[PATCH v2] net: dsa: Fix conditional handling of Wake-on-Lan configuration in dsa_user_set_wol

[Mohammed Anees]

In the original implementation of dsa_user_set_wol(), the return
value of phylink_ethtool_set_wol() was not checked, which could
lead to errors being ignored. This wouldn't matter if it returned
-EOPNOTSUPP, since that indicates the PHY layer doesn't support
the option, but if any other value is returned, it is problematic
and must be checked. The solution is to check the return value of
phylink_ethtool_set_wol(), and if it returns anything other than
-EOPNOTSUPP, immediately return the error. Only if it returns
-EOPNOTSUPP should the function proceed to check whether WoL can
be set by ds->ops->set_wol().

Fixes: 57719771a244 ("Merge tag 'sound-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound")
Signed-off-by: Mohammed Anees <pvmohammedanees2003@xxxxxxxxx>
---
v2:
- Added error checking for phylink_ethtool_set_wol(), ensuring correct
handling compared to v1.
___
 net/dsa/user.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/net/dsa/user.c b/net/dsa/user.c
index 74eda9b30608..bae5ed22db91 100644
--- a/net/dsa/user.c
+++ b/net/dsa/user.c
@@ -1215,14 +1215,17 @@ static int dsa_user_set_wol(struct net_device *dev, struct ethtool_wolinfo *w)
 {
 	struct dsa_port *dp = dsa_user_to_port(dev);
 	struct dsa_switch *ds = dp->ds;
-	int ret = -EOPNOTSUPP;
-
-	phylink_ethtool_set_wol(dp->pl, w);
-
+	int ret;
+
+	ret = phylink_ethtool_get_wol(dp->pl, w);
+
+	if (ret != -EOPNOTSUPP)
+		return ret;
+
 	if (ds->ops->set_wol)
-		ret = ds->ops->set_wol(ds, dp->index, w);
+		return ds->ops->set_wol(ds, dp->index, w);
 
-	return ret;
+	return -EOPNOTSUPP;
 }
 
 static int dsa_user_set_eee(struct net_device *dev, struct ethtool_keee *e)
-- 
2.46.0