x86, PAT: Consolidate code in pat_x_mtrr_type() and reserve_memtype()

Fix pat_x_mtrr_type() to use UC_MINUS when the mtrr type return UC. This
is to be  consistent with ioremap() and ioremap_nocache() which uses
UC_MINUS.

Consolidate the code such that reserve_memtype() also uses
pat_x_mtrr_type() when the caller doesn't specify any special attribute
(non WB attribute).

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <20090409212708.939936000@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 329387e..d4c4b2c 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -375,7 +375,8 @@
 	 * - UC_MINUS for non-WB-able memory with no other conflicting mappings
 	 * - Inherit from confliting mappings otherwise
 	 */
-	err = reserve_memtype(phys_addr, phys_addr + size, -1, &flags);
+	err = reserve_memtype(phys_addr, phys_addr + size,
+				_PAGE_CACHE_WB, &flags);
 	if (err < 0)
 		return NULL;