2022-08-04 12:41:44

by Arvind Yadav

Subject: [PATCH RFC] dma-buf: To check DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT status on debug

If core DMA-buf framework forgets to call dma_fence_enable_signaling()
before calling the dma_fence_is_signaled(). To handle this scenario on
debug kernel the DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT needs to be checked
before checking the actual signaling status.

Signed-off-by: Arvind Yadav <[email protected]>
---
include/linux/dma-fence.h | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index 775cdc0b4f24..7c95c8d5e5f5 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -428,6 +428,10 @@ dma_fence_is_signaled_locked(struct dma_fence *fence)
static inline bool
dma_fence_is_signaled(struct dma_fence *fence)
{
+#ifdef CONFIG_DEBUG_FS
+ if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags))
+ return true;
+#endif
if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
return true;

--
2.25.1

2022-08-08 20:01:20

by Christian König

Subject: Re: [PATCH RFC] dma-buf: To check DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT status on debug

Am 04.08.22 um 14:19 schrieb Arvind Yadav:
> If core DMA-buf framework forgets to call dma_fence_enable_signaling()
> before calling the dma_fence_is_signaled(). To handle this scenario on
> debug kernel the DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT needs to be checked
> before checking the actual signaling status.
>
> Signed-off-by: Arvind Yadav <[email protected]>
> ---
> include/linux/dma-fence.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
> index 775cdc0b4f24..7c95c8d5e5f5 100644
> --- a/include/linux/dma-fence.h
> +++ b/include/linux/dma-fence.h
> @@ -428,6 +428,10 @@ dma_fence_is_signaled_locked(struct dma_fence *fence)
> static inline bool
> dma_fence_is_signaled(struct dma_fence *fence)
> {
> +#ifdef CONFIG_DEBUG_FS
> + if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags))
> + return true;

The logic is just inverted. The test should be !test_bit(...) return false;

And please give that some testing as well.

Regards,
Christian.

> +#endif
> if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
> return true;
>