[SPARC64]: Temporarily remove IOMMU merging code.

Changeset fde6a3c82d67f592eb587be4d12222b0ae6d4321 ("iommu sg merging:
sparc64: make iommu respect the segment size limits") broke sparc64
because whilst it added the segment limiting code to the first pass of
SG mapping (in prepare_sg()) it did not add matching code to the
second pass handling (in fill_sg())

As a result the two passes disagree where the segment boundaries
should be, resulting in OOPSes, DMA corruption, and corrupted
superblocks.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 0 deletions

diff --git a/arch/sparc64/kernel/iommu_common.h b/arch/sparc64/kernel/iommu_common.h
index a90d046e8024..4b5cafa2877a 100644
--- a/arch/sparc64/kernel/iommu_common.h
+++ b/arch/sparc64/kernel/iommu_common.h
@@ -30,6 +30,32 @@
  */
 #define IOMMU_PAGE_SHIFT                13
 
+#define SG_ENT_PHYS_ADDRESS(SG) (__pa(sg_virt((SG))))
+
+static inline unsigned long iommu_num_pages(unsigned long vaddr,
+                                            unsigned long slen)
+{
+        unsigned long npages;
+
+        npages = IO_PAGE_ALIGN(vaddr + slen) - (vaddr & IO_PAGE_MASK);
+        npages >>= IO_PAGE_SHIFT;
+
+        return npages;
+}
+
+static inline unsigned long calc_npages(struct scatterlist *sglist, int nelems)
+{
+        unsigned long i, npages = 0;
+        struct scatterlist *sg;
+
+        for_each_sg(sglist, sg, nelems, i) {
+                unsigned long paddr = SG_ENT_PHYS_ADDRESS(sg);
+                npages += iommu_num_pages(paddr, sg->length);
+        }
+
+        return npages;
+}
+
 /* You are _strongly_ advised to enable the following debugging code
  * any time you make changes to the sg code below, run it for a while
  * with filesystems mounted read-only before buying the farm... -DaveM