[PATCH 4.9 23/28] net: usb: asix: replace mii_nway_restart in resume path

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Couzens <lyn...@fe80.eu>

[ Upstream commit 5c968f48021a9b3faa61ac2543cfab32461c0e05 ]

mii_nway_restart is not pm aware which results in a rtnl deadlock.
Implement mii_nway_restart manual by setting BMCR_ANRESTART if
BMCR_ANENABLE is set.

To reproduce:
* plug an asix based usb network interface
* wait until the device enters PM (~5 sec)
* `ip link set eth1 up` will never return

Fixes: d9fe64e51114 ("net: asix: Add in_pm parameter")
Signed-off-by: Alexander Couzens <lyn...@fe80.eu>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/usb/asix_devices.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -640,10 +640,12 @@ static void ax88772_restore_phy(struct u
                                     priv->presvd_phy_advertise);
 
                /* Restore BMCR */
+               if (priv->presvd_phy_bmcr & BMCR_ANENABLE)
+                       priv->presvd_phy_bmcr |= BMCR_ANRESTART;
+
                asix_mdio_write_nopm(dev->net, dev->mii.phy_id, MII_BMCR,
                                     priv->presvd_phy_bmcr);
 
-               mii_nway_restart(&dev->mii);
                priv->presvd_phy_advertise = 0;
                priv->presvd_phy_bmcr = 0;
        }