[PATCH 2/2] drm/amdgpu/dma_buf: fix page_link check

[Christian König]

Am 07.04.25 um 16:18 schrieb Matthew Auld:
> The page_link lower bits of the first sg could contain something like
> SG_END, if we are mapping a single VRAM page or contiguous blob which
> fits into one sg entry. Rather pull out the struct page, and use that in
> our check to know if we mapped struct pages vs VRAM.
>
> Fixes: f44ffd677fb3 ("drm/amdgpu: add support for exporting VRAM using DMA-buf v3")
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Cc: Christian König <christian.koenig at amd.com>
> Cc: amd-gfx at lists.freedesktop.org
> Cc: <stable at vger.kernel.org> # v5.8+

Good point, haven't thought about that at all since we only abuse the sg table as DMA addr container.

Reviewed-by: Christian König <christian.koenig at amd.com>

Were is patch #1 from this series?

Thanks,
Christian.

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> index 9f627caedc3f..c9842a0e2a1c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> @@ -184,7 +184,7 @@ static void amdgpu_dma_buf_unmap(struct dma_buf_attachment *attach,
>  				 struct sg_table *sgt,
>  				 enum dma_data_direction dir)
>  {
> -	if (sgt->sgl->page_link) {
> +	if (sg_page(sgt->sgl)) {
>  		dma_unmap_sgtable(attach->dev, sgt, dir, 0);
>  		sg_free_table(sgt);
>  		kfree(sgt);