[PATCH] Added xen_is_contiguous_region

[Jambunathan K <jambunathan@netxen.com>]

Continuation of the following thread
http://lists.xensource.com/archives/html/xen-devel/2007-04/msg00135.html

I haven't compiled the changes for IA64. Consider the changes as indicative.


Added xen_is_contiguous_region

diff -r a839e331f06f linux-2.6-xen-sparse/arch/i386/kernel/pci-dma-xen.c
--- a/linux-2.6-xen-sparse/arch/i386/kernel/pci-dma-xen.c       Thu Apr 12 13:13:04 2007
+++ b/linux-2.6-xen-sparse/arch/i386/kernel/pci-dma-xen.c       Fri Apr 13 23:16:15 2007
@@ -327,7 +327,7 @@
                 dma = swiotlb_map_single(dev, ptr, size, direction);
         } else {
                 dma = virt_to_bus(ptr);
-               IOMMU_BUG_ON(range_straddles_page_boundary(ptr, size));
+               IOMMU_BUG_ON(!xen_is_contiguous_region(ptr, size));
                 IOMMU_BUG_ON(address_needs_mapping(dev, dma));
         }

diff -r a839e331f06f linux-2.6-xen-sparse/arch/i386/kernel/swiotlb.c
--- a/linux-2.6-xen-sparse/arch/i386/kernel/swiotlb.c   Thu Apr 12 13:13:04 2007
+++ b/linux-2.6-xen-sparse/arch/i386/kernel/swiotlb.c   Fri Apr 13 23:16:15 2007
@@ -479,7 +479,7 @@
          * we can safely return the device addr and not worry about bounce
          * buffering it.
          */
-       if (!range_straddles_page_boundary(ptr, size) &&
+       if (xen_is_contiguous_region(ptr, size) &&
             !address_needs_mapping(hwdev, dev_addr))
                 return dev_addr;

diff -r a839e331f06f linux-2.6-xen-sparse/arch/i386/mm/hypervisor.c
--- a/linux-2.6-xen-sparse/arch/i386/mm/hypervisor.c    Thu Apr 12 13:13:04 2007
+++ b/linux-2.6-xen-sparse/arch/i386/mm/hypervisor.c    Fri Apr 13 23:16:15 2007
@@ -440,6 +440,13 @@
  }
  EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);

+int xen_is_contiguous_region(void *vaddr, size_t size)
+{
+       return (((((unsigned long)vaddr & ~PAGE_MASK) + size) <= PAGE_SIZE) ||
+               test_bit(__pa(vaddr) >> PAGE_SHIFT, contiguous_bitmap));
+}
+EXPORT_SYMBOL_GPL(xen_is_contiguous_region);
+
  #ifdef __i386__
  int write_ldt_entry(void *ldt, int entry, __u32 entry_a, __u32 entry_b)
  {
diff -r a839e331f06f linux-2.6-xen-sparse/include/asm-i386/mach-xen/asm/dma-mapping.h
--- a/linux-2.6-xen-sparse/include/asm-i386/mach-xen/asm/dma-mapping.h  Thu Apr 12 13:13:04 2007
+++ b/linux-2.6-xen-sparse/include/asm-i386/mach-xen/asm/dma-mapping.h  Fri Apr 13 23:16:15 2007
@@ -25,9 +25,7 @@
  static inline int
  range_straddles_page_boundary(void *p, size_t size)
  {
-       extern unsigned long *contiguous_bitmap;
-       return (((((unsigned long)p & ~PAGE_MASK) + size) > PAGE_SIZE) &&
-               !test_bit(__pa(p) >> PAGE_SHIFT, contiguous_bitmap));
+       return !xen_is_contiguous_region(p, size);
  }

  #define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)
diff -r a839e331f06f linux-2.6-xen-sparse/include/asm-i386/mach-xen/asm/hypervisor.h
--- a/linux-2.6-xen-sparse/include/asm-i386/mach-xen/asm/hypervisor.h   Thu Apr 12 13:13:04 2007
+++ b/linux-2.6-xen-sparse/include/asm-i386/mach-xen/asm/hypervisor.h   Fri Apr 13 23:16:15 2007
@@ -118,6 +118,7 @@
      unsigned long vstart, unsigned int order, unsigned int address_bits);
  void xen_destroy_contiguous_region(
      unsigned long vstart, unsigned int order);
+int xen_is_contiguous_region(void *vaddr, size_t size);

  /* Turn jiffies into Xen system time. */
  u64 jiffies_to_st(unsigned long jiffies);
diff -r a839e331f06f linux-2.6-xen-sparse/include/asm-ia64/dma-mapping.h
--- a/linux-2.6-xen-sparse/include/asm-ia64/dma-mapping.h       Thu Apr 12 13:13:04 2007
+++ b/linux-2.6-xen-sparse/include/asm-ia64/dma-mapping.h       Fri Apr 13 23:16:15 2007
@@ -127,9 +127,7 @@
  static inline int
  range_straddles_page_boundary(void *p, size_t size)
  {
-       extern unsigned long *contiguous_bitmap;
-       return (((((unsigned long)p & ~PAGE_MASK) + size) > PAGE_SIZE) &&
-               !test_bit(__pa(p) >> PAGE_SHIFT, contiguous_bitmap));
+       return !xen_is_contiguous_region(p, size);
  }
  #endif

diff -r a839e331f06f linux-2.6-xen-sparse/include/asm-ia64/hypervisor.h
--- a/linux-2.6-xen-sparse/include/asm-ia64/hypervisor.h        Thu Apr 12 13:13:04 2007
+++ b/linux-2.6-xen-sparse/include/asm-ia64/hypervisor.h        Fri Apr 13 23:16:15 2007
@@ -146,7 +146,7 @@

  #ifndef CONFIG_VMX_GUEST
  int __xen_create_contiguous_region(unsigned long vstart, unsigned int order, unsigned int address_bits);
-static inline int
+int
  xen_create_contiguous_region(unsigned long vstart,
                               unsigned int order, unsigned int address_bits)
  {
@@ -157,14 +157,24 @@
         }
         return ret;
  }
+EXPORT_SYMBOL_GPL(xen_create_contiguous_region);

  void __xen_destroy_contiguous_region(unsigned long vstart, unsigned int order);
-static inline void
+void
  xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
  {
         if (is_running_on_xen())
                 __xen_destroy_contiguous_region(vstart, order);
  }
+EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
+
+int xen_is_contiguous_region(void *vaddr, size_t size)
+{
+       return (((((unsigned long)vaddr & ~PAGE_MASK) + size) <= PAGE_SIZE) ||
+               test_bit(__pa(vaddr) >> PAGE_SHIFT, contiguous_bitmap));
+}
+EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
+

  #endif /* !CONFIG_VMX_GUEST */