[PATCH 4.2 08/54] net: dsa: fix preparation of a port STP update

Greg Kroah-Hartman
2015-10-23T17:47:01Z

From: Vivien Didelot <vivien.didelot@savoirfairelinux.com>

[ Upstream commit 57a47532c4312159935c98b7f1cf0e62296b9171 ]

Because of the default 0 value of ret in dsa_slave_port_attr_set, a
driver may return -EOPNOTSUPP from the commit phase of a STP state,
which triggers a WARN() from switchdev.

This happened on a 6185 switch which does not support hardware bridging.

Fixes: 3563606258cf ("switchdev: convert STP update to switchdev attr set")
Reported-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/dsa/slave.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -348,12 +348,17 @@ static int dsa_slave_stp_update(struct n
static int dsa_slave_port_attr_set(struct net_device *dev,
struct switchdev_attr *attr)
{
- int ret = 0;
+ struct dsa_slave_priv *p = netdev_priv(dev);
+ struct dsa_switch *ds = p->parent;
+ int ret;

switch (attr->id) {
case SWITCHDEV_ATTR_PORT_STP_STATE:
- if (attr->trans == SWITCHDEV_TRANS_COMMIT)
- ret = dsa_slave_stp_update(dev, attr->u.stp_state);
+ if (attr->trans == SWITCHDEV_TRANS_PREPARE)
+ ret = ds->drv->port_stp_update ? 0 : -EOPNOTSUPP;
+ else
+ ret = ds->drv->port_stp_update(ds, p->port,
+ attr->u.stp_state);
break;
default:
ret = -EOPNOTSUPP;