---

yaml --- r: 98676 b: refs/heads/master c: 251b97f h: refs/heads/master v: v3
git-mirror · Jul 4, 2008 · df2ddd5 · df2ddd5
1 parent f8fa674
commit df2ddd5
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Showing 2 changed files with 14 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: cde53535991fbb5c34a1566f25955297c1487b8d
+refs/heads/master: 251b97f552b1ad414cc5a9ccc8e4e94503edd5fc
diff --git a/trunk/mm/memory.c b/trunk/mm/memory.c
@@ -1697,8 +1697,19 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	struct page *dirty_page = NULL;
 
 	old_page = vm_normal_page(vma, address, orig_pte);
-	if (!old_page)
+	if (!old_page) {
+		/*
+		 * VM_MIXEDMAP !pfn_valid() case
+		 *
+		 * We should not cow pages in a shared writeable mapping.
+		 * Just mark the pages writable as we can't do any dirty
+		 * accounting on raw pfn maps.
+		 */
+		if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
+				     (VM_WRITE|VM_SHARED))
+			goto reuse;
 		goto gotten;
+	}
 
 	/*
 	 * Take out anonymous pages first, anonymous shared vmas are
@@ -1751,6 +1762,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	}
 
 	if (reuse) {
+reuse:
 		flush_cache_page(vma, address, pte_pfn(orig_pte));
 		entry = pte_mkyoung(orig_pte);
 		entry = maybe_mkwrite(pte_mkdirty(entry), vma);