The phy_mutex should be held while reading and writing to the phy.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>