V4L/DVB: videobuf: add queue argument to videobuf_waiton()

videobuf_waiton() must unlock and relock ext_lock if it has to wait.
For that to happen it needs the videobuf_queue pointer.

Don't attempt to unlock/relock q->ext_lock unless it was locked in the
first place.

vb->state has to be protected by a spinlock to be safe.

This patch is based on code from Mauro Carvalho Chehab <mchehab@redhat.com>.

[mchehab@redhat.com: add extra argument to a few missing places]
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/cx23885/cx23885-core.c b/drivers/media/video/cx23885/cx23885-core.c
index f6b62e7..2a34e95 100644
--- a/drivers/media/video/cx23885/cx23885-core.c
+++ b/drivers/media/video/cx23885/cx23885-core.c
@@ -1221,7 +1221,7 @@
 	struct videobuf_dmabuf *dma = videobuf_to_dma(&buf->vb);
 
 	BUG_ON(in_interrupt());
-	videobuf_waiton(&buf->vb, 0, 0);
+	videobuf_waiton(q, &buf->vb, 0, 0);
 	videobuf_dma_unmap(q->dev, dma);
 	videobuf_dma_free(dma);
 	btcx_riscmem_free(to_pci_dev(q->dev), &buf->risc);