From: Petr Machata <petrm@nvidia•com>
To: Rasmus Villemoes <rasmus.villemoes@prevas•dk>
Cc: <netdev@vger•kernel.org>,
Horatiu Vultur <horatiu.vultur@microchip•com>,
Jiri Pirko <jiri@mellanox•com>,
Florian Fainelli <f.fainelli@gmail•com>,
"Petr Machata" <petrm@mellanox•com>,
Ido Schimmel <idosch@mellanox•com>,
"David S . Miller" <davem@davemloft•net>,
Ivan Vecera <ivecera@redhat•com>,
"Jakub Kicinski" <kuba@kernel•org>
Subject: Re: [PATCH resend net] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP
Date: Fri, 22 Jan 2021 14:42:45 +0100 [thread overview]
Message-ID: <87y2glay0a.fsf@nvidia.com> (raw)
In-Reply-To: <20210121234317.65936-1-rasmus.villemoes@prevas.dk>
Rasmus Villemoes <rasmus.villemoes@prevas•dk> writes:
> It's not true that switchdev_port_obj_notify() only inspects the
> ->handled field of "struct switchdev_notifier_port_obj_info" if
> call_switchdev_blocking_notifiers() returns 0 - there's a WARN_ON()
> triggering for a non-zero return combined with ->handled not being
> true. But the real problem here is that -EOPNOTSUPP is not being
> properly handled.
>
> The wrapper functions switchdev_handle_port_obj_add() et al change a
> return value of -EOPNOTSUPP to 0, and the treatment of ->handled in
> switchdev_port_obj_notify() seems to be designed to change that back
> to -EOPNOTSUPP in case nobody actually acted on the notifier (i.e.,
> everybody returned -EOPNOTSUPP).
>
> Currently, as soon as some device down the stack passes the check_cb()
> check, ->handled gets set to true, which means that
> switchdev_port_obj_notify() cannot actually ever return -EOPNOTSUPP.
>
> This, for example, means that the detection of hardware offload
> support in the MRP code is broken - br_mrp_set_ring_role() always ends
> up setting mrp->ring_role_offloaded to 1, despite not a single
> mainline driver implementing any of the SWITCHDEV_OBJ_ID*_MRP. So
> since the MRP code thinks the generation of MRP test frames has been
> offloaded, no such frames are actually put on the wire.
>
> So, continue to set ->handled true if any callback returns success or
> any error distinct from -EOPNOTSUPP. But if all the callbacks return
> -EOPNOTSUPP, make sure that ->handled stays false, so the logic in
> switchdev_port_obj_notify() can propagate that information.
>
> Fixes: f30f0601eb93 ("switchdev: Add helpers to aid traversal through lower devices")
> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas•dk>
Looks good.
Reviewed-by: Petr Machata <petrm@nvidia•com>
Thanks!
prev parent reply other threads:[~2021-01-22 13:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 23:43 [PATCH resend net] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP Rasmus Villemoes
2021-01-22 9:05 ` Horatiu Vultur
2021-01-22 13:36 ` Rasmus Villemoes
2021-01-23 20:44 ` Jakub Kicinski
2021-01-22 13:42 ` Petr Machata [this message]
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