net: fix ETHTOOL_SFEATURES compatibility with old ethtool_ops.set_flags

Current code squashes flags to bool - this makes set_flags fail whenever
some ETH_FLAG_* equivalent features are set. Fix this.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 1 deletions

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 84e7304532e..fd14116ad7f 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -233,6 +233,29 @@ static int ethtool_set_feature_compat(struct net_device *dev,
         return 1;
 }
 
+static int ethtool_set_flags_compat(struct net_device *dev,
+        int (*legacy_set)(struct net_device *, u32),
+        struct ethtool_set_features_block *features, u32 mask)
+{
+        u32 value;
+
+        if (!legacy_set)
+                return 0;
+
+        if (!(features[0].valid & mask))
+                return 0;
+
+        value = dev->features & ~features[0].valid;
+        value |= features[0].requested;
+
+        features[0].valid &= ~mask;
+
+        if (legacy_set(dev, value & mask) < 0)
+                netdev_info(dev, "Legacy flags change failed\n");
+
+        return 1;
+}
+
 static int ethtool_set_features_compat(struct net_device *dev,
         struct ethtool_set_features_block *features)
 {
@@ -249,7 +272,7 @@ static int ethtool_set_features_compat(struct net_device *dev,
                 features, NETIF_F_ALL_TSO);
         compat |= ethtool_set_feature_compat(dev, dev->ethtool_ops->set_rx_csum,
                 features, NETIF_F_RXCSUM);
-        compat |= ethtool_set_feature_compat(dev, dev->ethtool_ops->set_flags,
+        compat |= ethtool_set_flags_compat(dev, dev->ethtool_ops->set_flags,
                 features, flags_dup_features);
 
         return compat;