net/core: revert "net: fix __netdev_update_features return.." and add comment

This reverts commit 00ee59271777 ("net: fix __netdev_update_features return
on ndo_set_features failure")
and adds a comment explaining why it's okay to return a value other than
0 upon error. Some drivers might actually change flags and return an
error so it's better to fire a spurious notification rather than miss
these.

CC: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 5dbc86ea6b58..ae00b894e675 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6436,7 +6436,10 @@ int __netdev_update_features(struct net_device *dev)
                 netdev_err(dev,
                         "set_features() failed (%d); wanted %pNF, left %pNF\n",
                         err, &features, &dev->features);
-                return 0;
+                /* return non-0 since some features might have changed and
+                 * it's better to fire a spurious notification than miss it
+                 */
+                return -1;
         }
 
 sync_lower: