From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60251) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aWsGp-0002wZ-SJ for qemu-devel@nongnu.org; Fri, 19 Feb 2016 16:07:29 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aWsGl-0005nI-6w for qemu-devel@nongnu.org; Fri, 19 Feb 2016 16:07:23 -0500 References: <1455905587-4347-1-git-send-email-wei@redhat.com> <56C781AE.5050004@redhat.com> <56C78227.4030207@redhat.com> From: Wei Huang Message-ID: <56C78405.4040307@redhat.com> Date: Fri, 19 Feb 2016 15:07:17 -0600 MIME-Version: 1.0 In-Reply-To: <56C78227.4030207@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/1] virtio-rng: fix condition checking on period_ms List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Laszlo Ersek , qemu-devel@nongnu.org Cc: qemu-trivial@nongnu.org, mst@redhat.com On 02/19/2016 02:59 PM, Laszlo Ersek wrote: > On 02/19/16 21:57, Laszlo Ersek wrote: >> On 02/19/16 19:13, Wei Huang wrote: >>> The condition checking on vrng->conf.period_ms appears to be wrong, >>> conflicting with the error comment following it. >>> >>> Signed-off-by: Wei Huang >>> --- >>> hw/virtio/virtio-rng.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c >>> index 473c044..a06427c 100644 >>> --- a/hw/virtio/virtio-rng.c >>> +++ b/hw/virtio/virtio-rng.c >>> @@ -149,7 +149,7 @@ static void virtio_rng_device_realize(DeviceState *dev, Error **errp) >>> VirtIORNG *vrng = VIRTIO_RNG(dev); >>> Error *local_err = NULL; >>> >>> - if (!vrng->conf.period_ms > 0) { >>> + if (!(vrng->conf.period_ms > 0)) { >>> error_setg(errp, "'period' parameter expects a positive integer"); >>> return; >>> } >>> >> >> The current condition is absolutely weird, but I think it happens to >> work correctly: >> >> Period_ms has type uint32_t. If it is positive, then !period_ms is zero. >> 0>0 is false, hence the error message is not printed. >> >> If period_ms is zero, then !period_ms is 1. 1>0 is true, hence the error >> message is printed. >> >> I would rewrite the check as >> >> if (vrng->conf.period_ms == 0) { >> error_setg(...) > > ... actually, what the heck are you looking at? :) This has been fixed > up in: > Oops. It looks like I was looking at an older HEAD. :-( Please ignore it. Sorry for the noise and thanks for pointing it out. -Wei > commit a3a292c420d2fec3c07a7ca56fbb064cd57a298a > Author: Amit Shah > Date: Thu Dec 11 13:17:42 2014 +0530 > > virtio-rng: fix check for period_ms validity > > Thanks > Laszlo >