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Subject: Re: [PATCH v9 16/32] drm: rockchip: use common helper for a
 scatterlist contiguity check
To:     Marek Szyprowski <m.szyprowski@samsung.com>,
        dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org,
        linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org
Cc:     Christoph Hellwig <hch@lst.de>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        linux-arm-kernel@lists.infradead.org,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Sandy Huang <hjc@rock-chips.com>,
        =?UTF-8?Q?Heiko_St=c3=bcbner?= <heiko@sntech.de>,
        linux-rockchip@lists.infradead.org
References: <20200826063316.23486-1-m.szyprowski@samsung.com>
 <CGME20200826063537eucas1p1462d4761c8eb6d762fe5ea0fbd3b6e3b@eucas1p1.samsung.com>
 <20200826063316.23486-17-m.szyprowski@samsung.com>
From:   Robin Murphy <robin.murphy@arm.com>
Message-ID: <263143f0-8b39-6daa-1d26-54ef32b54c27@arm.com>
Date:   Tue, 1 Sep 2020 20:34:28 +0100
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On 2020-08-26 07:33, Marek Szyprowski wrote:
> Use common helper for checking the contiguity of the imported dma-buf.

Reviewed-by: Robin Murphy <robin.murphy@arm.com>

> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>   drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 19 +------------------
>   1 file changed, 1 insertion(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> index b9275ba7c5a5..2970e534e2bb 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> @@ -460,23 +460,6 @@ struct sg_table *rockchip_gem_prime_get_sg_table(struct drm_gem_object *obj)
>   	return sgt;
>   }
>   
> -static unsigned long rockchip_sg_get_contiguous_size(struct sg_table *sgt,
> -						     int count)
> -{
> -	struct scatterlist *s;
> -	dma_addr_t expected = sg_dma_address(sgt->sgl);
> -	unsigned int i;
> -	unsigned long size = 0;
> -
> -	for_each_sg(sgt->sgl, s, count, i) {
> -		if (sg_dma_address(s) != expected)
> -			break;
> -		expected = sg_dma_address(s) + sg_dma_len(s);
> -		size += sg_dma_len(s);
> -	}
> -	return size;
> -}
> -
>   static int
>   rockchip_gem_iommu_map_sg(struct drm_device *drm,
>   			  struct dma_buf_attachment *attach,
> @@ -498,7 +481,7 @@ rockchip_gem_dma_map_sg(struct drm_device *drm,
>   	if (!count)
>   		return -EINVAL;
>   
> -	if (rockchip_sg_get_contiguous_size(sg, count) < attach->dmabuf->size) {
> +	if (drm_prime_get_contiguous_size(sg) < attach->dmabuf->size) {
>   		DRM_ERROR("failed to map sg_table to contiguous linear address.\n");
>   		dma_unmap_sg(drm->dev, sg->sgl, sg->nents,
>   			     DMA_BIDIRECTIONAL);
>