Re: [PATCH net-next v6 14/23] bridge: restore br_setlink back to original

From: Scott Feldman <sfeldma@gmail.com>
To: roopa <roopa@cumulusnetworks.com>
Cc: Jiri Pirko <jiri@resnulli.us>, Netdev <netdev@vger.kernel.org>,
	Guenter Roeck <linux@roeck-us.net>,
	Florian Fainelli <f.fainelli@gmail.com>,
	"andrew@lunn.ch" <andrew@lunn.ch>,
	"simon.horman@netronome.com" <simon.horman@netronome.com>,
	Joe Perches <joe@perches.com>,
	"Samudrala, Sridhar" <sridhar.samudrala@intel.com>,
	"Arad, Ronen" <ronen.arad@intel.com>
Subject: Re: [PATCH net-next v6 14/23] bridge: restore br_setlink back to original
Date: Sun, 10 May 2015 16:55:46 -0700	[thread overview]
Message-ID: <CAE4R7bBQw+GJ0APt57tf+JBnbE7vyCRmbTozcVxRV3QP8ZNe+w@mail.gmail.com> (raw)
In-Reply-To: <554F8300.5070709@cumulusnetworks.com>

On Sun, May 10, 2015 at 9:10 AM, roopa <roopa@cumulusnetworks.com> wrote:
> On 5/9/15, 12:00 PM, Jiri Pirko wrote:
>>
>> Sat, May 09, 2015 at 07:40:16PM CEST, sfeldma@gmail.com wrote:
>>>
>>> From: Scott Feldman <sfeldma@gmail.com>
>>>
>>> Restore br_setlink back to original and don't call into SELF port driver.
>>> rtnetlink.c:bridge_setlink() already does a call into port driver for
>>> SELF.
>>>
>>> bridge set link cmd defaults to MASTER.  From man page for bridge link
>>> set
>>> cmd:
>>>
>>>        self   link setting is configured on specified physical device
>>>
>>>        master link setting is configured on the software bridge (default)
>>>
>>> The link setting has two values: the device-side value and the software
>>> bridge-side value.  These are independent and settable using the bridge
>>> link set cmd by specifying some combination of [master] | [self].
>>> Futhermore, the device-side and bridge-side settings have their own
>>> initial
>>> value, viewable from bridge -d link show cmd.
>>>
>>> Restoring br_setlink back to original makes rocker (the only in-kernel
>>> user
>>> of SELF link settings) work as first implement: two-sided values.
>>>
>>> It's true that when both MASTER and SELF are specified from the command,
>>> two netlink notifications are generated, one for each side of the
>>> settings.
>>> The user-space app can distiquish between the two notifications by
>>> observing the MASTER or SELF flag.
>>
>> This is revert of:
>>
>> commit 68e331c785b85b78f4155e2ab6f90e976b609dc1
>> Author: Roopa Prabhu <roopa@cumulusnetworks.com>
>> Date:   Thu Jan 29 22:40:14 2015 -0800
>>
>>      bridge: offload bridge port attributes to switch asic if feature flag
>> set
>>
>> Noting that because I want to make sure everybody is ok with new
>> behaviour. I tend to like it more.
>>
> I am not ok with it. I have raised this earlier. same argument as the fib
> code, app now has to remember to call with both master and self. I do
> however feel that this code needs some rework..,.add to hardware first and
> then software
> just like fib and rollback hardware on failure. In which case, i am ok with
> submitting a new patch to do it differently.

The problem with your patch to br_setlink/br_dellink is it hard-coded
a default in the kernel bridge driver, inconsistent with the default
of the application (iproute2/bridge).  Reverting it keeps the kernel
out of the default decision and lets the application define a default
that suits it.