From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Gora <dg@adax.com>
Subject: Re: [PATCH v2 10/10] kni: add API to set link status on
 kernel interface
Date: Tue, 11 Sep 2018 18:45:49 -0300
Message-ID: <CAGyogRZ5pr2-F71ToBgLLDsnbZEMJWZrVDcU1QCOsfadipuT_g@mail.gmail.com>
References: <20180628224513.18391-1-dg@adax.com>
 <20180629015508.26599-1-dg@adax.com>
 <20180629015508.26599-11-dg@adax.com> <20180829085410.4411c07e@xeon-e3>
 <CAGyogRaVWeCdEqL_-PqhMvd784axgn2ntm9ZHwBv7CNfUX0adQ@mail.gmail.com>
 <20180829150014.0ae59128@xeon-e3>
 <CAGyogRbhNrqR9xQ=0iuizbrZNtLNB4FW-CpnBDvGWCKHrSWAPg@mail.gmail.com>
 <CAGyogRbBBAU92KdqVwghpon1brMo=4XJNPotiBYpztQkzB4mGQ@mail.gmail.com>
 <20180829161043.11bb2434@xeon-e3>
 <CAF+s_Fx=x8wO5Ygxr4sxUj2G1hh+dRyFr7XiwYHL4SUPRNhX4g@mail.gmail.com>
 <CAGyogRattGkEds7dkwLmwyyfj3t0M_ygRxSJarrgLM=k3EWoiA@mail.gmail.com>
 <20180830150911.6b0e7901@xeon-e3>
 <CAGyogRYOXDPS=nUh-eNBUDoc4MWV+B6YA3KpbabnV_aaSpvU-w@mail.gmail.com>
 <CAGyogRZDNjGhnxk_=aSSvy46sN=aEQJcPdaa5ns+pQtQMOOxiw@mail.gmail.com>
 <20180905135751.74f6c14b@shemminger-XPS-13-9360>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Cc: Igor Ryzhov <iryzhov@nfware.com>, Ferruh Yigit <ferruh.yigit@intel.com>,
 dev@dpdk.org
To: Stephen Hemminger <stephen@networkplumber.org>
Return-path: <dev-bounces@dpdk.org>
Received: from mail-wr1-f46.google.com (mail-wr1-f46.google.com
 [209.85.221.46]) by dpdk.org (Postfix) with ESMTP id 4B3B92BF9
 for <dev@dpdk.org>; Tue, 11 Sep 2018 23:46:30 +0200 (CEST)
Received: by mail-wr1-f46.google.com with SMTP id e1-v6so18499563wrt.3
 for <dev@dpdk.org>; Tue, 11 Sep 2018 14:46:30 -0700 (PDT)
In-Reply-To: <20180905135751.74f6c14b@shemminger-XPS-13-9360>
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

Hi All,

So I implemented the "write to /sys/devices/virtual/net/*/carrier"
method to change the link status, but there is one more minor thing
that I wanted to point out about this approach.  The problem is that
you cannot read or write the '/sys/devices/virtual/net/*/carrier' file
while the interface is marked 'down'.  This means that link status
changes can only be performed by the DPDK application while the
interface is in the "up" state.  With the ioctl method, you can change
the carrier state at pretty much any time.

Is this a problem?  It's not a huge one, I guess, but it is something
else to consider.

Please let me know what you all think.

thanks
dan