From: Vladimir Oltean <olteanv@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Rakesh Sankaranarayanan <rakesh.sankaranarayanan@microchip.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
f.fainelli@gmail.com, davem@davemloft.net, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com, woojung.huh@microchip.com,
UNGLinuxDriver@microchip.com, linux@armlinux.org.uk
Subject: Re: [RFC PATCH net-next 07/11] net: dsa: microchip: lan937x: update switch register
Date: Sat, 4 Feb 2023 01:37:17 +0200 [thread overview]
Message-ID: <20230203233717.m3s6xm4fynqmkx7h@skbuf> (raw)
In-Reply-To: <Y9vZdMQgqhaGIcdf@lunn.ch>
On Thu, Feb 02, 2023 at 04:40:36PM +0100, Andrew Lunn wrote:
> On Thu, Feb 02, 2023 at 06:29:26PM +0530, Rakesh Sankaranarayanan wrote:
> > Second switch in cascaded connection doesn't have port with macb
> > interface. dsa_switch_register returns error if macb interface is
> > not up. Due to this reason, second switch in cascaded connection will
> > not report error during dsa_switch_register and mib thread work will be
> > invoked even if actual switch register is not done. This will lead to
> > kernel warning and it can be avoided by checking device tree setup
> > status. This will return true only after actual switch register is done.
>
> What i think you need to do is move the code into ksz_setup().
>
> With a D in DSA setup, dsa_switch_register() adds the switch to the
> list of switches, and then a check is performed to see if all switches
> in the cluster have been registered. If not, it just returns. If all
> switches have been registered, it then iterates over all the switches
> can calls dsa_switch_ops.setup().
>
> By moving the start of the MIB counter into setup(), it will only be
> started once all the switches are present, and it means you don't need
> to look at DSA core internal state.
+1
Also there's a bug in its own right in ksz_mib_read_work(), here:
if (!netif_carrier_ok(dp->slave))
mib->cnt_ptr = dev->info->reg_mib_cnt;
The code accesses dp->slave, so naturally it kicks the bucket for
cascade ports.
It doesn't crash with CPU ports because dp->slave is in a union with
dp->master, which is also a struct net_device * with its own carrier:
struct dsa_port {
/* A CPU port is physically connected to a master device.
* A user port exposed to userspace has a slave device.
*/
union {
struct net_device *master;
struct net_device *slave;
};
This needs to be fixed, since accessing the DSA master through a
dp->slave pointer is dangerous and unintended.
Easiest thing to do would be to only check link state if (dsa_port_is_user(dp)).
For other ports always read all MIB counters.
next prev parent reply other threads:[~2023-02-03 23:37 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-02 12:59 [RFC PATCH net-next 00/11] net: dsa: microchip: lan937x: add switch cascade support Rakesh Sankaranarayanan
2023-02-02 12:59 ` [RFC PATCH net-next 01/11] net: dsa: microchip: lan937x: add cascade tailtag Rakesh Sankaranarayanan
2023-02-03 23:10 ` Vladimir Oltean
2023-02-02 12:59 ` [RFC PATCH net-next 02/11] net: dsa: microchip: lan937x: update SMI index Rakesh Sankaranarayanan
2023-02-03 23:18 ` Vladimir Oltean
2023-02-02 12:59 ` [RFC PATCH net-next 03/11] net: dsa: microchip: lan937x: enable cascade port Rakesh Sankaranarayanan
2023-02-03 23:24 ` Vladimir Oltean
2023-02-02 12:59 ` [RFC PATCH net-next 04/11] net: dsa: microchip: lan937x: update port number for LAN9373 Rakesh Sankaranarayanan
2023-02-02 15:19 ` Andrew Lunn
2023-02-03 10:43 ` Rakesh.Sankaranarayanan
2023-02-03 23:26 ` Vladimir Oltean
2023-02-06 14:38 ` Arun.Ramadoss
2023-02-02 12:59 ` [RFC PATCH net-next 05/11] net: dsa: microchip: lan937x: add shared global interrupt Rakesh Sankaranarayanan
2023-02-02 15:25 ` Andrew Lunn
2023-02-02 12:59 ` [RFC PATCH net-next 06/11] net: dsa: microchip: lan937x: get cascade tag protocol Rakesh Sankaranarayanan
2023-02-03 23:30 ` Vladimir Oltean
2023-02-02 12:59 ` [RFC PATCH net-next 07/11] net: dsa: microchip: lan937x: update switch register Rakesh Sankaranarayanan
2023-02-02 15:40 ` Andrew Lunn
2023-02-03 10:48 ` Rakesh.Sankaranarayanan
2023-02-03 23:37 ` Vladimir Oltean [this message]
2023-02-02 12:59 ` [RFC PATCH net-next 08/11] net: dsa: microchip: lan937x: avoid mib read for cascaded port Rakesh Sankaranarayanan
2023-02-02 15:45 ` Andrew Lunn
2023-02-02 12:59 ` [RFC PATCH net-next 09/11] net: dsa: microchip: lan937x: update port membership with dsa port Rakesh Sankaranarayanan
2023-02-03 23:47 ` Vladimir Oltean
2023-02-02 12:59 ` [RFC PATCH net-next 10/11] net: dsa: microchip: lan937x: update vlan untag membership Rakesh Sankaranarayanan
2023-02-03 23:48 ` Vladimir Oltean
2023-02-02 12:59 ` [RFC PATCH net-next 11/11] net: dsa: microchip: lan937x: update multicast table Rakesh Sankaranarayanan
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