[PATCH] x86_64: no_iommu removal in pci-gart.c

In previous versions of pci-gart.c, no_iommu was used to determine if IOMMU was
disabled in the GART DMA mapping functions.  This changed in 2.6.16 and now
gart_xxx() functions are only called if gart is enabled.  Therefore, uses of
no_iommu in the GART code are no longer necessary and can be removed.

Also, it removes double deceleration of no_iommu and force_iommu in pci.h and
proto.h, by removing the deceleration in pci.h.

Lastly, end_pfn off by one error.

Tested (along with patch 1/2) on dual opteron with gart enabled, iommu=soft,
and iommu=off.

Signed-off-by: Jon Mason <jdmason@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 6 insertions, 20 deletions

diff --git a/arch/x86_64/kernel/aperture.c b/arch/x86_64/kernel/aperture.c
index e4e2b7d01f89..a0f955b9995f 100644
--- a/arch/x86_64/kernel/aperture.c
+++ b/arch/x86_64/kernel/aperture.c
@@ -248,7 +248,7 @@ void __init iommu_hole_init(void)
                 /* Got the aperture from the AGP bridge */
         } else if (swiotlb && !valid_agp) {
                 /* Do nothing */
-        } else if ((!no_iommu && end_pfn >= MAX_DMA32_PFN) ||
+        } else if ((!no_iommu && end_pfn > MAX_DMA32_PFN) ||
                    force_iommu ||
                    valid_agp ||
                    fallback_aper_force) { 
diff --git a/arch/x86_64/kernel/pci-gart.c b/arch/x86_64/kernel/pci-gart.c
index dd0718dc178b..0c3f052ba6ce 100644
--- a/arch/x86_64/kernel/pci-gart.c
+++ b/arch/x86_64/kernel/pci-gart.c
@@ -228,11 +228,6 @@ static inline int need_iommu(struct device *dev, unsigned long addr, size_t size
         int mmu = high;
         if (force_iommu) 
                 mmu = 1; 
-        if (no_iommu) { 
-                if (high) 
-                        panic("PCI-DMA: high address but no IOMMU.\n"); 
-                mmu = 0; 
-        }       
         return mmu; 
 }
 
@@ -241,11 +236,6 @@ static inline int nonforced_iommu(struct device *dev, unsigned long addr, size_t
         u64 mask = *dev->dma_mask;
         int high = addr + size >= mask;
         int mmu = high;
-        if (no_iommu) { 
-                if (high) 
-                        panic("PCI-DMA: high address but no IOMMU.\n"); 
-                mmu = 0; 
-        }       
         return mmu; 
 }
 
@@ -310,7 +300,7 @@ void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, int di
 
         for (i = 0; i < nents; i++) {
                 struct scatterlist *s = &sg[i];
-                if (!s->dma_length)
+                if (!s->dma_length || !s->length)
                         break;
                 dma_unmap_single(dev, s->dma_address, s->dma_length, dir);
         }
@@ -364,6 +354,7 @@ static int __dma_map_cont(struct scatterlist *sg, int start, int stopat,
                 
                 BUG_ON(i > start && s->offset);
                 if (i == start) {
+                        *sout = *s; 
                         sout->dma_address = iommu_bus_base;
                         sout->dma_address += iommu_page*PAGE_SIZE + s->offset;
                         sout->dma_length = s->length;
@@ -390,6 +381,7 @@ static inline int dma_map_cont(struct scatterlist *sg, int start, int stopat,
 {
         if (!need) { 
                 BUG_ON(stopat - start != 1);
+                *sout = sg[start]; 
                 sout->dma_length = sg[start].length; 
                 return 0;
         } 
@@ -632,17 +624,13 @@ static int __init pci_iommu_init(void)
                 (agp_copy_info(agp_bridge, &info) < 0);
 #endif  
 
-        if (swiotlb) { 
-                no_iommu = 1;
+        if (swiotlb)
                 return -1; 
-        } 
-        
+
         if (no_iommu ||
             (!force_iommu && end_pfn <= MAX_DMA32_PFN) ||
             !iommu_aperture ||
             (no_agp && init_k8_gatt(&info) < 0)) {
-                no_iommu = 1;
-                no_iommu_init();
                 printk(KERN_INFO "PCI-DMA: Disabling IOMMU.\n");
                 if (end_pfn > MAX_DMA32_PFN) {
                         printk(KERN_ERR "WARNING more than 4GB of memory "
diff --git a/include/asm-x86_64/pci.h b/include/asm-x86_64/pci.h
index fd03e15d7ea6..8a05af264d18 100644
--- a/include/asm-x86_64/pci.h
+++ b/include/asm-x86_64/pci.h
@@ -19,8 +19,6 @@ extern unsigned int pcibios_assign_all_busses(void);
 #endif
 #define pcibios_scan_all_fns(a, b)      0
 
-extern int no_iommu, force_iommu;
-
 extern unsigned long pci_mem_start;
 #define PCIBIOS_MIN_IO          0x1000
 #define PCIBIOS_MIN_MEM         (pci_mem_start)