From: Rob Clark <robdclark@xxxxxxxxxxxx> Fixes a race condition reported here: https://github.com/AsahiLinux/linux/issues/309#issuecomment-2238968609 The whole premise of lockless access to a single-producer-single- consumer queue is that there is just a single producer and single consumer. That means we can't call drm_sched_can_queue() (which is about queueing more work to the hw, not to the spsc queue) from anywhere other than the consumer (wq). This call in the producer is just an optimization to avoid scheduling the consuming worker if it cannot yet queue more work to the hw. It is safe to drop this optimization to avoid the race condition. Suggested-by: Asahi Lina <lina@xxxxxxxxxxxxx> Fixes: a78422e9dff3 ("drm/sched: implement dynamic job-flow control") Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx> --- drivers/gpu/drm/scheduler/sched_main.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index ab53ab486fe6..1af1dbe757d5 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -1020,8 +1020,7 @@ EXPORT_SYMBOL(drm_sched_job_cleanup); void drm_sched_wakeup(struct drm_gpu_scheduler *sched, struct drm_sched_entity *entity) { - if (drm_sched_can_queue(sched, entity)) - drm_sched_run_job_queue(sched); + drm_sched_run_job_queue(sched); } /** -- 2.46.0
