[PATCH] drm/buddy: Fix the range bias clear memory allocation issue

[Paneer Selvam, Arunpravin]

Hi Daniel,

On 5/8/2024 2:11 PM, Daniel Vetter wrote:
> On Wed, May 08, 2024 at 12:27:20PM +0530, Arunpravin Paneer Selvam wrote:
>> Problem statement: During the system boot time, an application request
>> for the bulk volume of cleared range bias memory when the clear_avail
>> is zero, we dont fallback into normal allocation method as we had an
>> unnecessary clear_avail check which prevents the fallback method leads
>> to fb allocation failure following system goes into unresponsive state.
>>
>> Solution: Remove the unnecessary clear_avail check in the range bias
>> allocation function.
>>
>> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>
>> Fixes: 96950929eb23 ("drm/buddy: Implement tracking clear page feature")
>> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
>> ---
>>   drivers/gpu/drm/drm_buddy.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
> Can you please also add a kunit test case to exercise this corner case and
> make sure it stays fixed?
I have sent the v2 along with a kunit test case for this corner case.

Thanks,
Arun.
>
> Thanks, Sima
>> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
>> index 284ebae71cc4..831929ac95eb 100644
>> --- a/drivers/gpu/drm/drm_buddy.c
>> +++ b/drivers/gpu/drm/drm_buddy.c
>> @@ -574,7 +574,7 @@ __drm_buddy_alloc_range_bias(struct drm_buddy *mm,
>>   
>>   	block = __alloc_range_bias(mm, start, end, order,
>>   				   flags, fallback);
>> -	if (IS_ERR(block) && mm->clear_avail)
>> +	if (IS_ERR(block))
>>   		return __alloc_range_bias(mm, start, end, order,
>>   					  flags, !fallback);
>>   
>> -- 
>> 2.25.1
>>