Re: [PATCH 1/9] dma-buf: fix dma_fence_array_signaled

From: Chris Wilson <chris@chris-wilson.co.uk>
To: "Christian König" <ckoenig.leichtzumerken@gmail.com>,
	daniel.vetter@ffwll.ch, dri-devel@lists.freedesktop.org,
	linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org,
	sumit.semwal@linaro.org
Subject: Re: [PATCH 1/9] dma-buf: fix dma_fence_array_signaled
Date: Tue, 27 Aug 2019 12:44:27 +0100	[thread overview]
Message-ID: <156690626744.15406.4672497135424922383@skylake-alporthouse-com> (raw)
In-Reply-To: <20190826145731.1725-2-christian.koenig@amd.com>

Quoting Christian König (2019-08-26 15:57:23)
> The function is supposed to give a hint even if signaling is not enabled.
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>
> ---
>  drivers/dma-buf/dma-fence-array.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c
> index d3fbd950be94..52068ee5eb35 100644
> --- a/drivers/dma-buf/dma-fence-array.c
> +++ b/drivers/dma-buf/dma-fence-array.c
> @@ -103,8 +103,18 @@ static bool dma_fence_array_enable_signaling(struct dma_fence *fence)
>  static bool dma_fence_array_signaled(struct dma_fence *fence)
>  {
>         struct dma_fence_array *array = to_dma_fence_array(fence);
> +       int i, num_pending;
>  
> -       return atomic_read(&array->num_pending) <= 0;
> +       num_pending = atomic_read(&array->num_pending);
> +       if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags))
> +               return num_pending <= 0;
> +
> +       for (i = 0; i < array->num_fences; ++i)
> +               if (dma_fence_is_signaled(array->fences[i]) &&
> +                   --num_pending == 0)
> +                       return true;

num_fences may be 0 (it's not rejected in construction and works
currently as a simple always-signaled stub).

	if (!test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags)) {
		for (i = 0; i < array->num_fences; ++i)
			if (dma_fence_is_signaled(array->fences[i]) &&
			    --num_pending == 0)
				break;
	}

	return num_pending <= 0;