Re: [PATCH 09/20] drm/sched: use inline locks for the drm-sched-fence

["Christian König" <christian.koenig@amd.com>]

On 11/4/25 16:12, Tvrtko Ursulin wrote:
> 
> On 31/10/2025 13:16, Christian König wrote:
>> Just as proof of concept and minor cleanup.
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
>> ---
>>   drivers/gpu/drm/scheduler/sched_fence.c | 11 +++++------
>>   include/drm/gpu_scheduler.h             |  4 ----
>>   2 files changed, 5 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c
>> index 9391d6f0dc01..7a94e03341cb 100644
>> --- a/drivers/gpu/drm/scheduler/sched_fence.c
>> +++ b/drivers/gpu/drm/scheduler/sched_fence.c
>> @@ -156,19 +156,19 @@ static void drm_sched_fence_set_deadline_finished(struct dma_fence *f,
>>       struct dma_fence *parent;
>>       unsigned long flags;
>>   -    spin_lock_irqsave(&fence->lock, flags);
>> +    dma_fence_lock(f, flags);
> 
> Moving to dma_fence_lock should either be a separate patch or squashed into the one which converts many other drivers. Even a separate patch before that previous patch would be better.

As far as I can see that won't work or would be at least rather tricky.

Previously from spin_lock_irqsave() locked drm_sched_fence->lock, but now it is locking dma_fence->lock.

That only works because we switched to using the internal lock.

> Naming wise, I however still think dma_fence_lock_irqsave would probably be better to stick with the same pattern everyone is so used too.

Oh, that is a good idea. Going to apply this to the patch set.

Regards,
Christian.

> 
> Regards,
> 
> Tvrtko
> 
>>         /* If we already have an earlier deadline, keep it: */
>>       if (test_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT, &f->flags) &&
>>           ktime_before(fence->deadline, deadline)) {
>> -        spin_unlock_irqrestore(&fence->lock, flags);
>> +        dma_fence_unlock(f, flags);
>>           return;
>>       }
>>         fence->deadline = deadline;
>>       set_bit(DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT, &f->flags);
>>   -    spin_unlock_irqrestore(&fence->lock, flags);
>> +    dma_fence_unlock(f, flags);
>>         /*
>>        * smp_load_aquire() to ensure that if we are racing another
>> @@ -217,7 +217,6 @@ struct drm_sched_fence *drm_sched_fence_alloc(struct drm_sched_entity *entity,
>>         fence->owner = owner;
>>       fence->drm_client_id = drm_client_id;
>> -    spin_lock_init(&fence->lock);
>>         return fence;
>>   }
>> @@ -230,9 +229,9 @@ void drm_sched_fence_init(struct drm_sched_fence *fence,
>>       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);
>> +               NULL, entity->fence_context, seq);
>>       dma_fence_init(&fence->finished, &drm_sched_fence_ops_finished,
>> -               &fence->lock, entity->fence_context + 1, seq);
>> +               NULL, entity->fence_context + 1, seq);
>>   }
>>     module_init(drm_sched_fence_slab_init);
>> diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
>> index fb88301b3c45..b77f24a783e3 100644
>> --- a/include/drm/gpu_scheduler.h
>> +++ b/include/drm/gpu_scheduler.h
>> @@ -297,10 +297,6 @@ struct drm_sched_fence {
>>            * belongs to.
>>            */
>>       struct drm_gpu_scheduler    *sched;
>> -        /**
>> -         * @lock: the lock used by the scheduled and the finished fences.
>> -         */
>> -    spinlock_t            lock;
>>           /**
>>            * @owner: job owner for debugging
>>            */
>