Re: [PATCH 1/4] dma-buf: add dma_fence_array_for_each (v2)

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 21.05.21 um 18:27 schrieb Jason Ekstrand:
> On Fri, May 21, 2021 at 2:51 AM Christian König
> <ckoenig.leichtzumerken@gmail.com> wrote:
>> Am 20.05.21 um 21:00 schrieb Jason Ekstrand:
>>> From: Christian König <ckoenig.leichtzumerken@gmail.com>
>>>
>>> Add a helper to iterate over all fences in a dma_fence_array object.
>>>
>>> v2 (Jason Ekstrand)
>>>    - Return NULL from dma_fence_array_first if head == NULL.  This matches
>>>      the iterator behavior of dma_fence_chain_for_each in that it iterates
>>>      zero times if head == NULL.
>>>    - Return NULL from dma_fence_array_next if index > array->num_fences.
>>>
>>> Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
>> Reviewed-by: Christian König <christian.koenig@amd.com>
>>
>> BTW: I'm only seeing this patch from the series. Looks like somehow the
>> rest didn't made it into my inbox.
> https://lists.freedesktop.org/archives/dri-devel/2021-May/307561.html
>
> Not sure why it didn't make your mail.  This one was CC'd to you
> because you're the author from a year ago or something.

Yeah, feel free to add an Acked-by on exporting the fences to the 
sync_file part.

But I think we really need to untangle the resource management from the 
implicit sync handling before the importing fence part can land.

Regards,
Christian.

>
> --Jason
>
>
>>> ---
>>>    drivers/dma-buf/dma-fence-array.c | 27 +++++++++++++++++++++++++++
>>>    include/linux/dma-fence-array.h   | 17 +++++++++++++++++
>>>    2 files changed, 44 insertions(+)
>>>
>>> diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c
>>> index d3fbd950be944..2ac1afc697d0f 100644
>>> --- a/drivers/dma-buf/dma-fence-array.c
>>> +++ b/drivers/dma-buf/dma-fence-array.c
>>> @@ -201,3 +201,30 @@ bool dma_fence_match_context(struct dma_fence *fence, u64 context)
>>>        return true;
>>>    }
>>>    EXPORT_SYMBOL(dma_fence_match_context);
>>> +
>>> +struct dma_fence *dma_fence_array_first(struct dma_fence *head)
>>> +{
>>> +     struct dma_fence_array *array;
>>> +
>>> +     if (!head)
>>> +             return NULL;
>>> +
>>> +     array = to_dma_fence_array(head);
>>> +     if (!array)
>>> +             return head;
>>> +
>>> +     return array->fences[0];
>>> +}
>>> +EXPORT_SYMBOL(dma_fence_array_first);
>>> +
>>> +struct dma_fence *dma_fence_array_next(struct dma_fence *head,
>>> +                                    unsigned int index)
>>> +{
>>> +     struct dma_fence_array *array = to_dma_fence_array(head);
>>> +
>>> +     if (!array || index >= array->num_fences)
>>> +             return NULL;
>>> +
>>> +     return array->fences[index];
>>> +}
>>> +EXPORT_SYMBOL(dma_fence_array_next);
>>> diff --git a/include/linux/dma-fence-array.h b/include/linux/dma-fence-array.h
>>> index 303dd712220fd..588ac8089dd61 100644
>>> --- a/include/linux/dma-fence-array.h
>>> +++ b/include/linux/dma-fence-array.h
>>> @@ -74,6 +74,19 @@ to_dma_fence_array(struct dma_fence *fence)
>>>        return container_of(fence, struct dma_fence_array, base);
>>>    }
>>>
>>> +/**
>>> + * dma_fence_array_for_each - iterate over all fences in array
>>> + * @fence: current fence
>>> + * @index: index into the array
>>> + * @head: potential dma_fence_array object
>>> + *
>>> + * Test if @array is a dma_fence_array object and if yes iterate over all fences
>>> + * in the array. If not just iterate over the fence in @array itself.
>>> + */
>>> +#define dma_fence_array_for_each(fence, index, head)                 \
>>> +     for (index = 0, fence = dma_fence_array_first(head); fence;     \
>>> +          ++(index), fence = dma_fence_array_next(head, index))
>>> +
>>>    struct dma_fence_array *dma_fence_array_create(int num_fences,
>>>                                               struct dma_fence **fences,
>>>                                               u64 context, unsigned seqno,
>>> @@ -81,4 +94,8 @@ struct dma_fence_array *dma_fence_array_create(int num_fences,
>>>
>>>    bool dma_fence_match_context(struct dma_fence *fence, u64 context);
>>>
>>> +struct dma_fence *dma_fence_array_first(struct dma_fence *head);
>>> +struct dma_fence *dma_fence_array_next(struct dma_fence *head,
>>> +                                    unsigned int index);
>>> +
>>>    #endif /* __LINUX_DMA_FENCE_ARRAY_H */