Am 09.09.24 um 19:19 schrieb Tvrtko Ursulin:

From: Tvrtko Ursulin tvrtko.ursulin@igalia.com

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

Alternative of moving the spin_unlock to after the wake up would for now be more problematic since the same lock is taken inside drm_sched_rq_update_fifo().

v2:

• Improve commit message. (Philipp)
• Cache the scheduler pointer directly. (Christian)

Signed-off-by: Tvrtko Ursulin tvrtko.ursulin@igalia.com Fixes: b37aced31eb0 ("drm/scheduler: implement a function to modify sched list") Cc: Christian König christian.koenig@amd.com Cc: Alex Deucher alexander.deucher@amd.com Cc: Luben Tuikov ltuikov89@gmail.com Cc: Matthew Brost matthew.brost@intel.com Cc: David Airlie airlied@gmail.com Cc: Daniel Vetter daniel@ffwll.ch Cc: Philipp Stanner pstanner@redhat.com Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v5.7+

---

drivers/gpu/drm/scheduler/sched_entity.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index ae8be30472cd..76e422548d40 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -599,6 +599,9 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job) /* first job wakes up scheduler */ if (first) {

• struct drm_gpu_scheduler *sched;
  

• struct drm_sched_rq *rq;
  

• /* Add the entity to the run queue */ spin_lock(&entity->rq_lock); if (entity->stopped) {

@@ -608,13 +611,16 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job) return; }

• drm_sched_rq_add_entity(entity->rq, entity);
  

• rq = entity->rq;
  

• sched = rq->sched;
  

The rq variable is now not needed any more except for getting the scheduler, isn't it? If yes I would ditch that as well.

Either way Reviewed-by: Christian König christian.koenig@amd.com to this patch.

Regards, Christian.

• 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(sched, entity);
  

  } } EXPORT_SYMBOL(drm_sched_entity_push_job);