linux-kernel - [PATCH 4/4] Pte simplify ops.patch

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Date:	Wed, 11 Apr 2007 22:31:08 -0700
From:	Zachary Amsden <zach@...are.com>
To:	Andrew Morton <akpm@...l.org>, Andi Kleen <ak@....de>,
	Jeremy Fitzhardinge <jeremy@...p.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Chris Wright <chrisw@...s-sol.org>,
	Hugh Dickins <hugh@...itas.com>,
	David Rientjes <rientjes@...gle.com>,
	Michel Lespinasse <walken@...are.com>,
	Virtualization Mailing List <virtualization@...ts.osdl.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Zachary Amsden <zach@...are.com>
Subject: [PATCH 4/4] Pte simplify ops.patch

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@...are.com>

diff -r b3bbc1b5e085 include/asm-i386/pgtable-2level.h
--- a/include/asm-i386/pgtable-2level.h	Wed Apr 11 18:23:44 2007 -0700
+++ b/include/asm-i386/pgtable-2level.h	Wed Apr 11 18:24:07 2007 -0700
@@ -39,16 +39,6 @@ static inline void native_pte_clear(stru
 static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *xp)
 {
 	*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
diff -r b3bbc1b5e085 include/asm-i386/pgtable-3level.h
--- a/include/asm-i386/pgtable-3level.h	Wed Apr 11 18:23:44 2007 -0700
+++ b/include/asm-i386/pgtable-3level.h	Wed Apr 11 18:23:49 2007 -0700
@@ -139,16 +139,6 @@ static inline void pud_clear (pud_t * pu
 #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)
 {
diff -r b3bbc1b5e085 include/asm-i386/pgtable.h
--- a/include/asm-i386/pgtable.h	Wed Apr 11 18:23:44 2007 -0700
+++ b/include/asm-i386/pgtable.h	Wed Apr 11 18:23:49 2007 -0700
@@ -267,6 +267,16 @@ static inline pte_t pte_mkhuge(pte_t pte
 #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
@@ -348,8 +358,11 @@ static inline pte_t ptep_get_and_clear_f
 {
 	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);
 	}
-
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