drm/amdgpu: fix and cleanup job destruction

Remove the job reference counting and just properly destroy it from a
work item which blocks on any potential running timeout handler.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Monk.Liu <monk.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

@@ -755,7 +755,6 @@ int amdgpu_job_alloc_with_ib(struct amdgpu_device *adev, unsigned size,
 			     struct amdgpu_job **job);
 
 void amdgpu_job_free(struct amdgpu_job *job);
-void amdgpu_job_free_func(struct kref *refcount);
 int amdgpu_job_submit(struct amdgpu_job *job, struct amdgpu_ring *ring,
 		      struct amd_sched_entity *entity, void *owner,
 		      struct fence **f);

drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c

@@ -838,8 +838,7 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
 	p->job = NULL;
 
 	r = amd_sched_job_init(&job->base, &ring->sched,
-			       entity, amdgpu_job_free_func,
-			       p->filp, &fence);
+			       entity, p->filp, &fence);
 	if (r) {
 		amdgpu_job_free(job);
 		return r;

drivers/gpu/drm/amd/amdgpu/amdgpu_job.c

@@ -28,12 +28,6 @@
 #include "amdgpu.h"
 #include "amdgpu_trace.h"
 
-static void amdgpu_job_free_handler(struct work_struct *ws)
-{
-	struct amdgpu_job *job = container_of(ws, struct amdgpu_job, base.work_free_job);
-	amd_sched_job_put(&job->base);
-}
-
 static void amdgpu_job_timedout(struct amd_sched_job *s_job)
 {
 	struct amdgpu_job *job = container_of(s_job, struct amdgpu_job, base);
@@ -42,8 +36,6 @@ static void amdgpu_job_timedout(struct amd_sched_job *s_job)
 		  job->base.sched->name,
 		  atomic_read(&job->ring->fence_drv.last_seq),
 		  job->ring->fence_drv.sync_seq);
-
-	amd_sched_job_put(&job->base);
 }
 
 int amdgpu_job_alloc(struct amdgpu_device *adev, unsigned num_ibs,
@@ -64,7 +56,6 @@ int amdgpu_job_alloc(struct amdgpu_device *adev, unsigned num_ibs,
 	(*job)->vm = vm;
 	(*job)->ibs = (void *)&(*job)[1];
 	(*job)->num_ibs = num_ibs;
-	INIT_WORK(&(*job)->base.work_free_job, amdgpu_job_free_handler);
 
 	amdgpu_sync_create(&(*job)->sync);
 
@@ -103,9 +94,10 @@ static void amdgpu_job_free_resources(struct amdgpu_job *job)
 	amdgpu_sync_free(&job->sync);
 }
 
-void amdgpu_job_free_func(struct kref *refcount)
+void amdgpu_job_free_cb(struct amd_sched_job *s_job)
 {
-	struct amdgpu_job *job = container_of(refcount, struct amdgpu_job, base.refcount);
+	struct amdgpu_job *job = container_of(s_job, struct amdgpu_job, base);
+
 	kfree(job);
 }
 
@@ -126,8 +118,7 @@ int amdgpu_job_submit(struct amdgpu_job *job, struct amdgpu_ring *ring,
 	if (!f)
 		return -EINVAL;
 
-	r = amd_sched_job_init(&job->base, &ring->sched,
-			       entity, amdgpu_job_free_func, owner, &fence);
+	r = amd_sched_job_init(&job->base, &ring->sched, entity, owner, &fence);
 	if (r)
 		return r;
 
@@ -198,4 +189,5 @@ const struct amd_sched_backend_ops amdgpu_sched_ops = {
 	.dependency = amdgpu_job_dependency,
 	.run_job = amdgpu_job_run,
 	.timedout_job = amdgpu_job_timedout,
+	.free_job = amdgpu_job_free_cb
 };

drivers/gpu/drm/amd/scheduler/gpu_scheduler.c

@@ -319,19 +319,13 @@ static bool amd_sched_entity_in(struct amd_sched_job *sched_job)
 	return added;
 }
 
-static void amd_sched_free_job(struct fence *f, struct fence_cb *cb) {
-	struct amd_sched_job *job = container_of(cb, struct amd_sched_job,
-						 cb_free_job);
-
-	schedule_work(&job->work_free_job);
-}
-
 /* job_finish is called after hw fence signaled, and
  * the job had already been deleted from ring_mirror_list
  */
-static void amd_sched_job_finish(struct amd_sched_job *s_job)
+static void amd_sched_job_finish(struct work_struct *work)
 {
-	struct amd_sched_job *next;
+	struct amd_sched_job *s_job = container_of(work, struct amd_sched_job,
+						   finish_work);
 	struct amd_gpu_scheduler *sched = s_job->sched;
 	unsigned long flags;
 
@@ -339,19 +333,26 @@ static void amd_sched_job_finish(struct amd_sched_job *s_job)
 	spin_lock_irqsave(&sched->job_list_lock, flags);
 	list_del_init(&s_job->node);
 	if (sched->timeout != MAX_SCHEDULE_TIMEOUT) {
-		if (cancel_delayed_work(&s_job->work_tdr))
-			amd_sched_job_put(s_job);
+		struct amd_sched_job *next;
+
+		cancel_delayed_work_sync(&s_job->work_tdr);
 
 		/* queue TDR for next job */
 		next = list_first_entry_or_null(&sched->ring_mirror_list,
 						struct amd_sched_job, node);
 
-		if (next) {
-			amd_sched_job_get(next);
+		if (next)
 			schedule_delayed_work(&next->work_tdr, sched->timeout);
 	}
-	}
 	spin_unlock_irqrestore(&sched->job_list_lock, flags);
+	sched->ops->free_job(s_job);
+}
+
+static void amd_sched_job_finish_cb(struct fence *f, struct fence_cb *cb)
+{
+	struct amd_sched_job *job = container_of(cb, struct amd_sched_job,
+						 finish_cb);
+	schedule_work(&job->finish_work);
 }
 
 static void amd_sched_job_begin(struct amd_sched_job *s_job)
@@ -364,10 +365,7 @@ static void amd_sched_job_begin(struct amd_sched_job *s_job)
 	if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
 	    list_first_entry_or_null(&sched->ring_mirror_list,
 				     struct amd_sched_job, node) == s_job)
-	{
-		amd_sched_job_get(s_job);
 		schedule_delayed_work(&s_job->work_tdr, sched->timeout);
-	}
 	spin_unlock_irqrestore(&sched->job_list_lock, flags);
 }
 
@@ -390,9 +388,9 @@ void amd_sched_entity_push_job(struct amd_sched_job *sched_job)
 {
 	struct amd_sched_entity *entity = sched_job->s_entity;
 
-	fence_add_callback(&sched_job->s_fence->base,
-			   &sched_job->cb_free_job, amd_sched_free_job);
 	trace_amd_sched_job(sched_job);
+	fence_add_callback(&sched_job->s_fence->base, &sched_job->finish_cb,
+			   amd_sched_job_finish_cb);
 	wait_event(entity->sched->job_scheduled,
 		   amd_sched_entity_in(sched_job));
 }
@@ -401,20 +399,17 @@ void amd_sched_entity_push_job(struct amd_sched_job *sched_job)
 int amd_sched_job_init(struct amd_sched_job *job,
 		       struct amd_gpu_scheduler *sched,
 		       struct amd_sched_entity *entity,
-		       void (*free_cb)(struct kref *refcount),
 		       void *owner, struct fence **fence)
 {
-	INIT_LIST_HEAD(&job->node);
-	kref_init(&job->refcount);
 	job->sched = sched;
 	job->s_entity = entity;
 	job->s_fence = amd_sched_fence_create(entity, owner);
 	if (!job->s_fence)
 		return -ENOMEM;
 
-	job->s_fence->s_job = job;
+	INIT_WORK(&job->finish_work, amd_sched_job_finish);
+	INIT_LIST_HEAD(&job->node);
 	INIT_DELAYED_WORK(&job->work_tdr, amd_sched_job_timedout);
-	job->free_callback = free_cb;
 
 	if (fence)
 		*fence = &job->s_fence->base;
@@ -468,9 +463,6 @@ static void amd_sched_process_job(struct fence *f, struct fence_cb *cb)
 	struct amd_gpu_scheduler *sched = s_fence->sched;
 
 	atomic_dec(&sched->hw_rq_count);
-
-	amd_sched_job_finish(s_fence->s_job);
-
 	amd_sched_fence_signal(s_fence);
 
 	trace_amd_sched_process_job(s_fence);

drivers/gpu/drm/amd/scheduler/gpu_scheduler.h

@@ -74,19 +74,16 @@ struct amd_sched_fence {
 	struct amd_gpu_scheduler	*sched;
 	spinlock_t			lock;
 	void                            *owner;
-	struct amd_sched_job	*s_job;
 };
 
 struct amd_sched_job {
-	struct kref refcount;
 	struct amd_gpu_scheduler        *sched;
 	struct amd_sched_entity         *s_entity;
 	struct amd_sched_fence          *s_fence;
-	struct fence_cb                cb_free_job;
-	struct work_struct             work_free_job;
+	struct fence_cb			finish_cb;
+	struct work_struct		finish_work;
 	struct list_head		node;
 	struct delayed_work		work_tdr;
-	void (*free_callback)(struct kref *refcount);
 };
 
 extern const struct fence_ops amd_sched_fence_ops;
@@ -109,6 +106,7 @@ struct amd_sched_backend_ops {
 	struct fence *(*dependency)(struct amd_sched_job *sched_job);
 	struct fence *(*run_job)(struct amd_sched_job *sched_job);
 	void (*timedout_job)(struct amd_sched_job *sched_job);
+	void (*free_job)(struct amd_sched_job *sched_job);
 };
 
 enum amd_sched_priority {
@@ -154,18 +152,5 @@ void amd_sched_fence_signal(struct amd_sched_fence *fence);
 int amd_sched_job_init(struct amd_sched_job *job,
 		       struct amd_gpu_scheduler *sched,
 		       struct amd_sched_entity *entity,
-		       void (*free_cb)(struct kref* refcount),
 		       void *owner, struct fence **fence);
-static inline void amd_sched_job_get(struct amd_sched_job *job)
-{
-	if (job)
-		kref_get(&job->refcount);
-}
-
-static inline void amd_sched_job_put(struct amd_sched_job *job)
-{
-	if (job)
-		kref_put(&job->refcount, job->free_callback);
-}
-
 #endif