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: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/mm/ioremap.c

@@ -124,6 +124,7 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size,
 	struct vm_struct *area;
 	unsigned long new_prot_val;
 	pgprot_t prot;
+	int retval;
 
 	/* Don't allow wraparound or zero size */
 	last_addr = phys_addr + size - 1;
@@ -163,8 +164,14 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size,
 	phys_addr &= PAGE_MASK;
 	size = PAGE_ALIGN(last_addr+1) - phys_addr;
 
-	if (reserve_memtype(phys_addr, phys_addr + size,
-	                    prot_val, &new_prot_val)) {
+	retval = reserve_memtype(phys_addr, phys_addr + size,
+						prot_val, &new_prot_val);
+	if (retval) {
+		printk("reserve_memtype returned %d\n", retval);
+		return NULL;
+	}
+
+	if (prot_val != new_prot_val) {
 		/*
 		 * Do not fallback to certain memory types with certain
 		 * requested type:

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: