Re: [PATCH 20/26] drm: use new iterator in drm_gem_fence_array_add_implicit v2

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

Am 17.09.21 um 16:53 schrieb Daniel Vetter:
> On Fri, Sep 17, 2021 at 02:35:07PM +0200, Christian König wrote:
>> Simplifying the code a bit.
>>
>> v2: add missing rcu_read_lock()/unlock()
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
> This will be gone as soon as I can land the last conversion patches. Plus
> it's always called with dma_resv_lock held.

Yeah, already thought so as well. I will just keep that around to get 
rid of dma_resv_get_excl_unlocked() for now until your patch lands.

Regards,
Christian.

>
> I wouldn't bother tbh.
> -Daniel
>
>> ---
>>   drivers/gpu/drm/drm_gem.c | 34 ++++++++++++----------------------
>>   1 file changed, 12 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
>> index 09c820045859..c2c41b668f40 100644
>> --- a/drivers/gpu/drm/drm_gem.c
>> +++ b/drivers/gpu/drm/drm_gem.c
>> @@ -1340,31 +1340,21 @@ int drm_gem_fence_array_add_implicit(struct xarray *fence_array,
>>   				     struct drm_gem_object *obj,
>>   				     bool write)
>>   {
>> -	int ret;
>> -	struct dma_fence **fences;
>> -	unsigned int i, fence_count;
>> -
>> -	if (!write) {
>> -		struct dma_fence *fence =
>> -			dma_resv_get_excl_unlocked(obj->resv);
>> -
>> -		return drm_gem_fence_array_add(fence_array, fence);
>> -	}
>> -
>> -	ret = dma_resv_get_fences(obj->resv, NULL,
>> -						&fence_count, &fences);
>> -	if (ret || !fence_count)
>> -		return ret;
>> -
>> -	for (i = 0; i < fence_count; i++) {
>> -		ret = drm_gem_fence_array_add(fence_array, fences[i]);
>> +	struct dma_resv_iter cursor;
>> +	struct dma_fence *fence;
>> +	int ret = 0;
>> +
>> +	rcu_read_lock();
>> +	dma_resv_iter_begin(&cursor, obj->resv, write);
>> +	dma_resv_for_each_fence_unlocked(&cursor, fence) {
>> +		rcu_read_unlock();
>> +		ret = drm_gem_fence_array_add(fence_array, fence);
>> +		rcu_read_lock();
>>   		if (ret)
>>   			break;
>>   	}
>> -
>> -	for (; i < fence_count; i++)
>> -		dma_fence_put(fences[i]);
>> -	kfree(fences);
>> +	dma_resv_iter_end(&cursor);
>> +	rcu_read_unlock();
>>   	return ret;
>>   }
>>   EXPORT_SYMBOL(drm_gem_fence_array_add_implicit);
>> -- 
>> 2.25.1
>>