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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-09-13 12:13:58 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-09-13 12:13:58 -0700 |
| commit | 504cb1c25b63ca434e9ced4226c026b54097391d (patch) | |
| tree | 7bdf8c7076ede1dcad22c318948c4312bbedfd0f /include | |
| parent | 7c2c1144164c0a6fd91642909042862db907e053 (diff) | |
| parent | d7127b5e5fa0551be21b86640f1648b224e36d43 (diff) | |
| download | linux-504cb1c25b63ca434e9ced4226c026b54097391d.tar.bz2 | |
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Ingo Molnar:
"Another lockless_dereference() Sparse fix"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/barriers: Don't use sizeof(void) in lockless_dereference()
Diffstat (limited to 'include')
| -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); \ }) |