[PATCH] drm/amdgpu: Fix incorrect max handle limit in userq wait ioctl

[PATCH] drm/amdgpu: Fix incorrect max handle limit in userq wait ioctl

[Srinivasan Shanmugam]

Clang reports that a comparison in amdgpu_userq_wait_ioctl()
is always false.

The field num_syncobj_timeline_handles is defined as __u16.
A __u16 value can only go up to 65535.

But AMDGPU_USERQ_MAX_HANDLES was defined as 65536.
So the check comparing the field with this limit could
never be true.

Change the limit to U16_MAX (65535) to match the field type.

Fixes the below:
amdgpu_userq_fence.c:642:46: warning: result of comparison of constant 65536 with expression of type '__u16' (aka 'unsigned short') is always false [-Wtautological-constant-out-of-range-compare]
            wait_info->num_syncobj_timeline_handles > AMDGPU_USERQ_MAX_HANDLES ||

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
index 136071172111..e4bca62bcf14 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
@@ -35,7 +35,7 @@
 static const struct dma_fence_ops amdgpu_userq_fence_ops;
 static struct kmem_cache *amdgpu_userq_fence_slab;
 
-#define AMDGPU_USERQ_MAX_HANDLES	(1U << 16)
+#define AMDGPU_USERQ_MAX_HANDLES       U16_MAX
 
 int amdgpu_userq_fence_slab_init(void)
 {
-- 
2.34.1

Re: [PATCH] drm/amdgpu: Fix incorrect max handle limit in userq wait ioctl

[Christian König]

On 2/25/26 08:20, Srinivasan Shanmugam wrote:
> Clang reports that a comparison in amdgpu_userq_wait_ioctl()
> is always false.
> 
> The field num_syncobj_timeline_handles is defined as __u16.
> A __u16 value can only go up to 65535.
> 
> But AMDGPU_USERQ_MAX_HANDLES was defined as 65536.
> So the check comparing the field with this limit could
> never be true.
> 
> Change the limit to U16_MAX (65535) to match the field type.
> 
> Fixes the below:
> amdgpu_userq_fence.c:642:46: warning: result of comparison of constant 65536 with expression of type '__u16' (aka 'unsigned short') is always false [-Wtautological-constant-out-of-range-compare]

Well that means that we actually don't need this check.

Adjusting the value just works around the problem.

Regards,
Christian.

>             wait_info->num_syncobj_timeline_handles > AMDGPU_USERQ_MAX_HANDLES ||
> 
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Christian König <christian.koenig@amd.com>
> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> index 136071172111..e4bca62bcf14 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
> @@ -35,7 +35,7 @@
>  static const struct dma_fence_ops amdgpu_userq_fence_ops;
>  static struct kmem_cache *amdgpu_userq_fence_slab;
>  
> -#define AMDGPU_USERQ_MAX_HANDLES	(1U << 16)
> +#define AMDGPU_USERQ_MAX_HANDLES       U16_MAX
>  
>  int amdgpu_userq_fence_slab_init(void)
>  {