From: Andrew Lunn <andrew@lunn.ch>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, Florian Fainelli <f.fainelli@gmail.com>,
Vivien Didelot <vivien.didelot@gmail.com>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Subject: Re: [PATCH net-next 1/4] net: dsa: automatically bring up DSA master when opening user port
Date: Thu, 28 Jan 2021 01:51:12 +0100 [thread overview]
Message-ID: <YBIKgGw+GExbsAcx@lunn.ch> (raw)
In-Reply-To: <20210127010028.1619443-2-olteanv@gmail.com>
On Wed, Jan 27, 2021 at 03:00:25AM +0200, Vladimir Oltean wrote:
> From: Vladimir Oltean <vladimir.oltean@nxp.com>
>
> DSA wants the master interface to be open before the user port is due to
> historical reasons. The promiscuity of interfaces that are down used to
> have issues, as referenced Lennert Buytenhek in commit df02c6ff2e39
> ("dsa: fix master interface allmulti/promisc handling").
>
> The bugfix mentioned there, commit b6c40d68ff64 ("net: only invoke
> dev->change_rx_flags when device is UP"), was basically a "don't do
> that" approach to working around the promiscuity while down issue.
>
> Further work done by Vlad Yasevich in commit d2615bf45069 ("net: core:
> Always propagate flag changes to interfaces") has resolved the
> underlying issue, and it is strictly up to the DSA and 8021q drivers
> now, it is no longer mandated by the networking core that the master
> interface must be up when changing its promiscuity.
>
> >From DSA's point of view, deciding to error out in dsa_slave_open
> because the master isn't up is (a) a bad user experience and (b) missing
> the forest for the trees. Even if there still was an issue with
> promiscuity while down, DSA could still do this and avoid it: open the
> DSA master manually, then do whatever. Voila, the DSA master is now up,
> no need to error out.
>
> Doing it this way has the additional benefit that user space can now
> remove DSA-specific workarounds, like systemd-networkd with BindCarrier:
> https://github.com/systemd/systemd/issues/7478
>
> And we can finally remove one of the 2 bullets in the "Common pitfalls
> using DSA setups" chapter.
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Andrew
next prev parent reply other threads:[~2021-01-28 0:52 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-27 1:00 [PATCH net-next 0/4] Automatically manage DSA master interface state Vladimir Oltean
2021-01-27 1:00 ` [PATCH net-next 1/4] net: dsa: automatically bring up DSA master when opening user port Vladimir Oltean
2021-01-28 0:51 ` Andrew Lunn [this message]
2021-01-28 1:41 ` Florian Fainelli
2021-01-27 1:00 ` [PATCH net-next 2/4] net: dsa: automatically bring user ports down when master goes down Vladimir Oltean
2021-01-28 0:46 ` Andrew Lunn
2021-01-28 0:50 ` Vladimir Oltean
2021-01-28 0:52 ` Andrew Lunn
2021-01-28 1:43 ` Florian Fainelli
2021-01-27 1:00 ` [PATCH net-next 3/4] Revert "net: Have netpoll bring-up DSA management interface" Vladimir Oltean
2021-01-28 0:52 ` Andrew Lunn
2021-01-28 1:43 ` Florian Fainelli
2021-01-27 1:00 ` [PATCH net-next 4/4] Revert "net: ipv4: handle DSA enabled master network devices" Vladimir Oltean
2021-01-28 0:56 ` Andrew Lunn
2021-01-28 1:43 ` Florian Fainelli
2021-01-27 1:25 ` [PATCH net-next 0/4] Automatically manage DSA master interface state Vladimir Oltean
2021-01-27 12:03 ` Vladimir Oltean
2021-01-28 1:03 ` Florian Fainelli
2021-01-28 1:30 ` Vladimir Oltean
2021-01-28 1:55 ` Florian Fainelli
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