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| author |   David S. Miller <davem@davemloft.net> | 2016-09-23 06:46:57 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-09-23 06:46:57 -0400 |
| commit | d6989d4bbe6c4d1c2a76696833a07f044e85694d (patch) | |
| tree | 2d9a70d0feee4d4a20568be1b39a961fa0d27d81 /include/linux/compiler.h | |
| parent | xen-netback: switch to threaded irq for control ring (diff) | |
| parent | Merge tag 'media/v4.8-7' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media (diff) | |
| download | linux-dev-d6989d4bbe6c4d1c2a76696833a07f044e85694d.tar.xz linux-dev-d6989d4bbe6c4d1c2a76696833a07f044e85694d.zip | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Diffstat (limited to 'include/linux/compiler.h')
| -rw-r--r-- | include/linux/compiler.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 436aa4e42221..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 * 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); \ }) |