[media] uvcvideo: Fix marking buffer erroneous in case of FID toggling

Set error bit for incomplete buffers when end of buffer is detected by
FID toggling (for example when last transaction with EOF is lost).
This prevents passing incomplete buffers to the userspace.
Signed-off-by: Anton Leontiev <bunder@t-25.ru>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/usb/uvc/uvc_video.c

@@ -1132,6 +1132,17 @@ static int uvc_video_encode_data(struct uvc_streaming *stream,
  * URB handling
  */
 
+/*
+ * Set error flag for incomplete buffer.
+ */
+static void uvc_video_validate_buffer(const struct uvc_streaming *stream,
+				      struct uvc_buffer *buf)
+{
+	if (buf->length != buf->bytesused &&
+	    !(stream->cur_format->flags & UVC_FMT_FLAG_COMPRESSED))
+		buf->error = 1;
+}
+
 /*
  * Completion handler for video URBs.
  */
@@ -1156,9 +1167,11 @@ static void uvc_video_decode_isoc(struct urb *urb, struct uvc_streaming *stream,
 		do {
 			ret = uvc_video_decode_start(stream, buf, mem,
 				urb->iso_frame_desc[i].actual_length);
-			if (ret == -EAGAIN)
+			if (ret == -EAGAIN) {
+				uvc_video_validate_buffer(stream, buf);
 				buf = uvc_queue_next_buffer(&stream->queue,
 							    buf);
+			}
 		} while (ret == -EAGAIN);
 
 		if (ret < 0)
@@ -1173,11 +1186,7 @@ static void uvc_video_decode_isoc(struct urb *urb, struct uvc_streaming *stream,
 			urb->iso_frame_desc[i].actual_length);
 
 		if (buf->state == UVC_BUF_STATE_READY) {
-			if (buf->length != buf->bytesused &&
-			    !(stream->cur_format->flags &
-			      UVC_FMT_FLAG_COMPRESSED))
-				buf->error = 1;
-
+			uvc_video_validate_buffer(stream, buf);
 			buf = uvc_queue_next_buffer(&stream->queue, buf);
 		}
 	}