[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <Y+EkiAyexZrPoCpP@corigine.com>
Date: Mon, 6 Feb 2023 17:02:16 +0100
From: Simon Horman <simon.horman@...igine.com>
To: netdev@...io-technology.com
Cc: Vladimir Oltean <olteanv@...il.com>, davem@...emloft.net,
kuba@...nel.org, netdev@...r.kernel.org,
Florian Fainelli <f.fainelli@...il.com>,
Andrew Lunn <andrew@...n.ch>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>,
Kurt Kanzenbach <kurt@...utronix.de>,
Hauke Mehrtens <hauke@...ke-m.de>,
Woojung Huh <woojung.huh@...rochip.com>,
"maintainer:MICROCHIP KSZ SERIES ETHERNET SWITCH DRIVER"
<UNGLinuxDriver@...rochip.com>, Sean Wang <sean.wang@...iatek.com>,
Landen Chao <Landen.Chao@...iatek.com>,
DENG Qingfang <dqfext@...il.com>,
Matthias Brugger <matthias.bgg@...il.com>,
Claudiu Manoil <claudiu.manoil@....com>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
Clément Léger <clement.leger@...tlin.com>,
Jiri Pirko <jiri@...nulli.us>,
Ivan Vecera <ivecera@...hat.com>,
Roopa Prabhu <roopa@...dia.com>,
Nikolay Aleksandrov <razor@...ckwall.org>,
Russell King <linux@...linux.org.uk>,
Christian Marangi <ansuelsmth@...il.com>,
open list <linux-kernel@...r.kernel.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-arm-kernel@...ts.infradead.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@...ts.infradead.org>,
"open list:RENESAS RZ/N1 A5PSW SWITCH DRIVER"
<linux-renesas-soc@...r.kernel.org>,
"moderated list:ETHERNET BRIDGE" <bridge@...ts.linux-foundation.org>
Subject: Re: [PATCH net-next 5/5] net: dsa: mv88e6xxx: implementation of
dynamic ATU entries
On Sat, Feb 04, 2023 at 09:48:24AM +0100, netdev@...io-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).
Powered by blists - more mailing lists