@@ -81,6 +81,8 @@ extern AioWait global_aio_wait;
AioContext *ctx_ = (ctx); \
/* Increment wait_->num_waiters before evaluating cond. */ \
qatomic_inc(&wait_->num_waiters); \
+ /* Paired with smp_mb in aio_wait_kick(). */ \
+ smp_mb(); \
if (ctx_ && in_aio_context_home_thread(ctx_)) { \
while ((cond)) { \
aio_poll(ctx_, true); \
@@ -35,7 +35,21 @@ static void dummy_bh_cb(void *opaque)
void aio_wait_kick(void)
{
- /* The barrier (or an atomic op) is in the caller. */
+ /*
+ * Paired with smp_mb in AIO_WAIT_WHILE. Here we have:
+ * write(condition);
+ * aio_wait_kick() {
+ * smp_mb();
+ * read(num_waiters);
+ * }
+ *
+ * And in AIO_WAIT_WHILE:
+ * write(num_waiters);
+ * smp_mb();
+ * read(condition);
+ */
+ smp_mb();
+
if (qatomic_read(&global_aio_wait.num_waiters)) {
aio_bh_schedule_oneshot(qemu_get_aio_context(), dummy_bh_cb, NULL);
}