Commit 588b9828 authored by Steven Price's avatar Steven Price Committed by Christian König
Browse files

drm: Don't free jobs in wait_event_interruptible() 



drm_sched_cleanup_jobs() attempts to free finished jobs, however because
it is called as the condition of wait_event_interruptible() it must not
sleep. Unfortunately some free callbacks (notably for Panfrost) do sleep.

Instead let's rename drm_sched_cleanup_jobs() to
drm_sched_get_cleanup_job() and simply return a job for processing if
there is one. The caller can then call the free_job() callback outside
the wait_event_interruptible() where sleeping is possible before
re-checking and returning to sleep if necessary.

Tested-by: default avatarChristian Gmeiner <christian.gmeiner@gmail.com>
Fixes: 5918045c ("drm/scheduler: rework job destruction")
Signed-off-by: default avatarSteven Price <steven.price@arm.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/337652/
parent 0f546217

drivers/gpu/drm/scheduler/sched_main.c

+24 −19
Original line number Diff line number Diff line
@@ -622,43 +622,41 @@ static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb) 
}



/**

 * drm_sched_cleanup_jobs - destroy finished jobs

 * drm_sched_get_cleanup_job - fetch the next finished job to be destroyed

 *

 * @sched: scheduler instance

 *

 * Remove all finished jobs from the mirror list and destroy them.

 * Returns the next finished job from the mirror list (if there is one)

 * ready for it to be destroyed.

 */

static void drm_sched_cleanup_jobs(struct drm_gpu_scheduler *sched)

static struct drm_sched_job *

drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)

{

	struct drm_sched_job *job;

	unsigned long flags;



	/* Don't destroy jobs while the timeout worker is running */

	if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&

	    !cancel_delayed_work(&sched->work_tdr))

		return;



		return NULL;



	while (!list_empty(&sched->ring_mirror_list)) {

		struct drm_sched_job *job;

	spin_lock_irqsave(&sched->job_list_lock, flags);



		job = list_first_entry(&sched->ring_mirror_list,

	job = list_first_entry_or_null(&sched->ring_mirror_list,

				       struct drm_sched_job, node);

		if (!dma_fence_is_signaled(&job->s_fence->finished))

			break;



		spin_lock_irqsave(&sched->job_list_lock, flags);

	if (job && dma_fence_is_signaled(&job->s_fence->finished)) {

		/* remove job from ring_mirror_list */

		list_del_init(&job->node);

		spin_unlock_irqrestore(&sched->job_list_lock, flags);



		sched->ops->free_job(job);

	}



	} else {

		job = NULL;

		/* queue timeout for next job */

	spin_lock_irqsave(&sched->job_list_lock, flags);

		drm_sched_start_timeout(sched);

	}



	spin_unlock_irqrestore(&sched->job_list_lock, flags);



	return job;

}



/**
@@ -698,12 +696,19 @@ static int drm_sched_main(void *param) 
		struct drm_sched_fence *s_fence;

		struct drm_sched_job *sched_job;

		struct dma_fence *fence;

		struct drm_sched_job *cleanup_job = NULL;



		wait_event_interruptible(sched->wake_up_worker,

					 (drm_sched_cleanup_jobs(sched),

					 (cleanup_job = drm_sched_get_cleanup_job(sched)) ||

					 (!drm_sched_blocked(sched) &&

					  (entity = drm_sched_select_entity(sched))) ||

					 kthread_should_stop()));

					 kthread_should_stop());



		if (cleanup_job) {

			sched->ops->free_job(cleanup_job);

			/* queue timeout for next job */

			drm_sched_start_timeout(sched);

		}



		if (!entity)

			continue;

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