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>

1 files changed, 13 insertions, 22 deletions

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 640339ee4fb2..8d3de9580508 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -182,10 +182,10 @@ static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
                 u8 mtrr_type;
 
                 mtrr_type = mtrr_type_lookup(start, end);
-                if (mtrr_type == MTRR_TYPE_UNCACHABLE)
-                        return _PAGE_CACHE_UC;
-                if (mtrr_type == MTRR_TYPE_WRCOMB)
-                        return _PAGE_CACHE_WC;
+                if (mtrr_type != MTRR_TYPE_WRBACK)
+                        return _PAGE_CACHE_UC_MINUS;
+
+                return _PAGE_CACHE_WB;
         }
 
         return req_type;
@@ -352,23 +352,13 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
                 return 0;
         }
 
-        if (req_type == -1) {
-                /*
-                 * Call mtrr_lookup to get the type hint. This is an
-                 * optimization for /dev/mem mmap'ers into WB memory (BIOS
-                 * tools and ACPI tools). Use WB request for WB memory and use
-                 * UC_MINUS otherwise.
-                 */
-                u8 mtrr_type = mtrr_type_lookup(start, end);
-
-                if (mtrr_type == MTRR_TYPE_WRBACK)
-                        actual_type = _PAGE_CACHE_WB;
-                else
-                        actual_type = _PAGE_CACHE_UC_MINUS;
-        } else {
-                actual_type = pat_x_mtrr_type(start, end,
-                                              req_type & _PAGE_CACHE_MASK);
-        }
+        /*
+         * Call mtrr_lookup to get the type hint. This is an
+         * optimization for /dev/mem mmap'ers into WB memory (BIOS
+         * tools and ACPI tools). Use WB request for WB memory and use
+         * UC_MINUS otherwise.
+         */
+        actual_type = pat_x_mtrr_type(start, end, req_type & _PAGE_CACHE_MASK);
 
         if (new_type)
                 *new_type = actual_type;
@@ -587,7 +577,8 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
         if (flags != -1) {
                 retval = reserve_memtype(offset, offset + size, flags, NULL);
         } else {
-                retval = reserve_memtype(offset, offset + size, -1, &flags);
+                retval = reserve_memtype(offset, offset + size,
+                                        _PAGE_CACHE_WB, &flags);
         }
 
         if (retval < 0)