sparc/iommu: create a common helper for map_sg

Share the code for the global and per-page flush map_sg loops using a
simple bool parameter to disable the per-page flush for the former
variant.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/mm/iommu.c b/arch/sparc/mm/iommu.c
index 7cb9ddd..f90d943 100644 (file)
--- a/arch/sparc/mm/iommu.c
+++ b/arch/sparc/mm/iommu.c
@@ -241,25 +241,9 @@ static dma_addr_t sbus_iommu_map_page_pflush(struct device *dev,
        return __sbus_iommu_map_page(dev, page, offset, len);
 }
 
-static int sbus_iommu_map_sg_gflush(struct device *dev, struct scatterlist *sgl,
-               int nents, enum dma_data_direction dir, unsigned long attrs)
-{
-       struct scatterlist *sg;
-       int i, n;
-
-       flush_page_for_dma(0);
-
-       for_each_sg(sgl, sg, nents, i) {
-               n = (sg->length + sg->offset + PAGE_SIZE-1) >> PAGE_SHIFT;
-               sg->dma_address = iommu_get_one(dev, sg_page(sg), n) + sg->offset;
-               sg->dma_length = sg->length;
-       }
-
-       return nents;
-}
-
-static int sbus_iommu_map_sg_pflush(struct device *dev, struct scatterlist *sgl,
-               int nents, enum dma_data_direction dir, unsigned long attrs)
+static int __sbus_iommu_map_sg(struct device *dev, struct scatterlist *sgl,
+               int nents, enum dma_data_direction dir, unsigned long attrs,
+               bool per_page_flush)
 {
        unsigned long page, oldpage = 0;
        struct scatterlist *sg;
@@ -273,7 +257,7 @@ static int sbus_iommu_map_sg_pflush(struct device *dev, struct scatterlist *sgl,
                 * XXX Is this a good assumption?
                 * XXX What if someone else unmaps it here and races us?
                 */
-               if (!PageHighMem(sg_page(sg))) {
+               if (per_page_flush && !PageHighMem(sg_page(sg))) {
                        page = (unsigned long)page_address(sg_page(sg));
                        for (i = 0; i < n; i++) {
                                if (page != oldpage) {  /* Already flushed? */
@@ -291,6 +275,19 @@ static int sbus_iommu_map_sg_pflush(struct device *dev, struct scatterlist *sgl,
        return nents;
 }
 
+static int sbus_iommu_map_sg_gflush(struct device *dev, struct scatterlist *sgl,
+               int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+       flush_page_for_dma(0);
+       return __sbus_iommu_map_sg(dev, sgl, nents, dir, attrs, false);
+}
+
+static int sbus_iommu_map_sg_pflush(struct device *dev, struct scatterlist *sgl,
+               int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+       return __sbus_iommu_map_sg(dev, sgl, nents, dir, attrs, true);
+}
+
 static void sbus_iommu_unmap_page(struct device *dev, dma_addr_t dma_addr,
                size_t len, enum dma_data_direction dir, unsigned long attrs)
 {