---

yaml --- r: 332355 b: refs/heads/master c: 48af0d7 h: refs/heads/master i: 332353: 891b138 332351: a62a70c v: v3
git-mirror · Oct 9, 2012 · 18da32b · 18da32b
1 parent 48bccae
commit 18da32b
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Showing 2 changed files with 12 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 00442ad04a5eac08a98255697c510e708f6082e2
+refs/heads/master: 48af0d7cb3c87fae2ff38af372821dcb0b019c9e
diff --git a/trunk/include/linux/mmu_notifier.h b/trunk/include/linux/mmu_notifier.h
@@ -311,14 +311,24 @@ static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
 	__young;							\
 })
 
+/*
+ * set_pte_at_notify() sets the pte _after_ running the notifier.
+ * This is safe to start by updating the secondary MMUs, because the primary MMU
+ * pte invalidate must have already happened with a ptep_clear_flush() before
+ * set_pte_at_notify() has been invoked.  Updating the secondary MMUs first is
+ * required when we change both the protection of the mapping from read-only to
+ * read-write and the pfn (like during copy on write page faults). Otherwise the
+ * old page would remain mapped readonly in the secondary MMUs after the new
+ * page is already writable by some CPU through the primary MMU.
+ */
 #define set_pte_at_notify(__mm, __address, __ptep, __pte)		\
 ({									\
 	struct mm_struct *___mm = __mm;					\
 	unsigned long ___address = __address;				\
 	pte_t ___pte = __pte;						\
 									\
-	set_pte_at(___mm, ___address, __ptep, ___pte);			\
 	mmu_notifier_change_pte(___mm, ___address, ___pte);		\
+	set_pte_at(___mm, ___address, __ptep, ___pte);			\
 })
 
 #else /* CONFIG_MMU_NOTIFIER */