x86-64: update pci-gart iommu to sg helpers

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

1 files changed, 36 insertions, 29 deletions

diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index 4918c575d582..cfcc84e6c350 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -23,6 +23,7 @@
 #include <linux/interrupt.h>
 #include <linux/bitops.h>
 #include <linux/kdebug.h>
+#include <linux/scatterlist.h>
 #include <asm/atomic.h>
 #include <asm/io.h>
 #include <asm/mtrr.h>
@@ -278,10 +279,10 @@ static void gart_unmap_single(struct device *dev, dma_addr_t dma_addr,
  */
 static void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 {
+        struct scatterlist *s;
         int i;
 
-        for (i = 0; i < nents; i++) {
-                struct scatterlist *s = &sg[i];
+        for_each_sg(sg, s, nents, i) {
                 if (!s->dma_length || !s->length)
                         break;
                 gart_unmap_single(dev, s->dma_address, s->dma_length, dir);
@@ -292,14 +293,14 @@ static void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
 static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
                                int nents, int dir)
 {
+        struct scatterlist *s;
         int i;
 
 #ifdef CONFIG_IOMMU_DEBUG
         printk(KERN_DEBUG "dma_map_sg overflow\n");
 #endif
 
-        for (i = 0; i < nents; i++ ) {
-                struct scatterlist *s = &sg[i];
+        for_each_sg(sg, s, nents, i) {
                 unsigned long addr = page_to_phys(s->page) + s->offset; 
                 if (nonforced_iommu(dev, addr, s->length)) { 
                         addr = dma_map_area(dev, addr, s->length, dir);
@@ -319,23 +320,23 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
 }
 
 /* Map multiple scatterlist entries continuous into the first. */
-static int __dma_map_cont(struct scatterlist *sg, int start, int stopat,
+static int __dma_map_cont(struct scatterlist *start, int nelems,
                       struct scatterlist *sout, unsigned long pages)
 {
         unsigned long iommu_start = alloc_iommu(pages);
         unsigned long iommu_page = iommu_start; 
+        struct scatterlist *s;
         int i;
 
         if (iommu_start == -1)
                 return -1;
-        
-        for (i = start; i < stopat; i++) {
-                struct scatterlist *s = &sg[i];
+
+        for_each_sg(start, s, nelems, i) {
                 unsigned long pages, addr;
                 unsigned long phys_addr = s->dma_address;
                 
-                BUG_ON(i > start && s->offset);
-                if (i == start) {
+                BUG_ON(s != start && s->offset);
+                if (s == start) {
                         *sout = *s; 
                         sout->dma_address = iommu_bus_base;
                         sout->dma_address += iommu_page*PAGE_SIZE + s->offset;
@@ -357,17 +358,17 @@ static int __dma_map_cont(struct scatterlist *sg, int start, int stopat,
         return 0;
 }
 
-static inline int dma_map_cont(struct scatterlist *sg, int start, int stopat,
+static inline int dma_map_cont(struct scatterlist *start, int nelems,
                       struct scatterlist *sout,
                       unsigned long pages, int need)
 {
-        if (!need) { 
-                BUG_ON(stopat - start != 1);
-                *sout = sg[start]; 
-                sout->dma_length = sg[start].length; 
+        if (!need) {
+                BUG_ON(nelems != 1);
+                *sout = *start;
+                sout->dma_length = start->length;
                 return 0;
-        } 
-        return __dma_map_cont(sg, start, stopat, sout, pages);
+        }
+        return __dma_map_cont(start, nelems, sout, pages);
 }
                 
 /*
@@ -381,6 +382,7 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
         int start;
         unsigned long pages = 0;
         int need = 0, nextneed;
+        struct scatterlist *s, *ps, *start_sg, *sgmap;
 
         if (nents == 0) 
                 return 0;
@@ -390,8 +392,9 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 
         out = 0;
         start = 0;
-        for (i = 0; i < nents; i++) {
-                struct scatterlist *s = &sg[i];
+        start_sg = sgmap = sg;
+        ps = NULL; /* shut up gcc */
+        for_each_sg(sg, s, nents, i) {
                 dma_addr_t addr = page_to_phys(s->page) + s->offset;
                 s->dma_address = addr;
                 BUG_ON(s->length == 0); 
@@ -400,29 +403,33 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 
                 /* Handle the previous not yet processed entries */
                 if (i > start) {
-                        struct scatterlist *ps = &sg[i-1];
                         /* Can only merge when the last chunk ends on a page 
                            boundary and the new one doesn't have an offset. */
                         if (!iommu_merge || !nextneed || !need || s->offset ||
-                            (ps->offset + ps->length) % PAGE_SIZE) { 
-                                if (dma_map_cont(sg, start, i, sg+out, pages,
-                                                 need) < 0)
+                            (ps->offset + ps->length) % PAGE_SIZE) {
+                                if (dma_map_cont(start_sg, i - start, sgmap,
+                                                  pages, need) < 0)
                                         goto error;
                                 out++;
+                                sgmap = sg_next(sgmap);
                                 pages = 0;
-                                start = i;      
+                                start = i;
+                                start_sg = s;
                         }
                 }
 
                 need = nextneed;
                 pages += to_pages(s->offset, s->length);
+                ps = s;
         }
-        if (dma_map_cont(sg, start, i, sg+out, pages, need) < 0)
+        if (dma_map_cont(start_sg, i - start, sgmap, pages, need) < 0)
                 goto error;
         out++;
         flush_gart();
-        if (out < nents) 
-                sg[out].dma_length = 0; 
+        if (out < nents) {
+                sgmap = sg_next(sgmap);
+                sgmap->dma_length = 0;
+        }
         return out;
 
 error:
@@ -437,8 +444,8 @@ error:
         if (panic_on_overflow)
                 panic("dma_map_sg: overflow on %lu pages\n", pages);
         iommu_full(dev, pages << PAGE_SHIFT, dir);
-        for (i = 0; i < nents; i++)
-                sg[i].dma_address = bad_dma_address;
+        for_each_sg(sg, s, nents, i)
+                s->dma_address = bad_dma_address;
         return 0;
 }