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 329387eca12ad67773ba985d797cf221a2137e95..d4c4b2c4dbbe8790e6ddf283bd675097f661bb6c 100644 (file)
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -375,7 +375,8 @@ static void __iomem *ioremap_default(resource_size_t phys_addr,
         * - 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;
 

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 640339ee4fb2ae7ab79c02302cf26d0647966344..8d3de95805088cc2636fa2907992c4d0b71892f4 100644 (file)
--- 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)