From: Simon Horman <simon.horman@corigine•com>
To: netdev@kapio-technology•com
Cc: "Vladimir Oltean" <olteanv@gmail•com>,
davem@davemloft•net, kuba@kernel•org, netdev@vger•kernel.org,
"Florian Fainelli" <f.fainelli@gmail•com>,
"Andrew Lunn" <andrew@lunn•ch>,
"Eric Dumazet" <edumazet@google•com>,
"Paolo Abeni" <pabeni@redhat•com>,
"Kurt Kanzenbach" <kurt@linutronix•de>,
"Hauke Mehrtens" <hauke@hauke-m•de>,
"Woojung Huh" <woojung.huh@microchip•com>,
"maintainer:MICROCHIP KSZ SERIES ETHERNET SWITCH DRIVER"
<UNGLinuxDriver@microchip•com>,
"Sean Wang" <sean.wang@mediatek•com>,
"Landen Chao" <Landen.Chao@mediatek•com>,
"DENG Qingfang" <dqfext@gmail•com>,
"Matthias Brugger" <matthias.bgg@gmail•com>,
"Claudiu Manoil" <claudiu.manoil@nxp•com>,
"Alexandre Belloni" <alexandre.belloni@bootlin•com>,
"Clément Léger" <clement.leger@bootlin•com>,
"Jiri Pirko" <jiri@resnulli•us>,
"Ivan Vecera" <ivecera@redhat•com>,
"Roopa Prabhu" <roopa@nvidia•com>,
"Nikolay Aleksandrov" <razor@blackwall•org>,
"Russell King" <linux@armlinux•org.uk>,
"Christian Marangi" <ansuelsmth@gmail•com>,
"open list" <linux-kernel@vger•kernel.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-arm-kernel@lists•infradead.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@lists•infradead.org>,
"open list:RENESAS RZ/N1 A5PSW SWITCH DRIVER"
<linux-renesas-soc@vger•kernel.org>,
"moderated list:ETHERNET BRIDGE"
<bridge@lists•linux-foundation.org>
Subject: Re: [PATCH net-next 5/5] net: dsa: mv88e6xxx: implementation of dynamic ATU entries
Date: Mon, 6 Feb 2023 17:02:16 +0100 [thread overview]
Message-ID: <Y+EkiAyexZrPoCpP@corigine.com> (raw)
In-Reply-To: <4abbe32d007240b9c3aea9c8ca936fa3@kapio-technology.com>
On Sat, Feb 04, 2023 at 09:48:24AM +0100, netdev@kapio-technology•com wrote:
> On 2023-02-04 09:12, Simon Horman wrote:
> > On Fri, Feb 03, 2023 at 10:44:22PM +0200, Vladimir Oltean wrote:
> > > On Fri, Feb 03, 2023 at 09:20:22AM +0100, Simon Horman wrote:
> > > > > else if (someflag)
> > > > > dosomething();
> > > > >
> > > > > For now only one flag will actually be set and they are mutually exclusive,
> > > > > as they will not make sense together with the potential flags I know, but
> > > > > that can change at some time of course.
> > > >
> > > > Yes, I see that is workable. I do feel that checking for other flags would
> > > > be a bit more robust. But as you say, there are none. So whichever
> > > > approach you prefer is fine by me.
> > >
> > > The model we have for unsupported bits in the
> > > SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS
> > > and SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS handlers is essentially this:
> > >
> > > if (flags & ~(supported_flag_mask))
> > > return -EOPNOTSUPP;
> > >
> > > if (flags & supported_flag_1)
> > > ...
> > >
> > > if (flags & supported_flag_2)
> > > ...
> > >
> > > I suppose applying this model here would address Simon's
> > > extensibility concern.
> >
> > Yes, that is the model I had in mind.
>
> The only thing is that we actually need to return both 0 and -EOPNOTSUPP for
> unsupported flags. The dynamic flag requires 0 when not supported (and
> supported) AFAICS.
> Setting a mask as 'supported' for a feature that is not really supported
> defeats the notion of 'supported' IMHO.
Just to clarify my suggestion one last time, it would be along the lines
of the following (completely untested!). I feel that it robustly covers
all cases for fdb_flags. And as a bonus doesn't need to be modified
if other (unsupported) flags are added in future.
if (fdb_flags & ~(DSA_FDB_FLAG_DYNAMIC))
return -EOPNOTSUPP;
is_dynamic = !!(fdb_flags & DSA_FDB_FLAG_DYNAMIC)
if (is_dynamic)
state = MV88E6XXX_G1_ATU_DATA_STATE_UC_AGE_7_NEWEST;
And perhaps for other drivers:
if (fdb_flags & ~(DSA_FDB_FLAG_DYNAMIC))
return -EOPNOTSUPP;
if (fdb_flags)
return 0;
Perhaps a helper would be warranted for the above.
But in writing this I think that, perhaps drivers could return -EOPNOTSUPP
for the DSA_FDB_FLAG_DYNAMIC case and the caller can handle, rather tha
propagate, -EOPNOTSUPP.
Returning -EOPNOTSUPP is the normal way to drivers to respond to requests
for unsupported hardware offloads. Sticking to that may be clearner
in the long run. That said, I do agree your current patch is correct
given the flag that is defined (by your patchset).
next prev parent reply other threads:[~2023-02-06 16:02 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-30 17:34 [PATCH net-next 0/5] ATU and FDB synchronization on locked ports Hans J. Schultz
2023-01-30 17:34 ` [PATCH net-next 1/5] net: bridge: add dynamic flag to switchdev notifier Hans J. Schultz
2023-02-01 18:10 ` Ido Schimmel
2023-02-02 7:28 ` netdev
2023-02-02 16:11 ` Ido Schimmel
2023-02-02 16:38 ` netdev
2023-02-03 16:14 ` Ido Schimmel
2023-02-03 16:26 ` Vladimir Oltean
2023-02-03 16:27 ` netdev
2023-02-03 17:06 ` Ido Schimmel
2023-01-30 17:34 ` [PATCH net-next 2/5] net: dsa: propagate flags down towards drivers Hans J. Schultz
2023-01-30 17:34 ` [PATCH net-next 3/5] drivers: net: dsa: add fdb entry flags incoming to switchcore drivers Hans J. Schultz
2023-01-31 18:54 ` Simon Horman
2023-02-02 16:45 ` netdev
2023-02-03 8:17 ` Simon Horman
2023-02-03 18:41 ` netdev
2023-01-30 17:34 ` [PATCH net-next 4/5] net: bridge: ensure FDB offloaded flag is handled as needed Hans J. Schultz
2023-02-01 18:24 ` Ido Schimmel
2023-02-02 7:32 ` netdev
2023-01-30 17:34 ` [PATCH net-next 5/5] net: dsa: mv88e6xxx: implementation of dynamic ATU entries Hans J. Schultz
2023-01-31 18:56 ` Simon Horman
2023-02-02 17:00 ` netdev
2023-02-03 8:20 ` Simon Horman
2023-02-03 20:44 ` Vladimir Oltean
2023-02-04 8:12 ` Simon Horman
2023-02-04 8:48 ` netdev
2023-02-06 16:02 ` Simon Horman [this message]
2023-02-14 21:14 ` Hans Schultz
2023-02-17 17:44 ` Vladimir Oltean
2023-02-20 14:11 ` Simon Horman
2023-01-31 19:25 ` [PATCH net-next 0/5] ATU and FDB synchronization on locked ports Ido Schimmel
2023-02-02 7:37 ` netdev
2023-02-02 15:43 ` Ido Schimmel
2023-02-02 16:19 ` netdev
2023-02-02 16:36 ` Ido Schimmel
2023-02-03 21:14 ` Vladimir Oltean
2023-02-02 17:18 ` netdev
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