i386 mm: use pte_update() in ptep_test_and_clear_dirty()

It is not safe to use pte_update_defer() in ptep_test_and_clear_young():
its only user, /proc/<pid>/clear_refs, drops pte lock before flushing TLB.
Use the safe though less efficient pte_update() paravirtop in its place.
Likewise in ptep_test_and_clear_dirty(), though that has no current use.

These are macros (header file dependency stops them from becoming inline
functions), so be more liberal with the underscores and parentheses.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h
index 2394589..d62bdb0 100644 (file)
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -295,22 +295,24 @@ do {                                                                      \
 
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
 #define ptep_test_and_clear_dirty(vma, addr, ptep) ({                  \
-       int ret = 0;                                                    \
-       if (pte_dirty(*ptep))                                           \
-               ret = test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low); \
-       if (ret)                                                        \
-               pte_update_defer(vma->vm_mm, addr, ptep);               \
-       ret;                                                            \
+       int __ret = 0;                                                  \
+       if (pte_dirty(*(ptep)))                                         \
+               __ret = test_and_clear_bit(_PAGE_BIT_DIRTY,             \
+                                               &(ptep)->pte_low);      \
+       if (__ret)                                                      \
+               pte_update((vma)->vm_mm, addr, ptep);                   \
+       __ret;                                                          \
 })
 
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 #define ptep_test_and_clear_young(vma, addr, ptep) ({                  \
-       int ret = 0;                                                    \
-       if (pte_young(*ptep))                                           \
-               ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low); \
-       if (ret)                                                        \
-               pte_update_defer(vma->vm_mm, addr, ptep);               \
-       ret;                                                            \
+       int __ret = 0;                                                  \
+       if (pte_young(*(ptep)))                                         \
+               __ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,          \
+                                               &(ptep)->pte_low);      \
+       if (__ret)                                                      \
+               pte_update((vma)->vm_mm, addr, ptep);                   \
+       __ret;                                                          \
 })
 
 /*