On 6/30/26 08:04, Baineng Shou wrote:
> Add a KUnit case verifying that dma_fence_dedup_array() returns 0,
> not 1, when called with num_fences == 0. This locks down the
> contract documented in the kernel-doc and prevents a regression
> of commit 77a9298741f8 ("dma-fence: Make dma_fence_dedup_array()
> robust against 0-count input").
>
> Suggested-by: Christian König <christian.koenig@amd.com>
> Signed-off-by: Baineng Shou <shoubaineng@gmail.com>

Reviewed-by: Christian König <christian.koenig@amd.com>

Going to push this to drm-misc-next later today. I also pinged our intern to write a cleanup patch whic consistently use size_t for the number of array elements in the code.

Thanks,
Christian.

> ---
>  drivers/dma-buf/st-dma-fence-unwrap.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/drivers/dma-buf/st-dma-fence-unwrap.c b/drivers/dma-buf/st-dma-fence-unwrap.c
> index 4e7ee25372ba..72dea6091d58 100644
> --- a/drivers/dma-buf/st-dma-fence-unwrap.c
> +++ b/drivers/dma-buf/st-dma-fence-unwrap.c
> @@ -370,6 +370,15 @@ static void test_unwrap_merge_seqno(struct kunit *test)
>       dma_fence_put(f1);
>  }
> 
> +static void test_dedup_empty(struct kunit *test)
> +{
> +     struct dma_fence *fence[1] = { NULL };
> +     int ret;
> +
> +     ret = dma_fence_dedup_array(fence, 0);
> +     KUNIT_EXPECT_EQ(test, ret, 0);
> +}
> +
>  static void test_unwrap_merge_order(struct kunit *test)
>  {
>       struct dma_fence *fence, *f1, *f2, *a1, *a2, *c1, *c2;
> @@ -595,6 +604,7 @@ static struct kunit_case dma_fence_unwrap_cases[] = {
>       KUNIT_CASE(test_unwrap_merge_order),
>       KUNIT_CASE(test_unwrap_merge_complex),
>       KUNIT_CASE(test_unwrap_merge_complex_seqno),
> +     KUNIT_CASE(test_dedup_empty),
>       {}
>  };
>