From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:56777) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UMh6u-0006Rz-PR for qemu-devel@nongnu.org; Mon, 01 Apr 2013 11:57:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UMh6t-0001WQ-8c for qemu-devel@nongnu.org; Mon, 01 Apr 2013 11:57:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61604) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UMh6t-0001Vw-1L for qemu-devel@nongnu.org; Mon, 01 Apr 2013 11:57:27 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r31FvPqZ029541 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 1 Apr 2013 11:57:25 -0400 Message-ID: <5159AF37.1090809@redhat.com> Date: Mon, 01 Apr 2013 18:00:55 +0200 From: Hans de Goede MIME-Version: 1.0 References: <1364477297-2083-1-git-send-email-hdegoede@redhat.com> <1364477297-2083-2-git-send-email-hdegoede@redhat.com> <20130329093114.GA14019@amit.redhat.com> In-Reply-To: <20130329093114.GA14019@amit.redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/7] virtio-console: Also throttle when less was written then requested List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Amit Shah Cc: Gerd Hoffmann , qemu-devel@nongnu.org Hi, On 03/29/2013 10:31 AM, Amit Shah wrote: > On (Thu) 28 Mar 2013 [14:28:11], Hans de Goede wrote: >> This is necessary so that we get properly woken up to write the rest. >> >> Signed-off-by: Hans de Goede >> Acked-by: Amit Shah >> --- >> hw/virtio-console.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/hw/virtio-console.c b/hw/virtio-console.c >> index 284180f..015947c 100644 >> --- a/hw/virtio-console.c >> +++ b/hw/virtio-console.c >> @@ -47,7 +47,7 @@ static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len) >> ret = qemu_chr_fe_write(vcon->chr, buf, len); >> trace_virtio_console_flush_buf(port->id, len, ret); >> >> - if (ret <= 0) { >> + if (ret < len) { > > Oops, there's a conversion bug here: len is size_t, and ret is > ssize_t. Both need to be the same type. > > Since we're not returning negative, ret should be changed to size_t. > The function signature changes too, but that's alright. Erm changing ret to a size_t will break things, since qemu_chr_fe_write can return < 0 and storing that into an unsigned will change it into a very large value instead ... A better fix would be to change len to ssize_t. Although that will cause issues if we ever get a single buf which is larger then 2^31 - 1. Note we already have that problem since qemu_chr_fe_write already cannot handle such large buffers... > >> VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port); >> >> /* >> @@ -56,7 +56,8 @@ static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len) >> * we had a finer-grained message, like -EPIPE, we could close >> * this connection. >> */ >> - ret = 0; >> + if (ret < 0) >> + ret = 0; > > And there need to be braces here. Ack. Regards, Hans