intel-iommu sg chaining support

x86_64 defines ARCH_HAS_SG_CHAIN. So if IOMMU implementations don't
support sg chaining, we will get data corruption.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 17 deletions

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 8f372c8f3d87..b3d70310af49 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -1963,7 +1963,7 @@ static void intel_free_coherent(struct device *hwdev, size_t size,
 }
 
 #define SG_ENT_VIRT_ADDRESS(sg) (page_address((sg)->page) + (sg)->offset)
-static void intel_unmap_sg(struct device *hwdev, struct scatterlist *sg,
+static void intel_unmap_sg(struct device *hwdev, struct scatterlist *sglist,
         int nelems, int dir)
 {
         int i;
@@ -1973,16 +1973,17 @@ static void intel_unmap_sg(struct device *hwdev, struct scatterlist *sg,
         struct iova *iova;
         size_t size = 0;
         void *addr;
+        struct scatterlist *sg;
 
         if (pdev->dev.archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO)
                 return;
 
         domain = find_domain(pdev);
 
-        iova = find_iova(&domain->iovad, IOVA_PFN(sg[0].dma_address));
+        iova = find_iova(&domain->iovad, IOVA_PFN(sglist[0].dma_address));
         if (!iova)
                 return;
-        for (i = 0; i < nelems; i++, sg++) {
+        for_each_sg(sglist, sg, nelems, i) {
                 addr = SG_ENT_VIRT_ADDRESS(sg);
                 size += aligned_size((u64)addr, sg->length);
         }
@@ -2003,21 +2004,21 @@ static void intel_unmap_sg(struct device *hwdev, struct scatterlist *sg,
 }
 
 static int intel_nontranslate_map_sg(struct device *hddev,
-        struct scatterlist *sg, int nelems, int dir)
+        struct scatterlist *sglist, int nelems, int dir)
 {
         int i;
+        struct scatterlist *sg;
 
-        for (i = 0; i < nelems; i++) {
-                struct scatterlist *s = &sg[i];
-                BUG_ON(!s->page);
-                s->dma_address = virt_to_bus(SG_ENT_VIRT_ADDRESS(s));
-                s->dma_length = s->length;
+        for_each_sg(sglist, sg, nelems, i) {
+                BUG_ON(!sg->page);
+                sg->dma_address = virt_to_bus(SG_ENT_VIRT_ADDRESS(sg));
+                sg->dma_length = sg->length;
         }
         return nelems;
 }
 
-static int intel_map_sg(struct device *hwdev, struct scatterlist *sg,
-        int nelems, int dir)
+static int intel_map_sg(struct device *hwdev, struct scatterlist *sglist,
+                                int nelems, int dir)
 {
         void *addr;
         int i;
@@ -2028,18 +2029,18 @@ static int intel_map_sg(struct device *hwdev, struct scatterlist *sg,
         size_t offset = 0;
         struct iova *iova = NULL;
         int ret;
-        struct scatterlist *orig_sg = sg;
+        struct scatterlist *sg;
         unsigned long start_addr;
 
         BUG_ON(dir == DMA_NONE);
         if (pdev->dev.archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO)
-                return intel_nontranslate_map_sg(hwdev, sg, nelems, dir);
+                return intel_nontranslate_map_sg(hwdev, sglist, nelems, dir);
 
         domain = get_valid_domain_for_dev(pdev);
         if (!domain)
                 return 0;
 
-        for (i = 0; i < nelems; i++, sg++) {
+        for_each_sg(sglist, sg, nelems, i) {
                 addr = SG_ENT_VIRT_ADDRESS(sg);
                 addr = (void *)virt_to_phys(addr);
                 size += aligned_size((u64)addr, sg->length);
@@ -2047,7 +2048,7 @@ static int intel_map_sg(struct device *hwdev, struct scatterlist *sg,
 
         iova = __intel_alloc_iova(hwdev, domain, size);
         if (!iova) {
-                orig_sg->dma_length = 0;
+                sglist->dma_length = 0;
                 return 0;
         }
 
@@ -2063,8 +2064,7 @@ static int intel_map_sg(struct device *hwdev, struct scatterlist *sg,
 
         start_addr = iova->pfn_lo << PAGE_SHIFT_4K;
         offset = 0;
-        sg = orig_sg;
-        for (i = 0; i < nelems; i++, sg++) {
+        for_each_sg(sglist, sg, nelems, i) {
                 addr = SG_ENT_VIRT_ADDRESS(sg);
                 addr = (void *)virt_to_phys(addr);
                 size = aligned_size((u64)addr, sg->length);