From: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
To: netdev@vger.kernel.org, Horatiu Vultur <horatiu.vultur@microchip.com>
Cc: linux-kernel@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Subject: [PATCH net 2/2] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP
Date: Wed, 23 Dec 2020 15:45:33 +0100 [thread overview]
Message-ID: <20201223144533.4145-3-rasmus.villemoes@prevas.dk> (raw)
In-Reply-To: <20201223144533.4145-1-rasmus.villemoes@prevas.dk>
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.
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
---
net/switchdev/switchdev.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 23d868545362..2c1ffc9ba2eb 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -460,10 +460,11 @@ static int __switchdev_handle_port_obj_add(struct net_device *dev,
extack = switchdev_notifier_info_to_extack(&port_obj_info->info);
if (check_cb(dev)) {
- /* This flag is only checked if the return value is success. */
- port_obj_info->handled = true;
- return add_cb(dev, port_obj_info->obj, port_obj_info->trans,
- extack);
+ err = add_cb(dev, port_obj_info->obj, port_obj_info->trans,
+ extack);
+ if (err != -EOPNOTSUPP)
+ port_obj_info->handled = true;
+ return err;
}
/* Switch ports might be stacked under e.g. a LAG. Ignore the
@@ -515,9 +516,10 @@ static int __switchdev_handle_port_obj_del(struct net_device *dev,
int err = -EOPNOTSUPP;
if (check_cb(dev)) {
- /* This flag is only checked if the return value is success. */
- port_obj_info->handled = true;
- return del_cb(dev, port_obj_info->obj);
+ err = del_cb(dev, port_obj_info->obj);
+ if (err != -EOPNOTSUPP)
+ port_obj_info->handled = true;
+ return err;
}
/* Switch ports might be stacked under e.g. a LAG. Ignore the
@@ -568,9 +570,10 @@ static int __switchdev_handle_port_attr_set(struct net_device *dev,
int err = -EOPNOTSUPP;
if (check_cb(dev)) {
- port_attr_info->handled = true;
- return set_cb(dev, port_attr_info->attr,
- port_attr_info->trans);
+ err = set_cb(dev, port_attr_info->attr, port_attr_info->trans);
+ if (err != -EOPNOTSUPP)
+ port_attr_info->handled = true;
+ return err;
}
/* Switch ports might be stacked under e.g. a LAG. Ignore the
--
2.23.0
next prev parent reply other threads:[~2020-12-23 14:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-23 14:45 [PATCH net 0/2] MRP without hardware offload? Rasmus Villemoes
2020-12-23 14:45 ` [PATCH net 1/2] net: mrp: fix definitions of MRP test packets Rasmus Villemoes
2020-12-23 17:59 ` Horatiu Vultur
2020-12-23 18:41 ` Andrew Lunn
2020-12-23 19:22 ` Horatiu Vultur
2020-12-28 22:24 ` Jakub Kicinski
2021-01-03 13:29 ` Horatiu Vultur
2021-01-19 15:42 ` Rasmus Villemoes
2021-01-19 17:45 ` Jakub Kicinski
2020-12-23 14:45 ` Rasmus Villemoes [this message]
2020-12-28 22:26 ` [PATCH net 2/2] net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP Jakub Kicinski
2020-12-23 18:14 ` [PATCH net 0/2] MRP without hardware offload? Horatiu Vultur
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