linux-kernel - [PATCH 04/19] dma-iommu: remove the flush

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Date:   Mon, 14 Jan 2019 10:41:44 +0100
From:   Christoph Hellwig <hch@....de>
To:     Robin Murphy <robin.murphy@....com>
Cc:     Joerg Roedel <joro@...tes.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Tom Lendacky <thomas.lendacky@....com>,
        iommu@...ts.linux-foundation.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 04/19] dma-iommu: remove the flush_page callback

We now have a arch_dma_prep_coherent architecture hook that is used
for the generic DMA remap allocator, and we should use the same
interface for the dma-iommu code.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 arch/arm64/mm/dma-mapping.c |  8 +-------
 drivers/iommu/dma-iommu.c   | 14 ++++----------
 include/linux/dma-iommu.h   |  3 +--
 3 files changed, 6 insertions(+), 19 deletions(-)

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index fb0908456a1f..75fe7273a1e4 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -104,12 +104,6 @@ arch_initcall(arm64_dma_init);
 #include <linux/platform_device.h>
 #include <linux/amba/bus.h>
 
-/* Thankfully, all cache ops are by VA so we can ignore phys here */
-static void flush_page(struct device *dev, const void *virt, phys_addr_t phys)
-{
-	__dma_flush_area(virt, PAGE_SIZE);
-}
-
 static void *__iommu_alloc_attrs(struct device *dev, size_t size,
 				 dma_addr_t *handle, gfp_t gfp,
 				 unsigned long attrs)
@@ -186,7 +180,7 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size,
 		struct page **pages;
 
 		pages = iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
-					handle, flush_page);
+					handle);
 		if (!pages)
 			return NULL;
 
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 4f5546a103d8..d6a437385b26 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -22,6 +22,7 @@
 #include <linux/acpi_iort.h>
 #include <linux/device.h>
 #include <linux/dma-iommu.h>
+#include <linux/dma-noncoherent.h>
 #include <linux/gfp.h>
 #include <linux/huge_mm.h>
 #include <linux/iommu.h>
@@ -533,8 +534,6 @@ void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
  * @attrs: DMA attributes for this allocation
  * @prot: IOMMU mapping flags
  * @handle: Out argument for allocated DMA handle
- * @flush_page: Arch callback which must ensure PAGE_SIZE bytes from the
- *		given VA/PA are visible to the given non-coherent device.
  *
  * If @size is less than PAGE_SIZE, then a full CPU page will be allocated,
  * but an IOMMU which supports smaller pages might not map the whole thing.
@@ -543,8 +542,7 @@ void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
  *	   or NULL on failure.
  */
 struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
-		unsigned long attrs, int prot, dma_addr_t *handle,
-		void (*flush_page)(struct device *, const void *, phys_addr_t))
+		unsigned long attrs, int prot, dma_addr_t *handle)
 {
 	struct iommu_domain *domain = iommu_get_dma_domain(dev);
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
@@ -580,12 +578,8 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
 	for (i = 0; i < count; i++) {
 		phys_addr_t phys = page_to_phys(pages[i]);
 
-		if (!(prot & IOMMU_CACHE)) {
-			void *vaddr = kmap_atomic(pages[i]);
-
-			flush_page(dev, vaddr, phys);
-			kunmap_atomic(vaddr);
-		}
+		if (!(prot & IOMMU_CACHE))
+			arch_dma_prep_coherent(pages[i], PAGE_SIZE);
 
 		if (iommu_map(domain, iova + mapped, phys, PAGE_SIZE, prot))
 			goto out_unmap;
diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
index 65aa888c2768..59e606f78626 100644
--- a/include/linux/dma-iommu.h
+++ b/include/linux/dma-iommu.h
@@ -43,8 +43,7 @@ int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
  * the arch code to take care of attributes and cache maintenance
  */
 struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
-		unsigned long attrs, int prot, dma_addr_t *handle,
-		void (*flush_page)(struct device *, const void *, phys_addr_t));
+		unsigned long attrs, int prot, dma_addr_t *handle);
 void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
 		dma_addr_t *handle);
 
-- 
2.20.1