[PULL 11/11] monitor/qmp: Stop processing requests when shutdown is requested

[Kevin Wolf <kwolf@redhat.com>]

Before this patch, monitor_qmp_dispatcher_co() used to check whether
shutdown is requested only when it would have to wait for new requests.
If there were still some queued requests, it would try to execute all of
them before shutting down.

This can be surprising when the queued QMP commands take long or hang
because Ctrl-C may not actually exit QEMU as soon as possible.

Change monitor_qmp_dispatcher_co() so that it additionally checks
whether shutdown is request before it gets a new request from the queue.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210212172028.288825-3-kwolf@redhat.com>
Tested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 monitor/qmp.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/monitor/qmp.c b/monitor/qmp.c
index 43880fa623..2326bd7f9b 100644
--- a/monitor/qmp.c
+++ b/monitor/qmp.c
@@ -227,6 +227,11 @@ void coroutine_fn monitor_qmp_dispatcher_co(void *data)
          */
         qatomic_mb_set(&qmp_dispatcher_co_busy, false);
 
+        /* On shutdown, don't take any more requests from the queue */
+        if (qmp_dispatcher_co_shutdown) {
+            return;
+        }
+
         while (!(req_obj = monitor_qmp_requests_pop_any_with_lock())) {
             /*
              * No more requests to process.  Wait to be reentered from
-- 
2.29.2