[PATCH] drm/scheduler: Unwrap job dependencies

[Luben Tuikov]

Hi,

On 2023-12-05 14:02, Rob Clark wrote:
> From: Rob Clark <robdclark at chromium.org>
> 
> Container fences have burner contexts, which makes the trick to store at
> most one fence per context somewhat useless if we don't unwrap array or
> chain fences.
> 
> Signed-off-by: Rob Clark <robdclark at chromium.org>

Link: https://lore.kernel.org/all/20230322224403.35742-1-robdclark@gmail.com/

Let's include a link to the original thread, as the main discussion can be found
therein.

Christian, could you review this patch please?

Thanks!
-- 
Regards,
Luben

> ---
>  drivers/gpu/drm/scheduler/sched_main.c | 47 ++++++++++++++++++--------
>  1 file changed, 32 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index 9762464e3f99..16b550949c57 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -52,6 +52,7 @@
>  #include <linux/wait.h>
>  #include <linux/sched.h>
>  #include <linux/completion.h>
> +#include <linux/dma-fence-unwrap.h>
>  #include <linux/dma-resv.h>
>  #include <uapi/linux/sched/types.h>
>  
> @@ -684,27 +685,14 @@ void drm_sched_job_arm(struct drm_sched_job *job)
>  }
>  EXPORT_SYMBOL(drm_sched_job_arm);
>  
> -/**
> - * drm_sched_job_add_dependency - adds the fence as a job dependency
> - * @job: scheduler job to add the dependencies to
> - * @fence: the dma_fence to add to the list of dependencies.
> - *
> - * Note that @fence is consumed in both the success and error cases.
> - *
> - * Returns:
> - * 0 on success, or an error on failing to expand the array.
> - */
> -int drm_sched_job_add_dependency(struct drm_sched_job *job,
> -				 struct dma_fence *fence)
> +static int drm_sched_job_add_single_dependency(struct drm_sched_job *job,
> +					       struct dma_fence *fence)
>  {
>  	struct dma_fence *entry;
>  	unsigned long index;
>  	u32 id = 0;
>  	int ret;
>  
> -	if (!fence)
> -		return 0;
> -
>  	/* Deduplicate if we already depend on a fence from the same context.
>  	 * This lets the size of the array of deps scale with the number of
>  	 * engines involved, rather than the number of BOs.
> @@ -728,6 +716,35 @@ int drm_sched_job_add_dependency(struct drm_sched_job *job,
>  
>  	return ret;
>  }
> +
> +/**
> + * drm_sched_job_add_dependency - adds the fence as a job dependency
> + * @job: scheduler job to add the dependencies to
> + * @fence: the dma_fence to add to the list of dependencies.
> + *
> + * Note that @fence is consumed in both the success and error cases.
> + *
> + * Returns:
> + * 0 on success, or an error on failing to expand the array.
> + */
> +int drm_sched_job_add_dependency(struct drm_sched_job *job,
> +				 struct dma_fence *fence)
> +{
> +	struct dma_fence_unwrap iter;
> +	struct dma_fence *f;
> +	int ret = 0;
> +
> +	dma_fence_unwrap_for_each (f, &iter, fence) {
> +		dma_fence_get(f);
> +		ret = drm_sched_job_add_single_dependency(job, f);
> +		if (ret)
> +			break;
> +	}
> +
> +	dma_fence_put(fence);
> +
> +	return ret;
> +}
>  EXPORT_SYMBOL(drm_sched_job_add_dependency);
>  
>  /**
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