linux-kernel - Re: [PATCH v2] drm/i915: Use symmetric free for vma resources

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Message-ID: <iox4deamqlg4o3wishu7m63d3d5yzpns6oh5sej3vcxyq3wfus@7ypetc2hez4u>
Date: Thu, 13 Nov 2025 08:02:38 +0000
From: Krzysztof Karas <krzysztof.karas@...el.com>
To: Zilin Guan <zilin@....edu.cn>
CC: <jani.nikula@...ux.intel.com>, <joonas.lahtinen@...ux.intel.com>,
	<rodrigo.vivi@...el.com>, <tursulin@...ulin.net>, <airlied@...il.com>,
	<simona@...ll.ch>, <andi.shyti@...ux.intel.com>, <mikolaj.wasiak@...el.com>,
	<krzysztof.niemiec@...el.com>, <nitin.r.gote@...el.com>,
	<intel-gfx@...ts.freedesktop.org>, <dri-devel@...ts.freedesktop.org>,
	<linux-kernel@...r.kernel.org>, <jianhao.xu@....edu.cn>
Subject: Re: [PATCH v2] drm/i915: Use symmetric free for vma resources

Hi Zilin,

Thanks for addressing my comments.

> The error paths in reserve_gtt_with_resource() and
> insert_gtt_with_resource() use kfree() to release a vma_res object
> that was allocated with i915_vma_resource_alloc().
> 
> While kfree() can handle slab-allocated objects, it is better practice
> to use the symmetric free function.
> 
> Replace kfree() with the specific i915_vma_resource_free() helper to
> improve readability and ensure the alloc/free pairing is explicit.
> 
> Signed-off-by: Zilin Guan <zilin@....edu.cn>
> ---
> Changes in v2:
> - Reword commit message to describe this as a readability change.
> - Drop the Fixes tag.
> ---
>  drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
> index 7ab4c4e60264..16e72ef57bed 100644
> --- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
> @@ -1524,7 +1524,7 @@ static int reserve_gtt_with_resource(struct i915_vma *vma, u64 offset)
>  		i915_vma_resource_init_from_vma(vma_res, vma);
>  		vma->resource = vma_res;
>  	} else {
> -		kfree(vma_res);
> +		i915_vma_resource_free(vma_res);
>  	}
>  	mutex_unlock(&vm->mutex);
>  
> @@ -1704,7 +1704,7 @@ static int insert_gtt_with_resource(struct i915_vma *vma)
>  		i915_vma_resource_init_from_vma(vma_res, vma);
>  		vma->resource = vma_res;
>  	} else {
> -		kfree(vma_res);
> +		i915_vma_resource_free(vma_res);
>  	}
>  	mutex_unlock(&vm->mutex);
>  
> -- 
> 2.34.1
> 

Reviewed-by: Krzysztof Karas <krzysztof.karas@...el.com>

-- 
Best Regards,
Krzysztof