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 7b0e754383cf..9001104b56b0 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 53bf64623bd8..2e16ca5778a3 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 e4ec6eee81a8..306a6f75b6c5 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