drm/sched: Optimise drm_sched_entity_push_job

In FIFO mode (which is the default), both drm_sched_entity_push_job() and
drm_sched_rq_update_fifo(), where the latter calls the former, are
currently taking and releasing the same entity->rq_lock.

We can avoid that design inelegance, and also have a miniscule
efficiency improvement on the submit from idle path, by introducing a new
drm_sched_rq_update_fifo_locked() helper and pulling up the lock taking to
its callers.

v2:
 * Remove drm_sched_rq_update_fifo() altogether. (Christian)

v3:
 * Improved commit message. (Philipp)

Signed-off-by: Tvrtko Ursulin <[email protected]>
Cc: Christian König <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Luben Tuikov <[email protected]>
Cc: Matthew Brost <[email protected]>
Cc: Philipp Stanner <[email protected]>
Reviewed-by: Christian König <[email protected]>
Signed-off-by: Philipp Stanner <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 36db5c7736fc..f2d47b382bdb 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -163,14 +163,15 @@ static inline void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *enti
 	}
 }
 
-void drm_sched_rq_update_fifo(struct drm_sched_entity *entity, ktime_t ts)
+void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity, ktime_t ts)
 {
 	/*
 	 * Both locks need to be grabbed, one to protect from entity->rq change
 	 * for entity from within concurrent drm_sched_entity_select_rq and the
 	 * other to update the rb tree structure.
 	 */
-	spin_lock(&entity->rq_lock);
+	lockdep_assert_held(&entity->rq_lock);
+
 	spin_lock(&entity->rq->lock);
 
 	drm_sched_rq_remove_fifo_locked(entity);
@@ -181,7 +182,6 @@ void drm_sched_rq_update_fifo(struct drm_sched_entity *entity, ktime_t ts)
 		      drm_sched_entity_compare_before);
 
 	spin_unlock(&entity->rq->lock);
-	spin_unlock(&entity->rq_lock);
 }
 
 /**