[PATCH 2/8] iommu/vt-d: Use default dma_direct_* mapping functions for direct mapped devices

[Tom Murphy]

We should only assign intel_dma_ops to devices which will actually use
the iommu and let the default fall back dma_direct_* functions handle
all other devices. This won't change any behaviour but will just use the
generic implementations for direct mapped devices rather than intel
specific ones.

Signed-off-by: Tom Murphy <murphyt7 at tcd.ie>
---
 drivers/iommu/intel-iommu.c | 52 +++++--------------------------------
 1 file changed, 6 insertions(+), 46 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index c1ea66467918..64b1a9793daa 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2794,17 +2794,6 @@ static int __init si_domain_init(int hw)
 	return 0;
 }
 
-static int identity_mapping(struct device *dev)
-{
-	struct device_domain_info *info;
-
-	info = dev->archdata.iommu;
-	if (info && info != DUMMY_DEVICE_DOMAIN_INFO && info != DEFER_DEVICE_DOMAIN_INFO)
-		return (info->domain == si_domain);
-
-	return 0;
-}
-
 static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 {
 	struct dmar_domain *ndomain;
@@ -3461,12 +3450,6 @@ static struct dmar_domain *get_private_domain_for_dev(struct device *dev)
 	return domain;
 }
 
-/* Check if the dev needs to go through non-identity map and unmap process.*/
-static bool iommu_no_mapping(struct device *dev)
-{
-	return iommu_dummy(dev) || identity_mapping(dev);
-}
-
 static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,
 				     size_t size, int dir, u64 dma_mask)
 {
@@ -3531,9 +3514,6 @@ static dma_addr_t intel_map_page(struct device *dev, struct page *page,
 				 enum dma_data_direction dir,
 				 unsigned long attrs)
 {
-	if (iommu_no_mapping(dev))
-		return dma_direct_map_page(dev, page, offset, size, dir, attrs);
-
 	return __intel_map_single(dev, page_to_phys(page) + offset, size, dir,
 			*dev->dma_mask);
 }
@@ -3542,10 +3522,6 @@ static dma_addr_t intel_map_resource(struct device *dev, phys_addr_t phys_addr,
 				     size_t size, enum dma_data_direction dir,
 				     unsigned long attrs)
 {
-	if (iommu_no_mapping(dev))
-		return dma_direct_map_resource(dev, phys_addr, size, dir,
-				attrs);
-
 	return __intel_map_single(dev, phys_addr, size, dir, *dev->dma_mask);
 }
 
@@ -3597,17 +3573,13 @@ static void intel_unmap_page(struct device *dev, dma_addr_t dev_addr,
 			     size_t size, enum dma_data_direction dir,
 			     unsigned long attrs)
 {
-	if (iommu_no_mapping(dev))
-		dma_direct_unmap_page(dev, dev_addr, size, dir, attrs);
-	else
-		intel_unmap(dev, dev_addr, size);
+	intel_unmap(dev, dev_addr, size);
 }
 
 static void intel_unmap_resource(struct device *dev, dma_addr_t dev_addr,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
-	if (!iommu_no_mapping(dev))
-		intel_unmap(dev, dev_addr, size);
+	intel_unmap(dev, dev_addr, size);
 }
 
 static void *intel_alloc_coherent(struct device *dev, size_t size,
@@ -3617,9 +3589,6 @@ static void *intel_alloc_coherent(struct device *dev, size_t size,
 	struct page *page = NULL;
 	int order;
 
-	if (iommu_no_mapping(dev))
-		return dma_direct_alloc(dev, size, dma_handle, flags, attrs);
-
 	size = PAGE_ALIGN(size);
 	order = get_order(size);
 
@@ -3653,9 +3622,6 @@ static void intel_free_coherent(struct device *dev, size_t size, void *vaddr,
 	int order;
 	struct page *page = virt_to_page(vaddr);
 
-	if (iommu_no_mapping(dev))
-		return dma_direct_free(dev, size, vaddr, dma_handle, attrs);
-
 	size = PAGE_ALIGN(size);
 	order = get_order(size);
 
@@ -3673,9 +3639,6 @@ static void intel_unmap_sg(struct device *dev, struct scatterlist *sglist,
 	struct scatterlist *sg;
 	int i;
 
-	if (iommu_no_mapping(dev))
-		return dma_direct_unmap_sg(dev, sglist, nelems, dir, attrs);
-
 	for_each_sg(sglist, sg, nelems, i) {
 		nrpages += aligned_nrpages(sg_dma_address(sg), sg_dma_len(sg));
 	}
@@ -3699,8 +3662,6 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
 	struct intel_iommu *iommu;
 
 	BUG_ON(dir == DMA_NONE);
-	if (iommu_no_mapping(dev))
-		return dma_direct_map_sg(dev, sglist, nelems, dir, attrs);
 
 	domain = deferred_attach_domain(dev);
 	if (!domain)
@@ -3747,8 +3708,6 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
 
 static u64 intel_get_required_mask(struct device *dev)
 {
-	if (iommu_no_mapping(dev))
-		return dma_direct_get_required_mask(dev);
 	return DMA_BIT_MASK(32);
 }
 
@@ -5014,7 +4973,6 @@ int __init intel_iommu_init(void)
 	if (!has_untrusted_dev() || intel_no_bounce)
 		swiotlb = 0;
 #endif
-	dma_ops = &intel_dma_ops;
 
 	init_iommu_pm_ops();
 
@@ -5623,6 +5581,8 @@ static int intel_iommu_add_device(struct device *dev)
 				dev_info(dev,
 					 "Device uses a private identity domain.\n");
 			}
+		} else {
+			dev->dma_ops = &intel_dma_ops;
 		}
 	} else {
 		if (device_def_domain_type(dev) == IOMMU_DOMAIN_DMA) {
@@ -5639,6 +5599,7 @@ static int intel_iommu_add_device(struct device *dev)
 				dev_info(dev,
 					 "Device uses a private dma domain.\n");
 			}
+			dev->dma_ops = &intel_dma_ops;
 		}
 	}
 
@@ -5665,8 +5626,7 @@ static void intel_iommu_remove_device(struct device *dev)
 
 	iommu_device_unlink(&iommu->iommu, dev);
 
-	if (device_needs_bounce(dev))
-		set_dma_ops(dev, NULL);
+	set_dma_ops(dev, NULL);
 }
 
 static void intel_iommu_get_resv_regions(struct device *device,
-- 
2.20.1