[PATCH 4.19 080/280] net: dsa: bcm_sf2: Do not assume DSA master supports WoL

[Greg Kroah-Hartman]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit c3152ec4c0691e351f35a2f63347a464b5f35151 ]

We assume in the bcm_sf2 driver that the DSA master network device
supports ethtool_ops::{get,set}_wol operations, which is not a given.
Avoid de-referencing potentially non-existent function pointers and
check them as we should.

Fixes: 96e65d7f3f88 ("net: dsa: bcm_sf2: add support for Wake-on-LAN")
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/dsa/bcm_sf2.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/dsa/bcm_sf2.c b/drivers/net/dsa/bcm_sf2.c
index bb26a193361e..2fa2caf7a746 100644
--- a/drivers/net/dsa/bcm_sf2.c
+++ b/drivers/net/dsa/bcm_sf2.c
@@ -724,10 +724,11 @@ static void bcm_sf2_sw_get_wol(struct dsa_switch *ds, int port,
 {
 	struct net_device *p = ds->ports[port].cpu_dp->master;
 	struct bcm_sf2_priv *priv = bcm_sf2_to_priv(ds);
-	struct ethtool_wolinfo pwol;
+	struct ethtool_wolinfo pwol = { };
 
 	/* Get the parent device WoL settings */
-	p->ethtool_ops->get_wol(p, &pwol);
+	if (p->ethtool_ops->get_wol)
+		p->ethtool_ops->get_wol(p, &pwol);
 
 	/* Advertise the parent device supported settings */
 	wol->supported = pwol.supported;
@@ -748,9 +749,10 @@ static int bcm_sf2_sw_set_wol(struct dsa_switch *ds, int port,
 	struct net_device *p = ds->ports[port].cpu_dp->master;
 	struct bcm_sf2_priv *priv = bcm_sf2_to_priv(ds);
 	s8 cpu_port = ds->ports[port].cpu_dp->index;
-	struct ethtool_wolinfo pwol;
+	struct ethtool_wolinfo pwol =  { };
 
-	p->ethtool_ops->get_wol(p, &pwol);
+	if (p->ethtool_ops->get_wol)
+		p->ethtool_ops->get_wol(p, &pwol);
 	if (wol->wolopts & ~pwol.supported)
 		return -EINVAL;
 
-- 
2.19.1