[PATCH 1/9] drm/amdgpu: use GEM references instead of TTMs

[Christian König]

Am 16.07.24 um 23:53 schrieb Matthew Brost:
> On Tue, Jul 16, 2024 at 02:35:11PM +0200, Christian König wrote:
>> Instead of a TTM reference grab a GEM reference whenever necessary.
>>
>> Signed-off-by: Christian König <christian.koenig at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c    | 8 ++++----
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 7 ++-----
>>   2 files changed, 6 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> index 67c234bcf89f..6be3d7cd1c51 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> @@ -87,11 +87,11 @@ static const struct vm_operations_struct amdgpu_gem_vm_ops = {
>>   
>>   static void amdgpu_gem_object_free(struct drm_gem_object *gobj)
>>   {
>> -	struct amdgpu_bo *robj = gem_to_amdgpu_bo(gobj);
>> +	struct amdgpu_bo *aobj = gem_to_amdgpu_bo(gobj);
>>   
>> -	if (robj) {
>> -		amdgpu_hmm_unregister(robj);
>> -		amdgpu_bo_unref(&robj);
>> +	if (aobj) {
>> +		amdgpu_hmm_unregister(aobj);
>> +		ttm_bo_put(&aobj->tbo);
> So, this relates to my comment in patch number #9 about dropping the TTM
> ref count. If TTM only uses the GEM ref count, could we convert this
> ttm_bo_put to something like ttm_bo_fini here (also in Xe and any other
> drivers with code like this)?

That's exactly what I was planning to do as a follow up.

Regards,
Christian.

>
> I think that might be cleaner.
>
> Matt
>
>>   	}
>>   }
>>   
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> index 8d8c39be6129..6c187e310034 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> @@ -853,7 +853,7 @@ struct amdgpu_bo *amdgpu_bo_ref(struct amdgpu_bo *bo)
>>   	if (bo == NULL)
>>   		return NULL;
>>   
>> -	ttm_bo_get(&bo->tbo);
>> +	drm_gem_object_get(&bo->tbo.base);
>>   	return bo;
>>   }
>>   
>> @@ -865,13 +865,10 @@ struct amdgpu_bo *amdgpu_bo_ref(struct amdgpu_bo *bo)
>>    */
>>   void amdgpu_bo_unref(struct amdgpu_bo **bo)
>>   {
>> -	struct ttm_buffer_object *tbo;
>> -
>>   	if ((*bo) == NULL)
>>   		return;
>>   
>> -	tbo = &((*bo)->tbo);
>> -	ttm_bo_put(tbo);
>> +	drm_gem_object_get(&(*bo)->tbo.base);
>>   	*bo = NULL;
>>   }
>>   
>> -- 
>> 2.34.1
>>