linux-kernel - [PATCH v8 5/7] dma-iommu: Check CONFIG

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Date:   Wed, 29 Sep 2021 11:32:58 +0900
From:   David Stevens <stevensd@...omium.org>
To:     Robin Murphy <robin.murphy@....com>, Christoph Hellwig <hch@....de>
Cc:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Tom Murphy <murphyt7@....ie>, Rajat Jain <rajatja@...gle.com>,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        David Stevens <stevensd@...omium.org>
Subject: [PATCH v8 5/7] dma-iommu: Check CONFIG_SWIOTLB more broadly

From: David Stevens <stevensd@...omium.org>

Introduce a new dev_use_swiotlb function to guard swiotlb code, instead
of overloading dev_is_untrusted. This allows CONFIG_SWIOTLB to be
checked more broadly, so the swiotlb related code can be removed more
aggressively.

Signed-off-by: David Stevens <stevensd@...omium.org>
Reviewed-by: Robin Murphy <robin.murphy@....com>
Reviewed-by: Christoph Hellwig <hch@....de>
---
 drivers/iommu/dma-iommu.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 4f77c44eaf14..85a005b268f6 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -317,6 +317,11 @@ static bool dev_is_untrusted(struct device *dev)
 	return dev_is_pci(dev) && to_pci_dev(dev)->untrusted;
 }
 
+static bool dev_use_swiotlb(struct device *dev)
+{
+	return IS_ENABLED(CONFIG_SWIOTLB) && dev_is_untrusted(dev);
+}
+
 /* sysfs updates are serialised by the mutex of the group owning @domain */
 int iommu_dma_init_fq(struct iommu_domain *domain)
 {
@@ -731,7 +736,7 @@ static void iommu_dma_sync_single_for_cpu(struct device *dev,
 {
 	phys_addr_t phys;
 
-	if (dev_is_dma_coherent(dev) && !dev_is_untrusted(dev))
+	if (dev_is_dma_coherent(dev) && !dev_use_swiotlb(dev))
 		return;
 
 	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
@@ -747,7 +752,7 @@ static void iommu_dma_sync_single_for_device(struct device *dev,
 {
 	phys_addr_t phys;
 
-	if (dev_is_dma_coherent(dev) && !dev_is_untrusted(dev))
+	if (dev_is_dma_coherent(dev) && !dev_use_swiotlb(dev))
 		return;
 
 	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
@@ -765,7 +770,7 @@ static void iommu_dma_sync_sg_for_cpu(struct device *dev,
 	struct scatterlist *sg;
 	int i;
 
-	if (dev_is_untrusted(dev))
+	if (dev_use_swiotlb(dev))
 		for_each_sg(sgl, sg, nelems, i)
 			iommu_dma_sync_single_for_cpu(dev, sg_dma_address(sg),
 						      sg->length, dir);
@@ -781,7 +786,7 @@ static void iommu_dma_sync_sg_for_device(struct device *dev,
 	struct scatterlist *sg;
 	int i;
 
-	if (dev_is_untrusted(dev))
+	if (dev_use_swiotlb(dev))
 		for_each_sg(sgl, sg, nelems, i)
 			iommu_dma_sync_single_for_device(dev,
 							 sg_dma_address(sg),
@@ -808,8 +813,7 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
 	 * If both the physical buffer start address and size are
 	 * page aligned, we don't need to use a bounce page.
 	 */
-	if (IS_ENABLED(CONFIG_SWIOTLB) && dev_is_untrusted(dev) &&
-	    iova_offset(iovad, phys | size)) {
+	if (dev_use_swiotlb(dev) && iova_offset(iovad, phys | size)) {
 		void *padding_start;
 		size_t padding_size;
 
@@ -994,7 +998,7 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
 		goto out;
 	}
 
-	if (dev_is_untrusted(dev))
+	if (dev_use_swiotlb(dev))
 		return iommu_dma_map_sg_swiotlb(dev, sg, nents, dir, attrs);
 
 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
@@ -1072,7 +1076,7 @@ static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 	struct scatterlist *tmp;
 	int i;
 
-	if (dev_is_untrusted(dev)) {
+	if (dev_use_swiotlb(dev)) {
 		iommu_dma_unmap_sg_swiotlb(dev, sg, nents, dir, attrs);
 		return;
 	}
-- 
2.33.0.685.g46640cef36-goog