monitor: Replaced qemu_mutex_lock calls with QEMU_LOCK_GUARD

Removed various qemu_mutex_lock and their respective qemu_mutex_unlock
calls and used lock guard macros (QEMU_LOCK_GUARD and
WITH_QEMU_LOCK_GUARD). This simplifies the code by
eliminating qemu_mutex_unlock calls.

Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
Message-Id: <20210311031538.5325-6-ma.mandourr@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

monitor/monitor.c

@@ -349,7 +349,7 @@ monitor_qapi_event_queue_no_reenter(QAPIEvent event, QDict *qdict)
     evconf = &monitor_qapi_event_conf[event];
     trace_monitor_protocol_event_queue(event, qdict, evconf->rate);
 
-    qemu_mutex_lock(&monitor_lock);
+    QEMU_LOCK_GUARD(&monitor_lock);
 
     if (!evconf->rate) {
         /* Unthrottled event */
@@ -391,8 +391,6 @@ monitor_qapi_event_queue_no_reenter(QAPIEvent event, QDict *qdict)
             timer_mod_ns(evstate->timer, now + evconf->rate);
         }
     }
-
-    qemu_mutex_unlock(&monitor_lock);
 }
 
 void qapi_event_emit(QAPIEvent event, QDict *qdict)
@@ -447,7 +445,7 @@ static void monitor_qapi_event_handler(void *opaque)
     MonitorQAPIEventConf *evconf = &monitor_qapi_event_conf[evstate->event];
 
     trace_monitor_protocol_event_handler(evstate->event, evstate->qdict);
-    qemu_mutex_lock(&monitor_lock);
+    QEMU_LOCK_GUARD(&monitor_lock);
 
     if (evstate->qdict) {
         int64_t now = qemu_clock_get_ns(monitor_get_event_clock());
@@ -462,8 +460,6 @@ static void monitor_qapi_event_handler(void *opaque)
         timer_free(evstate->timer);
         g_free(evstate);
     }
-
-    qemu_mutex_unlock(&monitor_lock);
 }
 
 static unsigned int qapi_event_throttle_hash(const void *key)

monitor/qmp.c

@@ -76,7 +76,7 @@ static void monitor_qmp_cleanup_req_queue_locked(MonitorQMP *mon)
 
 static void monitor_qmp_cleanup_queue_and_resume(MonitorQMP *mon)
 {
-    qemu_mutex_lock(&mon->qmp_queue_lock);
+    QEMU_LOCK_GUARD(&mon->qmp_queue_lock);
 
     /*
      * Same condition as in monitor_qmp_dispatcher_co(), but before
@@ -103,7 +103,6 @@ static void monitor_qmp_cleanup_queue_and_resume(MonitorQMP *mon)
         monitor_resume(&mon->common);
     }
 
-    qemu_mutex_unlock(&mon->qmp_queue_lock);
 }
 
 void qmp_send_response(MonitorQMP *mon, const QDict *rsp)
@@ -179,7 +178,7 @@ static QMPRequest *monitor_qmp_requests_pop_any_with_lock(void)
     Monitor *mon;
     MonitorQMP *qmp_mon;
 
-    qemu_mutex_lock(&monitor_lock);
+    QEMU_LOCK_GUARD(&monitor_lock);
 
     QTAILQ_FOREACH(mon, &mon_list, entry) {
         if (!monitor_is_qmp(mon)) {
@@ -205,8 +204,6 @@ static QMPRequest *monitor_qmp_requests_pop_any_with_lock(void)
         QTAILQ_INSERT_TAIL(&mon_list, mon, entry);
     }
 
-    qemu_mutex_unlock(&monitor_lock);
-
     return req_obj;
 }
 
@@ -376,30 +373,30 @@ static void handle_qmp_command(void *opaque, QObject *req, Error *err)
     req_obj->err = err;
 
     /* Protect qmp_requests and fetching its length. */
-    qemu_mutex_lock(&mon->qmp_queue_lock);
+    WITH_QEMU_LOCK_GUARD(&mon->qmp_queue_lock) {
 
-    /*
-     * Suspend the monitor when we can't queue more requests after
-     * this one.  Dequeuing in monitor_qmp_dispatcher_co() or
-     * monitor_qmp_cleanup_queue_and_resume() will resume it.
-     * Note that when OOB is disabled, we queue at most one command,
-     * for backward compatibility.
-     */
-    if (!qmp_oob_enabled(mon) ||
-        mon->qmp_requests->length == QMP_REQ_QUEUE_LEN_MAX - 1) {
-        monitor_suspend(&mon->common);
-    }
+        /*
+         * Suspend the monitor when we can't queue more requests after
+         * this one.  Dequeuing in monitor_qmp_dispatcher_co() or
+         * monitor_qmp_cleanup_queue_and_resume() will resume it.
+         * Note that when OOB is disabled, we queue at most one command,
+         * for backward compatibility.
+         */
+        if (!qmp_oob_enabled(mon) ||
+            mon->qmp_requests->length == QMP_REQ_QUEUE_LEN_MAX - 1) {
+            monitor_suspend(&mon->common);
+        }
 
-    /*
-     * Put the request to the end of queue so that requests will be
-     * handled in time order.  Ownership for req_obj, req,
-     * etc. will be delivered to the handler side.
-     */
-    trace_monitor_qmp_in_band_enqueue(req_obj, mon,
-                                      mon->qmp_requests->length);
-    assert(mon->qmp_requests->length < QMP_REQ_QUEUE_LEN_MAX);
-    g_queue_push_tail(mon->qmp_requests, req_obj);
-    qemu_mutex_unlock(&mon->qmp_queue_lock);
+        /*
+         * Put the request to the end of queue so that requests will be
+         * handled in time order.  Ownership for req_obj, req,
+         * etc. will be delivered to the handler side.
+         */
+        trace_monitor_qmp_in_band_enqueue(req_obj, mon,
+                                          mon->qmp_requests->length);
+        assert(mon->qmp_requests->length < QMP_REQ_QUEUE_LEN_MAX);
+        g_queue_push_tail(mon->qmp_requests, req_obj);
+    }
 
     /* Kick the dispatcher routine */
     if (!qatomic_xchg(&qmp_dispatcher_co_busy, true)) {