[PATCHv2] drm/amdkfd: Remove vla

[PATCHv2] drm/amdkfd: Remove vla

[Laura Abbott]

There's an ongoing effort to remove VLAs[1] from the kernel to eventually
turn on -Wvla. Switch to a constant value that covers all hardware.

[1] https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Laura Abbott <labbott@redhat.com>
---
v2: Switch to a larger size to account for other hardware
---
 drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c | 8 +++++---
 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..c3a5a80e31ae 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)
 {
 	struct kfd_dev *dev = container_of(work, struct kfd_dev,
 						interrupt_work);
+	uint32_t ih_ring_entry[8];
 
-	uint32_t ih_ring_entry[DIV_ROUND_UP(
-				dev->device_info->ih_ring_entry_size,
-				sizeof(uint32_t))];
+	if (dev->device_info->ih_ring_entry_size > (8 * sizeof(uint32_t))) {
+		dev_err(kfd_chardev(), "Ring entry too small\n");
+		return;
+	}
 
 	while (dequeue_ih_ring_entry(dev, ih_ring_entry))
 		dev->device_info->event_interrupt_class->interrupt_wq(dev,
-- 
2.14.3

Re: [PATCHv2] drm/amdkfd: Remove vla

[Christian König]

Am 11.04.2018 um 03:02 schrieb Laura Abbott:
> There's an ongoing effort to remove VLAs[1] from the kernel to eventually
> turn on -Wvla. Switch to a constant value that covers all hardware.
>
> [1] https://lkml.org/lkml/2018/3/7/621
>
> Signed-off-by: Laura Abbott <labbott@redhat.com>

It would be nicer to have a define for that somewhere.

Anyway the patch is Acked-by: Christian König <christian.koenig@amd.com> 
for now.

Regards,
Christian.

> ---
> v2: Switch to a larger size to account for other hardware
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c | 8 +++++---
>   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..c3a5a80e31ae 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)
>   {
>   	struct kfd_dev *dev = container_of(work, struct kfd_dev,
>   						interrupt_work);
> +	uint32_t ih_ring_entry[8];
>   
> -	uint32_t ih_ring_entry[DIV_ROUND_UP(
> -				dev->device_info->ih_ring_entry_size,
> -				sizeof(uint32_t))];
> +	if (dev->device_info->ih_ring_entry_size > (8 * sizeof(uint32_t))) {
> +		dev_err(kfd_chardev(), "Ring entry too small\n");
> +		return;
> +	}
>   
>   	while (dequeue_ih_ring_entry(dev, ih_ring_entry))
>   		dev->device_info->event_interrupt_class->interrupt_wq(dev,

Re: [PATCHv2] drm/amdkfd: Remove vla

[Felix Kuehling]

On 2018-04-10 09:02 PM, Laura Abbott wrote:
> There's an ongoing effort to remove VLAs[1] from the kernel to eventually
> turn on -Wvla. Switch to a constant value that covers all hardware.
>
> [1] https://lkml.org/lkml/2018/3/7/621
>
> Signed-off-by: Laura Abbott <labbott@redhat.com>
> ---
> v2: Switch to a larger size to account for other hardware
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c | 8 +++++---
>  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..c3a5a80e31ae 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)
>  {
>  	struct kfd_dev *dev = container_of(work, struct kfd_dev,
>  						interrupt_work);
> +	uint32_t ih_ring_entry[8];
>  
> -	uint32_t ih_ring_entry[DIV_ROUND_UP(
> -				dev->device_info->ih_ring_entry_size,
> -				sizeof(uint32_t))];
> +	if (dev->device_info->ih_ring_entry_size > (8 * sizeof(uint32_t))) {
> +		dev_err(kfd_chardev(), "Ring entry too small\n");

When the ring entry size really is too small, this will potentially
flood the kernel log. Maybe a WARN_ONCE would be more helpful. With that
fixed, this patch is Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>

Regards,
  Felix

> +		return;
> +	}
>  
>  	while (dequeue_ih_ring_entry(dev, ih_ring_entry))
>  		dev->device_info->event_interrupt_class->interrupt_wq(dev,