[v4,01/18] drm/sched: Split drm_sched_job_init

Commit Message

Daniel Vetter July 12, 2021, 5:53 p.m. UTC

This is a very confusingly named function, because not just does it
init an object, it arms it and provides a point of no return for
pushing a job into the scheduler. It would be nice if that's a bit
clearer in the interface.

But the real reason is that I want to push the dependency tracking
helpers into the scheduler code, and that means drm_sched_job_init
must be called a lot earlier, without arming the job.

v2:
- don't change .gitignore (Steven)
- don't forget v3d (Emma)

v3: Emma noticed that I leak the memory allocated in
drm_sched_job_init if we bail out before the point of no return in
subsequent driver patches. To be able to fix this change
drm_sched_job_cleanup() so it can handle being called both before and
after drm_sched_job_arm().

Also improve the kerneldoc for this.

v4:
- Fix the drm_sched_job_cleanup logic, I inverted the booleans, as
  usual (Melissa)

- Christian pointed out that drm_sched_entity_select_rq() also needs
  to be moved into drm_sched_job_arm, which made me realize that the
  job->id definitely needs to be moved too.

  Shuffle things to fit between job_init and job_arm.

v5:
Reshuffle the split between init/arm once more, amdgpu abuses
drm_sched.ready to signal gpu reset failures. Also document this
somewhat. (Christian)

Cc: Melissa Wen <[e-mail]>
Acked-by: Steven Price <[e-mail]> (v2)
Signed-off-by: Daniel Vetter <[e-mail]>
Cc: Lucas Stach <[e-mail]>
Cc: Russell King <[e-mail]>
Cc: Christian Gmeiner <[e-mail]>
Cc: Qiang Yu <[e-mail]>
Cc: Rob Herring <[e-mail]>
Cc: Tomeu Vizoso <[e-mail]>
Cc: Steven Price <[e-mail]>
Cc: Alyssa Rosenzweig <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: Sumit Semwal <[e-mail]>
Cc: "Christian König" <[e-mail]>
Cc: Masahiro Yamada <[e-mail]>
Cc: Kees Cook <[e-mail]>
Cc: Adam Borowski <[e-mail]>
Cc: Nick Terrell <[e-mail]>
Cc: Mauro Carvalho Chehab <[e-mail]>
Cc: Paul Menzel <[e-mail]>
Cc: Sami Tolvanen <[e-mail]>
Cc: Viresh Kumar <[e-mail]>
Cc: Alex Deucher <[e-mail]>
Cc: Dave Airlie <[e-mail]>
Cc: Nirmoy Das <[e-mail]>
Cc: Deepak R Varma <[e-mail]>
Cc: Lee Jones <[e-mail]>
Cc: Kevin Wang <[e-mail]>
Cc: Chen Li <[e-mail]>
Cc: Luben Tuikov <[e-mail]>
Cc: "Marek Olšák" <[e-mail]>
Cc: Dennis Li <[e-mail]>
Cc: Maarten Lankhorst <[e-mail]>
Cc: Andrey Grodzovsky <[e-mail]>
Cc: Sonny Jiang <[e-mail]>
Cc: Boris Brezillon <[e-mail]>
Cc: Tian Tao <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: Emma Anholt <[e-mail]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c   |  2 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_job.c  |  2 +
 drivers/gpu/drm/etnaviv/etnaviv_sched.c  |  2 +
 drivers/gpu/drm/lima/lima_sched.c        |  2 +
 drivers/gpu/drm/panfrost/panfrost_job.c  |  2 +
 drivers/gpu/drm/scheduler/sched_entity.c |  6 +--
 drivers/gpu/drm/scheduler/sched_fence.c  | 19 ++++---
 drivers/gpu/drm/scheduler/sched_main.c   | 69 ++++++++++++++++++++----
 drivers/gpu/drm/v3d/v3d_gem.c            |  2 +
 include/drm/gpu_scheduler.h              |  7 ++-
 10 files changed, 91 insertions(+), 22 deletions(-)

Comments

Emma Anholt July 12, 2021, 8:22 p.m. UTC | #1

On Mon, Jul 12, 2021 at 1:01 PM Daniel Vetter <[e-mail]> wrote:
>
> This is a very confusingly named function, because not just does it
> init an object, it arms it and provides a point of no return for
> pushing a job into the scheduler. It would be nice if that's a bit
> clearer in the interface.
>
> But the real reason is that I want to push the dependency tracking
> helpers into the scheduler code, and that means drm_sched_job_init
> must be called a lot earlier, without arming the job.
>
> v2:
> - don't change .gitignore (Steven)
> - don't forget v3d (Emma)
>
> v3: Emma noticed that I leak the memory allocated in
> drm_sched_job_init if we bail out before the point of no return in
> subsequent driver patches. To be able to fix this change
> drm_sched_job_cleanup() so it can handle being called both before and
> after drm_sched_job_arm().
>
> Also improve the kerneldoc for this.
>
> v4:
> - Fix the drm_sched_job_cleanup logic, I inverted the booleans, as
>   usual (Melissa)
>
> - Christian pointed out that drm_sched_entity_select_rq() also needs
>   to be moved into drm_sched_job_arm, which made me realize that the
>   job->id definitely needs to be moved too.
>
>   Shuffle things to fit between job_init and job_arm.
>
> v5:
> Reshuffle the split between init/arm once more, amdgpu abuses
> drm_sched.ready to signal gpu reset failures. Also document this
> somewhat. (Christian)

Ack from me for the changes I was Cced on.

Christian König July 13, 2021, 6:40 a.m. UTC | #2

Am 12.07.21 um 19:53 schrieb Daniel Vetter:
> This is a very confusingly named function, because not just does it
> init an object, it arms it and provides a point of no return for
> pushing a job into the scheduler. It would be nice if that's a bit
> clearer in the interface.
>
> But the real reason is that I want to push the dependency tracking
> helpers into the scheduler code, and that means drm_sched_job_init
> must be called a lot earlier, without arming the job.
>
> v2:
> - don't change .gitignore (Steven)
> - don't forget v3d (Emma)
>
> v3: Emma noticed that I leak the memory allocated in
> drm_sched_job_init if we bail out before the point of no return in
> subsequent driver patches. To be able to fix this change
> drm_sched_job_cleanup() so it can handle being called both before and
> after drm_sched_job_arm().
>
> Also improve the kerneldoc for this.
>
> v4:
> - Fix the drm_sched_job_cleanup logic, I inverted the booleans, as
>    usual (Melissa)
>
> - Christian pointed out that drm_sched_entity_select_rq() also needs
>    to be moved into drm_sched_job_arm, which made me realize that the
>    job->id definitely needs to be moved too.

As far as I can see you still have drm_sched_entity_select_rq() in 
drm_sched_job_init()?

Christian.

>
>    Shuffle things to fit between job_init and job_arm.
>
> v5:
> Reshuffle the split between init/arm once more, amdgpu abuses
> drm_sched.ready to signal gpu reset failures. Also document this
> somewhat. (Christian)
>
> Cc: Melissa Wen <[e-mail]>
> Acked-by: Steven Price <[e-mail]> (v2)
> Signed-off-by: Daniel Vetter <[e-mail]>
> Cc: Lucas Stach <[e-mail]>
> Cc: Russell King <[e-mail]>
> Cc: Christian Gmeiner <[e-mail]>
> Cc: Qiang Yu <[e-mail]>
> Cc: Rob Herring <[e-mail]>
> Cc: Tomeu Vizoso <[e-mail]>
> Cc: Steven Price <[e-mail]>
> Cc: Alyssa Rosenzweig <[e-mail]>
> Cc: David Airlie <[e-mail]>
> Cc: Daniel Vetter <[e-mail]>
> Cc: Sumit Semwal <[e-mail]>
> Cc: "Christian König" <[e-mail]>
> Cc: Masahiro Yamada <[e-mail]>
> Cc: Kees Cook <[e-mail]>
> Cc: Adam Borowski <[e-mail]>
> Cc: Nick Terrell <[e-mail]>
> Cc: Mauro Carvalho Chehab <[e-mail]>
> Cc: Paul Menzel <[e-mail]>
> Cc: Sami Tolvanen <[e-mail]>
> Cc: Viresh Kumar <[e-mail]>
> Cc: Alex Deucher <[e-mail]>
> Cc: Dave Airlie <[e-mail]>
> Cc: Nirmoy Das <[e-mail]>
> Cc: Deepak R Varma <[e-mail]>
> Cc: Lee Jones <[e-mail]>
> Cc: Kevin Wang <[e-mail]>
> Cc: Chen Li <[e-mail]>
> Cc: Luben Tuikov <[e-mail]>
> Cc: "Marek Olšák" <[e-mail]>
> Cc: Dennis Li <[e-mail]>
> Cc: Maarten Lankhorst <[e-mail]>
> Cc: Andrey Grodzovsky <[e-mail]>
> Cc: Sonny Jiang <[e-mail]>
> Cc: Boris Brezillon <[e-mail]>
> Cc: Tian Tao <[e-mail]>
> Cc: [e-mail]
> Cc: [e-mail]
> Cc: [e-mail]
> Cc: [e-mail]
> Cc: Emma Anholt <[e-mail]>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c   |  2 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_job.c  |  2 +
>   drivers/gpu/drm/etnaviv/etnaviv_sched.c  |  2 +
>   drivers/gpu/drm/lima/lima_sched.c        |  2 +
>   drivers/gpu/drm/panfrost/panfrost_job.c  |  2 +
>   drivers/gpu/drm/scheduler/sched_entity.c |  6 +--
>   drivers/gpu/drm/scheduler/sched_fence.c  | 19 ++++---
>   drivers/gpu/drm/scheduler/sched_main.c   | 69 ++++++++++++++++++++----
>   drivers/gpu/drm/v3d/v3d_gem.c            |  2 +
>   include/drm/gpu_scheduler.h              |  7 ++-
>   10 files changed, 91 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index c5386d13eb4a..a4ec092af9a7 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -1226,6 +1226,8 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
>   	if (r)
>   		goto error_unlock;
>   
> +	drm_sched_job_arm(&job->base);
> +
>   	/* No memory allocation is allowed while holding the notifier lock.
>   	 * The lock is held until amdgpu_cs_submit is finished and fence is
>   	 * added to BOs.
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> index d33e6d97cc89..5ddb955d2315 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> @@ -170,6 +170,8 @@ int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity,
>   	if (r)
>   		return r;
>   
> +	drm_sched_job_arm(&job->base);
> +
>   	*f = dma_fence_get(&job->base.s_fence->finished);
>   	amdgpu_job_free_resources(job);
>   	drm_sched_entity_push_job(&job->base, entity);
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> index feb6da1b6ceb..05f412204118 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> @@ -163,6 +163,8 @@ int etnaviv_sched_push_job(struct drm_sched_entity *sched_entity,
>   	if (ret)
>   		goto out_unlock;
>   
> +	drm_sched_job_arm(&submit->sched_job);
> +
>   	submit->out_fence = dma_fence_get(&submit->sched_job.s_fence->finished);
>   	submit->out_fence_id = idr_alloc_cyclic(&submit->gpu->fence_idr,
>   						submit->out_fence, 0,
> diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
> index dba8329937a3..38f755580507 100644
> --- a/drivers/gpu/drm/lima/lima_sched.c
> +++ b/drivers/gpu/drm/lima/lima_sched.c
> @@ -129,6 +129,8 @@ int lima_sched_task_init(struct lima_sched_task *task,
>   		return err;
>   	}
>   
> +	drm_sched_job_arm(&task->base);
> +
>   	task->num_bos = num_bos;
>   	task->vm = lima_vm_get(vm);
>   
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 71a72fb50e6b..2992dc85325f 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -288,6 +288,8 @@ int panfrost_job_push(struct panfrost_job *job)
>   		goto unlock;
>   	}
>   
> +	drm_sched_job_arm(&job->base);
> +
>   	job->render_done_fence = dma_fence_get(&job->base.s_fence->finished);
>   
>   	ret = panfrost_acquire_object_fences(job->bos, job->bo_count,
> diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
> index 79554aa4dbb1..f7347c284886 100644
> --- a/drivers/gpu/drm/scheduler/sched_entity.c
> +++ b/drivers/gpu/drm/scheduler/sched_entity.c
> @@ -485,9 +485,9 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
>    * @sched_job: job to submit
>    * @entity: scheduler entity
>    *
> - * Note: To guarantee that the order of insertion to queue matches
> - * the job's fence sequence number this function should be
> - * called with drm_sched_job_init under common lock.
> + * Note: To guarantee that the order of insertion to queue matches the job's
> + * fence sequence number this function should be called with drm_sched_job_arm()
> + * under common lock.
>    *
>    * Returns 0 for success, negative error code otherwise.
>    */
> diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c
> index 69de2c76731f..bcea035cf4c6 100644
> --- a/drivers/gpu/drm/scheduler/sched_fence.c
> +++ b/drivers/gpu/drm/scheduler/sched_fence.c
> @@ -90,7 +90,7 @@ static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f)
>    *
>    * Free up the fence memory after the RCU grace period.
>    */
> -static void drm_sched_fence_free(struct rcu_head *rcu)
> +void drm_sched_fence_free(struct rcu_head *rcu)
>   {
>   	struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
>   	struct drm_sched_fence *fence = to_drm_sched_fence(f);
> @@ -152,27 +152,32 @@ struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f)
>   }
>   EXPORT_SYMBOL(to_drm_sched_fence);
>   
> -struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity,
> -					       void *owner)
> +struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity,
> +					      void *owner)
>   {
>   	struct drm_sched_fence *fence = NULL;
> -	unsigned seq;
>   
>   	fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL);
>   	if (fence == NULL)
>   		return NULL;
>   
>   	fence->owner = owner;
> -	fence->sched = entity->rq->sched;
>   	spin_lock_init(&fence->lock);
>   
> +	return fence;
> +}
> +
> +void drm_sched_fence_init(struct drm_sched_fence *fence,
> +			  struct drm_sched_entity *entity)
> +{
> +	unsigned seq;
> +
> +	fence->sched = entity->rq->sched;
>   	seq = atomic_inc_return(&entity->fence_seq);
>   	dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled,
>   		       &fence->lock, entity->fence_context, seq);
>   	dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished,
>   		       &fence->lock, entity->fence_context + 1, seq);
> -
> -	return fence;
>   }
>   
>   module_init(drm_sched_fence_slab_init);
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index 33c414d55fab..454cb6164bdc 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -48,9 +48,11 @@
>   #include <linux/wait.h>
>   #include <linux/sched.h>
>   #include <linux/completion.h>
> +#include <linux/dma-resv.h>
>   #include <uapi/linux/sched/types.h>
>   
>   #include <drm/drm_print.h>
> +#include <drm/drm_gem.h>
>   #include <drm/gpu_scheduler.h>
>   #include <drm/spsc_queue.h>
>   
> @@ -569,7 +571,6 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
>   
>   /**
>    * drm_sched_job_init - init a scheduler job
> - *
>    * @job: scheduler job to init
>    * @entity: scheduler entity to use
>    * @owner: job owner for debugging
> @@ -577,27 +578,28 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
>    * Refer to drm_sched_entity_push_job() documentation
>    * for locking considerations.
>    *
> + * Drivers must make sure drm_sched_job_cleanup() if this function returns
> + * successfully, even when @job is aborted before drm_sched_job_arm() is called.
> + *
> + * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware
> + * has died, which can mean that there's no valid runqueue for a @entity.
> + * This function returns -ENOENT in this case (which probably should be -EIO as
> + * a more meanigful return value).
> + *
>    * Returns 0 for success, negative error code otherwise.
>    */
>   int drm_sched_job_init(struct drm_sched_job *job,
>   		       struct drm_sched_entity *entity,
>   		       void *owner)
>   {
> -	struct drm_gpu_scheduler *sched;
> -
>   	drm_sched_entity_select_rq(entity);
>   	if (!entity->rq)
>   		return -ENOENT;
>   
> -	sched = entity->rq->sched;
> -
> -	job->sched = sched;
>   	job->entity = entity;
> -	job->s_priority = entity->rq - sched->sched_rq;
> -	job->s_fence = drm_sched_fence_create(entity, owner);
> +	job->s_fence = drm_sched_fence_alloc(entity, owner);
>   	if (!job->s_fence)
>   		return -ENOMEM;
> -	job->id = atomic64_inc_return(&sched->job_id_count);
>   
>   	INIT_LIST_HEAD(&job->list);
>   
> @@ -606,13 +608,58 @@ int drm_sched_job_init(struct drm_sched_job *job,
>   EXPORT_SYMBOL(drm_sched_job_init);
>   
>   /**
> - * drm_sched_job_cleanup - clean up scheduler job resources
> + * drm_sched_job_arm - arm a scheduler job for execution
> + * @job: scheduler job to arm
> + *
> + * This arms a scheduler job for execution. Specifically it initializes the
> + * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv
> + * or other places that need to track the completion of this job.
> + *
> + * Refer to drm_sched_entity_push_job() documentation for locking
> + * considerations.
>    *
> + * This can only be called if drm_sched_job_init() succeeded.
> + */
> +void drm_sched_job_arm(struct drm_sched_job *job)
> +{
> +	struct drm_gpu_scheduler *sched;
> +	struct drm_sched_entity *entity = job->entity;
> +
> +	BUG_ON(!entity);
> +
> +	sched = entity->rq->sched;
> +
> +	job->sched = sched;
> +	job->s_priority = entity->rq - sched->sched_rq;
> +	job->id = atomic64_inc_return(&sched->job_id_count);
> +
> +	drm_sched_fence_init(job->s_fence, job->entity);
> +}
> +EXPORT_SYMBOL(drm_sched_job_arm);
> +
> +/**
> + * drm_sched_job_cleanup - clean up scheduler job resources
>    * @job: scheduler job to clean up
> + *
> + * Cleans up the resources allocated with drm_sched_job_init().
> + *
> + * Drivers should call this from their error unwind code if @job is aborted
> + * before drm_sched_job_arm() is called.
> + *
> + * After that point of no return @job is committed to be executed by the
> + * scheduler, and this function should be called from the
> + * &drm_sched_backend_ops.free_job callback.
>    */
>   void drm_sched_job_cleanup(struct drm_sched_job *job)
>   {
> -	dma_fence_put(&job->s_fence->finished);
> +	if (kref_read(&job->s_fence->finished.refcount)) {
> +		/* drm_sched_job_arm() has been called */
> +		dma_fence_put(&job->s_fence->finished);
> +	} else {
> +		/* aborted job before committing to run it */
> +		drm_sched_fence_free(&job->s_fence->finished.rcu);
> +	}
> +
>   	job->s_fence = NULL;
>   }
>   EXPORT_SYMBOL(drm_sched_job_cleanup);
> diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
> index 4eb354226972..5c3a99027ecd 100644
> --- a/drivers/gpu/drm/v3d/v3d_gem.c
> +++ b/drivers/gpu/drm/v3d/v3d_gem.c
> @@ -475,6 +475,8 @@ v3d_push_job(struct v3d_file_priv *v3d_priv,
>   	if (ret)
>   		return ret;
>   
> +	drm_sched_job_arm(&job->base);
> +
>   	job->done_fence = dma_fence_get(&job->base.s_fence->finished);
>   
>   	/* put by scheduler job completion */
> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> index 88ae7f331bb1..83afc3aa8e2f 100644
> --- a/include/drm/gpu_scheduler.h
> +++ b/include/drm/gpu_scheduler.h
> @@ -348,6 +348,7 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched);
>   int drm_sched_job_init(struct drm_sched_job *job,
>   		       struct drm_sched_entity *entity,
>   		       void *owner);
> +void drm_sched_job_arm(struct drm_sched_job *job);
>   void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
>   				    struct drm_gpu_scheduler **sched_list,
>                                      unsigned int num_sched_list);
> @@ -387,8 +388,12 @@ void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
>   				   enum drm_sched_priority priority);
>   bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
>   
> -struct drm_sched_fence *drm_sched_fence_create(
> +struct drm_sched_fence *drm_sched_fence_alloc(
>   	struct drm_sched_entity *s_entity, void *owner);
> +void drm_sched_fence_init(struct drm_sched_fence *fence,
> +			  struct drm_sched_entity *entity);
> +void drm_sched_fence_free(struct rcu_head *rcu);
> +
>   void drm_sched_fence_scheduled(struct drm_sched_fence *fence);
>   void drm_sched_fence_finished(struct drm_sched_fence *fence);
>

Daniel Vetter July 13, 2021, 6:53 a.m. UTC | #3

On Tue, Jul 13, 2021 at 8:40 AM Christian König
<[e-mail]> wrote:
>
> Am 12.07.21 um 19:53 schrieb Daniel Vetter:
> > This is a very confusingly named function, because not just does it
> > init an object, it arms it and provides a point of no return for
> > pushing a job into the scheduler. It would be nice if that's a bit
> > clearer in the interface.
> >
> > But the real reason is that I want to push the dependency tracking
> > helpers into the scheduler code, and that means drm_sched_job_init
> > must be called a lot earlier, without arming the job.
> >
> > v2:
> > - don't change .gitignore (Steven)
> > - don't forget v3d (Emma)
> >
> > v3: Emma noticed that I leak the memory allocated in
> > drm_sched_job_init if we bail out before the point of no return in
> > subsequent driver patches. To be able to fix this change
> > drm_sched_job_cleanup() so it can handle being called both before and
> > after drm_sched_job_arm().
> >
> > Also improve the kerneldoc for this.
> >
> > v4:
> > - Fix the drm_sched_job_cleanup logic, I inverted the booleans, as
> >    usual (Melissa)
> >
> > - Christian pointed out that drm_sched_entity_select_rq() also needs
> >    to be moved into drm_sched_job_arm, which made me realize that the
> >    job->id definitely needs to be moved too.
>
> As far as I can see you still have drm_sched_entity_select_rq() in
> drm_sched_job_init()?

Yeah it's again in there, but everything else which changes entity->rq
state isn't in there anymore, but in job_arm(). I also checked the
cleanup code, and we only update entity state in there, not job state,
so there's no additional complications for cleanup.

Of course this is quite a bit earlier, than if we do it in job_arm(),
but also not fundamentally a new race window. Just a bigger one, so
assuming the current code is correct, should be all fine. But also,
very possible I missed something else again :-)
-Daniel

> Christian.
>
> >
> >    Shuffle things to fit between job_init and job_arm.
> >
> > v5:
> > Reshuffle the split between init/arm once more, amdgpu abuses
> > drm_sched.ready to signal gpu reset failures. Also document this
> > somewhat. (Christian)
> >
> > Cc: Melissa Wen <[e-mail]>
> > Acked-by: Steven Price <[e-mail]> (v2)
> > Signed-off-by: Daniel Vetter <[e-mail]>
> > Cc: Lucas Stach <[e-mail]>
> > Cc: Russell King <[e-mail]>
> > Cc: Christian Gmeiner <[e-mail]>
> > Cc: Qiang Yu <[e-mail]>
> > Cc: Rob Herring <[e-mail]>
> > Cc: Tomeu Vizoso <[e-mail]>
> > Cc: Steven Price <[e-mail]>
> > Cc: Alyssa Rosenzweig <[e-mail]>
> > Cc: David Airlie <[e-mail]>
> > Cc: Daniel Vetter <[e-mail]>
> > Cc: Sumit Semwal <[e-mail]>
> > Cc: "Christian König" <[e-mail]>
> > Cc: Masahiro Yamada <[e-mail]>
> > Cc: Kees Cook <[e-mail]>
> > Cc: Adam Borowski <[e-mail]>
> > Cc: Nick Terrell <[e-mail]>
> > Cc: Mauro Carvalho Chehab <[e-mail]>
> > Cc: Paul Menzel <[e-mail]>
> > Cc: Sami Tolvanen <[e-mail]>
> > Cc: Viresh Kumar <[e-mail]>
> > Cc: Alex Deucher <[e-mail]>
> > Cc: Dave Airlie <[e-mail]>
> > Cc: Nirmoy Das <[e-mail]>
> > Cc: Deepak R Varma <[e-mail]>
> > Cc: Lee Jones <[e-mail]>
> > Cc: Kevin Wang <[e-mail]>
> > Cc: Chen Li <[e-mail]>
> > Cc: Luben Tuikov <[e-mail]>
> > Cc: "Marek Olšák" <[e-mail]>
> > Cc: Dennis Li <[e-mail]>
> > Cc: Maarten Lankhorst <[e-mail]>
> > Cc: Andrey Grodzovsky <[e-mail]>
> > Cc: Sonny Jiang <[e-mail]>
> > Cc: Boris Brezillon <[e-mail]>
> > Cc: Tian Tao <[e-mail]>
> > Cc: [e-mail]
> > Cc: [e-mail]
> > Cc: [e-mail]
> > Cc: [e-mail]
> > Cc: Emma Anholt <[e-mail]>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c   |  2 +
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_job.c  |  2 +
> >   drivers/gpu/drm/etnaviv/etnaviv_sched.c  |  2 +
> >   drivers/gpu/drm/lima/lima_sched.c        |  2 +
> >   drivers/gpu/drm/panfrost/panfrost_job.c  |  2 +
> >   drivers/gpu/drm/scheduler/sched_entity.c |  6 +--
> >   drivers/gpu/drm/scheduler/sched_fence.c  | 19 ++++---
> >   drivers/gpu/drm/scheduler/sched_main.c   | 69 ++++++++++++++++++++----
> >   drivers/gpu/drm/v3d/v3d_gem.c            |  2 +
> >   include/drm/gpu_scheduler.h              |  7 ++-
> >   10 files changed, 91 insertions(+), 22 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > index c5386d13eb4a..a4ec092af9a7 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > @@ -1226,6 +1226,8 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
> >       if (r)
> >               goto error_unlock;
> >
> > +     drm_sched_job_arm(&job->base);
> > +
> >       /* No memory allocation is allowed while holding the notifier lock.
> >        * The lock is held until amdgpu_cs_submit is finished and fence is
> >        * added to BOs.
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> > index d33e6d97cc89..5ddb955d2315 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> > @@ -170,6 +170,8 @@ int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity,
> >       if (r)
> >               return r;
> >
> > +     drm_sched_job_arm(&job->base);
> > +
> >       *f = dma_fence_get(&job->base.s_fence->finished);
> >       amdgpu_job_free_resources(job);
> >       drm_sched_entity_push_job(&job->base, entity);
> > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> > index feb6da1b6ceb..05f412204118 100644
> > --- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> > +++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
> > @@ -163,6 +163,8 @@ int etnaviv_sched_push_job(struct drm_sched_entity *sched_entity,
> >       if (ret)
> >               goto out_unlock;
> >
> > +     drm_sched_job_arm(&submit->sched_job);
> > +
> >       submit->out_fence = dma_fence_get(&submit->sched_job.s_fence->finished);
> >       submit->out_fence_id = idr_alloc_cyclic(&submit->gpu->fence_idr,
> >                                               submit->out_fence, 0,
> > diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
> > index dba8329937a3..38f755580507 100644
> > --- a/drivers/gpu/drm/lima/lima_sched.c
> > +++ b/drivers/gpu/drm/lima/lima_sched.c
> > @@ -129,6 +129,8 @@ int lima_sched_task_init(struct lima_sched_task *task,
> >               return err;
> >       }
> >
> > +     drm_sched_job_arm(&task->base);
> > +
> >       task->num_bos = num_bos;
> >       task->vm = lima_vm_get(vm);
> >
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> > index 71a72fb50e6b..2992dc85325f 100644
> > --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> > +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> > @@ -288,6 +288,8 @@ int panfrost_job_push(struct panfrost_job *job)
> >               goto unlock;
> >       }
> >
> > +     drm_sched_job_arm(&job->base);
> > +
> >       job->render_done_fence = dma_fence_get(&job->base.s_fence->finished);
> >
> >       ret = panfrost_acquire_object_fences(job->bos, job->bo_count,
> > diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
> > index 79554aa4dbb1..f7347c284886 100644
> > --- a/drivers/gpu/drm/scheduler/sched_entity.c
> > +++ b/drivers/gpu/drm/scheduler/sched_entity.c
> > @@ -485,9 +485,9 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
> >    * @sched_job: job to submit
> >    * @entity: scheduler entity
> >    *
> > - * Note: To guarantee that the order of insertion to queue matches
> > - * the job's fence sequence number this function should be
> > - * called with drm_sched_job_init under common lock.
> > + * Note: To guarantee that the order of insertion to queue matches the job's
> > + * fence sequence number this function should be called with drm_sched_job_arm()
> > + * under common lock.
> >    *
> >    * Returns 0 for success, negative error code otherwise.
> >    */
> > diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c
> > index 69de2c76731f..bcea035cf4c6 100644
> > --- a/drivers/gpu/drm/scheduler/sched_fence.c
> > +++ b/drivers/gpu/drm/scheduler/sched_fence.c
> > @@ -90,7 +90,7 @@ static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f)
> >    *
> >    * Free up the fence memory after the RCU grace period.
> >    */
> > -static void drm_sched_fence_free(struct rcu_head *rcu)
> > +void drm_sched_fence_free(struct rcu_head *rcu)
> >   {
> >       struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
> >       struct drm_sched_fence *fence = to_drm_sched_fence(f);
> > @@ -152,27 +152,32 @@ struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f)
> >   }
> >   EXPORT_SYMBOL(to_drm_sched_fence);
> >
> > -struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity,
> > -                                            void *owner)
> > +struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity,
> > +                                           void *owner)
> >   {
> >       struct drm_sched_fence *fence = NULL;
> > -     unsigned seq;
> >
> >       fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL);
> >       if (fence == NULL)
> >               return NULL;
> >
> >       fence->owner = owner;
> > -     fence->sched = entity->rq->sched;
> >       spin_lock_init(&fence->lock);
> >
> > +     return fence;
> > +}
> > +
> > +void drm_sched_fence_init(struct drm_sched_fence *fence,
> > +                       struct drm_sched_entity *entity)
> > +{
> > +     unsigned seq;
> > +
> > +     fence->sched = entity->rq->sched;
> >       seq = atomic_inc_return(&entity->fence_seq);
> >       dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled,
> >                      &fence->lock, entity->fence_context, seq);
> >       dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished,
> >                      &fence->lock, entity->fence_context + 1, seq);
> > -
> > -     return fence;
> >   }
> >
> >   module_init(drm_sched_fence_slab_init);
> > diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> > index 33c414d55fab..454cb6164bdc 100644
> > --- a/drivers/gpu/drm/scheduler/sched_main.c
> > +++ b/drivers/gpu/drm/scheduler/sched_main.c
> > @@ -48,9 +48,11 @@
> >   #include <linux/wait.h>
> >   #include <linux/sched.h>
> >   #include <linux/completion.h>
> > +#include <linux/dma-resv.h>
> >   #include <uapi/linux/sched/types.h>
> >
> >   #include <drm/drm_print.h>
> > +#include <drm/drm_gem.h>
> >   #include <drm/gpu_scheduler.h>
> >   #include <drm/spsc_queue.h>
> >
> > @@ -569,7 +571,6 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
> >
> >   /**
> >    * drm_sched_job_init - init a scheduler job
> > - *
> >    * @job: scheduler job to init
> >    * @entity: scheduler entity to use
> >    * @owner: job owner for debugging
> > @@ -577,27 +578,28 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
> >    * Refer to drm_sched_entity_push_job() documentation
> >    * for locking considerations.
> >    *
> > + * Drivers must make sure drm_sched_job_cleanup() if this function returns
> > + * successfully, even when @job is aborted before drm_sched_job_arm() is called.
> > + *
> > + * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware
> > + * has died, which can mean that there's no valid runqueue for a @entity.
> > + * This function returns -ENOENT in this case (which probably should be -EIO as
> > + * a more meanigful return value).
> > + *
> >    * Returns 0 for success, negative error code otherwise.
> >    */
> >   int drm_sched_job_init(struct drm_sched_job *job,
> >                      struct drm_sched_entity *entity,
> >                      void *owner)
> >   {
> > -     struct drm_gpu_scheduler *sched;
> > -
> >       drm_sched_entity_select_rq(entity);
> >       if (!entity->rq)
> >               return -ENOENT;
> >
> > -     sched = entity->rq->sched;
> > -
> > -     job->sched = sched;
> >       job->entity = entity;
> > -     job->s_priority = entity->rq - sched->sched_rq;
> > -     job->s_fence = drm_sched_fence_create(entity, owner);
> > +     job->s_fence = drm_sched_fence_alloc(entity, owner);
> >       if (!job->s_fence)
> >               return -ENOMEM;
> > -     job->id = atomic64_inc_return(&sched->job_id_count);
> >
> >       INIT_LIST_HEAD(&job->list);
> >
> > @@ -606,13 +608,58 @@ int drm_sched_job_init(struct drm_sched_job *job,
> >   EXPORT_SYMBOL(drm_sched_job_init);
> >
> >   /**
> > - * drm_sched_job_cleanup - clean up scheduler job resources
> > + * drm_sched_job_arm - arm a scheduler job for execution
> > + * @job: scheduler job to arm
> > + *
> > + * This arms a scheduler job for execution. Specifically it initializes the
> > + * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv
> > + * or other places that need to track the completion of this job.
> > + *
> > + * Refer to drm_sched_entity_push_job() documentation for locking
> > + * considerations.
> >    *
> > + * This can only be called if drm_sched_job_init() succeeded.
> > + */
> > +void drm_sched_job_arm(struct drm_sched_job *job)
> > +{
> > +     struct drm_gpu_scheduler *sched;
> > +     struct drm_sched_entity *entity = job->entity;
> > +
> > +     BUG_ON(!entity);
> > +
> > +     sched = entity->rq->sched;
> > +
> > +     job->sched = sched;
> > +     job->s_priority = entity->rq - sched->sched_rq;
> > +     job->id = atomic64_inc_return(&sched->job_id_count);
> > +
> > +     drm_sched_fence_init(job->s_fence, job->entity);
> > +}
> > +EXPORT_SYMBOL(drm_sched_job_arm);
> > +
> > +/**
> > + * drm_sched_job_cleanup - clean up scheduler job resources
> >    * @job: scheduler job to clean up
> > + *
> > + * Cleans up the resources allocated with drm_sched_job_init().
> > + *
> > + * Drivers should call this from their error unwind code if @job is aborted
> > + * before drm_sched_job_arm() is called.
> > + *
> > + * After that point of no return @job is committed to be executed by the
> > + * scheduler, and this function should be called from the
> > + * &drm_sched_backend_ops.free_job callback.
> >    */
> >   void drm_sched_job_cleanup(struct drm_sched_job *job)
> >   {
> > -     dma_fence_put(&job->s_fence->finished);
> > +     if (kref_read(&job->s_fence->finished.refcount)) {
> > +             /* drm_sched_job_arm() has been called */
> > +             dma_fence_put(&job->s_fence->finished);
> > +     } else {
> > +             /* aborted job before committing to run it */
> > +             drm_sched_fence_free(&job->s_fence->finished.rcu);
> > +     }
> > +
> >       job->s_fence = NULL;
> >   }
> >   EXPORT_SYMBOL(drm_sched_job_cleanup);
> > diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
> > index 4eb354226972..5c3a99027ecd 100644
> > --- a/drivers/gpu/drm/v3d/v3d_gem.c
> > +++ b/drivers/gpu/drm/v3d/v3d_gem.c
> > @@ -475,6 +475,8 @@ v3d_push_job(struct v3d_file_priv *v3d_priv,
> >       if (ret)
> >               return ret;
> >
> > +     drm_sched_job_arm(&job->base);
> > +
> >       job->done_fence = dma_fence_get(&job->base.s_fence->finished);
> >
> >       /* put by scheduler job completion */
> > diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
> > index 88ae7f331bb1..83afc3aa8e2f 100644
> > --- a/include/drm/gpu_scheduler.h
> > +++ b/include/drm/gpu_scheduler.h
> > @@ -348,6 +348,7 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched);
> >   int drm_sched_job_init(struct drm_sched_job *job,
> >                      struct drm_sched_entity *entity,
> >                      void *owner);
> > +void drm_sched_job_arm(struct drm_sched_job *job);
> >   void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
> >                                   struct drm_gpu_scheduler **sched_list,
> >                                      unsigned int num_sched_list);
> > @@ -387,8 +388,12 @@ void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
> >                                  enum drm_sched_priority priority);
> >   bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
> >
> > -struct drm_sched_fence *drm_sched_fence_create(
> > +struct drm_sched_fence *drm_sched_fence_alloc(
> >       struct drm_sched_entity *s_entity, void *owner);
> > +void drm_sched_fence_init(struct drm_sched_fence *fence,
> > +                       struct drm_sched_entity *entity);
> > +void drm_sched_fence_free(struct rcu_head *rcu);
> > +
> >   void drm_sched_fence_scheduled(struct drm_sched_fence *fence);
> >   void drm_sched_fence_finished(struct drm_sched_fence *fence);
> >
>

Patch

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index c5386d13eb4a..a4ec092af9a7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1226,6 +1226,8 @@  static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
 	if (r)
 		goto error_unlock;
 
+	drm_sched_job_arm(&job->base);
+
 	/* No memory allocation is allowed while holding the notifier lock.
 	 * The lock is held until amdgpu_cs_submit is finished and fence is
 	 * added to BOs.
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index d33e6d97cc89..5ddb955d2315 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -170,6 +170,8 @@  int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity,
 	if (r)
 		return r;
 
+	drm_sched_job_arm(&job->base);
+
 	*f = dma_fence_get(&job->base.s_fence->finished);
 	amdgpu_job_free_resources(job);
 	drm_sched_entity_push_job(&job->base, entity);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
index feb6da1b6ceb..05f412204118 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
@@ -163,6 +163,8 @@  int etnaviv_sched_push_job(struct drm_sched_entity *sched_entity,
 	if (ret)
 		goto out_unlock;
 
+	drm_sched_job_arm(&submit->sched_job);
+
 	submit->out_fence = dma_fence_get(&submit->sched_job.s_fence->finished);
 	submit->out_fence_id = idr_alloc_cyclic(&submit->gpu->fence_idr,
 						submit->out_fence, 0,
diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
index dba8329937a3..38f755580507 100644
--- a/drivers/gpu/drm/lima/lima_sched.c
+++ b/drivers/gpu/drm/lima/lima_sched.c
@@ -129,6 +129,8 @@  int lima_sched_task_init(struct lima_sched_task *task,
 		return err;
 	}
 
+	drm_sched_job_arm(&task->base);
+
 	task->num_bos = num_bos;
 	task->vm = lima_vm_get(vm);
 
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 71a72fb50e6b..2992dc85325f 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -288,6 +288,8 @@  int panfrost_job_push(struct panfrost_job *job)
 		goto unlock;
 	}
 
+	drm_sched_job_arm(&job->base);
+
 	job->render_done_fence = dma_fence_get(&job->base.s_fence->finished);
 
 	ret = panfrost_acquire_object_fences(job->bos, job->bo_count,
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 79554aa4dbb1..f7347c284886 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -485,9 +485,9 @@  void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
  * @sched_job: job to submit
  * @entity: scheduler entity
  *
- * Note: To guarantee that the order of insertion to queue matches
- * the job's fence sequence number this function should be
- * called with drm_sched_job_init under common lock.
+ * Note: To guarantee that the order of insertion to queue matches the job's
+ * fence sequence number this function should be called with drm_sched_job_arm()
+ * under common lock.
  *
  * Returns 0 for success, negative error code otherwise.
  */
diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c
index 69de2c76731f..bcea035cf4c6 100644
--- a/drivers/gpu/drm/scheduler/sched_fence.c
+++ b/drivers/gpu/drm/scheduler/sched_fence.c
@@ -90,7 +90,7 @@  static const char *drm_sched_fence_get_timeline_name(struct dma_fence *f)
  *
  * Free up the fence memory after the RCU grace period.
  */
-static void drm_sched_fence_free(struct rcu_head *rcu)
+void drm_sched_fence_free(struct rcu_head *rcu)
 {
 	struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
 	struct drm_sched_fence *fence = to_drm_sched_fence(f);
@@ -152,27 +152,32 @@  struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f)
 }
 EXPORT_SYMBOL(to_drm_sched_fence);
 
-struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity,
-					       void *owner)
+struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity,
+					      void *owner)
 {
 	struct drm_sched_fence *fence = NULL;
-	unsigned seq;
 
 	fence = kmem_cache_zalloc(sched_fence_slab, GFP_KERNEL);
 	if (fence == NULL)
 		return NULL;
 
 	fence->owner = owner;
-	fence->sched = entity->rq->sched;
 	spin_lock_init(&fence->lock);
 
+	return fence;
+}
+
+void drm_sched_fence_init(struct drm_sched_fence *fence,
+			  struct drm_sched_entity *entity)
+{
+	unsigned seq;
+
+	fence->sched = entity->rq->sched;
 	seq = atomic_inc_return(&entity->fence_seq);
 	dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled,
 		       &fence->lock, entity->fence_context, seq);
 	dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished,
 		       &fence->lock, entity->fence_context + 1, seq);
-
-	return fence;
 }
 
 module_init(drm_sched_fence_slab_init);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 33c414d55fab..454cb6164bdc 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -48,9 +48,11 @@ 
 #include <linux/wait.h>
 #include <linux/sched.h>
 #include <linux/completion.h>
+#include <linux/dma-resv.h>
 #include <uapi/linux/sched/types.h>
 
 #include <drm/drm_print.h>
+#include <drm/drm_gem.h>
 #include <drm/gpu_scheduler.h>
 #include <drm/spsc_queue.h>
 
@@ -569,7 +571,6 @@  EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
 
 /**
  * drm_sched_job_init - init a scheduler job
- *
  * @job: scheduler job to init
  * @entity: scheduler entity to use
  * @owner: job owner for debugging
@@ -577,27 +578,28 @@  EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
  * Refer to drm_sched_entity_push_job() documentation
  * for locking considerations.
  *
+ * Drivers must make sure drm_sched_job_cleanup() if this function returns
+ * successfully, even when @job is aborted before drm_sched_job_arm() is called.
+ *
+ * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware
+ * has died, which can mean that there's no valid runqueue for a @entity.
+ * This function returns -ENOENT in this case (which probably should be -EIO as
+ * a more meanigful return value).
+ *
  * Returns 0 for success, negative error code otherwise.
  */
 int drm_sched_job_init(struct drm_sched_job *job,
 		       struct drm_sched_entity *entity,
 		       void *owner)
 {
-	struct drm_gpu_scheduler *sched;
-
 	drm_sched_entity_select_rq(entity);
 	if (!entity->rq)
 		return -ENOENT;
 
-	sched = entity->rq->sched;
-
-	job->sched = sched;
 	job->entity = entity;
-	job->s_priority = entity->rq - sched->sched_rq;
-	job->s_fence = drm_sched_fence_create(entity, owner);
+	job->s_fence = drm_sched_fence_alloc(entity, owner);
 	if (!job->s_fence)
 		return -ENOMEM;
-	job->id = atomic64_inc_return(&sched->job_id_count);
 
 	INIT_LIST_HEAD(&job->list);
 
@@ -606,13 +608,58 @@  int drm_sched_job_init(struct drm_sched_job *job,
 EXPORT_SYMBOL(drm_sched_job_init);
 
 /**
- * drm_sched_job_cleanup - clean up scheduler job resources
+ * drm_sched_job_arm - arm a scheduler job for execution
+ * @job: scheduler job to arm
+ *
+ * This arms a scheduler job for execution. Specifically it initializes the
+ * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv
+ * or other places that need to track the completion of this job.
+ *
+ * Refer to drm_sched_entity_push_job() documentation for locking
+ * considerations.
  *
+ * This can only be called if drm_sched_job_init() succeeded.
+ */
+void drm_sched_job_arm(struct drm_sched_job *job)
+{
+	struct drm_gpu_scheduler *sched;
+	struct drm_sched_entity *entity = job->entity;
+
+	BUG_ON(!entity);
+
+	sched = entity->rq->sched;
+
+	job->sched = sched;
+	job->s_priority = entity->rq - sched->sched_rq;
+	job->id = atomic64_inc_return(&sched->job_id_count);
+
+	drm_sched_fence_init(job->s_fence, job->entity);
+}
+EXPORT_SYMBOL(drm_sched_job_arm);
+
+/**
+ * drm_sched_job_cleanup - clean up scheduler job resources
  * @job: scheduler job to clean up
+ *
+ * Cleans up the resources allocated with drm_sched_job_init().
+ *
+ * Drivers should call this from their error unwind code if @job is aborted
+ * before drm_sched_job_arm() is called.
+ *
+ * After that point of no return @job is committed to be executed by the
+ * scheduler, and this function should be called from the
+ * &drm_sched_backend_ops.free_job callback.
  */
 void drm_sched_job_cleanup(struct drm_sched_job *job)
 {
-	dma_fence_put(&job->s_fence->finished);
+	if (kref_read(&job->s_fence->finished.refcount)) {
+		/* drm_sched_job_arm() has been called */
+		dma_fence_put(&job->s_fence->finished);
+	} else {
+		/* aborted job before committing to run it */
+		drm_sched_fence_free(&job->s_fence->finished.rcu);
+	}
+
 	job->s_fence = NULL;
 }
 EXPORT_SYMBOL(drm_sched_job_cleanup);
diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
index 4eb354226972..5c3a99027ecd 100644
--- a/drivers/gpu/drm/v3d/v3d_gem.c
+++ b/drivers/gpu/drm/v3d/v3d_gem.c
@@ -475,6 +475,8 @@  v3d_push_job(struct v3d_file_priv *v3d_priv,
 	if (ret)
 		return ret;
 
+	drm_sched_job_arm(&job->base);
+
 	job->done_fence = dma_fence_get(&job->base.s_fence->finished);
 
 	/* put by scheduler job completion */
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 88ae7f331bb1..83afc3aa8e2f 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -348,6 +348,7 @@  void drm_sched_fini(struct drm_gpu_scheduler *sched);
 int drm_sched_job_init(struct drm_sched_job *job,
 		       struct drm_sched_entity *entity,
 		       void *owner);
+void drm_sched_job_arm(struct drm_sched_job *job);
 void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
 				    struct drm_gpu_scheduler **sched_list,
                                    unsigned int num_sched_list);
@@ -387,8 +388,12 @@  void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
 				   enum drm_sched_priority priority);
 bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
 
-struct drm_sched_fence *drm_sched_fence_create(
+struct drm_sched_fence *drm_sched_fence_alloc(
 	struct drm_sched_entity *s_entity, void *owner);
+void drm_sched_fence_init(struct drm_sched_fence *fence,
+			  struct drm_sched_entity *entity);
+void drm_sched_fence_free(struct rcu_head *rcu);
+
 void drm_sched_fence_scheduled(struct drm_sched_fence *fence);
 void drm_sched_fence_finished(struct drm_sched_fence *fence);