[Qemu-devel] [RFC PATCH 1/3] qemu-timer: do del+mod atomically

[Paolo Bonzini <pbonzini@redhat.com>]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 qemu-timer.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/qemu-timer.c b/qemu-timer.c
index 04869f4..d650247 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -319,13 +319,10 @@ void timer_free(QEMUTimer *ts)
     g_free(ts);
 }
 
-/* stop a timer, but do not dealloc it */
-void timer_del(QEMUTimer *ts)
+static void timer_del_locked(QEMUTimerList *timer_list, QEMUTimer *ts)
 {
-    QEMUTimerList *timer_list = ts->timer_list;
     QEMUTimer **pt, *t;
 
-    qemu_mutex_lock(&timer_list->active_timers_lock);
     pt = &timer_list->active_timers;
     for(;;) {
         t = *pt;
@@ -337,6 +334,15 @@ void timer_del(QEMUTimer *ts)
         }
         pt = &t->next;
     }
+}
+
+/* stop a timer, but do not dealloc it */
+void timer_del(QEMUTimer *ts)
+{
+    QEMUTimerList *timer_list = ts->timer_list;
+
+    qemu_mutex_lock(&timer_list->active_timers_lock);
+    timer_del_locked(timer_list, ts);
     qemu_mutex_unlock(&timer_list->active_timers_lock);
 }
 
@@ -347,10 +353,10 @@ void timer_mod_ns(QEMUTimer *ts, int64_t expire_time)
     QEMUTimerList *timer_list = ts->timer_list;
     QEMUTimer **pt, *t;
 
-    timer_del(ts);
+    qemu_mutex_lock(&timer_list->active_timers_lock);
+    timer_del_locked(timer_list, ts);
 
     /* add the timer in the sorted list */
-    qemu_mutex_lock(&timer_list->active_timers_lock);
     pt = &timer_list->active_timers;
     for(;;) {
         t = *pt;
-- 
1.8.3.1