drm/amdgpu: fix wait queue handling in the scheduler

Freeing up a queue after signalling it isn't race free.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>

2 files changed, 10 insertions, 10 deletions

diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
index 6dfbdea85e87..d99fe90991dc 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
@@ -117,7 +117,6 @@ int amd_sched_entity_init(struct amd_gpu_scheduler *sched,
         memset(entity, 0, sizeof(struct amd_sched_entity));
         entity->belongto_rq = rq;
         entity->scheduler = sched;
-        init_waitqueue_head(&entity->wait_queue);
         entity->fence_context = fence_context_alloc(1);
         if(kfifo_alloc(&entity->job_queue,
                        jobs * sizeof(void *),
@@ -183,7 +182,7 @@ void amd_sched_entity_fini(struct amd_gpu_scheduler *sched,
          * The client will not queue more IBs during this fini, consume existing
          * queued IBs
         */
-        wait_event(entity->wait_queue, amd_sched_entity_is_idle(entity));
+        wait_event(sched->job_scheduled, amd_sched_entity_is_idle(entity));
 
         amd_sched_rq_remove_entity(rq, entity);
         kfifo_free(&entity->job_queue);
@@ -236,7 +235,7 @@ int amd_sched_entity_push_job(struct amd_sched_job *sched_job)
         fence_get(&fence->base);
         sched_job->s_fence = fence;
 
-        r = wait_event_interruptible(entity->wait_queue,
+        r = wait_event_interruptible(entity->scheduler->job_scheduled,
                                      amd_sched_entity_in(sched_job));
 
         return r;
@@ -257,7 +256,7 @@ static bool amd_sched_ready(struct amd_gpu_scheduler *sched)
 static void amd_sched_wakeup(struct amd_gpu_scheduler *sched)
 {
         if (amd_sched_ready(sched))
-                wake_up_interruptible(&sched->wait_queue);
+                wake_up_interruptible(&sched->wake_up_worker);
 }
 
 /**
@@ -290,7 +289,7 @@ static void amd_sched_process_job(struct fence *f, struct fence_cb *cb)
         atomic_dec(&sched->hw_rq_count);
         fence_put(&sched_job->s_fence->base);
         sched->ops->process_job(sched_job);
-        wake_up_interruptible(&sched->wait_queue);
+        wake_up_interruptible(&sched->wake_up_worker);
 }
 
 static int amd_sched_main(void *param)
@@ -306,7 +305,7 @@ static int amd_sched_main(void *param)
                 struct amd_sched_job *job;
                 struct fence *fence;
 
-                wait_event_interruptible(sched->wait_queue,
+                wait_event_interruptible(sched->wake_up_worker,
                         kthread_should_stop() ||
                         (c_entity = amd_sched_select_context(sched)));
 
@@ -329,7 +328,7 @@ static int amd_sched_main(void *param)
                         fence_put(fence);
                 }
 
-                wake_up(&c_entity->wait_queue);
+                wake_up(&sched->job_scheduled);
         }
         return 0;
 }
@@ -361,7 +360,8 @@ struct amd_gpu_scheduler *amd_sched_create(struct amd_sched_backend_ops *ops,
         amd_sched_rq_init(&sched->sched_rq);
         amd_sched_rq_init(&sched->kernel_rq);
 
-        init_waitqueue_head(&sched->wait_queue);
+        init_waitqueue_head(&sched->wake_up_worker);
+        init_waitqueue_head(&sched->job_scheduled);
         atomic_set(&sched->hw_rq_count, 0);
         /* Each scheduler will run on a seperate kernel thread */
         sched->thread = kthread_run(amd_sched_main, sched, sched->name);
diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
index 13349a6a00af..e797796dcad7 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
@@ -44,7 +44,6 @@ struct amd_sched_entity {
         struct kfifo                    job_queue;
         spinlock_t                      queue_lock;
         struct amd_gpu_scheduler        *scheduler;
-        wait_queue_head_t               wait_queue;
         uint64_t                        fence_context;
 };
 
@@ -104,7 +103,8 @@ struct amd_gpu_scheduler {
         atomic_t                        hw_rq_count;
         struct amd_sched_backend_ops    *ops;
         uint32_t                        ring_id;
-        wait_queue_head_t               wait_queue;
+        wait_queue_head_t               wake_up_worker;
+        wait_queue_head_t               job_scheduled;
         uint32_t                        hw_submission_limit;
         char                            name[20];
         void                            *priv;