[PATCH v4] drm/i915: ensure segment offset never exceeds allowed max

[Andi Shyti]

Hi Krzysztof,

> diff --git a/drivers/gpu/drm/i915/i915_mm.c b/drivers/gpu/drm/i915/i915_mm.c
> index f5c97a620962..76e2801619f0 100644
> --- a/drivers/gpu/drm/i915/i915_mm.c
> +++ b/drivers/gpu/drm/i915/i915_mm.c
> @@ -143,8 +143,8 @@ int remap_io_sg(struct vm_area_struct *vma,
>  	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
>  	GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
>  
> -	while (offset >= sg_dma_len(r.sgt.sgp) >> PAGE_SHIFT) {
> -		offset -= sg_dma_len(r.sgt.sgp) >> PAGE_SHIFT;
> +	while (offset >= r.sgt.max >> PAGE_SHIFT) {
> +		offset -= r.sgt.max >> PAGE_SHIFT;

I finally defeated my laziness and looked at this a little
closer, I think you are right, I missed in my first comment a few
calculation.

Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com>

Thanks,
Andi