From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:54632) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UN50x-0001FY-59 for qemu-devel@nongnu.org; Tue, 02 Apr 2013 13:28:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UN50u-0000WQ-D1 for qemu-devel@nongnu.org; Tue, 02 Apr 2013 13:28:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60113) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UN50u-0000WF-2p for qemu-devel@nongnu.org; Tue, 02 Apr 2013 13:28:52 -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 r32HSpV5006338 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 2 Apr 2013 13:28:51 -0400 Message-ID: <515B1649.2040008@redhat.com> Date: Tue, 02 Apr 2013 19:32:57 +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> <5159AF37.1090809@redhat.com> <20130402104004.GD15084@amit.redhat.com> In-Reply-To: <20130402104004.GD15084@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 04/02/2013 12:40 PM, Amit Shah wrote: > On (Mon) 01 Apr 2013 [18:00:55], Hans de Goede wrote: >> 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 ... > > Oh, definitely. I meant changing the return type of flush_buf(), but > that doesn't help matters much... > >> 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... > > Yep. Do you want to do that as part of this series? Yes, I'll send a v2 of this patch incorporating the change for Gerd to pick up. Regards, Hans