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| author | Paolo Bonzini <pbonzini@redhat.com> | 2023-03-03 14:37:51 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-06-06 09:42:14 +0200 |
| commit | 06831001ac8949b0801e0d20c347d97339769a20 (patch) | |
| tree | 01c418078a78ff8049bf5eb7bc36cf3e3bddcb14 /util | |
| parent | 09a49afeae2542993d4cdc5d7af22abdfce7a3ba (diff) | |
| download | qemu-06831001ac8949b0801e0d20c347d97339769a20.zip qemu-06831001ac8949b0801e0d20c347d97339769a20.tar.gz qemu-06831001ac8949b0801e0d20c347d97339769a20.tar.bz2 | |
atomics: eliminate mb_read/mb_set
qatomic_mb_read and qatomic_mb_set were the very first atomic primitives
introduced for QEMU; their semantics are unclear and they provide a false
sense of safety.
The last use of qatomic_mb_read() has been removed, so delete it.
qatomic_mb_set() instead can survive as an optimized
qatomic_set()+smp_mb(), similar to Linux's smp_store_mb(), but
rename it to qatomic_set_mb() to match the order of the two
operations.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'util')
| -rw-r--r-- | util/qemu-coroutine-lock.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c index 84a50a9..2534435 100644 --- a/util/qemu-coroutine-lock.c +++ b/util/qemu-coroutine-lock.c @@ -202,7 +202,7 @@ static void coroutine_fn qemu_co_mutex_lock_slowpath(AioContext *ctx, push_waiter(mutex, &w); /* - * Add waiter before reading mutex->handoff. Pairs with qatomic_mb_set + * Add waiter before reading mutex->handoff. Pairs with qatomic_set_mb * in qemu_co_mutex_unlock. */ smp_mb__after_rmw(); @@ -310,7 +310,7 @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex) our_handoff = mutex->sequence; /* Set handoff before checking for waiters. */ - qatomic_mb_set(&mutex->handoff, our_handoff); + qatomic_set_mb(&mutex->handoff, our_handoff); if (!has_waiters(mutex)) { /* The concurrent lock has not added itself yet, so it * will be able to pick our handoff. |