---

yaml --- r: 176309 b: refs/heads/master c: c9d0bf2 h: refs/heads/master i: 176307: de94a00 v: v3
git-mirror · Dec 15, 2009 · 40e14bd · 40e14bd
1 parent 5ec2c1b
commit 40e14bd
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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: 62c0c2f198c1f2ead05c961e83ef486c45888325
+refs/heads/master: c9d0bf241451a3ab7d02e1652c22b80cd7d93e8f
diff --git a/trunk/mm/mmap.c b/trunk/mm/mmap.c
@@ -1198,8 +1198,20 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 			goto free_vma;
 	}
 
-	if (vma_wants_writenotify(vma))
+	if (vma_wants_writenotify(vma)) {
+		pgprot_t pprot = vma->vm_page_prot;
+
+		/* Can vma->vm_page_prot have changed??
+		 *
+		 * Answer: Yes, drivers may have changed it in their
+		 *         f_op->mmap method.
+		 *
+		 * Ensures that vmas marked as uncached stay that way.
+		 */
 		vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
+		if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
+			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	}
 
 	vma_link(mm, vma, prev, rb_link, rb_parent);
 	file = vma->vm_file;