From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58751) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V6Fzx-0005tV-Ch for qemu-devel@nongnu.org; Mon, 05 Aug 2013 04:18:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V6Fzp-000611-UR for qemu-devel@nongnu.org; Mon, 05 Aug 2013 04:18:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23265) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V6Fzp-00060d-Ms for qemu-devel@nongnu.org; Mon, 05 Aug 2013 04:18:29 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r758ISvn010852 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 5 Aug 2013 04:18:28 -0400 From: Gal Hammer Date: Mon, 5 Aug 2013 11:18:25 +0300 Message-Id: <1375690705-17266-1-git-send-email-ghammer@redhat.com> Subject: [Qemu-devel] [PATCH] virtio: Do not notify virtqueue if no element was pushed back. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Gal Hammer Signed-off-by: Gal Hammer --- hw/char/virtio-serial-bus.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c index da417c7..0d38b4b 100644 --- a/hw/char/virtio-serial-bus.c +++ b/hw/char/virtio-serial-bus.c @@ -105,6 +105,7 @@ static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq, VirtIODevice *vdev) { VirtIOSerialPortClass *vsc; + bool elem_pushed = false; assert(port); assert(virtio_queue_ready(vq)); @@ -145,9 +146,12 @@ static void do_flush_queued_data(VirtIOSerialPort *port, VirtQueue *vq, break; } virtqueue_push(vq, &port->elem, 0); + elem_pushed = true; port->elem.out_num = 0; } - virtio_notify(vdev, vq); + if (elem_pushed) { + virtio_notify(vdev, vq); + } } static void flush_queued_data(VirtIOSerialPort *port) -- 1.8.1.4