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atomics: Remove redundant barrier()'s

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Remove the redundant barrier() after the fence as agreed in previous
discussion here:
https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg00489.html

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Message-Id: <20160824204424.14041-3-bobby.prani@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Pranith Kumar 2016-08-24 16:44:23 -04:00 committed by Paolo Bonzini
parent c2cd627ddb
commit 705ac1ca53
1 changed files with 4 additions and 4 deletions
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8
include/qemu/atomic.h
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@ -72,16 +72,16 @@
* Add one here, and similarly in smp_rmb() and smp_read_barrier_depends(). * Add one here, and similarly in smp_rmb() and smp_read_barrier_depends().
*/ */
#define smp_mb() ({ barrier(); __atomic_thread_fence(__ATOMIC_SEQ_CST); barrier(); }) #define smp_mb() ({ barrier(); __atomic_thread_fence(__ATOMIC_SEQ_CST); })
#define smp_wmb() ({ barrier(); __atomic_thread_fence(__ATOMIC_RELEASE); barrier(); }) #define smp_wmb() ({ barrier(); __atomic_thread_fence(__ATOMIC_RELEASE); })
#define smp_rmb() ({ barrier(); __atomic_thread_fence(__ATOMIC_ACQUIRE); barrier(); }) #define smp_rmb() ({ barrier(); __atomic_thread_fence(__ATOMIC_ACQUIRE); })
/* Most compilers currently treat consume and acquire the same, but really /* Most compilers currently treat consume and acquire the same, but really
* no processors except Alpha need a barrier here. Leave it in if * no processors except Alpha need a barrier here. Leave it in if
* using Thread Sanitizer to avoid warnings, otherwise optimize it away. * using Thread Sanitizer to avoid warnings, otherwise optimize it away.
*/ */
#if defined(__SANITIZE_THREAD__) #if defined(__SANITIZE_THREAD__)
#define smp_read_barrier_depends() ({ barrier(); __atomic_thread_fence(__ATOMIC_CONSUME); barrier(); }) #define smp_read_barrier_depends() ({ barrier(); __atomic_thread_fence(__ATOMIC_CONSUME); })
#elsif defined(__alpha__) #elsif defined(__alpha__)
#define smp_read_barrier_depends() asm volatile("mb":::"memory") #define smp_read_barrier_depends() asm volatile("mb":::"memory")
#else #else