PPC: sg chaining support

This updates the ppc iommu/pci dma mappers to sg chaining. Includes
further fixes from FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

3 files changed, 23 insertions, 16 deletions

diff --git a/arch/powerpc/kernel/dma_64.c b/arch/powerpc/kernel/dma_64.c
index 7b0e754383c..9001104b56b 100644
--- a/arch/powerpc/kernel/dma_64.c
+++ b/arch/powerpc/kernel/dma_64.c
@@ -154,12 +154,13 @@ static void dma_direct_unmap_single(struct device *dev, dma_addr_t dma_addr,
 {
 }
 
-static int dma_direct_map_sg(struct device *dev, struct scatterlist *sg,
+static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
 			     int nents, enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	int i;
 
-	for (i = 0; i < nents; i++, sg++) {
+	for_each_sg(sgl, sg, nents, i) {
 		sg->dma_address = (page_to_phys(sg->page) + sg->offset) |
 			dma_direct_offset;
 		sg->dma_length = sg->length;
diff --git a/arch/powerpc/kernel/ibmebus.c b/arch/powerpc/kernel/ibmebus.c
index 53bf64623bd..2e16ca5778a 100644
--- a/arch/powerpc/kernel/ibmebus.c
+++ b/arch/powerpc/kernel/ibmebus.c
@@ -87,15 +87,16 @@ static void ibmebus_unmap_single(struct device *dev,
 }
 
 static int ibmebus_map_sg(struct device *dev,
-			  struct scatterlist *sg,
+			  struct scatterlist *sgl,
 			  int nents, enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	int i;
 
-	for (i = 0; i < nents; i++) {
-		sg[i].dma_address = (dma_addr_t)page_address(sg[i].page)
-			+ sg[i].offset;
-		sg[i].dma_length = sg[i].length;
+	for_each_sg(sgl, sg, nents, i) {
+		sg->dma_address = (dma_addr_t)page_address(sg->page)
+			+ sg->offset;
+		sg->dma_length = sg->length;
 	}
 
 	return nents;
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index e4ec6eee81a..306a6f75b6c 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -277,7 +277,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 	dma_addr_t dma_next = 0, dma_addr;
 	unsigned long flags;
 	struct scatterlist *s, *outs, *segstart;
-	int outcount, incount;
+	int outcount, incount, i;
 	unsigned long handle;
 
 	BUG_ON(direction == DMA_NONE);
@@ -297,7 +297,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 
 	spin_lock_irqsave(&(tbl->it_lock), flags);
 
-	for (s = outs; nelems; nelems--, s++) {
+	for_each_sg(sglist, s, nelems, i) {
 		unsigned long vaddr, npages, entry, slen;
 
 		slen = s->length;
@@ -341,7 +341,8 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 			if (novmerge || (dma_addr != dma_next)) {
 				/* Can't merge: create a new segment */
 				segstart = s;
-				outcount++; outs++;
+				outcount++;
+				outs = sg_next(outs);
 				DBG("    can't merge, new segment.\n");
 			} else {
 				outs->dma_length += s->length;
@@ -374,7 +375,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 	 * next entry of the sglist if we didn't fill the list completely
 	 */
 	if (outcount < incount) {
-		outs++;
+		outs = sg_next(outs);
 		outs->dma_address = DMA_ERROR_CODE;
 		outs->dma_length = 0;
 	}
@@ -385,7 +386,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 	return outcount;
 
  failure:
-	for (s = &sglist[0]; s <= outs; s++) {
+	for_each_sg(sglist, s, nelems, i) {
 		if (s->dma_length != 0) {
 			unsigned long vaddr, npages;
 
@@ -395,6 +396,8 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 			s->dma_address = DMA_ERROR_CODE;
 			s->dma_length = 0;
 		}
+		if (s == outs)
+			break;
 	}
 	spin_unlock_irqrestore(&(tbl->it_lock), flags);
 	return 0;
@@ -404,6 +407,7 @@ int iommu_map_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 		int nelems, enum dma_data_direction direction)
 {
+	struct scatterlist *sg;
 	unsigned long flags;
 
 	BUG_ON(direction == DMA_NONE);
@@ -413,15 +417,16 @@ void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 
 	spin_lock_irqsave(&(tbl->it_lock), flags);
 
+	sg = sglist;
 	while (nelems--) {
 		unsigned int npages;
-		dma_addr_t dma_handle = sglist->dma_address;
+		dma_addr_t dma_handle = sg->dma_address;
 
-		if (sglist->dma_length == 0)
+		if (sg->dma_length == 0)
 			break;
-		npages = iommu_num_pages(dma_handle,sglist->dma_length);
+		npages = iommu_num_pages(dma_handle, sg->dma_length);
 		__iommu_free(tbl, dma_handle, npages);
-		sglist++;
+		sg = sg_next(sg);
 	}
 
 	/* Flush/invalidate TLBs if necessary. As for iommu_free(), we