configure, meson: rename targetos to host_os

[mirror_qemu.git] / util / aio-wait.c

diff --git a/util/aio-wait.c b/util/aio-wait.c
index bdb3d3af22ddbb0b77b52e12b4e9538acebba08e..b5336cf5fd2932dd0f54d98c96c68a4a16231bd7 100644 (file)
--- a/util/aio-wait.c
+++ b/util/aio-wait.c
@@ -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);
     }
@@ -68,5 +82,5 @@ void aio_wait_bh_oneshot(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
     assert(qemu_get_current_aio_context() == qemu_get_aio_context());
 
     aio_bh_schedule_oneshot(ctx, aio_wait_bh, &data);
-    AIO_WAIT_WHILE(ctx, !data.done);
+    AIO_WAIT_WHILE_UNLOCKED(NULL, !data.done);
 }