[RFC 2/4] drm/sched: Always wake up correct scheduler in drm_sched_entity_push_job

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursu...@igalia.com>

Since drm_sched_entity_modify_sched() can modify the entities run queue
lets make sure to only derefernce the pointer once so both adding and
waking up are guaranteed to be consistent.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursu...@igalia.com>
Fixes: b37aced31eb0 ("drm/scheduler: implement a function to modify sched list")
Cc: Christian König <christian.koe...@amd.com>
Cc: Alex Deucher <alexander.deuc...@amd.com>
Cc: Luben Tuikov <ltuiko...@gmail.com>
Cc: Matthew Brost <matthew.br...@intel.com>
Cc: David Airlie <airl...@gmail.com>
Cc: Daniel Vetter <dan...@ffwll.ch>
Cc: dri-de...@lists.freedesktop.org
Cc: <sta...@vger.kernel.org> # v5.7+
---
 drivers/gpu/drm/scheduler/sched_entity.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c 
b/drivers/gpu/drm/scheduler/sched_entity.c
index ae8be30472cd..62b07ef7630a 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -599,6 +599,8 @@ void drm_sched_entity_push_job(struct drm_sched_job 
*sched_job)
 
        /* first job wakes up scheduler */
        if (first) {
+               struct drm_sched_rq *rq;
+
                /* Add the entity to the run queue */
                spin_lock(&entity->rq_lock);
                if (entity->stopped) {
@@ -608,13 +610,15 @@ void drm_sched_entity_push_job(struct drm_sched_job 
*sched_job)
                        return;
                }
 
-               drm_sched_rq_add_entity(entity->rq, entity);
+               rq = entity->rq;
+
+               drm_sched_rq_add_entity(rq, entity);
                spin_unlock(&entity->rq_lock);
 
                if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
                        drm_sched_rq_update_fifo(entity, submit_ts);
 
-               drm_sched_wakeup(entity->rq->sched, entity);
+               drm_sched_wakeup(rq->sched, entity);
        }
 }
 EXPORT_SYMBOL(drm_sched_entity_push_job);
-- 
2.46.0