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| author | Peter Zijlstra <peterz@infradead.org> | 2017-06-09 14:05:06 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-08-10 13:28:54 +0300 |
| commit | 9d664c0aec3bfdb77fcf7de61cfe1febbecdd389 (patch) | |
| tree | 58c96472de25e0ebcbf2f47b7a53d262edcb3e94 /arch/sparc | |
| parent | 35a2897c2a306cca344ca5c0b43416707018f434 (diff) | |
| download | linux-9d664c0aec3bfdb77fcf7de61cfe1febbecdd389.tar.xz | |
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/sparc')
| -rw-r--r-- | arch/sparc/include/asm/atomic_32.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/sparc/include/asm/atomic_32.h b/arch/sparc/include/asm/atomic_32.h index ee3f11c43cda..7643e979e333 100644 --- a/arch/sparc/include/asm/atomic_32.h +++ b/arch/sparc/include/asm/atomic_32.h @@ -29,6 +29,8 @@ int atomic_xchg(atomic_t *, int); int __atomic_add_unless(atomic_t *, int, int); void atomic_set(atomic_t *, int); +#define atomic_set_release(v, i) atomic_set((v), (i)) + #define atomic_read(v) ACCESS_ONCE((v)->counter) #define atomic_add(i, v) ((void)atomic_add_return( (int)(i), (v))) |