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-rw-r--r--drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c
index 07dc82b..182f27c 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c
@@ -65,14 +65,17 @@ nvkm_timer_alarm(struct nvkm_timer *tmr, u32 nsec, struct nvkm_alarm *alarm)
struct nvkm_alarm *list;
unsigned long flags;
- alarm->timestamp = nvkm_timer_read(tmr) + nsec;
-
- /* append new alarm to list, in soonest-alarm-first order */
+ /* Remove alarm from pending list.
+ *
+ * This both protects against the corruption of the list,
+ * and implements alarm rescheduling/cancellation.
+ */
spin_lock_irqsave(&tmr->lock, flags);
- if (!nsec) {
- if (!list_empty(&alarm->head))
- list_del(&alarm->head);
- } else {
+ list_del_init(&alarm->head);
+
+ if (nsec) {
+ /* Insert into pending list, ordered earliest to latest. */
+ alarm->timestamp = nvkm_timer_read(tmr) + nsec;
list_for_each_entry(list, &tmr->alarms, head) {
if (list->timestamp > alarm->timestamp)
break;