X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fieee1394%2Fdv1394.c;h=c19f23267157621b2fa613c9ea23a3bf82af5393;hb=6572a281cfd805dd54718597d6c33261b5be052b;hp=965cfdb84ebc757c0c170e437be99bf637b88dbd;hpb=67d112842586aa11506b7a8afec29391bf8f3cca;p=linux-2.6-omap-h63xx.git

diff --git a/drivers/ieee1394/dv1394.c b/drivers/ieee1394/dv1394.c
index 965cfdb84eb..c19f2326715 100644
--- a/drivers/ieee1394/dv1394.c
+++ b/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);