From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <jianfeng.tan@intel.com>
Received: from mga09.intel.com (mga09.intel.com [134.134.136.24])
 by dpdk.org (Postfix) with ESMTP id CCFFF11C5
 for <dev@dpdk.org>; Wed, 11 Jan 2017 03:30:49 +0100 (CET)
Received: from fmsmga005.fm.intel.com ([10.253.24.32])
 by orsmga102.jf.intel.com with ESMTP; 10 Jan 2017 18:30:48 -0800
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="5.33,345,1477983600"; d="scan'208,217";a="51837413"
Received: from shwdeisgchi083.ccr.corp.intel.com (HELO [10.239.67.193])
 ([10.239.67.193])
 by fmsmga005.fm.intel.com with ESMTP; 10 Jan 2017 18:30:47 -0800
To: Jason Wang <jasowang@redhat.com>, dev@dpdk.org
References: <1480689075-66977-1-git-send-email-jianfeng.tan@intel.com>
 <1482477266-39199-1-git-send-email-jianfeng.tan@intel.com>
 <1482477266-39199-6-git-send-email-jianfeng.tan@intel.com>
 <46af618f-c01b-3571-78fc-12d10859a4a1@redhat.com>
Cc: yuanhan.liu@linux.intel.com, ferruh.yigit@intel.com,
 cunming.liang@intel.com
From: "Tan, Jianfeng" <jianfeng.tan@intel.com>
Message-ID: <271f1854-8cd8-8671-95ed-79cfa52d8ad7@intel.com>
Date: Wed, 11 Jan 2017 10:30:46 +0800
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101
 Thunderbird/45.6.0
MIME-Version: 1.0
In-Reply-To: <46af618f-c01b-3571-78fc-12d10859a4a1@redhat.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
X-Content-Filtered-By: Mailman/MimeDel 2.1.15
Subject: Re: [dpdk-dev] [PATCH v2 5/7] net/virtio_user: add vhost kernel
 support
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Wed, 11 Jan 2017 02:30:50 -0000

Hi Jason,


On 1/9/2017 12:39 PM, Jason Wang wrote:
>> +    if (!enable) {
>> +        if (dev->tapfds[pair_idx]) {
>> +            close(dev->tapfds[pair_idx]);
>> +            dev->tapfds[pair_idx] = -1;
>> +        }
>> +        return vhost_kernel_set_backend(vhostfd, -1);
>
> If this is used to for thing like ethtool -L in guest, we should use 
> TUNSETQUEUE here.

To make it clear, why we need to ioctl(..., TUNSETQUEUE, ...) here. 
According to Linux/Documentation/networking/tuntap.txt,
     "A new ioctl(TUNSETQUEUE) were introduced to enable or disable a 
queue. When
     calling it with IFF_DETACH_QUEUE flag, the queue were disabled. And 
when
     calling it with IFF_ATTACH_QUEUE flag, the queue were enabled. The 
queue were
     enabled by default after it was created through TUNSETIFF."

As it's enabled by default, do you still see the necessity to call it 
explicitly?

Thanks,
Jianfeng