netdev - Re: [RFC net-next v4 0/9] net: bridge: mrp: Add support for Media Redundancy Protocol(MRP)

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Date:   Wed, 1 Apr 2020 18:12:48 +0200
From:   Horatiu Vultur <horatiu.vultur@...rochip.com>
To:     Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
CC:     <davem@...emloft.net>, <jiri@...nulli.us>, <ivecera@...hat.com>,
        <kuba@...nel.org>, <roopa@...ulusnetworks.com>,
        <olteanv@...il.com>, <andrew@...n.ch>,
        <UNGLinuxDriver@...rochip.com>, <linux-kernel@...r.kernel.org>,
        <netdev@...r.kernel.org>, <bridge@...ts.linux-foundation.org>
Subject: Re: [RFC net-next v4 0/9] net: bridge: mrp: Add support for Media
 Redundancy Protocol(MRP)

The 03/30/2020 19:21, Nikolay Aleksandrov wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 27/03/2020 11:21, Horatiu Vultur wrote:
> > Media Redundancy Protocol is a data network protocol standardized by
> > International Electrotechnical Commission as IEC 62439-2. It allows rings of
> > Ethernet switches to overcome any single failure with recovery time faster than
> > STP. It is primarily used in Industrial Ethernet applications.
> >
> > Based on the previous RFC[1][2][3], the MRP state machine and all the timers
> > were moved to userspace, except for the timers used to generate MRP Test frames.
> > In this way the userspace doesn't know and should not know if the HW or the
> > kernel will generate the MRP Test frames. The following changes were added to
> > the bridge to support the MRP:
> > - the existing netlink interface was extended with MRP support,
> > - allow to detect when a MRP frame was received on a MRP ring port
> > - allow MRP instance to forward/terminate MRP frames
> > - generate MRP Test frames in case the HW doesn't have support for this
> >
> > To be able to offload MRP support to HW, the switchdev API  was extend.
> >
> > With these changes the userspace doesn't do the following because already the
> > kernel/HW will do:
> > - doesn't need to forward/terminate MRP frames
> > - doesn't need to generate MRP Test frames
> > - doesn't need to detect when the ring is open/closed.
> >
> > The userspace application that is using the new netlink can be found here[4].
> >
> 
> Hi Horatiu,

Hi Nik,

> One issue in general - some functions are used before they're defined (the switchdev
> API integration ones) patch 4 vs 7 which doesn't make sense. Also I see that the BRIDGE_MRP is used
> (ifdef) before it's added to the Kconfig which doesn't make much sense either.
> I think you should rearrange the patches and maybe combine some of them.

Thanks for the feedback, in the next patch series I will make sure that
everything is defined before it is used.


> 
> Thanks,
>  Nik
> 

-- 
/Horatiu