[PATCH net] net: usb: lan78xx: only stop phylink if the interface is running

[YuanZhe Liu]

lan78xx_disconnect() unconditionally calls phylink_stop(), but
phylink_start() is only called from lan78xx_open(). When the device is
unplugged before the interface has been brought up, the attached PHY is
still in PHY_READY and phy_stop() reports:

  called from state READY
  WARNING: drivers/net/phy/phy.c:1670 at phy_stop+0xad/0x380

The same warning is emitted after an ifup/ifdown cycle, where the PHY is
already in PHY_HALTED. Call phylink_stop() only when the network device is
running, which is when phylink_start() has been called.

Fixes: e110bc825897 ("net: usb: lan78xx: Convert to PHYLINK for improved PHY and MAC management")
Cc: stable@xxxxxxxxxxxxxxx
Co-developed-by: Bin Yu <byu@xxxxxxxxxxxxx>
Signed-off-by: Bin Yu <byu@xxxxxxxxxxxxx>
Co-developed-by: Cheng Wen <wencheng@xxxxxxxxxxxxx>
Signed-off-by: Cheng Wen <wencheng@xxxxxxxxxxxxx>
Signed-off-by: YuanZhe Liu <25031212351@xxxxxxxxxxxxxxxxx>
---
 drivers/net/usb/lan78xx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 5655941f1478..68e61004b3d7 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -4581,7 +4581,8 @@ static void lan78xx_disconnect(struct usb_interface *intf)
 	net = dev->net;
 
 	rtnl_lock();
-	phylink_stop(dev->phylink);
+	if (netif_running(net))
+		phylink_stop(dev->phylink);
 	phylink_disconnect_phy(dev->phylink);
 	rtnl_unlock();
 
-- 
2.34.1