drm/scheduler: Add stopped flag to drm_sched_entity

The flag will prevent another thread from same process to
reinsert the entity queue into scheduler's rq after it was already
removewd from there by another thread during drm_sched_entity_flush.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

include/drm/gpu_scheduler.h

@@ -70,6 +70,7 @@ enum drm_sched_priority {
  * @fini_status: contains the exit status in case the process was signalled.
  * @last_scheduled: points to the finished fence of the last scheduled job.
  * @last_user: last group leader pushing a job into the entity.
+ * @stopped: Marks the enity as removed from rq and destined for termination.
  *
  * Entities will emit jobs in order to their corresponding hardware
  * ring, and the scheduler will alternate between entities based on
@@ -92,6 +93,7 @@ struct drm_sched_entity {
 	atomic_t			*guilty;
 	struct dma_fence                *last_scheduled;
 	struct task_struct		*last_user;
+	bool 				stopped;
 };
 
 /**