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From: David Ahern <dsahern@gmail.com>
To: yzhu1 <Yanjun.Zhu@windriver.com>,
	Stephen Hemminger <stephen@networkplumber.org>
Cc: netdev <netdev@vger.kernel.org>,
	"Wu, Kuaikuai" <Kuaikuai.Wu@windriver.com>,
	"Tao, Yue" <Yue.Tao@windriver.com>
Subject: Re: If bridge have no sub-interfaces, it's status may be still with 'RUNNING'
Date: Mon, 16 Feb 2015 08:47:11 -0700	[thread overview]
Message-ID: <54E210FF.2050502@gmail.com> (raw)
In-Reply-To: <54E17853.8070106@windriver.com>

On 2/15/15 9:55 PM, yzhu1 wrote:
>>> 1. brctl addbr br0
>>>
>>> 2. ifconfig br0 up
>>>
>>> 3. ifconfig br0 (br0's status is with 'RUNNING')
>>>
>>> 4. brctl addif br0 eth0
>>>
>>> 5. brctl delif br0 eth0
>>>
>>> 6. ifconfig br0 (br0's status is without 'RUNNING')
>>>
>>> When there is no sub-interface, the flag "RUNNING" is missing after the
>>> last sub-interface is removed.

I do not see that behavior with Fedora 21 and 3.18.5-201.fc21.x86_64. 
ie., after interface is removed br0 is still in up state. Perhaps a 
regression with 3.19.

>>>
>>> As such, should we keep "RUNNING" flag after the last sub-interface is
>>> removed?
>> This is intentional. If there are no active ports in bridge, then
>> we want to tell applications that packets will go nowhere.

It changes current behavior with respect to tcpdump. Today I can launch 
tcpdump on a bridge interface before starting a VM. With this change I 
will not be able to do that.

David

  reply	other threads:[~2015-02-16 15:47 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-13  9:57 If bridge have no sub-interfaces, it's status may be still with 'RUNNING' yzhu1
2015-02-13 10:00 ` yzhu1
2015-02-13 18:30 ` Stephen Hemminger
2015-02-15  7:49   ` Wu, Kuaikuai
2015-02-16  4:55   ` yzhu1
2015-02-16 15:47     ` David Ahern [this message]
2015-02-16 16:51       ` Stephen Hemminger
2015-02-17 16:14         ` Zhu, Yanjun
2015-02-25  2:55           ` yzhu1
2015-02-25  4:23             ` David Ahern
2015-02-25  5:29               ` yzhu1
2015-02-16 16:52     ` Stephen Hemminger
2015-03-10  6:07     ` yzhu1

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