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From: "Christian König" <christian.koenig@amd.com>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "DRI Development" <dri-devel@lists.freedesktop.org>,
	"Steven Price" <steven.price@arm.com>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"Lucas Stach" <l.stach@pengutronix.de>,
	"Russell King" <linux+etnaviv@armlinux.org.uk>,
	"Christian Gmeiner" <christian.gmeiner@gmail.com>,
	"Qiang Yu" <yuq825@gmail.com>, "Rob Herring" <robh@kernel.org>,
	"Tomeu Vizoso" <tomeu.vizoso@collabora.com>,
	"Alyssa Rosenzweig" <alyssa.rosenzweig@collabora.com>,
	"David Airlie" <airlied@linux.ie>,
	"Sumit Semwal" <sumit.semwal@linaro.org>,
	"Masahiro Yamada" <masahiroy@kernel.org>,
	"Kees Cook" <keescook@chromium.org>,
	"Adam Borowski" <kilobyte@angband.pl>,
	"Nick Terrell" <terrelln@fb.com>,
	"Mauro Carvalho Chehab" <mchehab+huawei@kernel.org>,
	"Paul Menzel" <pmenzel@molgen.mpg.de>,
	"Sami Tolvanen" <samitolvanen@google.com>,
	"Viresh Kumar" <viresh.kumar@linaro.org>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"Dave Airlie" <airlied@redhat.com>,
	"Nirmoy Das" <nirmoy.das@amd.com>,
	"Deepak R Varma" <mh12gx2825@gmail.com>,
	"Lee Jones" <lee.jones@linaro.org>,
	"Kevin Wang" <kevin1.wang@amd.com>,
	"Chen Li" <chenli@uniontech.com>,
	"Luben Tuikov" <luben.tuikov@amd.com>,
	"Marek Olšák" <marek.olsak@amd.com>,
	"Dennis Li" <Dennis.Li@amd.com>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Andrey Grodzovsky" <andrey.grodzovsky@amd.com>,
	"Sonny Jiang" <sonny.jiang@amd.com>,
	"Boris Brezillon" <boris.brezillon@collabora.com>,
	"Tian Tao" <tiantao6@hisilicon.com>,
	"Jack Zhang" <Jack.Zhang1@amd.com>,
	"The etnaviv authors" <etnaviv@lists.freedesktop.org>,
	lima@lists.freedesktop.org,
	"open list:DMA BUFFER SHARING FRAMEWORK"
	<linux-media@vger.kernel.org>,
	"moderated list:DMA BUFFER SHARING FRAMEWORK"
	<linaro-mm-sig@lists.linaro.org>, "Emma Anholt" <emma@anholt.net>
Subject: Re: [PATCH v2 01/11] drm/sched: Split drm_sched_job_init
Date: Wed, 7 Jul 2021 14:58:10 +0200	[thread overview]
Message-ID: <7933a995-0c95-9339-5385-a24681f6df3a@amd.com> (raw)
In-Reply-To: <CAKMK7uFu7V0QzsbMGPJPnMjXOB7FrKB_d+oDwkFMVaEvgy5EOQ@mail.gmail.com>

Am 07.07.21 um 14:13 schrieb Daniel Vetter:
> On Wed, Jul 7, 2021 at 1:57 PM Christian König <christian.koenig@amd.com> wrote:
>> Am 07.07.21 um 13:14 schrieb Daniel Vetter:
>>> On Wed, Jul 7, 2021 at 11:30 AM Christian König
>>> <christian.koenig@amd.com> 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.

Christian.


> -Daniel
>
>> Regards
>> Christian.
>>
>>> -Daniel
>>>
>>>> Christian.
>>>>
>>>>> Also improve the kerneldoc for this.
>>>>>
>>>>> Acked-by: Steven Price <steven.price@arm.com> (v2)
>>>>> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
>>>>> Cc: Lucas Stach <l.stach@pengutronix.de>
>>>>> Cc: Russell King <linux+etnaviv@armlinux.org.uk>
>>>>> Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
>>>>> Cc: Qiang Yu <yuq825@gmail.com>
>>>>> Cc: Rob Herring <robh@kernel.org>
>>>>> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
>>>>> Cc: Steven Price <steven.price@arm.com>
>>>>> Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
>>>>> Cc: David Airlie <airlied@linux.ie>
>>>>> Cc: Daniel Vetter <daniel@ffwll.ch>
>>>>> Cc: Sumit Semwal <sumit.semwal@linaro.org>
>>>>> Cc: "Christian König" <christian.koenig@amd.com>
>>>>> Cc: Masahiro Yamada <masahiroy@kernel.org>
>>>>> Cc: Kees Cook <keescook@chromium.org>
>>>>> Cc: Adam Borowski <kilobyte@angband.pl>
>>>>> Cc: Nick Terrell <terrelln@fb.com>
>>>>> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
>>>>> Cc: Paul Menzel <pmenzel@molgen.mpg.de>
>>>>> Cc: Sami Tolvanen <samitolvanen@google.com>
>>>>> Cc: Viresh Kumar <viresh.kumar@linaro.org>
>>>>> Cc: Alex Deucher <alexander.deucher@amd.com>
>>>>> Cc: Dave Airlie <airlied@redhat.com>
>>>>> Cc: Nirmoy Das <nirmoy.das@amd.com>
>>>>> Cc: Deepak R Varma <mh12gx2825@gmail.com>
>>>>> Cc: Lee Jones <lee.jones@linaro.org>
>>>>> Cc: Kevin Wang <kevin1.wang@amd.com>
>>>>> Cc: Chen Li <chenli@uniontech.com>
>>>>> Cc: Luben Tuikov <luben.tuikov@amd.com>
>>>>> Cc: "Marek Olšák" <marek.olsak@amd.com>
>>>>> Cc: Dennis Li <Dennis.Li@amd.com>
>>>>> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>>>>> Cc: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
>>>>> Cc: Sonny Jiang <sonny.jiang@amd.com>
>>>>> Cc: Boris Brezillon <boris.brezillon@collabora.com>
>>>>> Cc: Tian Tao <tiantao6@hisilicon.com>
>>>>> Cc: Jack Zhang <Jack.Zhang1@amd.com>
>>>>> Cc: etnaviv@lists.freedesktop.org
>>>>> Cc: lima@lists.freedesktop.org
>>>>> Cc: linux-media@vger.kernel.org
>>>>> Cc: linaro-mm-sig@lists.linaro.org
>>>>> Cc: Emma Anholt <emma@anholt.net>
>>>>> ---
>>>>>     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);
>>>>>
>


WARNING: multiple messages have this Message-ID
From: "Christian König" <christian.koenig@amd.com>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Emma Anholt" <emma@anholt.net>,
	"Adam Borowski" <kilobyte@angband.pl>,
	"David Airlie" <airlied@linux.ie>,
	"Viresh Kumar" <viresh.kumar@linaro.org>,
	"DRI Development" <dri-devel@lists.freedesktop.org>,
	"Sonny Jiang" <sonny.jiang@amd.com>,
	"Nirmoy Das" <nirmoy.das@amd.com>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"Lee Jones" <lee.jones@linaro.org>,
	"Jack Zhang" <Jack.Zhang1@amd.com>,
	lima@lists.freedesktop.org,
	"Mauro Carvalho Chehab" <mchehab+huawei@kernel.org>,
	"Masahiro Yamada" <masahiroy@kernel.org>,
	"Steven Price" <steven.price@arm.com>,
	"Luben Tuikov" <luben.tuikov@amd.com>,
	"Alyssa Rosenzweig" <alyssa.rosenzweig@collabora.com>,
	"Sami Tolvanen" <samitolvanen@google.com>,
	"Russell King" <linux+etnaviv@armlinux.org.uk>,
	"Dave Airlie" <airlied@redhat.com>,
	"Dennis Li" <Dennis.Li@amd.com>, "Chen Li" <chenli@uniontech.com>,
	"Paul Menzel" <pmenzel@molgen.mpg.de>,
	"Kees Cook" <keescook@chromium.org>,
	"Marek Olšák" <marek.olsak@amd.com>,
	"Kevin Wang" <kevin1.wang@amd.com>,
	"The etnaviv authors" <etnaviv@lists.freedesktop.org>,
	"moderated list:DMA BUFFER SHARING FRAMEWORK"
	<linaro-mm-sig@lists.linaro.org>,
	"Nick Terrell" <terrelln@fb.com>,
	"Deepak R Varma" <mh12gx2825@gmail.com>,
	"Tomeu Vizoso" <tomeu.vizoso@collabora.com>,
	"Boris Brezillon" <boris.brezillon@collabora.com>,
	"Qiang Yu" <yuq825@gmail.com>,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"Tian Tao" <tiantao6@hisilicon.com>,
	"open list:DMA BUFFER SHARING FRAMEWORK"
	<linux-media@vger.kernel.org>
Subject: Re: [PATCH v2 01/11] drm/sched: Split drm_sched_job_init
Date: Wed, 7 Jul 2021 14:58:10 +0200	[thread overview]
Message-ID: <7933a995-0c95-9339-5385-a24681f6df3a@amd.com> (raw)
In-Reply-To: <CAKMK7uFu7V0QzsbMGPJPnMjXOB7FrKB_d+oDwkFMVaEvgy5EOQ@mail.gmail.com>

Am 07.07.21 um 14:13 schrieb Daniel Vetter:
> On Wed, Jul 7, 2021 at 1:57 PM Christian König <christian.koenig@amd.com> wrote:
>> Am 07.07.21 um 13:14 schrieb Daniel Vetter:
>>> On Wed, Jul 7, 2021 at 11:30 AM Christian König
>>> <christian.koenig@amd.com> 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.

Christian.


> -Daniel
>
>> Regards
>> Christian.
>>
>>> -Daniel
>>>
>>>> Christian.
>>>>
>>>>> Also improve the kerneldoc for this.
>>>>>
>>>>> Acked-by: Steven Price <steven.price@arm.com> (v2)
>>>>> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
>>>>> Cc: Lucas Stach <l.stach@pengutronix.de>
>>>>> Cc: Russell King <linux+etnaviv@armlinux.org.uk>
>>>>> Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
>>>>> Cc: Qiang Yu <yuq825@gmail.com>
>>>>> Cc: Rob Herring <robh@kernel.org>
>>>>> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
>>>>> Cc: Steven Price <steven.price@arm.com>
>>>>> Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
>>>>> Cc: David Airlie <airlied@linux.ie>
>>>>> Cc: Daniel Vetter <daniel@ffwll.ch>
>>>>> Cc: Sumit Semwal <sumit.semwal@linaro.org>
>>>>> Cc: "Christian König" <christian.koenig@amd.com>
>>>>> Cc: Masahiro Yamada <masahiroy@kernel.org>
>>>>> Cc: Kees Cook <keescook@chromium.org>
>>>>> Cc: Adam Borowski <kilobyte@angband.pl>
>>>>> Cc: Nick Terrell <terrelln@fb.com>
>>>>> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
>>>>> Cc: Paul Menzel <pmenzel@molgen.mpg.de>
>>>>> Cc: Sami Tolvanen <samitolvanen@google.com>
>>>>> Cc: Viresh Kumar <viresh.kumar@linaro.org>
>>>>> Cc: Alex Deucher <alexander.deucher@amd.com>
>>>>> Cc: Dave Airlie <airlied@redhat.com>
>>>>> Cc: Nirmoy Das <nirmoy.das@amd.com>
>>>>> Cc: Deepak R Varma <mh12gx2825@gmail.com>
>>>>> Cc: Lee Jones <lee.jones@linaro.org>
>>>>> Cc: Kevin Wang <kevin1.wang@amd.com>
>>>>> Cc: Chen Li <chenli@uniontech.com>
>>>>> Cc: Luben Tuikov <luben.tuikov@amd.com>
>>>>> Cc: "Marek Olšák" <marek.olsak@amd.com>
>>>>> Cc: Dennis Li <Dennis.Li@amd.com>
>>>>> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>>>>> Cc: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
>>>>> Cc: Sonny Jiang <sonny.jiang@amd.com>
>>>>> Cc: Boris Brezillon <boris.brezillon@collabora.com>
>>>>> Cc: Tian Tao <tiantao6@hisilicon.com>
>>>>> Cc: Jack Zhang <Jack.Zhang1@amd.com>
>>>>> Cc: etnaviv@lists.freedesktop.org
>>>>> Cc: lima@lists.freedesktop.org
>>>>> Cc: linux-media@vger.kernel.org
>>>>> Cc: linaro-mm-sig@lists.linaro.org
>>>>> Cc: Emma Anholt <emma@anholt.net>
>>>>> ---
>>>>>     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);
>>>>>
>


  reply	other threads:[~2021-07-07 12:58 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-02 21:38 [PATCH v2 00/11] drm/scheduler dependency tracking Daniel Vetter
2021-07-02 21:38 ` [PATCH v2 01/11] drm/sched: Split drm_sched_job_init Daniel Vetter
2021-07-02 21:38   ` Daniel Vetter
2021-07-07  9:29   ` Christian König
2021-07-07  9:29     ` Christian König
2021-07-07 11:14     ` Daniel Vetter
2021-07-07 11:14       ` Daniel Vetter
2021-07-07 11:57       ` Christian König
2021-07-07 11:57         ` Christian König
2021-07-07 12:13         ` Daniel Vetter
2021-07-07 12:13           ` Daniel Vetter
2021-07-07 12:58           ` Christian König [this message]
2021-07-07 12:58             ` Christian König
2021-07-07 16:32             ` Daniel Vetter
2021-07-07 16:32               ` Daniel Vetter
2021-07-08  6:56               ` Christian König
2021-07-08  6:56                 ` Christian König
2021-07-08  7:09                 ` Daniel Vetter
2021-07-08  7:09                   ` Daniel Vetter
2021-07-08  7:19                   ` Daniel Vetter
2021-07-08  7:19                     ` Daniel Vetter
2021-07-08  7:53                     ` Christian König
2021-07-08  7:53                       ` Christian König
2021-07-08 10:02                       ` Daniel Vetter
2021-07-08 10:02                         ` Daniel Vetter
2021-07-08 10:54                         ` Christian König
2021-07-08 10:54                           ` Christian König
2021-07-08 11:20                           ` Daniel Vetter
2021-07-08 11:20                             ` Daniel Vetter
2021-07-08 11:28                             ` Christian König
2021-07-08 11:28                               ` Christian König
2021-07-02 21:38 ` [PATCH v2 02/11] drm/sched: Add dependency tracking Daniel Vetter
2021-07-02 21:38   ` Daniel Vetter
2021-07-07  9:26   ` [Linaro-mm-sig] " Christian König
2021-07-07  9:26     ` Christian König
2021-07-07 11:23     ` Daniel Vetter
2021-07-07 11:23       ` Daniel Vetter
2021-07-02 21:38 ` [PATCH v2 03/11] drm/sched: drop entity parameter from drm_sched_push_job Daniel Vetter
2021-07-02 21:38   ` Daniel Vetter
2021-07-02 21:38 ` [PATCH v2 04/11] drm/panfrost: use scheduler dependency tracking Daniel Vetter
2021-07-02 21:38   ` Daniel Vetter
2021-07-02 21:38 ` [PATCH v2 05/11] drm/lima: " Daniel Vetter
2021-07-02 21:38 ` [PATCH v2 06/11] drm/v3d: Move drm_sched_job_init to v3d_job_init Daniel Vetter
2021-07-02 21:38 ` [PATCH v2 07/11] drm/v3d: Use scheduler dependency handling Daniel Vetter
2021-07-02 21:38 ` [PATCH v2 08/11] drm/etnaviv: " Daniel Vetter
2021-07-02 21:38   ` Daniel Vetter
2021-07-07  9:08   ` Lucas Stach
2021-07-07  9:08     ` Lucas Stach
2021-07-07 11:26     ` Daniel Vetter
2021-07-07 11:26       ` Daniel Vetter
2021-07-07 11:32       ` Daniel Vetter
2021-07-07 11:32         ` Daniel Vetter
2021-07-07 12:34         ` Lucas Stach
2021-07-07 12:34           ` Lucas Stach
2021-07-02 21:38 ` [PATCH v2 09/11] drm/gem: Delete gem array fencing helpers Daniel Vetter
2021-07-02 21:38   ` Daniel Vetter
2021-07-02 21:38 ` [PATCH v2 10/11] drm/sched: Don't store self-dependencies Daniel Vetter
2021-07-02 21:38 ` [PATCH v2 11/11] drm/sched: Check locking in drm_sched_job_await_implicit Daniel Vetter

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