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Commit b4e382ca authored by Ben Skeggs's avatar Ben Skeggs
Browse files

drm/nouveau/tmr: fully separate alarm execution/pending lists 



Reusing the list_head for both is a bad idea.  Callback execution is done
with the lock dropped so that alarms can be rescheduled from the callback,
which means that with some unfortunate timing, lists can get corrupted.

The execution list should not require its own locking, the single function
that uses it can only be called from a single context.

Signed-off-by: default avatarBen Skeggs <bskeggs@redhat.com>
Cc: stable@vger.kernel.org
parent 8fa4338a

drivers/gpu/drm/nouveau/include/nvkm/subdev/timer.h

+1 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 


struct nvkm_alarm {

	struct list_head head;

	struct list_head exec;

	u64 timestamp;

	void (*func)(struct nvkm_alarm *);

};

drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c

+4 −3
Original line number Diff line number Diff line
@@ -50,7 +50,8 @@ nvkm_timer_alarm_trigger(struct nvkm_timer *tmr) 
		/* Move to completed list.  We'll drop the lock before

		 * executing the callback so it can reschedule itself.

		 */

		list_move_tail(&alarm->head, &exec);

		list_del_init(&alarm->head);

		list_add(&alarm->exec, &exec);

	}



	/* Shut down interrupt if no more pending alarms. */
@@ -59,8 +60,8 @@ nvkm_timer_alarm_trigger(struct nvkm_timer *tmr) 
	spin_unlock_irqrestore(&tmr->lock, flags);



	/* Execute completed callbacks. */

	list_for_each_entry_safe(alarm, atemp, &exec, head) {

		list_del_init(&alarm->head);

	list_for_each_entry_safe(alarm, atemp, &exec, exec) {

		list_del(&alarm->exec);

		alarm->func(alarm);

	}

}