linux-kernel - [PATCH 10/19] dma-iommu: factor atomic pool allocations into helpers

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Date:   Mon, 14 Jan 2019 10:41:50 +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 10/19] dma-iommu: factor atomic pool allocations into helpers

This keeps the code together and will simplify compiling the code
out on architectures that are always dma coherent.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 drivers/iommu/dma-iommu.c | 51 +++++++++++++++++++++++++++++----------
 1 file changed, 38 insertions(+), 13 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 95d30b96e5bd..fdd283f45656 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -666,6 +666,35 @@ static int iommu_dma_get_sgtable_remap(struct sg_table *sgt, void *cpu_addr,
 			GFP_KERNEL);
 }
 
+static void iommu_dma_free_pool(struct device *dev, size_t size,
+		void *vaddr, dma_addr_t dma_handle)
+{
+	__iommu_dma_unmap(iommu_get_domain_for_dev(dev), dma_handle, size);
+	dma_free_from_pool(vaddr, PAGE_ALIGN(size));
+}
+
+static void *iommu_dma_alloc_pool(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
+{
+	bool coherent = dev_is_dma_coherent(dev);
+	struct page *page;
+	void *vaddr;
+
+	vaddr = dma_alloc_from_pool(PAGE_ALIGN(size), &page, gfp);
+	if (!vaddr)
+		return NULL;
+
+	*dma_handle = __iommu_dma_map(dev, page_to_phys(page), size,
+			dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs),
+			iommu_get_domain_for_dev(dev));
+	if (*dma_handle == DMA_MAPPING_ERROR) {
+		dma_free_from_pool(vaddr, PAGE_ALIGN(size));
+		return NULL;
+	}
+
+	return vaddr;
+}
+
 static void iommu_dma_sync_single_for_cpu(struct device *dev,
 		dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
 {
@@ -974,21 +1003,18 @@ static void *iommu_dma_alloc(struct device *dev, size_t size,
 		 * get the virtually contiguous buffer we need by way of a
 		 * physically contiguous allocation.
 		 */
-		if (coherent) {
-			page = alloc_pages(gfp, get_order(size));
-			addr = page ? page_address(page) : NULL;
-		} else {
-			addr = dma_alloc_from_pool(size, &page, gfp);
-		}
-		if (!addr)
+		if (!coherent)
+			return iommu_dma_alloc_pool(dev, iosize, handle, gfp,
+					attrs);
+
+		page = alloc_pages(gfp, get_order(size));
+		if (!page)
 			return NULL;
 
+		addr = page_address(page);
 		*handle = __iommu_dma_map_page(dev, page, 0, iosize, ioprot);
 		if (*handle == DMA_MAPPING_ERROR) {
-			if (coherent)
-				__free_pages(page, get_order(size));
-			else
-				dma_free_from_pool(addr, size);
+			__free_pages(page, get_order(size));
 			addr = NULL;
 		}
 	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
@@ -1042,8 +1068,7 @@ static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,
 	 * Hence how dodgy the below logic looks...
 	 */
 	if (dma_in_atomic_pool(cpu_addr, size)) {
-		__iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
-		dma_free_from_pool(cpu_addr, size);
+		iommu_dma_free_pool(dev, size, cpu_addr, handle);
 	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
 		struct page *page = vmalloc_to_page(cpu_addr);
 
-- 
2.20.1