[PATCH 14/15] drm/gem: Tiny kernel clarification for drm_gem_fence_array_add

[Christian König]

Am 24.06.21 um 15:41 schrieb Daniel Vetter:
> On Thu, Jun 24, 2021 at 03:35:19PM +0200, Christian König wrote:
>> Am 24.06.21 um 15:32 schrieb Daniel Vetter:
>>> On Thu, Jun 24, 2021 at 02:48:54PM +0200, Christian König wrote:
>>>> Am 24.06.21 um 14:41 schrieb Daniel Vetter:
>>>>> On Wed, Jun 23, 2021 at 10:42:50AM +0200, Christian König wrote:
>>>>>> Am 22.06.21 um 18:55 schrieb Daniel Vetter:
>>>>>>> Spotted while trying to convert panfrost to these.
>>>>>>>
>>>>>>> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
>>>>>>> Cc: "Christian König" <christian.koenig at amd.com>
>>>>>>> Cc: Lucas Stach <l.stach at pengutronix.de>
>>>>>>> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>>>>>>> Cc: Maxime Ripard <mripard at kernel.org>
>>>>>>> Cc: Thomas Zimmermann <tzimmermann at suse.de>
>>>>>>> Cc: David Airlie <airlied at linux.ie>
>>>>>>> Cc: Daniel Vetter <daniel at ffwll.ch>
>>>>>>> ---
>>>>>>>      drivers/gpu/drm/drm_gem.c | 3 +++
>>>>>>>      1 file changed, 3 insertions(+)
>>>>>>>
>>>>>>> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
>>>>>>> index ba2e64ed8b47..68deb1de8235 100644
>>>>>>> --- a/drivers/gpu/drm/drm_gem.c
>>>>>>> +++ b/drivers/gpu/drm/drm_gem.c
>>>>>>> @@ -1302,6 +1302,9 @@ EXPORT_SYMBOL(drm_gem_unlock_reservations);
>>>>>>>       * @fence_array: array of dma_fence * for the job to block on.
>>>>>>>       * @fence: the dma_fence to add to the list of dependencies.
>>>>>>>       *
>>>>>>> + * This functions consumes the reference for @fence both on success and error
>>>>>>> + * cases.
>>>>>>> + *
>>>>>> Oh, the later is a bit ugly I think. But good to know.
>>>>>>
>>>>>> Reviewed-by: Christian König <christian.koenig at amd.com>
>>>>> Merged to drm-misc-next, thanks for taking a look. Can you perhaps take a
>>>>> look at the drm/armada patch too, then I think I have reviews/acks for all
>>>>> of them?
>>>> What are you talking about? I only see drm/armada patches for the irq stuff
>>>> Thomas is working on.
>>> There was one in this series, but Maxime was quicker. I'm going to apply
>>> all the remaining ones now. After that I'll send out a patch set to add
>>> some dependency tracking to drm_sched_job so that there's not so much
>>> copypasta going on there. I stumbled over that when reviewing how we
>>> handle dependencies.
>> Do you mean a common container for dma_fence objects a drm_sched_job depends
>> on?
> Yup. Well the real usefulness is the interfaces, so that you can just grep
> for those when trying to figure out htf a driver handles its implicit
> dependencies. And amdgpu is unfortunately going to be a bit in the cold
> because it's special (but should be able to benefit too, just more than
> 1-2 patches to convert it over).

I had that on the TODO list for quite a while as well.

Essentially extracting what the dma_resv_list object is doing into a new 
object (but maybe without RCU).

Christian.

>
> Anyway I'm going to type the cover letter rsn.
> -Daniel