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

Christian König
2021-09-20T13:28:40Z

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
>>