[PATCH] drm/amdkfd: Remove vla

[labbott@xxxxxxxxxx (Laura Abbott)]

On 04/09/2018 11:38 PM, Christian König wrote:
> Am 09.04.2018 um 23:06 schrieb Laura Abbott:
>> There's an ongoing effort to remove VLAs[1] from the kernel to eventually
>> turn on -Wvla. The single VLA usage in the amdkfd driver is actually
>> constant across all current platforms.
> 
> Actually that isn't correct.
> 
> Could be that we haven't upstreamed KFD support for them, but Vega10 have a different interrupt ring entry size and so would cause the error message here.
> 
>> Switch to a constant size array
>> instead.
> 
> I would say to just make make the array bigger.
> 
> Regards,
> Christian.
> 

What array size would accommodate future chips?

>>
>> [1] https://lkml.org/lkml/2018/3/7/621
>>
>> Signed-off-by: Laura Abbott <labbott at redhat.com>
>> ---
>> Â  drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c | 8 +++++---
>> Â  1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c b/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
>> index 035c351f47c5..c9863858f343 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
>> @@ -139,10 +139,12 @@ static void interrupt_wq(struct work_struct *work)
>> Â  {
>> Â Â Â Â Â  struct kfd_dev *dev = container_of(work, struct kfd_dev,
>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  interrupt_work);
>> +Â Â Â  uint32_t ih_ring_entry[4];
>> -Â Â Â  uint32_t ih_ring_entry[DIV_ROUND_UP(
>> -Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  dev->device_info->ih_ring_entry_size,
>> -Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  sizeof(uint32_t))];
>> +Â Â Â  if (dev->device_info->ih_ring_entry_size > (4 * sizeof(uint32_t))) {
>> +Â Â Â Â Â Â Â  dev_err(kfd_chardev(), "Ring entry too small\n");
>> +Â Â Â Â Â Â Â  return;
>> +Â Â Â  }
>> Â Â Â Â Â  while (dequeue_ih_ring_entry(dev, ih_ring_entry))
>> Â Â Â Â Â Â Â Â Â  dev->device_info->event_interrupt_class->interrupt_wq(dev,
>