x86: PAT bug fix for attribute type check after reserve_memtype

Bug fixes for reserve_memtype() call in __ioremap and pci_mmap_page_range().
If reserve_memtype returns non-zero, then it is an error and subsequent free is
not required. Requested and returned prot value check should be done when
reserve_memtype returns success.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index 4ebf52f6b1fd..2ead72363077 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -328,6 +328,7 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
         unsigned long len = vma->vm_end - vma->vm_start;
         unsigned long flags;
         unsigned long new_flags;
+        int retval;
 
         /* I/O space cannot be accessed via normal processor loads and
          * stores on this platform.
@@ -344,7 +345,11 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
         vma->vm_page_prot = __pgprot(prot);
 
         flags = pgprot_val(vma->vm_page_prot) & _PAGE_CACHE_MASK;
-        if (reserve_memtype(addr, addr + len, flags, &new_flags)) {
+        retval = reserve_memtype(addr, addr + len, flags, &new_flags);
+        if (retval)
+                return retval;
+
+        if (flags != new_flags) {
                 /*
                  * Do not fallback to certain memory types with certain
                  * requested type: