diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2015-09-18 13:22:52 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-09-23 09:54:29 +0200 |
| commit | e3e72ab80a3fac0b88e07d358a2c75724ccd66b4 (patch) | |
| tree | 3cc1b2f6fbe8ca8d3649d95d14f7c093cea11480 /include/asm-generic | |
| parent | 62e8a3258bda118f24ff462fe04cfbe75b8189b5 (diff) | |
atomic: Implement atomic_read_ctrl()
Provide atomic_read_ctrl() to mirror READ_ONCE_CTRL(), such that we can
more conveniently use atomics in control dependencies.
Since we can assume atomic_read() implies a READ_ONCE(), we must only
emit an extra smp_read_barrier_depends() in order to upgrade to
READ_ONCE_CTRL() semantics.
Requested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/20150918115637.GM3604@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/atomic-long.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/asm-generic/atomic-long.h b/include/asm-generic/atomic-long.h index c7a5c1ad2ed3..8942cdc676a7 100644 --- a/include/asm-generic/atomic-long.h +++ b/include/asm-generic/atomic-long.h @@ -35,7 +35,7 @@ typedef atomic_t atomic_long_t; #endif #define ATOMIC_LONG_READ_OP(mo) \ -static inline long atomic_long_read##mo(atomic_long_t *l) \ +static inline long atomic_long_read##mo(const atomic_long_t *l) \ { \ ATOMIC_LONG_PFX(_t) *v = (ATOMIC_LONG_PFX(_t) *)l; \ \ @@ -43,6 +43,7 @@ static inline long atomic_long_read##mo(atomic_long_t *l) \ } ATOMIC_LONG_READ_OP() ATOMIC_LONG_READ_OP(_acquire) +ATOMIC_LONG_READ_OP(_ctrl) #undef ATOMIC_LONG_READ_OP |