Re: [Intel-gfx] [PATCH 1/2] dma-buf/sync-file: fix logic error in new fence merge code

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Mar 29, 2022 at 09:00:00AM +0200, Christian König wrote:
> When the array is empty because everything is signaled we can't use
> add_fence() to add something because that would filter the signaled
> fence again.
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>
> Fixes: 519f490db07e ("dma-buf/sync-file: fix warning about fence containers")
> ---
>  drivers/dma-buf/sync_file.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
> index b8dea4ec123b..514d213261df 100644
> --- a/drivers/dma-buf/sync_file.c
> +++ b/drivers/dma-buf/sync_file.c
> @@ -262,7 +262,7 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
>  	}
>  
>  	if (index == 0)
> -		add_fence(fences, &index, dma_fence_get_stub());
> +		fences[index++] = dma_fence_get_stub();

Uh idiot me wondered about this and somehow convinced myself that adding a
random fences instead of a singalled stub is ok. I should have checked
more carefully :-/

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

>  
>  	if (num_fences > index) {
>  		struct dma_fence **tmp;
> -- 
> 2.25.1
> 

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