[Intel-gfx] [PATCH 15/26] drm/i915: use the new iterator in i915_request_await_object

[Christian König]

Am 14.09.21 um 12:26 schrieb Tvrtko Ursulin:
>
> On 13/09/2021 14:16, Christian König wrote:
>> Simplifying the code a bit.
>>
>> Signed-off-by: Christian König <christian.koenig at amd.com>
>> ---
>>   drivers/gpu/drm/i915/i915_request.c | 36 ++++++-----------------------
>>   1 file changed, 7 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_request.c 
>> b/drivers/gpu/drm/i915/i915_request.c
>> index 37aef1308573..b81045ceb619 100644
>> --- a/drivers/gpu/drm/i915/i915_request.c
>> +++ b/drivers/gpu/drm/i915/i915_request.c
>> @@ -1583,38 +1583,16 @@ i915_request_await_object(struct i915_request 
>> *to,
>>                 struct drm_i915_gem_object *obj,
>>                 bool write)
>>   {
>> -    struct dma_fence *excl;
>> +    struct dma_resv_cursor cursor;
>> +    struct dma_fence *fence;
>>       int ret = 0;
>>   -    if (write) {
>> -        struct dma_fence **shared;
>> -        unsigned int count, i;
>> -
>> -        ret = dma_resv_get_fences(obj->base.resv, &excl, &count,
>> -                      &shared);
>> -        if (ret)
>> -            return ret;
>> -
>> -        for (i = 0; i < count; i++) {
>> -            ret = i915_request_await_dma_fence(to, shared[i]);
>> -            if (ret)
>> -                break;
>> -
>> -            dma_fence_put(shared[i]);
>> +    dma_resv_for_each_fence_unlocked(obj->base.resv, &cursor, write, 
>> fence) {
>
> I think callers have the object locked for this one. At least if you 
> haven't tried it it's worth asking CI (you have the assert already so 
> it will tell you). But I think it's important to have an atomic 
> snapshot here.

Thanks for the info. In this case I'm just going to use the locked 
variant of the iterator here for the next round.

Could you point me to the place where the lock is grabed/released for 
reference?

Thanks,
Christian.

>
> Regards,
>
> Tvrtko
>
>> +        ret = i915_request_await_dma_fence(to, fence);
>> +        if (ret) {
>> +            dma_fence_put(fence);
>> +            break;
>>           }
>> -
>> -        for (; i < count; i++)
>> -            dma_fence_put(shared[i]);
>> -        kfree(shared);
>> -    } else {
>> -        excl = dma_resv_get_excl_unlocked(obj->base.resv);
>> -    }
>> -
>> -    if (excl) {
>> -        if (ret == 0)
>> -            ret = i915_request_await_dma_fence(to, excl);
>> -
>> -        dma_fence_put(excl);
>>       }
>>         return ret;
>>