On Tue, 2026-06-02 at 16:33 +0100, Tvrtko Ursulin wrote:
> Commit
> 28c5bf28763d ("drm/sched: Disallow initializing entities with no schedulers")
> failed to notice clearing of entity->rq in drm_sched_entity_init() is now
By clearing you also mean the setting to NULL?
I'd just use "initialization" consistently, like in the commit title.
> redundant and can be removed.
>
> Given that entity->rq can now never be NULL, we also remove two impossible
> checks, from drm_sched_entity_kill() and drm_sched_entity_flush()
> respectively.
>
> Similarly, we can also remove the !entity->rq check in
> drm_sched_job_init(). And for the better, given that the error message, if
> it ever triggered, would have dereferenced the yet un-initialized job->
> sched (only initialized later in drm_sched_job_arm()). This appears to
> have been theoretically broken ever since commit
> 56e449603f0a ("drm/sched: Convert the GPU scheduler to variable number of
> run-queues")
> .
>
> Signed-off-by: Tvrtko Ursulin <[email protected]>
> Cc: Christian König <[email protected]>
> Cc: Danilo Krummrich <[email protected]>
> Cc: Matthew Brost <[email protected]>
> Cc: Philipp Stanner <[email protected]>
> ---
> drivers/gpu/drm/scheduler/sched_entity.c | 11 ++---------
> drivers/gpu/drm/scheduler/sched_main.c | 9 ---------
> 2 files changed, 2 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/scheduler/sched_entity.c
> b/drivers/gpu/drm/scheduler/sched_entity.c
> index 4ebb513255ed..c51101ec70c1 100644
> --- a/drivers/gpu/drm/scheduler/sched_entity.c
> +++ b/drivers/gpu/drm/scheduler/sched_entity.c
> @@ -129,7 +129,6 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
> return -ENOMEM;
>
> INIT_LIST_HEAD(&entity->list);
> - entity->rq = NULL;
It would seem that has always been redundant because of the memset(0)
directly above.
> entity->guilty = guilty;
> entity->priority = priority;
> entity->last_user = current->group_leader;
> @@ -280,9 +279,6 @@ void drm_sched_entity_kill(struct drm_sched_entity
> *entity)
> struct drm_sched_job *job;
> struct dma_fence *prev;
>
> - if (!entity->rq)
> - return;
> -
> spin_lock(&entity->lock);
> entity->stopped = true;
> drm_sched_rq_remove_entity(entity->rq, entity);
> @@ -329,14 +325,11 @@ EXPORT_SYMBOL(drm_sched_entity_kill);
> */
> long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout)
> {
> - struct drm_gpu_scheduler *sched;
> + struct drm_gpu_scheduler *sched =
> + container_of(entity->rq, typeof(*sched), rq);
> struct task_struct *last_user;
> long ret = timeout;
>
> - if (!entity->rq)
> - return 0;
> -
> - sched = container_of(entity->rq, typeof(*sched), rq);
> /*
> * The client will not queue more jobs during this fini - consume
> * existing queued ones, or discard them on SIGKILL.
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c
> b/drivers/gpu/drm/scheduler/sched_main.c
> index 818d3d4434b5..d2ca01b31ee4 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -588,15 +588,6 @@ int drm_sched_job_init(struct drm_sched_job *job,
> u32 credits, void *owner,
> uint64_t drm_client_id)
> {
> - if (!entity->rq) {
> - /* This will most likely be followed by missing frames
> - * or worse--a blank screen--leave a trail in the
> - * logs, so this can be debugged easier.
> - */
> - dev_err(job->sched->dev, "%s: entity has no rq!\n", __func__);
> - return -ENOENT;
> - }
> -
> if (unlikely(!credits)) {
> pr_err("*ERROR* %s: credits cannot be 0!\n", __func__);
> return -EINVAL;
But overall a very nice cleanup
P.
