[PATCH v2 2/2] media: uvcvideo: Use wait queue for metadata streamoff

[Ricardo Ribalda]

We are now using a schedule()/loop to wait for in-flight buffers. This
works, but it is not beautiful. Instead we can use wait queues.

Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
 drivers/media/usb/uvc/uvc_queue.c | 7 ++-----
 drivers/media/usb/uvc/uvc_video.c | 2 ++
 drivers/media/usb/uvc/uvcvideo.h  | 1 +
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
index af9dbfcf6f53..266a75862f0a 100644
--- a/drivers/media/usb/uvc/uvc_queue.c
+++ b/drivers/media/usb/uvc/uvc_queue.c
@@ -214,11 +214,8 @@ static void uvc_stop_streaming_meta(struct vb2_queue *vq)
 	lockdep_assert_irqs_enabled();
 
 	spin_lock_irq(&stream->meta.irqlock);
-	while (stream->meta.in_flight) {
-		spin_unlock_irq(&stream->meta.irqlock);
-		schedule();
-		spin_lock_irq(&stream->meta.irqlock);
-	}
+	wait_event_lock_irq(stream->meta.wq, !stream->meta.in_flight,
+			    stream->meta.irqlock);
 	stream->meta.in_flight = true;
 	spin_unlock_irq(&stream->meta.irqlock);
 
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index f6b55b3a3308..735080d40862 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -1802,6 +1802,7 @@ static void uvc_video_complete(struct urb *urb)
 		scoped_guard(spinlock_irqsave, &stream->meta.irqlock) {
 			stream->meta.in_flight = false;
 		}
+		wake_up(&stream->meta.wq);
 	}
 
 	/* If no async work is needed, resubmit the URB immediately. */
@@ -2357,6 +2358,7 @@ int uvc_video_init(struct uvc_streaming *stream)
 		INIT_WORK(&uvc_urb->work, uvc_video_copy_data_work);
 
 	spin_lock_init(&stream->meta.irqlock);
+	init_waitqueue_head(&stream->meta.wq);
 
 	return 0;
 }
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 6f1a3381d392..b28f418c6543 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -486,6 +486,7 @@ struct uvc_streaming {
 		u32 buffersize;
 		bool in_flight;
 		spinlock_t irqlock; /* Protects in_flight. */
+		wait_queue_head_t wq;
 	} meta;
 
 	/* Context data used by the bulk completion handler. */

-- 
2.55.0.rc0.799.gd6f94ed593-goog