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| author | Peter Zijlstra <peterz@infradead.org> | 2017-06-09 13:05:06 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-08-10 12:28:54 +0200 |
| commit | 9d664c0aec3bfdb77fcf7de61cfe1febbecdd389 (patch) | |
| tree | 58c96472de25e0ebcbf2f47b7a53d262edcb3e94 /arch/parisc | |
| parent | sched/wait: Remove the lockless swait_active() check in swake_up*() (diff) | |
| download | linux-9d664c0aec3bfdb77fcf7de61cfe1febbecdd389.tar.xz linux-9d664c0aec3bfdb77fcf7de61cfe1febbecdd389.zip | |
locking/atomic: Fix atomic_set_release() for 'funny' architectures
Those architectures that have a special atomic_set implementation also
need a special atomic_set_release(), because for the very same reason
WRITE_ONCE() is broken for them, smp_store_release() is too.
The vast majority is architectures that have spinlock hash based atomic
implementation except hexagon which seems to have a hardware 'feature'.
The spinlock based atomics should be SC, that is, none of them appear to
place extra barriers in atomic_cmpxchg() or any of the other SC atomic
primitives and therefore seem to rely on their spinlock implementation
being SC (I did not fully validate all that).
Therefore, the normal atomic_set() is SC and can be used at
atomic_set_release().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Chris Metcalf <cmetcalf@mellanox.com> [for tile]
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: davem@davemloft.net
Cc: james.hogan@imgtec.com
Cc: jejb@parisc-linux.org
Cc: rkuo@codeaurora.org
Cc: vgupta@synopsys.com
Link: http://lkml.kernel.org/r/20170609110506.yod47flaav3wgoj5@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/parisc')
| -rw-r--r-- | arch/parisc/include/asm/atomic.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/parisc/include/asm/atomic.h b/arch/parisc/include/asm/atomic.h index 5394b9c5f914..17b98a87e5e2 100644 --- a/arch/parisc/include/asm/atomic.h +++ b/arch/parisc/include/asm/atomic.h @@ -65,6 +65,8 @@ static __inline__ void atomic_set(atomic_t *v, int i) _atomic_spin_unlock_irqrestore(v, flags); } +#define atomic_set_release(v, i) atomic_set((v), (i)) + static __inline__ int atomic_read(const atomic_t *v) { return READ_ONCE((v)->counter); |