aio / timers: Add a notify callback to QEMUTimerList

Add a notify pointer to QEMUTimerList so it knows what to notify
on a timer change.
Signed-off-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

async.c

@@ -234,6 +234,11 @@ void aio_notify(AioContext *ctx)
     event_notifier_set(&ctx->notifier);
 }
 
+static void aio_timerlist_notify(void *opaque)
+{
+    aio_notify(opaque);
+}
+
 AioContext *aio_context_new(void)
 {
     AioContext *ctx;
@@ -245,7 +250,7 @@ AioContext *aio_context_new(void)
     aio_set_event_notifier(ctx, &ctx->notifier, 
                            (EventNotifierHandler *)
                            event_notifier_test_and_clear);
-    timerlistgroup_init(&ctx->tlg);
+    timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);
 
     return ctx;
 }

include/qemu/timer.h

@@ -59,6 +59,7 @@ struct QEMUTimerListGroup {
 };
 
 typedef void QEMUTimerCB(void *opaque);
+typedef void QEMUTimerListNotifyCB(void *opaque);
 
 struct QEMUTimer {
     int64_t expire_time;        /* in nanoseconds */
@@ -137,13 +138,16 @@ QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClock *clock);
 /**
  * timerlist_new:
  * @type: the clock type to associate with the timerlist
+ * @cb: the callback to call on notification
+ * @opaque: the opaque pointer to pass to the callback
  *
  * Create a new timerlist associated with the clock of
  * type @type.
  *
  * Returns: a pointer to the QEMUTimerList created
  */
-QEMUTimerList *timerlist_new(QEMUClockType type);
+QEMUTimerList *timerlist_new(QEMUClockType type,
+                             QEMUTimerListNotifyCB *cb, void *opaque);
 
 /**
  * timerlist_free:
@@ -223,14 +227,29 @@ QEMUClock *timerlist_get_clock(QEMUTimerList *timer_list);
  */
 bool timerlist_run_timers(QEMUTimerList *timer_list);
 
+/**
+ * timerlist_notify:
+ * @timer_list: the timer list to use
+ *
+ * call the notifier callback associated with the timer list.
+ */
+void timerlist_notify(QEMUTimerList *timer_list);
+
 /**
  * timerlistgroup_init:
  * @tlg: the timer list group
+ * @cb: the callback to call when a notify is required
+ * @opaque: the opaque pointer to be passed to the callback.
  *
  * Initialise a timer list group. This must already be
- * allocated in memory and zeroed.
- */
-void timerlistgroup_init(QEMUTimerListGroup *tlg);
+ * allocated in memory and zeroed. The notifier callback is
+ * called whenever a clock in the timer list group is
+ * reenabled or whenever a timer associated with any timer
+ * list is modified. If @cb is specified as null, qemu_notify()
+ * is used instead.
+ */
+void timerlistgroup_init(QEMUTimerListGroup *tlg,
+                         QEMUTimerListNotifyCB *cb, void *opaque);
 
 /**
  * timerlistgroup_deinit:

qemu-timer.c

@@ -73,6 +73,8 @@ struct QEMUTimerList {
     QEMUClock *clock;
     QEMUTimer *active_timers;
     QLIST_ENTRY(QEMUTimerList) list;
+    QEMUTimerListNotifyCB *notify_cb;
+    void *notify_opaque;
 };
 
 struct qemu_alarm_timer {
@@ -243,7 +245,9 @@ next:
     }
 }
 
-static QEMUTimerList *timerlist_new_from_clock(QEMUClock *clock)
+static QEMUTimerList *timerlist_new_from_clock(QEMUClock *clock,
+                                               QEMUTimerListNotifyCB *cb,
+                                               void *opaque)
 {
     QEMUTimerList *timer_list;
 
@@ -257,13 +261,16 @@ static QEMUTimerList *timerlist_new_from_clock(QEMUClock *clock)
 
     timer_list = g_malloc0(sizeof(QEMUTimerList));
     timer_list->clock = clock;
+    timer_list->notify_cb = cb;
+    timer_list->notify_opaque = opaque;
     QLIST_INSERT_HEAD(&clock->timerlists, timer_list, list);
     return timer_list;
 }
 
-QEMUTimerList *timerlist_new(QEMUClockType type)
+QEMUTimerList *timerlist_new(QEMUClockType type,
+                             QEMUTimerListNotifyCB *cb, void *opaque)
 {
-    return timerlist_new_from_clock(qemu_clock_ptr(type));
+    return timerlist_new_from_clock(qemu_clock_ptr(type), cb, opaque);
 }
 
 void timerlist_free(QEMUTimerList *timer_list)
@@ -288,7 +295,7 @@ static QEMUClock *qemu_clock_new(QEMUClockType type)
     clock->last = INT64_MIN;
     QLIST_INIT(&clock->timerlists);
     notifier_list_init(&clock->reset_notifiers);
-    clock->main_loop_timerlist = timerlist_new_from_clock(clock);
+    clock->main_loop_timerlist = timerlist_new_from_clock(clock, NULL, NULL);
     return clock;
 }
 
@@ -386,6 +393,15 @@ QEMUTimerList *qemu_clock_get_main_loop_timerlist(QEMUClock *clock)
     return clock->main_loop_timerlist;
 }
 
+void timerlist_notify(QEMUTimerList *timer_list)
+{
+    if (timer_list->notify_cb) {
+        timer_list->notify_cb(timer_list->notify_opaque);
+    } else {
+        qemu_notify_event();
+    }
+}
+
 /* Transition function to convert a nanosecond timeout to ms
  * This is used where a system does not support ppoll
  */
@@ -507,7 +523,7 @@ void qemu_mod_timer_ns(QEMUTimer *ts, int64_t expire_time)
         /* Interrupt execution to force deadline recalculation.  */
         qemu_clock_warp(ts->timer_list->clock);
         if (use_icount) {
-            qemu_notify_event();
+            timerlist_notify(ts->timer_list);
         }
     }
 }
@@ -565,11 +581,12 @@ bool qemu_run_timers(QEMUClock *clock)
     return timerlist_run_timers(clock->main_loop_timerlist);
 }
 
-void timerlistgroup_init(QEMUTimerListGroup *tlg)
+void timerlistgroup_init(QEMUTimerListGroup *tlg,
+                         QEMUTimerListNotifyCB *cb, void *opaque)
 {
     QEMUClockType type;
     for (type = 0; type < QEMU_CLOCK_MAX; type++) {
-        tlg->tl[type] = timerlist_new(type);
+        tlg->tl[type] = timerlist_new(type, cb, opaque);
     }
 }