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From:   Christoph Hellwig <hch@lst.de>
To:     Robin Murphy <robin.murphy@arm.com>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        iommu@lists.linux-foundation.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 06/26] iommu/dma: Use for_each_sg in iommu_dma_alloc
Date:   Mon, 22 Apr 2019 19:59:22 +0200
Message-Id: <20190422175942.18788-7-hch@lst.de>
In-Reply-To: <20190422175942.18788-1-hch@lst.de>
References: <20190422175942.18788-1-hch@lst.de>
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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.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
---
 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)
-- 
2.20.1