Fix loop terminating conditions in fill_sg().

[deliverable/linux.git] / arch / sparc64 / kernel / iommu.c

diff --git a/arch/sparc64/kernel/iommu.c b/arch/sparc64/kernel/iommu.c
index b35a62167e9ce31af6f957b28902ca0259bf3b5d..29af777d7ac920d138d9c8e7598f5fbd0d14a3de 100644 (file)
--- a/arch/sparc64/kernel/iommu.c
+++ b/arch/sparc64/kernel/iommu.c
@@ -475,12 +475,11 @@ static void dma_4u_unmap_single(struct device *dev, dma_addr_t bus_addr,
 #define SG_ENT_PHYS_ADDRESS(SG)        \
        (__pa(page_address((SG)->page)) + (SG)->offset)
 
-static inline void fill_sg(iopte_t *iopte, struct scatterlist *sg,
-                          int nused, int nelems,
-                          unsigned long iopte_protection)
+static void fill_sg(iopte_t *iopte, struct scatterlist *sg,
+                   int nused, int nelems,
+                   unsigned long iopte_protection)
 {
        struct scatterlist *dma_sg = sg;
-       struct scatterlist *sg_end = sg + nelems;
        int i;
 
        for (i = 0; i < nused; i++) {
@@ -515,7 +514,8 @@ static inline void fill_sg(iopte_t *iopte, struct scatterlist *sg,
                                        len -= (IO_PAGE_SIZE - (tmp & (IO_PAGE_SIZE - 1UL)));
                                        break;
                                }
-                               sg++;
+                               sg = sg_next(sg);
+                               nelems--;
                        }
 
                        pteval = iopte_protection | (pteval & IOPTE_PAGE);
@@ -528,24 +528,26 @@ static inline void fill_sg(iopte_t *iopte, struct scatterlist *sg,
                        }
 
                        pteval = (pteval & IOPTE_PAGE) + len;
-                       sg++;
+                       sg = sg_next(sg);
+                       nelems--;
 
                        /* Skip over any tail mappings we've fully mapped,
                         * adjusting pteval along the way.  Stop when we
                         * detect a page crossing event.
                         */
-                       while (sg < sg_end &&
+                       while (nelems &&
                               (pteval << (64 - IO_PAGE_SHIFT)) != 0UL &&
                               (pteval == SG_ENT_PHYS_ADDRESS(sg)) &&
                               ((pteval ^
                                 (SG_ENT_PHYS_ADDRESS(sg) + sg->length - 1UL)) >> IO_PAGE_SHIFT) == 0UL) {
                                pteval += sg->length;
-                               sg++;
+                               sg = sg_next(sg);
+                               nelems--;
                        }
                        if ((pteval << (64 - IO_PAGE_SHIFT)) == 0UL)
                                pteval = ~0UL;
                } while (dma_npages != 0);
-               dma_sg++;
+               dma_sg = sg_next(dma_sg);
        }
 }
 
@@ -606,7 +608,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
        sgtmp = sglist;
        while (used && sgtmp->dma_length) {
                sgtmp->dma_address += dma_base;
-               sgtmp++;
+               sgtmp = sg_next(sgtmp);
                used--;
        }
        used = nelems - used;
@@ -642,6 +644,7 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
        struct strbuf *strbuf;
        iopte_t *base;
        unsigned long flags, ctx, i, npages;
+       struct scatterlist *sg, *sgprv;
        u32 bus_addr;
 
        if (unlikely(direction == DMA_NONE)) {
@@ -654,11 +657,14 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
 
        bus_addr = sglist->dma_address & IO_PAGE_MASK;
 
-       for (i = 1; i < nelems; i++)
-               if (sglist[i].dma_length == 0)
+       sgprv = NULL;
+       for_each_sg(sglist, sg, nelems, i) {
+               if (sg->dma_length == 0)
                        break;
-       i--;
-       npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length) -
+               sgprv = sg;
+       }
+
+       npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length) -
                  bus_addr) >> IO_PAGE_SHIFT;
 
        base = iommu->page_table +
@@ -730,6 +736,7 @@ static void dma_4u_sync_sg_for_cpu(struct device *dev,
        struct iommu *iommu;
        struct strbuf *strbuf;
        unsigned long flags, ctx, npages, i;
+       struct scatterlist *sg, *sgprv;
        u32 bus_addr;
 
        iommu = dev->archdata.iommu;
@@ -753,11 +760,14 @@ static void dma_4u_sync_sg_for_cpu(struct device *dev,
 
        /* Step 2: Kick data out of streaming buffers. */
        bus_addr = sglist[0].dma_address & IO_PAGE_MASK;
-       for(i = 1; i < nelems; i++)
-               if (!sglist[i].dma_length)
+       sgprv = NULL;
+       for_each_sg(sglist, sg, nelems, i) {
+               if (sg->dma_length == 0)
                        break;
-       i--;
-       npages = (IO_PAGE_ALIGN(sglist[i].dma_address + sglist[i].dma_length)
+               sgprv = sg;
+       }
+
+       npages = (IO_PAGE_ALIGN(sgprv->dma_address + sgprv->dma_length)
                  - bus_addr) >> IO_PAGE_SHIFT;
        strbuf_flush(strbuf, iommu, bus_addr, ctx, npages, direction);