONCE(p); \
536 __maybe_unused const void * const _________p2 = _________p1; \ 537 typeof(*(p)) *___typecheck_p __maybe_unused; \
537 smp_read_barrier_depends(); /* Dependency order vs. p above. */ \ 538 smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
538 (_________p1); \ 539 (_________p1); \
539}) 540})