[PATCH 13/21] dma-iommu: factor contiguous allocations into helpers

[Christoph Hellwig <hch@lst.de>]

This keeps the code together and will simplify using it in different
ways.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/iommu/dma-iommu.c | 110 ++++++++++++++++++++------------------
 1 file changed, 59 insertions(+), 51 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 8ec69176673d..da2e0f4a63b6 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -458,6 +458,48 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
 	return iova + iova_off;
 }
 
+static void iommu_dma_free_contiguous(struct device *dev, size_t size,
+		struct page *page, dma_addr_t dma_handle)
+{
+	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+
+	__iommu_dma_unmap(iommu_get_domain_for_dev(dev), dma_handle, size);
+	if (!dma_release_from_contiguous(dev, page, count))
+		__free_pages(page, get_order(size));
+}
+
+
+static void *iommu_dma_alloc_contiguous(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
+{
+	bool coherent = dev_is_dma_coherent(dev);
+	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
+	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	unsigned int page_order = get_order(size);
+	struct page *page = NULL;
+
+	if (gfpflags_allow_blocking(gfp))
+		page = dma_alloc_from_contiguous(dev, count, page_order,
+						 gfp & __GFP_NOWARN);
+
+	if (page)
+		memset(page_address(page), 0, PAGE_ALIGN(size));
+	else
+		page = alloc_pages(gfp, page_order);
+	if (!page)
+		return NULL;
+
+	*dma_handle = __iommu_dma_map(dev, page_to_phys(page), size, ioprot,
+			iommu_get_dma_domain(dev));
+	if (*dma_handle == DMA_MAPPING_ERROR) {
+		if (!dma_release_from_contiguous(dev, page, count))
+			__free_pages(page, page_order);
+		return NULL;
+	}
+
+	return page_address(page);
+}
+
 static void __iommu_dma_free_pages(struct page **pages, int count)
 {
 	while (count--)
@@ -754,19 +796,6 @@ static void iommu_dma_sync_sg_for_device(struct device *dev,
 		arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
 }
 
-static dma_addr_t __iommu_dma_map_page(struct device *dev, struct page *page,
-		unsigned long offset, size_t size, int prot)
-{
-	return __iommu_dma_map(dev, page_to_phys(page) + offset, size, prot,
-			iommu_get_dma_domain(dev));
-}
-
-static void __iommu_dma_unmap_page(struct device *dev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir, unsigned long attrs)
-{
-	__iommu_dma_unmap(iommu_get_dma_domain(dev), handle, size);
-}
-
 static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
 		unsigned long offset, size_t size, enum dma_data_direction dir,
 		unsigned long attrs)
@@ -991,7 +1020,6 @@ static void *iommu_dma_alloc(struct device *dev, size_t size,
 		dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
 {
 	bool coherent = dev_is_dma_coherent(dev);
-	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
 	size_t iosize = size;
 	void *addr;
 
@@ -1004,7 +1032,6 @@ static void *iommu_dma_alloc(struct device *dev, size_t size,
 	gfp |= __GFP_ZERO;
 
 	if (!gfpflags_allow_blocking(gfp)) {
-		struct page *page;
 		/*
 		 * In atomic context we can't remap anything, so we'll only
 		 * get the virtually contiguous buffer we need by way of a
@@ -1013,44 +1040,27 @@ static void *iommu_dma_alloc(struct device *dev, size_t size,
 		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) {
-			__free_pages(page, get_order(size));
-			addr = NULL;
-		}
+		return iommu_dma_alloc_contiguous(dev, iosize, handle, gfp,
+				attrs);
 	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
 		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
 		struct page *page;
 
-		page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
-					get_order(size), gfp & __GFP_NOWARN);
-		if (!page)
+		addr = iommu_dma_alloc_contiguous(dev, iosize, handle, gfp,
+				attrs);
+		if (!addr)
 			return NULL;
+		page = virt_to_page(addr);
 
-		*handle = __iommu_dma_map_page(dev, page, 0, iosize, ioprot);
-		if (*handle == DMA_MAPPING_ERROR) {
-			dma_release_from_contiguous(dev, page,
-						    size >> PAGE_SHIFT);
+		addr = dma_common_contiguous_remap(page, size, VM_USERMAP, prot,
+				__builtin_return_address(0));
+		if (!addr) {
+			iommu_dma_free_contiguous(dev, iosize, page, *handle);
 			return NULL;
 		}
-		addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
-						   prot,
-						   __builtin_return_address(0));
-		if (addr) {
-			if (!coherent)
-				arch_dma_prep_coherent(page, iosize);
-			memset(addr, 0, size);
-		} else {
-			__iommu_dma_unmap_page(dev, *handle, iosize, 0, attrs);
-			dma_release_from_contiguous(dev, page,
-						    size >> PAGE_SHIFT);
-		}
+
+		if (!coherent)
+			arch_dma_prep_coherent(page, iosize);
 	} else {
 		addr = iommu_dma_alloc_remap(dev, iosize, handle, gfp, attrs);
 	}
@@ -1077,16 +1087,14 @@ static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,
 	if (dma_in_atomic_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);
-
-		__iommu_dma_unmap_page(dev, handle, iosize, 0, attrs);
-		dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
+		iommu_dma_free_contiguous(dev, iosize,
+				vmalloc_to_page(cpu_addr), handle);
 		dma_common_free_remap(cpu_addr, size, VM_USERMAP);
 	} else if (is_vmalloc_addr(cpu_addr)){
 		iommu_dma_free_remap(dev, iosize, cpu_addr, handle);
 	} else {
-		__iommu_dma_unmap_page(dev, handle, iosize, 0, 0);
-		__free_pages(virt_to_page(cpu_addr), get_order(size));
+		iommu_dma_free_contiguous(dev, iosize, virt_to_page(cpu_addr),
+				handle);
 	}
 }
 
-- 
2.20.1