Re: [PATCH] drm/ttm: dma: Don't crash on memory in the vmalloc range

[Alexandre Courbot]

On 05/16/2015 04:55 AM, Konrad Rzeszutek Wilk wrote:
> On Fri, May 15, 2015 at 04:09:54PM +0900, Alexandre Courbot wrote:
> > dma_alloc_coherent() can return memory in the vmalloc range.
> > virt_to_page() cannot handle such addresses and crashes. This
> > patch detects such cases and obtains the struct page * using
> > vmalloc_to_page() instead.
> >
> > Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
> > ---
> > This patch is a follow-up of the following discussion:
> >
> > https://www.marc.info/?l=dri-devel&m=141579595431254&w=3
> >
> > It works for me on both 32-bit and 64-bit Tegra, so I am not convinced
> > that Thierry's initial change from virt_to_page() to phys_to_page() is
> > still required - Thierry, can you confirm whether your patch is still
> > relevant after this one?
> >
> >   drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 9 ++++++---
> >   1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> > index 01e1d27eb078..3077f1554099 100644
> > --- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> > +++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> > @@ -342,9 +342,12 @@ static struct dma_page *__ttm_dma_alloc_page(struct dma_pool *pool)
> >   	d_page->vaddr = dma_alloc_coherent(pool->dev, pool->size,
> >   					   &d_page->dma,
> >   					   pool->gfp_flags);
> > -	if (d_page->vaddr)
> > -		d_page->p = virt_to_page(d_page->vaddr);
> > -	else {
> > +	if (d_page->vaddr) {
> > +		if (is_vmalloc_addr(d_page->vaddr))
> > +			d_page->p = vmalloc_to_page(d_page->vaddr);
> > +		else
> > +			d_page->p = virt_to_page(d_page->vaddr);
> > +	} else {
>
>
> Looks OK to me.

Thanks guys. Could we translate these approvals into 
Acked-bys/Reviewed-bys so Dave (?) can merge this patch?
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