Commit c48981ee authored by Marco Elver's avatar Marco Elver Committed by Paul E. McKenney
Browse files

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: default avatarMarco 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: default avatarPaul E. McKenney <paulmck@kernel.org>
parent dfd402a4

include/linux/compiler.h

+20 −0
Original line number Diff line number Diff line
@@ -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__ */



/*