Re: [PATCH drm-misc-next v9 02/12] drm/gpuvm: don't always WARN in drm_gpuvm_check_overflow()

[Boris Brezillon <boris.brezillon@collabora.com>]

On Wed,  8 Nov 2023 01:12:32 +0100
Danilo Krummrich <dakr@redhat.com> wrote:

> Don't always WARN in drm_gpuvm_check_overflow() and separate it into a
> drm_gpuvm_check_overflow() and a dedicated
> drm_gpuvm_warn_check_overflow() variant.
> 
> This avoids printing warnings due to invalid userspace requests.
> 
> Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Signed-off-by: Danilo Krummrich <dakr@redhat.com>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> ---
>  drivers/gpu/drm/drm_gpuvm.c | 20 +++++++++++++-------
>  1 file changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gpuvm.c b/drivers/gpu/drm/drm_gpuvm.c
> index d7367a202fee..445767f8fbc4 100644
> --- a/drivers/gpu/drm/drm_gpuvm.c
> +++ b/drivers/gpu/drm/drm_gpuvm.c
> @@ -614,12 +614,18 @@ static int __drm_gpuva_insert(struct drm_gpuvm *gpuvm,
>  static void __drm_gpuva_remove(struct drm_gpuva *va);
>  
>  static bool
> -drm_gpuvm_check_overflow(struct drm_gpuvm *gpuvm, u64 addr, u64 range)
> +drm_gpuvm_check_overflow(u64 addr, u64 range)
>  {
>  	u64 end;
>  
> -	return drm_WARN(gpuvm->drm, check_add_overflow(addr, range, &end),
> -			"GPUVA address limited to %zu bytes.\n", sizeof(end));
> +	return check_add_overflow(addr, range, &end);
> +}
> +
> +static bool
> +drm_gpuvm_warn_check_overflow(struct drm_gpuvm *gpuvm, u64 addr, u64 range)
> +{
> +	return drm_WARN(gpuvm->drm, drm_gpuvm_check_overflow(addr, range),
> +			"GPUVA address limited to %zu bytes.\n", sizeof(addr));
>  }
>  
>  static bool
> @@ -647,7 +653,7 @@ static bool
>  drm_gpuvm_range_valid(struct drm_gpuvm *gpuvm,
>  		      u64 addr, u64 range)
>  {
> -	return !drm_gpuvm_check_overflow(gpuvm, addr, range) &&
> +	return !drm_gpuvm_check_overflow(addr, range) &&
>  	       drm_gpuvm_in_mm_range(gpuvm, addr, range) &&
>  	       !drm_gpuvm_in_kernel_node(gpuvm, addr, range);
>  }
> @@ -682,7 +688,7 @@ drm_gpuvm_init(struct drm_gpuvm *gpuvm, const char *name,
>  	gpuvm->ops = ops;
>  	gpuvm->drm = drm;
>  
> -	drm_gpuvm_check_overflow(gpuvm, start_offset, range);
> +	drm_gpuvm_warn_check_overflow(gpuvm, start_offset, range);
>  	gpuvm->mm_start = start_offset;
>  	gpuvm->mm_range = range;
>  
> @@ -691,8 +697,8 @@ drm_gpuvm_init(struct drm_gpuvm *gpuvm, const char *name,
>  		gpuvm->kernel_alloc_node.va.addr = reserve_offset;
>  		gpuvm->kernel_alloc_node.va.range = reserve_range;
>  
> -		if (likely(!drm_gpuvm_check_overflow(gpuvm, reserve_offset,
> -						     reserve_range)))
> +		if (likely(!drm_gpuvm_warn_check_overflow(gpuvm, reserve_offset,
> +							  reserve_range)))
>  			__drm_gpuva_insert(gpuvm, &gpuvm->kernel_alloc_node);
>  	}
>  }