HI Chenbo,
See below example
1.
ret = read_vhost_message(dev, fd, &ctx);
if (ret <= 0) {
if (ret < 0)
VHOST_LOG_CONFIG(dev->ifname, ERR, "vhost read message
failed\n");
else
VHOST_LOG_CONFIG(dev->ifname, INFO, "vhost peer
closed\n");
return -1;
}
2.
ret = vhost_user_check_and_alloc_queue_pair(dev, &ctx);
if (ret < 0) {
VHOST_LOG_CONFIG(dev->ifname, ERR, "failed to alloc queue\n");
return -1;
}
3. ret = -1
} else if (ret == RTE_VHOST_MSG_RESULT_ERR) {
VHOST_LOG_CONFIG(dev->ifname, ERR, "vhost message handling
failed.\n");
ret = -1;
goto unlock;
}
I mean ret is used to check the function is returned successfully or not while
it is also used to store vhost msg return code like "RTE_VHOST_MSG_RESULT_XXX".
> -----Original Message-----
> From: Xia, Chenbo <chenbo....@intel.com>
> Sent: Monday, July 11, 2022 4:54 PM
> To: Pei, Andy <andy....@intel.com>; Maxime Coquelin
> <maxime.coque...@redhat.com>; Ma, WenwuX <wenwux...@intel.com>;
> dev@dpdk.org
> Cc: Hu, Jiayu <jiayu...@intel.com>; Wang, Yinan <yinan.w...@intel.com>; He,
> Xingguang <xingguang...@intel.com>; sta...@dpdk.org
> Subject: RE: [PATCH v3] vhost: fix deadlock when message handling failed
>
> > -----Original Message-----
> > From: Pei, Andy <andy....@intel.com>
> > Sent: Monday, July 11, 2022 4:42 PM
> > To: Maxime Coquelin <maxime.coque...@redhat.com>; Ma, WenwuX
> > <wenwux...@intel.com>; Xia, Chenbo <chenbo....@intel.com>;
> > dev@dpdk.org
> > Cc: Hu, Jiayu <jiayu...@intel.com>; Wang, Yinan
> > <yinan.w...@intel.com>; He, Xingguang <xingguang...@intel.com>;
> > sta...@dpdk.org
> > Subject: RE: [PATCH v3] vhost: fix deadlock when message handling
> > failed
> >
> > HI ALL,
> >
> > I see that in function vhost_user_msg_handler.
> > We use "ret" to store both vhost msg return code like
> > "RTE_VHOST_MSG_RESULT_XXX" and function return value.
> > I wonder if it is better to use two different variable to make it easy
> > to read.
>
> By saying 'function return value', you mean which function? Can you elaborate
> more?
>
> Thanks,
> Chenbo
>
> >
> > > -----Original Message-----
> > > From: Maxime Coquelin <maxime.coque...@redhat.com>
> > > Sent: Tuesday, May 17, 2022 9:24 PM
> > > To: Ma, WenwuX <wenwux...@intel.com>; Xia, Chenbo
> > > <chenbo....@intel.com>; dev@dpdk.org
> > > Cc: Hu, Jiayu <jiayu...@intel.com>; Wang, Yinan
> > > <yinan.w...@intel.com>;
> > He,
> > > Xingguang <xingguang...@intel.com>; sta...@dpdk.org
> > > Subject: Re: [PATCH v3] vhost: fix deadlock when message handling
> > > failed
> > >
> > >
> > >
> > > On 5/7/22 15:27, Wenwu Ma wrote:
> > > > In vhost_user_msg_handler(), if vhost message handling failed, we
> > > > should check whether the queue is locked and release the lock
> > > > before returning. Or, it will cause a deadlock later.
> > > >
> > > > Fixes: 7f31d4ea05ca ("vhost: fix lock on device readiness
> > > > notification")
> > > > Cc: sta...@dpdk.org
> > > >
> > > > Signed-off-by: Wenwu Ma <wenwux...@intel.com>
> > > > ---
> > > > lib/vhost/vhost_user.c | 10 ++++++----
> > > > 1 file changed, 6 insertions(+), 4 deletions(-)
> > > >
> > >
> > > Applied to dpdk-next-virtio/main.
> > >
> > > Thanks,
> > > Maxime
