x86, PAT: Change order of cpa and free in set_memory_wb

To be free of aliasing due to races, set_memory_* interfaces should
follow ordering of reserving, changing memtype to UC/WC, changing
memtype back to WB followed by free.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20090409212708.512280000@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 4 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index d71e1b636ce6..d487eaa17bff 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1021,15 +1021,19 @@ int _set_memory_wb(unsigned long addr, int numpages)
 
 int set_memory_wb(unsigned long addr, int numpages)
 {
+        int ret = _set_memory_wb(addr, numpages);
         free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
-
-        return _set_memory_wb(addr, numpages);
+        return ret;
 }
 EXPORT_SYMBOL(set_memory_wb);
 
 int set_memory_array_wb(unsigned long *addr, int addrinarray)
 {
         int i;
+        int ret;
+
+        ret = change_page_attr_clear(addr, addrinarray,
+                                      __pgprot(_PAGE_CACHE_MASK), 1);
 
         for (i = 0; i < addrinarray; i++) {
                 unsigned long start = __pa(addr[i]);
@@ -1042,8 +1046,7 @@ int set_memory_array_wb(unsigned long *addr, int addrinarray)
                 }
                 free_memtype(start, end);
         }
-        return change_page_attr_clear(addr, addrinarray,
-                                      __pgprot(_PAGE_CACHE_MASK), 1);
+        return ret;
 }
 EXPORT_SYMBOL(set_memory_array_wb);