[Intel-gfx] [PATCH 2/2] drm/i915: Add a test that we terminate the trimmed sgtable as expected

[Tvrtko Ursulin]

On 19/12/2016 12:43, Chris Wilson wrote:
> In commit 0c40ce130e38 ("drm/i915: Trim the object sg table"), we expect
> to copy exactly orig_st->nents across and allocate the table thusly.
> The copy loop should therefore end with the new_sg being NULL.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 4e263df2afc3..0a82cce5f731 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2316,6 +2316,7 @@ static void i915_sg_trim(struct sg_table *orig_st)
>  		/* called before being DMA mapped, no need to copy sg->dma_* */
>  		new_sg = sg_next(new_sg);
>  	}
> +	GEM_BUG_ON(new_sg); /* Should walk exactly nents and hit the end */
>
>  	sg_free_table(orig_st);
>

I was sure I had this in the code back then, hm.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko