usbnet: smsc95xx: disable carrier check while suspending

[Frieder Schrempf <frieder.schrempf@kontron.de>]

We need to make sure, that the carrier check polling is disabled
while suspending. Otherwise we can end up with usbnet_read_cmd()
being issued when only usbnet_read_cmd_nopm() is allowed. If this
happens, read operations lock up.

Fixes: d69d169493 ("usbnet: smsc95xx: fix link detection for disabled autonegotiation")
Cc: <stable@vger.kernel.org>
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
---
 drivers/net/usb/smsc95xx.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index 262e7a3..3bc9633 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -1592,6 +1592,8 @@ static int smsc95xx_suspend(struct usb_interface *intf, pm_message_t message)
 	u32 val, link_up;
 	int ret;
 
+	cancel_delayed_work_sync(&pdata->carrier_check);
+
 	ret = usbnet_suspend(intf, message);
 	if (ret < 0) {
 		netdev_warn(dev->net, "usbnet_suspend error\n");
@@ -1840,6 +1842,11 @@ static int smsc95xx_suspend(struct usb_interface *intf, pm_message_t message)
 	 */
 	if (ret && PMSG_IS_AUTO(message))
 		usbnet_resume(intf);
+
+	if (ret)
+		schedule_delayed_work(&pdata->carrier_check,
+				      CARRIER_CHECK_DELAY);
+
 	return ret;
 }