[PATCH v3] net: phy: fix uninitalized WOL parameters in phy_ethtool_get_wol

[Sebastian Hesselbarth]

phy_ethtool_get_wol is a helper to get current WOL settings from
a phy device. When using this helper on a PHY without .get_wol
callback, struct ethtool_wolinfo is never set-up correctly and
may contain misleading information about WOL status.

To fix this, always zero relevant fields of struct ethtool_wolinfo
regardless of .get_wol callback availability.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth at gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli at gmail.com>
---
Changelog:
v1->v2:
- clear whole struct ethtool_wolinfo
- check for non-NULL phy_device
v2->v3:
- only clear ->supported and ->wolopts (Suggested by Ben Hutchings)

Cc: David Miller <davem at davemloft.net>
Cc: Florian Fainelli <f.fainelli at gmail.com>
Cc: Ben Hutchings <ben at decadent.org.uk>
Cc: netdev at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
---
 drivers/net/phy/phy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 19c9eca0ef26..94234a91a50f 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -1092,7 +1092,9 @@ EXPORT_SYMBOL(phy_ethtool_set_wol);
 
 void phy_ethtool_get_wol(struct phy_device *phydev, struct ethtool_wolinfo *wol)
 {
-	if (phydev->drv->get_wol)
+	wol->supported = wol->wolopts = 0;
+
+	if (phydev && phydev->drv->get_wol)
 		phydev->drv->get_wol(phydev, wol);
 }
 EXPORT_SYMBOL(phy_ethtool_get_wol);
-- 
1.8.5.3