[PATCH 4.4 276/312] net: ethernet: davinci_emac: Fix devioctl while in fixed link

[Greg Kroah-Hartman]

From: Neil Armstrong <narmstrong@xxxxxxxxxxxx>

commit 62522ef3c399996f6c8120bfd14b94280bc9f490 upstream.

When configured in fixed link, the DaVinci emac driver sets the
priv->phydev to NULL and further ioctl calls to the phy_mii_ioctl()
causes the kernel to crash.

Cc: Brian Hutchinson <b.hutchman@xxxxxxxxx>
Fixes: 1bb6aa56bb38 ("net: davinci_emac: Add support for fixed-link PHY")
Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
Reviewed-by: Mugunthan V N <mugunthanvnm@xxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/net/ethernet/ti/davinci_emac.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/ti/davinci_emac.c
+++ b/drivers/net/ethernet/ti/davinci_emac.c
@@ -1512,7 +1512,10 @@ static int emac_devioctl(struct net_devi
 
 	/* TODO: Add phy read and write and private statistics get feature */
 
-	return phy_mii_ioctl(priv->phydev, ifrq, cmd);
+	if (priv->phydev)
+		return phy_mii_ioctl(priv->phydev, ifrq, cmd);
+	else
+		return -EOPNOTSUPP;
 }
 
 static int match_first_device(struct device *dev, void *data)