On 7/1/26 08:52, Philipp Stanner wrote:
> On Tue, 2026-06-30 at 12:04 -0400, Shahyan Soltani wrote:
>> The num_fences, count, i, and j variables in dma_fence_dedup_array() and
>> __dma_fence_unwrap_merge() have inconsistent integer types, mixing both
>> unsigned int and int.
>>
>> Use type size_t consistently for these instead, and update the return
>> type of dma_fence_dedup_array() accordingly.
>>
>> Signed-off-by: Shahyan Soltani <[email protected]>
>> Suggested-by: Philipp Stanner <[email protected]>
>
> Thx for fixing this, cool work
>
> Reviewed-by: Philipp Stanner <[email protected]>
>
>> ---
>> The rest of the subsystems (dma_resv_reserve_fences, drm_exec, drm_gpuvm,
>> xe, nouveau, etc) uses "unsigned int" for num_fences, for example the
>> amdgpu caller in amdgpu_userq_fence.c.
Good point.
>
> You mention that because you can't / won't change them?
>
> My suggestion actually has been to go for `unsigned int`. Christian
> opinioned that it should be size_t. Shouldn't be a big deal, though, my
> issue was just the possibility for negative numbers.
Yeah, unsigned int would probably work as well. But ARRAY_SIZE() returns size_t
if I'm not completely mistaken and I have seen size_t being used elsewhere as
well.
>
> Christian, would it be a bit better to be consistent with the parties
> Shayan mentions?
For the amdgpu use cases I don't care much because we limit num_fences to 16bit
anyway and don't allow larger allocations.
The drm_exec and drm_gpuvm should definitely be fixed as well. Not sure about
XE or Nouveau,
It should just not be a signed type anywhere, cause that can indeed mean
trouble.
Regards,
Christian.
>
>
> P.
>
>>
>> drivers/dma-buf/dma-fence-unwrap.c | 8 ++++----
>> include/linux/dma-fence-unwrap.h | 6 ++++--
>> 2 files changed, 8 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/dma-buf/dma-fence-unwrap.c
>> b/drivers/dma-buf/dma-fence-unwrap.c
>> index 53bb40e70b27..65e87d263c3a 100644
>> --- a/drivers/dma-buf/dma-fence-unwrap.c
>> +++ b/drivers/dma-buf/dma-fence-unwrap.c
>> @@ -93,9 +93,9 @@ static int fence_cmp(const void *_a, const void *_b)
>> *
>> * Return: Number of unique fences remaining in the array.
>> */
>> -int dma_fence_dedup_array(struct dma_fence **fences, int num_fences)
>> +size_t dma_fence_dedup_array(struct dma_fence **fences, size_t num_fences)
>> {
>> - int i, j;
>> + size_t i, j;
>>
>> sort(fences, num_fences, sizeof(*fences), fence_cmp, NULL);
>>
>> @@ -115,14 +115,14 @@ int dma_fence_dedup_array(struct dma_fence **fences,
>> int num_fences)
>> EXPORT_SYMBOL_GPL(dma_fence_dedup_array);
>>
>> /* Implementation for the dma_fence_merge() marco, don't use directly */
>> -struct dma_fence *__dma_fence_unwrap_merge(unsigned int num_fences,
>> +struct dma_fence *__dma_fence_unwrap_merge(size_t num_fences,
>> struct dma_fence **fences,
>> struct dma_fence_unwrap *iter)
>> {
>> struct dma_fence *tmp, *unsignaled = NULL, **array;
>> struct dma_fence_array *result;
>> ktime_t timestamp;
>> - int i, count;
>> + size_t i, count;
>>
>> count = 0;
>> timestamp = ns_to_ktime(0);
>> diff --git a/include/linux/dma-fence-unwrap.h
>> b/include/linux/dma-fence-unwrap.h
>> index 62df222fe0f1..7bfacdf79de2 100644
>> --- a/include/linux/dma-fence-unwrap.h
>> +++ b/include/linux/dma-fence-unwrap.h
>> @@ -8,6 +8,8 @@
>> #ifndef __LINUX_DMA_FENCE_UNWRAP_H
>> #define __LINUX_DMA_FENCE_UNWRAP_H
>>
>> +#include <linux/types.h>
>> +
>> struct dma_fence;
>>
>> /**
>> @@ -48,11 +50,11 @@ struct dma_fence *dma_fence_unwrap_next(struct
>> dma_fence_unwrap *cursor);
>> for (fence = dma_fence_unwrap_first(head, cursor); fence; \
>> fence = dma_fence_unwrap_next(cursor))
>>
>> -struct dma_fence *__dma_fence_unwrap_merge(unsigned int num_fences,
>> +struct dma_fence *__dma_fence_unwrap_merge(size_t num_fences,
>> struct dma_fence **fences,
>> struct dma_fence_unwrap *cursors);
>>
>> -int dma_fence_dedup_array(struct dma_fence **array, int num_fences);
>> +size_t dma_fence_dedup_array(struct dma_fence **array, size_t num_fences);
>>
>> /**
>> * dma_fence_unwrap_merge - unwrap and merge fences
