Re: [PATCH] drm/amdgpu: Fix minmax error

[Luben Tuikov <luben.tuikov@amd.com>]

On 2022-11-25 02:45, Christian König wrote:
> 
> 
> Am 24.11.22 um 22:19 schrieb Luben Tuikov:
>> Fix minmax compilation error by using min_t()/max_t(), of the assignment type.
>>
>> Cc: James Zhu <James.Zhu@amd.com>
>> Cc: Felix Kuehling <Felix.Kuehling@amd.com>
>> Fixes: 58170a7a002ad6 ("drm/amdgpu: fix stall on CPU when allocate large system memory")
>> Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 10 +++++++---
>>   1 file changed, 7 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>> index 8a2e5716d8dba2..d22d14b0ef0c84 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>> @@ -191,14 +191,18 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
>>   	hmm_range->dev_private_owner = owner;
>>   
>>   	do {
>> -		hmm_range->end = min(hmm_range->start + MAX_WALK_BYTE, end);
>> +		hmm_range->end = min_t(typeof(hmm_range->end),
>> +				       hmm_range->start + MAX_WALK_BYTE,
>> +				       end);
> 
> Since end is a local variable I would strongly prefer to just have it 
> use the correct type for it.
> 
> Otherwise we might end up using something which doesn't work on all 
> architectures.

They all appear to be "unsigned long". I thought, since we assign to
hmm_range->end, we use that type.

Would you prefer at the top of the function to define "timeout" and "end" as,
	typeof(hmm_range->end) end, timeout;

Regards,
Luben