Re: [PATCH 5/5] drm: use dma_fence_unwrap_merge() in drm_syncobj

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, May 04, 2022 at 02:22:56PM +0200, Christian König wrote:
> The unwrap merge function is now intended for this use case.
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>

Yeah this starts to make sense now as refactor.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/drm_syncobj.c | 57 +++++------------------------------
>  1 file changed, 7 insertions(+), 50 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index 7e48dcd1bee4..bbad9e4696e7 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -184,6 +184,7 @@
>   */
>  
>  #include <linux/anon_inodes.h>
> +#include <linux/dma-fence-unwrap.h>
>  #include <linux/file.h>
>  #include <linux/fs.h>
>  #include <linux/sched/signal.h>
> @@ -853,57 +854,12 @@ drm_syncobj_fd_to_handle_ioctl(struct drm_device *dev, void *data,
>  					&args->handle);
>  }
>  
> -
> -/*
> - * Try to flatten a dma_fence_chain into a dma_fence_array so that it can be
> - * added as timeline fence to a chain again.
> - */
> -static int drm_syncobj_flatten_chain(struct dma_fence **f)
> -{
> -	struct dma_fence_chain *chain = to_dma_fence_chain(*f);
> -	struct dma_fence *tmp, **fences;
> -	struct dma_fence_array *array;
> -	unsigned int count;
> -
> -	if (!chain)
> -		return 0;
> -
> -	count = 0;
> -	dma_fence_chain_for_each(tmp, &chain->base)
> -		++count;
> -
> -	fences = kmalloc_array(count, sizeof(*fences), GFP_KERNEL);
> -	if (!fences)
> -		return -ENOMEM;
> -
> -	count = 0;
> -	dma_fence_chain_for_each(tmp, &chain->base)
> -		fences[count++] = dma_fence_get(tmp);
> -
> -	array = dma_fence_array_create(count, fences,
> -				       dma_fence_context_alloc(1),
> -				       1, false);
> -	if (!array)
> -		goto free_fences;
> -
> -	dma_fence_put(*f);
> -	*f = &array->base;
> -	return 0;
> -
> -free_fences:
> -	while (count--)
> -		dma_fence_put(fences[count]);
> -
> -	kfree(fences);
> -	return -ENOMEM;
> -}
> -
>  static int drm_syncobj_transfer_to_timeline(struct drm_file *file_private,
>  					    struct drm_syncobj_transfer *args)
>  {
>  	struct drm_syncobj *timeline_syncobj = NULL;
> +	struct dma_fence *fence, *tmp;
>  	struct dma_fence_chain *chain;
> -	struct dma_fence *fence;
>  	int ret;
>  
>  	timeline_syncobj = drm_syncobj_find(file_private, args->dst_handle);
> @@ -912,13 +868,14 @@ static int drm_syncobj_transfer_to_timeline(struct drm_file *file_private,
>  	}
>  	ret = drm_syncobj_find_fence(file_private, args->src_handle,
>  				     args->src_point, args->flags,
> -				     &fence);
> +				     &tmp);
>  	if (ret)
>  		goto err_put_timeline;
>  
> -	ret = drm_syncobj_flatten_chain(&fence);
> -	if (ret)
> -		goto err_free_fence;
> +	fence = dma_fence_unwrap_merge(tmp);
> +	dma_fence_put(tmp);
> +	if (!fence)
> +		goto err_put_timeline;
>  
>  	chain = dma_fence_chain_alloc();
>  	if (!chain) {
> -- 
> 2.25.1
> 

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