[PATCH 4.19 08/36] net: phy: smsc: bail out in lan87xx_read_status if genphy_read_status fails

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Heiner Kallweit <hkallweit1@gmail.com>

[ Upstream commit c22c3bbf351e4ce905f082649cffa1ff893ea8c1 ]

If genphy_read_status fails then further access to the PHY may result
in unpredictable behavior. To prevent this bail out immediately if
genphy_read_status fails.

Fixes: 4223dbffed9f ("net: phy: smsc: Re-enable EDPD mode for LAN87xx")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/026aa4f2-36f5-1c10-ab9f-cdb17dda6ac4@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/phy/smsc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
index c328208388da7..fd7c9f5ff99eb 100644
--- a/drivers/net/phy/smsc.c
+++ b/drivers/net/phy/smsc.c
@@ -112,8 +112,11 @@ static int lan911x_config_init(struct phy_device *phydev)
 static int lan87xx_read_status(struct phy_device *phydev)
 {
 	struct smsc_phy_priv *priv = phydev->priv;
+	int err;
 
-	int err = genphy_read_status(phydev);
+	err = genphy_read_status(phydev);
+	if (err)
+		return err;
 
 	if (!phydev->link && priv->energy_enable) {
 		int i;
-- 
2.39.2