On Mon, Mar 11, 2019 at 08:47:44AM -0700, Alexander Duyck wrote:
> > drivers/iommu/amd_iommu.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> > index 6b0760dafb3e..949621f33624 100644
> > --- a/drivers/iommu/amd_iommu.c
> > +++ b/drivers/iommu/amd_iommu.c
> > @@ -2604,7 +2604,7 @@ static int map_sg(struct device *dev, struct
> > scatterlist *sglist,
> >
> > /* Everything is mapped - write the right values into s->dma_address */
> > for_each_sg(sglist, s, nelems, i) {
> > - s->dma_address += address + s->offset;
> > + s->dma_address += address + (s->offset & ~PAGE_MASK);
> > s->dma_length = s->length;
> > }
> >
>
> You should add a comment calling out that this is needed because the
> sg_phys(s) call above this is masked with PAGE_MASK. Then this makes
> much more sense. Otherwise I would have assumed you needed either the
> full offset or none.
Would something like this
/*
* Everything is mapped - write the right values into s->dma_address.
* Take into account s->offset can be bigger than page size and sg_phys(s)
* address has to be aligned to page granularity.
*/
be appropriate ?
Stanislaw
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