[Xen-devel] [PATCH] linux: Add trivial forwarding of dma_{, un}map_page when not using highmem

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

Use non-trivial dma_{un,}map_page only when CONFIG_HIGHMEM, allowing to not
compile swiotlb_{un,}map_page in that case, which in neither case need 
exporting.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

Index: sle10-sp1-2006-12-21/arch/i386/kernel/swiotlb.c
===================================================================
--- sle10-sp1-2006-12-21.orig/arch/i386/kernel/swiotlb.c        2007-01-02 
12:48:40.000000000 +0100
+++ sle10-sp1-2006-12-21/arch/i386/kernel/swiotlb.c     2007-01-02 
14:01:59.000000000 +0100
@@ -617,6 +617,8 @@ swiotlb_sync_sg_for_device(struct device
                                    sg->dma_length, dir);
 }
 
+#ifdef CONFIG_HIGHMEM
+
 dma_addr_t
 swiotlb_map_page(struct device *hwdev, struct page *page,
                 unsigned long offset, size_t size,
@@ -650,6 +652,8 @@ swiotlb_unmap_page(struct device *hwdev,
                unmap_single(hwdev, bus_to_virt(dma_address), size, direction);
 }
 
+#endif
+
 int
 swiotlb_dma_mapping_error(dma_addr_t dma_addr)
 {
@@ -677,7 +681,5 @@ EXPORT_SYMBOL(swiotlb_sync_single_for_cp
 EXPORT_SYMBOL(swiotlb_sync_single_for_device);
 EXPORT_SYMBOL(swiotlb_sync_sg_for_cpu);
 EXPORT_SYMBOL(swiotlb_sync_sg_for_device);
-EXPORT_SYMBOL(swiotlb_map_page);
-EXPORT_SYMBOL(swiotlb_unmap_page);
 EXPORT_SYMBOL(swiotlb_dma_mapping_error);
 EXPORT_SYMBOL(swiotlb_dma_supported);
Index: sle10-sp1-2006-12-21/arch/i386/kernel/pci-dma-xen.c
===================================================================
--- sle10-sp1-2006-12-21.orig/arch/i386/kernel/pci-dma-xen.c    2007-01-02 
10:32:16.000000000 +0100
+++ sle10-sp1-2006-12-21/arch/i386/kernel/pci-dma-xen.c 2007-01-02 
14:01:59.000000000 +0100
@@ -94,13 +94,7 @@ dma_unmap_sg(struct device *hwdev, struc
 }
 EXPORT_SYMBOL(dma_unmap_sg);
 
-/*
- * XXX This file is also used by xenLinux/ia64. 
- * "defined(__i386__) || defined (__x86_64__)" means "!defined(__ia64__)".
- * This #if work around should be removed once this file is merbed back into
- * i386' pci-dma or is moved to drivers/xen/core.
- */
-#if defined(__i386__) || defined(__x86_64__)
+#ifdef CONFIG_HIGHMEM
 dma_addr_t
 dma_map_page(struct device *dev, struct page *page, unsigned long offset,
             size_t size, enum dma_data_direction direction)
@@ -130,7 +124,7 @@ dma_unmap_page(struct device *dev, dma_a
                swiotlb_unmap_page(dev, dma_address, size, direction);
 }
 EXPORT_SYMBOL(dma_unmap_page);
-#endif /* defined(__i386__) || defined(__x86_64__) */
+#endif /* CONFIG_HIGHMEM */
 
 int
 dma_mapping_error(dma_addr_t dma_addr)
Index: sle10-sp1-2006-12-21/include/asm-i386/mach-xen/asm/dma-mapping.h
===================================================================
--- sle10-sp1-2006-12-21.orig/include/asm-i386/mach-xen/asm/dma-mapping.h       
2007-01-02 14:26:42.000000000 +0100
+++ sle10-sp1-2006-12-21/include/asm-i386/mach-xen/asm/dma-mapping.h    
2007-01-02 14:01:59.000000000 +0100
@@ -53,6 +53,7 @@ extern int dma_map_sg(struct device *hwd
 extern void dma_unmap_sg(struct device *hwdev, struct scatterlist *sg,
                         int nents, enum dma_data_direction direction);
 
+#ifdef CONFIG_HIGHMEM
 extern dma_addr_t
 dma_map_page(struct device *dev, struct page *page, unsigned long offset,
             size_t size, enum dma_data_direction direction);
@@ -60,6 +61,11 @@ dma_map_page(struct device *dev, struct 
 extern void
 dma_unmap_page(struct device *dev, dma_addr_t dma_address, size_t size,
               enum dma_data_direction direction);
+#else
+#define dma_map_page(dev, page, offset, size, dir) \
+       dma_map_single(dev, page_address(page) + (offset), (size), (dir))
+#define dma_unmap_page dma_unmap_single
+#endif
 
 extern void
 dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, size_t size,
Index: sle10-sp1-2006-12-21/include/asm-i386/mach-xen/asm/swiotlb.h
===================================================================
--- sle10-sp1-2006-12-21.orig/include/asm-i386/mach-xen/asm/swiotlb.h   
2007-01-02 10:28:31.000000000 +0100
+++ sle10-sp1-2006-12-21/include/asm-i386/mach-xen/asm/swiotlb.h        
2007-01-02 14:01:59.000000000 +0100
@@ -26,11 +26,13 @@ extern int swiotlb_map_sg(struct device 
 extern void swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg,
                         int nents, int direction);
 extern int swiotlb_dma_mapping_error(dma_addr_t dma_addr);
+#ifdef CONFIG_HIGHMEM
 extern dma_addr_t swiotlb_map_page(struct device *hwdev, struct page *page,
                                    unsigned long offset, size_t size,
                                    enum dma_data_direction direction);
 extern void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dma_address,
                                size_t size, enum dma_data_direction direction);
+#endif
 extern int swiotlb_dma_supported(struct device *hwdev, u64 mask);
 extern void swiotlb_init(void);
 


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