diff options
Diffstat (limited to 'drivers/ieee1394/dv1394.c')
| -rw-r--r-- | drivers/ieee1394/dv1394.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/ieee1394/dv1394.c b/drivers/ieee1394/dv1394.c index 965cfdb84ebc..c19f23267157 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); |