Merge branch 'upstream' into topic/asoc

1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/ieee1394/dv1394.c b/drivers/ieee1394/dv1394.c
index 2f83543..c19f232 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);
@@ -1828,9 +1834,6 @@ static int dv1394_release(struct inode *inode, struct file *file)
 	/* OK to free the DMA buffer, no more mappings can exist */
 	do_dv1394_shutdown(video, 1);
 
-	/* clean up async I/O users */
-	dv1394_fasync(-1, file, 0);
-
 	/* give someone else a turn */
 	clear_bit(0, &video->open);