[PATCH v3 1/3] drm/prime: use length macro when mapping sgl

[Christian König]

Am 25.03.20 um 01:24 schrieb Shane Francis:
> As dma_map_sg can reorganize scatter-gather lists in a
> way that can cause some later segments to be empty we should
> always use the sg_dma_len macro to fetch the actual length.
>
> This could now be 0 and not need to be mapped to a page or
> address array
>
> Signed-off-by: Shane Francis <bigbeeshane at gmail.com>
> ---
>   drivers/gpu/drm/drm_prime.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index 86d9b0e45c8c..e4eff5b84597 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -965,12 +965,14 @@ int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
>   	u32 len, index;
>   	dma_addr_t addr;
>   
> +

Unrelated newline change, apart from that the patch looks good to me.

Christian.

>   	index = 0;
>   	for_each_sg(sgt->sgl, sg, sgt->nents, count) {
> -		len = sg->length;
> +		len = sg_dma_len(sg);
>   		page = sg_page(sg);
>   		addr = sg_dma_address(sg);
>   
> +
>   		while (len > 0) {
>   			if (WARN_ON(index >= max_entries))
>   				return -1;