[PATCH] i386: pte simplify ops

Add comment and condense code to make use of native_local_ptep_get_and_clear
function.  Also, it turns out the 2-level and 3-level paging definitions were
identical, so move the common definition into pgtable.h

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 15 insertions, 2 deletions

diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h
index 00e97a9d367e..c6b8b944120c 100644
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -269,6 +269,16 @@ extern void vmalloc_sync_all(void);
 #define pte_update_defer(mm, addr, ptep)        do { } while (0)
 #endif
 
+/* local pte updates need not use xchg for locking */
+static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
+{
+        pte_t res = *ptep;
+
+        /* Pure native function needs no input for mm, addr */
+        native_pte_clear(NULL, 0, ptep);
+        return res;
+}
+
 /*
  * We only update the dirty/accessed state if we set
  * the dirty bit by hand in the kernel, since the hardware
@@ -343,8 +353,11 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, unsigned long
 {
         pte_t pte;
         if (full) {
-                pte = *ptep;
-                native_pte_clear(mm, addr, ptep);
+                /*
+                 * Full address destruction in progress; paravirt does not
+                 * care about updates and native needs no locking
+                 */
+                pte = native_local_ptep_get_and_clear(ptep);
         } else {
                 pte = ptep_get_and_clear(mm, addr, ptep);
         }