x86 PAT: consolidate old memtype new memtype check into a function

Impact: cleanup Move the new memtype old memtype allowed check to header so that is can be shared by other users. Subsequent patch uses this in pat.c in remap_pfn_range() code path. No functionality change in this patch. Signed-off-by: Venkatesh Pallipadi <[email protected]> Signed-off-by: Suresh Siddha <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
niw · Jan 13, 2009 · afc7d20 · afc7d20
1 parent a367061
commit afc7d20
Show file tree

Hide file tree

Showing 2 changed files with 20 additions and 11 deletions.
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
@@ -341,6 +341,25 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 
 #define canon_pgprot(p) __pgprot(pgprot_val(p) & __supported_pte_mask)
 
+static inline int is_new_memtype_allowed(unsigned long flags,
+						unsigned long new_flags)
+{
+	/*
+	 * Certain new memtypes are not allowed with certain
+	 * requested memtype:
+	 * - request is uncached, return cannot be write-back
+	 * - request is write-combine, return cannot be write-back
+	 */
+	if ((flags == _PAGE_CACHE_UC_MINUS &&
+	     new_flags == _PAGE_CACHE_WB) ||
+	    (flags == _PAGE_CACHE_WC &&
+	     new_flags == _PAGE_CACHE_WB)) {
+		return 0;
+	}
+
+	return 1;
+}
+
 #ifndef __ASSEMBLY__
 /* Indicate that x86 has its own track and untrack pfn vma functions */
 #define __HAVE_PFNMAP_TRACKING

diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
@@ -314,17 +314,7 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
 		return retval;
 
 	if (flags != new_flags) {
-		/*
-		 * Do not fallback to certain memory types with certain
-		 * requested type:
-		 * - request is uncached, return cannot be write-back
-		 * - request is uncached, return cannot be write-combine
-		 * - request is write-combine, return cannot be write-back
-		 */
-		if ((flags == _PAGE_CACHE_UC_MINUS &&
-		     (new_flags == _PAGE_CACHE_WB)) ||
-		    (flags == _PAGE_CACHE_WC &&
-		     new_flags == _PAGE_CACHE_WB)) {
+		if (!is_new_memtype_allowed(flags, new_flags)) {
 			free_memtype(addr, addr+len);
 			return -EINVAL;
 		}