From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34868) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8sEL-0005HG-TQ for qemu-devel@nongnu.org; Mon, 12 Aug 2013 09:32:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V8sEF-0002QJ-IS for qemu-devel@nongnu.org; Mon, 12 Aug 2013 09:32:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63456) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8sEF-0002Q7-BD for qemu-devel@nongnu.org; Mon, 12 Aug 2013 09:32:11 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r7CDWATQ007448 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 12 Aug 2013 09:32:10 -0400 Message-ID: <5208E46F.7010506@redhat.com> Date: Mon, 12 Aug 2013 15:34:39 +0200 From: Laszlo Ersek MIME-Version: 1.0 References: <1376227525-28639-1-git-send-email-ghammer@redhat.com> In-Reply-To: <1376227525-28639-1-git-send-email-ghammer@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2] virtio-serial: Do not notify virtqueue if no element was pushed back. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gal Hammer Cc: qemu-devel@nongnu.org On 08/11/13 15:25, Gal Hammer wrote: > The redundant notification caused the Windows' driver to duplicate the > pending write request's buffer. The driver was fixed, but I think this > change is still required. > > 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) > Differs from v1 only in a more precise subject / more details in the commit msg. Reviewed-by: Laszlo Ersek