Re: [PATCH v2 01/11] drm/sched: Split drm_sched_job_init

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On Thu, Jul 8, 2021 at 9:09 AM Daniel Vetter <daniel.vetter@xxxxxxxx> wrote:
> On Thu, Jul 8, 2021 at 8:56 AM Christian König <christian.koenig@xxxxxxx> wrote:
> > Am 07.07.21 um 18:32 schrieb Daniel Vetter:
> > > On Wed, Jul 7, 2021 at 2:58 PM Christian König <christian.koenig@xxxxxxx> wrote:
> > >> Am 07.07.21 um 14:13 schrieb Daniel Vetter:
> > >>> On Wed, Jul 7, 2021 at 1:57 PM Christian König <christian.koenig@xxxxxxx> wrote:
> > >>>> Am 07.07.21 um 13:14 schrieb Daniel Vetter:
> > >>>>> On Wed, Jul 7, 2021 at 11:30 AM Christian König
> > >>>>> <christian.koenig@xxxxxxx> wrote:
> > >>>>>> Am 02.07.21 um 23:38 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().
> > >>>>>> Thinking more about this, I'm not sure if this really works.
> > >>>>>>
> > >>>>>> See drm_sched_job_init() was also calling drm_sched_entity_select_rq()
> > >>>>>> to update the entity->rq association.
> > >>>>>>
> > >>>>>> And that can only be done later on when we arm the fence as well.
> > >>>>> Hm yeah, but that's a bug in the existing code I think: We already
> > >>>>> fail to clean up if we fail to allocate the fences. So I think the
> > >>>>> right thing to do here is to split the checks into job_init, and do
> > >>>>> the actual arming/rq selection in job_arm? I'm not entirely sure
> > >>>>> what's all going on there, the first check looks a bit like trying to
> > >>>>> schedule before the entity is set up, which is a driver bug and should
> > >>>>> have a WARN_ON?
> > >>>> No you misunderstood me, the problem is something else.
> > >>>>
> > >>>> You asked previously why the call to drm_sched_job_init() was so late in
> > >>>> the CS.
> > >>>>
> > >>>> The reason for this was not alone the scheduler fence init, but also the
> > >>>> call to drm_sched_entity_select_rq().
> > >>> Ah ok, I think I can fix that. Needs a prep patch to first make
> > >>> drm_sched_entity_select infallible, then should be easy to do.
> > >>>
> > >>>>> The 2nd check around last_scheduled I have honeslty no idea what it's
> > >>>>> even trying to do.
> > >>>> You mean that here?
> > >>>>
> > >>>>            fence = READ_ONCE(entity->last_scheduled);
> > >>>>            if (fence && !dma_fence_is_signaled(fence))
> > >>>>                    return;
> > >>>>
> > >>>> This makes sure that load balancing is not moving the entity to a
> > >>>> different scheduler while there are still jobs running from this entity
> > >>>> on the hardware,
> > >>> Yeah after a nap that idea crossed my mind too. But now I have locking
> > >>> questions, afaiui the scheduler thread updates this, without taking
> > >>> any locks - entity dequeuing is lockless. And here we read the fence
> > >>> and then seem to yolo check whether it's signalled? What's preventing
> > >>> a use-after-free here? There's no rcu or anything going on here at
> > >>> all, and it's outside of the spinlock section, which starts a bit
> > >>> further down.
> > >> The last_scheduled fence of an entity can only change when there are
> > >> jobs on the entities queued, and we have just ruled that out in the
> > >> check before.
> > > There aren't any barriers, so the cpu could easily run the two checks
> > > the other way round. I'll ponder this and figure out where exactly we
> > > need docs for the constraint and/or barriers to make this work as
> > > intended. As-is I'm not seeing how it does ...
> >
> > spsc_queue_count() provides the necessary barrier with the atomic_read().
>
> atomic_t is fully unordered, except when it's a read-modify-write

Wasn't awake yet, I think the rule is read-modify-write and return
previous value gives you full barrier. So stuff like cmpxchg, but also
a few others. See atomic_t.txt under ODERING heading (yes that
maintainer refuses to accept .rst so I can't just link you to the
right section, it's silly). get/set and even RMW atomic ops that don't
return anything are all fully unordered.
-Daniel


> atomic op, then it's a full barrier. So yeah you need more here. But
> also since you only need a read barrier on one side, and a write
> barrier on the other, you don't actually need a cpu barriers on x86.
> And READ_ONCE gives you the compiler barrier on one side at least, I
> haven't found it on the writer side yet.
>
> > But yes a comment would be really nice here. I had to think for a while
> > why we don't need this as well.
>
> I'm typing a patch, which after a night's sleep I realized has the
> wrong barriers. And now I'm also typing some doc improvements for
> drm_sched_entity and related functions.
>
> >
> > Christian.
> >
> > > -Daniel
> > >
> > >> Christian.
> > >>
> > >>
> > >>> -Daniel
> > >>>
> > >>>> Regards
> > >>>> Christian.
> > >>>>
> > >>>>> -Daniel
> > >>>>>
> > >>>>>> Christian.
> > >>>>>>
> > >>>>>>> Also improve the kerneldoc for this.
> > >>>>>>>
> > >>>>>>> Acked-by: Steven Price <steven.price@xxxxxxx> (v2)
> > >>>>>>> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> > >>>>>>> Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> > >>>>>>> Cc: Russell King <linux+etnaviv@xxxxxxxxxxxxxxx>
> > >>>>>>> Cc: Christian Gmeiner <christian.gmeiner@xxxxxxxxx>
> > >>>>>>> Cc: Qiang Yu <yuq825@xxxxxxxxx>
> > >>>>>>> Cc: Rob Herring <robh@xxxxxxxxxx>
> > >>>>>>> Cc: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
> > >>>>>>> Cc: Steven Price <steven.price@xxxxxxx>
> > >>>>>>> Cc: Alyssa Rosenzweig <alyssa.rosenzweig@xxxxxxxxxxxxx>
> > >>>>>>> Cc: David Airlie <airlied@xxxxxxxx>
> > >>>>>>> Cc: Daniel Vetter <daniel@xxxxxxxx>
> > >>>>>>> Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
> > >>>>>>> Cc: "Christian König" <christian.koenig@xxxxxxx>
> > >>>>>>> Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> > >>>>>>> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> > >>>>>>> Cc: Adam Borowski <kilobyte@xxxxxxxxxx>
> > >>>>>>> Cc: Nick Terrell <terrelln@xxxxxx>
> > >>>>>>> Cc: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
> > >>>>>>> Cc: Paul Menzel <pmenzel@xxxxxxxxxxxxx>
> > >>>>>>> Cc: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
> > >>>>>>> Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> > >>>>>>> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> > >>>>>>> Cc: Dave Airlie <airlied@xxxxxxxxxx>
> > >>>>>>> Cc: Nirmoy Das <nirmoy.das@xxxxxxx>
> > >>>>>>> Cc: Deepak R Varma <mh12gx2825@xxxxxxxxx>
> > >>>>>>> Cc: Lee Jones <lee.jones@xxxxxxxxxx>
> > >>>>>>> Cc: Kevin Wang <kevin1.wang@xxxxxxx>
> > >>>>>>> Cc: Chen Li <chenli@xxxxxxxxxxxxx>
> > >>>>>>> Cc: Luben Tuikov <luben.tuikov@xxxxxxx>
> > >>>>>>> Cc: "Marek Olšák" <marek.olsak@xxxxxxx>
> > >>>>>>> Cc: Dennis Li <Dennis.Li@xxxxxxx>
> > >>>>>>> Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> > >>>>>>> Cc: Andrey Grodzovsky <andrey.grodzovsky@xxxxxxx>
> > >>>>>>> Cc: Sonny Jiang <sonny.jiang@xxxxxxx>
> > >>>>>>> Cc: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
> > >>>>>>> Cc: Tian Tao <tiantao6@xxxxxxxxxxxxx>
> > >>>>>>> Cc: Jack Zhang <Jack.Zhang1@xxxxxxx>
> > >>>>>>> Cc: etnaviv@xxxxxxxxxxxxxxxxxxxxx
> > >>>>>>> Cc: lima@xxxxxxxxxxxxxxxxxxxxx
> > >>>>>>> Cc: linux-media@xxxxxxxxxxxxxxx
> > >>>>>>> Cc: linaro-mm-sig@xxxxxxxxxxxxxxxx
> > >>>>>>> Cc: Emma Anholt <emma@xxxxxxxxxx>
> > >>>>>>> ---
> > >>>>>>>      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  | 17 +++++----
> > >>>>>>>      drivers/gpu/drm/scheduler/sched_main.c   | 46 +++++++++++++++++++++---
> > >>>>>>>      drivers/gpu/drm/v3d/v3d_gem.c            |  2 ++
> > >>>>>>>      include/drm/gpu_scheduler.h              |  7 +++-
> > >>>>>>>      10 files changed, 74 insertions(+), 14 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..c451ee9a30d7 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);
> > >>>>>>> @@ -152,11 +152,10 @@ 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)
> > >>>>>>> @@ -166,13 +165,19 @@ struct drm_sched_fence *drm_sched_fence_create(struct drm_sched_entity *entity,
> > >>>>>>>          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;
> > >>>>>>> +
> > >>>>>>>          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..5e84e1500c32 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
> > >>>>>>> @@ -577,6 +578,9 @@ 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.
> > >>>>>>> + *
> > >>>>>>>       * Returns 0 for success, negative error code otherwise.
> > >>>>>>>       */
> > >>>>>>>      int drm_sched_job_init(struct drm_sched_job *job,
> > >>>>>>> @@ -594,7 +598,7 @@ int drm_sched_job_init(struct drm_sched_job *job,
> > >>>>>>>          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);
> > >>>>>>> @@ -606,13 +610,47 @@ 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)
> > >>>>>>> +{
> > >>>>>>> +     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
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch



--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch




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