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Subject[PATCH 4/9] sparc/iommu: create a common helper for map_sg
Date
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>
---
arch/sparc/mm/iommu.c | 37 +++++++++++++++++--------------------
1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/arch/sparc/mm/iommu.c b/arch/sparc/mm/iommu.c
index 7cb9ddda7531..f90d943a3a27 100644
--- 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)
{
--
2.20.1
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