[Intel-xe] [PATCH 1/1] drm/xe: don't repin a userptr if mm is closed

[Yang, Fei]

> On Wed, Oct 04, 2023 at 04:47:21PM -0700, fei.yang at intel.com wrote:
>> From: Fei Yang <fei.yang at intel.com>
>>
>> Ran into a problem where xe_vma_userptr_pin_pages failed with -EFAULT
>> due to the mmu_notifier.mm had been closed. In such case, the userptr
>> vma should not had been added to the invalidated list in the first
>> place.
>>
>
> A few questions here. First how / where did you hit this problem? i.e.
> What IGT test or UMD? What platform? How often can you reproduce this?
> Do you have a dmesg or other debug info?

VLK-50463

> Also by design xe_vma_userptr_pin_pages returns -EFAULT when the mm is
> closed from a kthread which seems correct. Is this the case you are
> hitting? If so, unsure if this is a problem.

Agreed that it's not a real problem, but the warning is distracting.
<4> [1977.900715] xe 0000:03:00.0: [drm] VM worker error: -14

> Matt
>
>> Signed-off-by: Fei Yang <fei.yang at intel.com>
>> ---
>>  drivers/gpu/drm/xe/xe_vm.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
>> index ea17d026546c..14ba3fb9defd 100644
>> --- a/drivers/gpu/drm/xe/xe_vm.c
>> +++ b/drivers/gpu/drm/xe/xe_vm.c
>> @@ -715,11 +715,13 @@ static bool vma_userptr_invalidate(struct mmu_interval_notifier *mni,
>>       * userptr.
>>       */
>>      if (!xe_vm_in_fault_mode(vm) &&
>> +        mmget_not_zero(vma->userptr.notifier.mm) &&
>>          !(vma->gpuva.flags & XE_VMA_DESTROYED) && vma->tile_present) {
>>              spin_lock(&vm->userptr.invalidated_lock);
>>              list_move_tail(&vma->userptr.invalidate_link,
>>                             &vm->userptr.invalidated);
>>              spin_unlock(&vm->userptr.invalidated_lock);
>> +            mmput(vma->userptr.notifier.mm);
>>      }
>>
>>      up_write(&vm->userptr.notifier_lock);
>> --
>> 2.25.1
>>