@@ -1360,6 +1360,22 @@ void bdrv_close_all(void)
}
}
+/* Check if any requests are in-flight (including throttled requests) */
+static bool bdrv_requests_pending(void)
+{
+ BlockDriverState *bs;
+
+ QTAILQ_FOREACH(bs, &bdrv_states, list) {
+ if (!QLIST_EMPTY(&bs->tracked_requests)) {
+ return true;
+ }
+ if (!qemu_co_queue_empty(&bs->throttled_reqs)) {
+ return true;
+ }
+ }
+ return false;
+}
+
/*
* Wait for pending requests to complete across all BlockDriverStates
*
@@ -1375,26 +1391,18 @@ void bdrv_close_all(void)
void bdrv_drain_all(void)
{
BlockDriverState *bs;
- bool busy;
-
- do {
- busy = qemu_aio_wait();
+ while (bdrv_requests_pending()) {
/* FIXME: We do not have timer support here, so this is effectively
* a busy wait.
*/
QTAILQ_FOREACH(bs, &bdrv_states, list) {
if (!qemu_co_queue_empty(&bs->throttled_reqs)) {
qemu_co_queue_restart_all(&bs->throttled_reqs);
- busy = true;
}
}
- } while (busy);
- /* If requests are still pending there is a bug somewhere */
- QTAILQ_FOREACH(bs, &bdrv_states, list) {
- assert(QLIST_EMPTY(&bs->tracked_requests));
- assert(qemu_co_queue_empty(&bs->throttled_reqs));
+ qemu_aio_wait();
}
}
If a block driver has no file descriptors to monitor but there are still active requests, it can return 1 from .io_flush(). This is used to spin during synchronous I/O. Stop relying on .io_flush() and instead check QLIST_EMPTY(&bs->tracked_requests) to decide whether there are active requests. This is the first step in removing .io_flush() so that event loops no longer need to have the concept of synchronous I/O. Eventually we may be able to kill synchronous I/O completely by running everything in a coroutine, but that is future work. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> --- block.c | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-)