[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: NZachary Amsden <zach@vmware.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>

include/asm-i386/pgtable-2level.h

@@ -41,16 +41,6 @@ static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr, pt
 	*xp = __pte(0);
 }
 
-/* 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;
-
-	res = *ptep;
-	native_pte_clear(NULL, 0, ptep);
-	return res;
-}
-
 #ifdef CONFIG_SMP
 static inline pte_t native_ptep_get_and_clear(pte_t *xp)
 {

include/asm-i386/pgtable-3level.h

@@ -139,16 +139,6 @@ static inline void pud_clear (pud_t * pud) { }
 #define pmd_offset(pud, address) ((pmd_t *) pud_page(*(pud)) + \
 			pmd_index(address))
 
-/* 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;
-
-	res = *ptep;
-	native_pte_clear(NULL, 0, ptep);
-	return res;
-}
-
 #ifdef CONFIG_SMP
 static inline pte_t native_ptep_get_and_clear(pte_t *ptep)
 {

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);
 	}