Messages in this thread | | | Subject | Re: [PATCH 06/21] dma-iommu: use for_each_sg in iommu_dma_alloc | From | Robin Murphy <> | Date | Fri, 5 Apr 2019 19:08:34 +0100 |
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On 27/03/2019 08:04, Christoph Hellwig wrote: > arch_dma_prep_coherent can handle physically contiguous ranges larger > than PAGE_SIZE just fine, which means we don't need a page-based > iterator.
Heh, I got several minutes into writing a "but highmem..." reply before finding csky's arch_dma_prep_coherent() implementation. And of course that's why it specifically takes a page instead of any addresses. In hindsight I now have no idea why I didn't just write the flush_page() logic to work that way in the first place...
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/iommu/dma-iommu.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index 77d704c8f565..f915cb7c46e6 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -577,15 +577,11 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp, > goto out_free_iova; > > if (!(prot & IOMMU_CACHE)) { > - struct sg_mapping_iter miter; > - /* > - * The CPU-centric flushing implied by SG_MITER_TO_SG isn't > - * sufficient here, so skip it by using the "wrong" direction. > - */ > - sg_miter_start(&miter, sgt.sgl, sgt.orig_nents, SG_MITER_FROM_SG); > - while (sg_miter_next(&miter)) > - arch_dma_prep_coherent(miter.page, PAGE_SIZE); > - sg_miter_stop(&miter); > + struct scatterlist *sg; > + int i; > + > + for_each_sg(sgt.sgl, sg, sgt.orig_nents, i) > + arch_dma_prep_coherent(sg_page(sg), sg->length); > } > > if (iommu_map_sg(domain, iova, sgt.sgl, sgt.orig_nents, prot) >
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