monitor/qmp: Stop processing requests when shutdown is requested

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>

diff --git a/monitor/qmp.c b/monitor/qmp.c
index 43880fa6232be1f0d4ff10830103e0ad8e9fc71d..2326bd7f9ba1ae8d303ba27144dec799b7b4f791 100644 (file)
--- 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