---

yaml --- r: 118514 b: refs/heads/master c: 8449fc3 h: refs/heads/master v: v3
git-mirror · Oct 31, 2008 · 09c4946 · 09c4946
1 parent eda5b7c
commit 09c4946
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Showing 2 changed files with 9 additions and 3 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 638570b54346f140bc09b986d93e76025d35180f
+refs/heads/master: 8449fc3ae58bf8ee5acbd2280754cde67b5db128
diff --git a/trunk/drivers/ieee1394/dv1394.c b/trunk/drivers/ieee1394/dv1394.c
@@ -1270,8 +1270,14 @@ static int dv1394_mmap(struct file *file, struct vm_area_struct *vma)
 	struct video_card *video = file_to_video_card(file);
 	int retval = -EINVAL;
 
-	/* serialize mmap */
-	mutex_lock(&video->mtx);
+	/*
+	 * We cannot use the blocking variant mutex_lock here because .mmap
+	 * is called with mmap_sem held, while .ioctl, .read, .write acquire
+	 * video->mtx and subsequently call copy_to/from_user which will
+	 * grab mmap_sem in case of a page fault.
+	 */
+	if (!mutex_trylock(&video->mtx))
+		return -EAGAIN;
 
 	if ( ! video_card_initialized(video) ) {
 		retval = do_dv1394_init_default(video);