[PATCH] drm/amdgpu: fix amdgpu_amdkfd_remove_eviction_fence v2

[Felix Kuehling]

Hi Christian,

Are you going to submit this change to amd-staging-drm-next?
amd-kfd-staging would pick it up from there automatically.

Regards,
  Felix


On 2018-08-15 01:57 PM, Felix Kuehling wrote:
> I applied your change to my local KFD staging branch and it through a
> presubmission build/test (sorry, only accessible from inside AMD):
> http://git.amd.com:8080/#/c/167906/
>
> It passed, but checkpatch pointed out one issue:
> http://git.amd.com:8080/#/c/167906/1/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c@247
> (see inline)
>
> With that fixed, this change is Reviewed-by: Felix Kuehling
> <Felix.Kuehling at amd.com>
>
> Regards,
>   Felix
>
>
> On 2018-08-15 03:46 AM, Christian König wrote:
>> Fix quite a number of bugs here. Unfortunately only compile tested.
>>
>> v2: fix copy&paste error
>>
>> Signed-off-by: Christian König <christian.koenig at amd.com>
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 103 ++++++++++-------------
>>  1 file changed, 46 insertions(+), 57 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> index fa38a960ce00..887663ede781 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
>> @@ -206,11 +206,9 @@ static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo,
>>  					struct amdgpu_amdkfd_fence ***ef_list,
>>  					unsigned int *ef_count)
>>  {
>> -	struct reservation_object_list *fobj;
>> -	struct reservation_object *resv;
>> -	unsigned int i = 0, j = 0, k = 0, shared_count;
>> -	unsigned int count = 0;
>> -	struct amdgpu_amdkfd_fence **fence_list;
>> +	struct reservation_object *resv = bo->tbo.resv;
>> +	struct reservation_object_list *old, *new;
>> +	unsigned int i, j, k;
>>  
>>  	if (!ef && !ef_list)
>>  		return -EINVAL;
>> @@ -220,76 +218,67 @@ static int amdgpu_amdkfd_remove_eviction_fence(struct amdgpu_bo *bo,
>>  		*ef_count = 0;
>>  	}
>>  
>> -	resv = bo->tbo.resv;
>> -	fobj = reservation_object_get_list(resv);
>> -
>> -	if (!fobj)
>> +	old = reservation_object_get_list(resv);
>> +	if (!old)
>>  		return 0;
>>  
>> -	preempt_disable();
>> -	write_seqcount_begin(&resv->seq);
>> +	new = kmalloc(offsetof(typeof(*new), shared[old->shared_max]),
>> +		      GFP_KERNEL);
>> +	if (!new)
>> +		return -ENOMEM;
>>  
>> -	/* Go through all the shared fences in the resevation object. If
>> -	 * ef is specified and it exists in the list, remove it and reduce the
>> -	 * count. If ef is not specified, then get the count of eviction fences
>> -	 * present.
>> +	/* Go through all the shared fences in the resevation object and sort
>> +	 * the interesting ones to the end of the list.
>>  	 */
>> -	shared_count = fobj->shared_count;
>> -	for (i = 0; i < shared_count; ++i) {
>> +	for (i = 0, j = old->shared_count, k = 0; i < old->shared_count; ++i) {
>>  		struct dma_fence *f;
>>  
>> -		f = rcu_dereference_protected(fobj->shared[i],
>> +		f = rcu_dereference_protected(old->shared[i],
>>  					      reservation_object_held(resv));
>>  
>> -		if (ef) {
>> -			if (f->context == ef->base.context) {
>> -				dma_fence_put(f);
>> -				fobj->shared_count--;
>> -			} else {
>> -				RCU_INIT_POINTER(fobj->shared[j++], f);
>> -			}
>> -		} else if (to_amdgpu_amdkfd_fence(f))
>> -			count++;
>> +		if ((ef && f->context == ef->base.context) ||
>> +		    (!ef && to_amdgpu_amdkfd_fence(f)))
>> +			RCU_INIT_POINTER(new->shared[--j], f);
>> +		else
>> +			RCU_INIT_POINTER(new->shared[k++], f);
>>  	}
>> -	write_seqcount_end(&resv->seq);
>> -	preempt_enable();
>> -
>> -	if (ef || !count)
>> -		return 0;
>> -
>> -	/* Alloc memory for count number of eviction fence pointers. Fill the
>> -	 * ef_list array and ef_count
>> -	 */
>> -	fence_list = kcalloc(count, sizeof(struct amdgpu_amdkfd_fence *),
>> -			     GFP_KERNEL);
>> -	if (!fence_list)
>> -		return -ENOMEM;
>> +	new->shared_max = old->shared_max;
>> +	new->shared_count = k;
>>  
>> -	preempt_disable();
>> -	write_seqcount_begin(&resv->seq);
>> +	if (!ef) {
>> +		unsigned int count = old->shared_count - j;
>>  
>> -	j = 0;
>> -	for (i = 0; i < shared_count; ++i) {
>> -		struct dma_fence *f;
>> -		struct amdgpu_amdkfd_fence *efence;
>> -
>> -		f = rcu_dereference_protected(fobj->shared[i],
>> -			reservation_object_held(resv));
>> +		/* Alloc memory for count number of eviction fence pointers. Fill the
> checkpatch.pl reports: WARNING: line over 80 characters
>
>> +		 * ef_list array and ef_count
>> +		 */
>> +		*ef_list = kcalloc(count, sizeof(**ef_list), GFP_KERNEL);
>> +		*ef_count = count;
>>  
>> -		efence = to_amdgpu_amdkfd_fence(f);
>> -		if (efence) {
>> -			fence_list[k++] = efence;
>> -			fobj->shared_count--;
>> -		} else {
>> -			RCU_INIT_POINTER(fobj->shared[j++], f);
>> +		if (!*ef_list) {
>> +			kfree(new);
>> +			return -ENOMEM;
>>  		}
>>  	}
>>  
>> +	/* Install the new fence list, seqcount provides the barriers */
>> +	preempt_disable();
>> +	write_seqcount_begin(&resv->seq);
>> +	RCU_INIT_POINTER(resv->fence, new);
>>  	write_seqcount_end(&resv->seq);
>>  	preempt_enable();
>>  
>> -	*ef_list = fence_list;
>> -	*ef_count = k;
>> +	/* Drop the references to the removed fences or move them to ef_list */
>> +	for (i = j, k = 0; i < old->shared_count; ++i) {
>> +		struct dma_fence *f;
>> +
>> +		f = rcu_dereference_protected(new->shared[i],
>> +					      reservation_object_held(resv));
>> +		if (!ef)
>> +			(*ef_list)[k++] = to_amdgpu_amdkfd_fence(f);
>> +		else
>> +			dma_fence_put(f);
>> +	}
>> +	kfree_rcu(old, rcu);
>>  
>>  	return 0;
>>  }