With moving netdev_sync_lower_features() after the .ndo_set_features
calls, I neglected to verify that devices added *after* a flag had been
disabled on an upper device were properly added with that flag disabled as
well. This currently happens, because we exit __netdev_update_features()
when we see dev->features == features for the upper dev. We can retain the
optimization of leaving without calling .ndo_set_features with a bit of
tweaking and a goto here.

Changing err to ret was somewhat arbitrary and makes the patch look more
involved, but seems to better fit the altered use.

Fixes: fd867d51f ("net/core: generic support for disabling netdev features down 
stack")
CC: "David S. Miller" <da...@davemloft.net>
CC: Eric Dumazet <eduma...@google.com>
CC: Jay Vosburgh <j.vosbu...@gmail.com>
CC: Veaceslav Falico <vfal...@gmail.com>
CC: Andy Gospodarek <go...@cumulusnetworks.com>
CC: Jiri Pirko <j...@resnulli.us>
CC: Nikolay Aleksandrov <ra...@blackwall.org>
CC: Michal Kubecek <mkube...@suse.cz>
CC: Alexander Duyck <alexander.du...@gmail.com>
CC: netdev@vger.kernel.org
Signed-off-by: Jarod Wilson <ja...@redhat.com>
---
 net/core/dev.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 8ce3f74..90e0a62 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6402,7 +6402,7 @@ int __netdev_update_features(struct net_device *dev)
        struct net_device *upper, *lower;
        netdev_features_t features;
        struct list_head *iter;
-       int err = 0;
+       int ret = 0;
 
        ASSERT_RTNL();
 
@@ -6419,31 +6419,34 @@ int __netdev_update_features(struct net_device *dev)
                features = netdev_sync_upper_features(dev, upper, features);
 
        if (dev->features == features)
-               return 0;
+               goto sync_lower;
 
        netdev_dbg(dev, "Features changed: %pNF -> %pNF\n",
                &dev->features, &features);
 
        if (dev->netdev_ops->ndo_set_features)
-               err = dev->netdev_ops->ndo_set_features(dev, features);
+               ret = dev->netdev_ops->ndo_set_features(dev, features);
 
-       if (unlikely(err < 0)) {
+       if (unlikely(ret < 0)) {
                netdev_err(dev,
                        "set_features() failed (%d); wanted %pNF, left %pNF\n",
-                       err, &features, &dev->features);
+                       ret, &features, &dev->features);
                return -1;
        }
 
+       if (!ret) {
+               dev->features = features;
+               ret = 1;
+       }
+
+sync_lower:
        /* some features must be disabled on lower devices when disabled
         * on an upper device (think: bonding master or bridge)
         */
        netdev_for_each_lower_dev(dev, lower, iter)
                netdev_sync_lower_features(dev, lower, features);
 
-       if (!err)
-               dev->features = features;
-
-       return 1;
+       return ret;
 }
 
 /**
-- 
1.8.3.1

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to