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| author | Marco Elver <elver@google.com> | 2019-11-14 19:02:55 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2019-11-16 07:23:13 -0800 |
| commit | c48981eeb0d56e107691df590007d6699441a689 (patch) | |
| tree | 1989c9076376899b35e10a430845aea992234f43 /include/linux/compiler.h | |
| parent | dfd402a4c4baae42398ce9180ff424d589b8bffc (diff) | |
| download | lwn-c48981eeb0d56e107691df590007d6699441a689.tar.gz lwn-c48981eeb0d56e107691df590007d6699441a689.zip | |
include/linux/compiler.h: Introduce data_race(expr) macro
This introduces the data_race(expr) macro, which can be used to annotate
expressions for purposes of (1) documenting, and (2) giving tooling such
as KCSAN information about which data races are deemed "safe".
More context:
http://lkml.kernel.org/r/CAHk-=wg5CkOEF8DTez1Qu0XTEFw_oHhxN98bDnFqbY7HL5AB2g@mail.gmail.com
Signed-off-by: Marco Elver <elver@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'include/linux/compiler.h')
| -rw-r--r-- | include/linux/compiler.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index c42fa83f23fb..7d3e77781578 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -310,6 +310,26 @@ unsigned long read_word_at_a_time(const void *addr) __u.__val; \ }) +#include <linux/kcsan.h> + +/* + * data_race: macro to document that accesses in an expression may conflict with + * other concurrent accesses resulting in data races, but the resulting + * behaviour is deemed safe regardless. + * + * This macro *does not* affect normal code generation, but is a hint to tooling + * that data races here should be ignored. + */ +#define data_race(expr) \ + ({ \ + typeof(({ expr; })) __val; \ + kcsan_nestable_atomic_begin(); \ + __val = ({ expr; }); \ + kcsan_nestable_atomic_end(); \ + __val; \ + }) +#else + #endif /* __KERNEL__ */ /* |