V4L/DVB (12004): poll method lose race condition
bttv-driver.c,cx23885-video.c,cx88-video.c: poll method lose race condition for capture video.
Signed-off-by: Figo.zhang <figo1802@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/cx23885/cx23885-video.c b/drivers/media/video/cx23885/cx23885-video.c
index 68068c6..66bbd2e 100644
--- a/drivers/media/video/cx23885/cx23885-video.c
+++ b/drivers/media/video/cx23885/cx23885-video.c
@@ -796,6 +796,7 @@
{
struct cx23885_fh *fh = file->private_data;
struct cx23885_buffer *buf;
+ unsigned int rc = POLLERR;
if (V4L2_BUF_TYPE_VBI_CAPTURE == fh->type) {
if (!res_get(fh->dev, fh, RESOURCE_VBI))
@@ -803,23 +804,28 @@
return videobuf_poll_stream(file, &fh->vbiq, wait);
}
+ mutex_lock(&fh->vidq.vb_lock);
if (res_check(fh, RESOURCE_VIDEO)) {
/* streaming capture */
if (list_empty(&fh->vidq.stream))
- return POLLERR;
+ goto done;
buf = list_entry(fh->vidq.stream.next,
struct cx23885_buffer, vb.stream);
} else {
/* read() capture */
buf = (struct cx23885_buffer *)fh->vidq.read_buf;
if (NULL == buf)
- return POLLERR;
+ goto done;
}
poll_wait(file, &buf->vb.done, wait);
if (buf->vb.state == VIDEOBUF_DONE ||
buf->vb.state == VIDEOBUF_ERROR)
- return POLLIN|POLLRDNORM;
- return 0;
+ rc = POLLIN|POLLRDNORM;
+ else
+ rc = 0;
+done:
+ mutex_unlock(&fh->vidq.vb_lock);
+ return rc;
}
static int video_release(struct file *file)