media: uvcvideo: Keep streaming state in the file handle

Add a variable in the file handle state to figure out if a camera is in
the streaming state or not. This variable will be used in the future for
power management policies.

Now that we are at it, make use of guards to simplify the code.

Reviewed-by: Laurent Pinchart <[email protected]>
Reviewed-by: Hans de Goede <[email protected]>
Signed-off-by: Ricardo Ribalda <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>

Author: ribalda

drivers/media/usb/uvc/uvc_v4l2.c

@@ -841,11 +841,18 @@ static int uvc_ioctl_streamon(struct file *file, void *fh,
 	if (!uvc_has_privileges(handle))
 		return -EBUSY;
 
-	mutex_lock(&stream->mutex);
+	guard(mutex)(&stream->mutex);
+
+	if (handle->is_streaming)
+		return 0;
+
 	ret = uvc_queue_streamon(&stream->queue, type);
-	mutex_unlock(&stream->mutex);
+	if (ret)
+		return ret;
 
-	return ret;
+	handle->is_streaming = true;
+
+	return 0;
 }
 
 static int uvc_ioctl_streamoff(struct file *file, void *fh,
@@ -857,9 +864,10 @@ static int uvc_ioctl_streamoff(struct file *file, void *fh,
 	if (!uvc_has_privileges(handle))
 		return -EBUSY;
 
-	mutex_lock(&stream->mutex);
+	guard(mutex)(&stream->mutex);
+
 	uvc_queue_streamoff(&stream->queue, type);
-	mutex_unlock(&stream->mutex);
+	handle->is_streaming = false;
 
 	return 0;
 }

drivers/media/usb/uvc/uvcvideo.h

@@ -630,6 +630,7 @@ struct uvc_fh {
 	struct uvc_streaming *stream;
 	enum uvc_handle_state state;
 	unsigned int pending_async_ctrls;
+	bool is_streaming;
 };
 
 /* ------------------------------------------------------------------------