[PATCH] net: usb: asix: replace mii_nway_restart in resume path

[PATCH] net: usb: asix: replace mii_nway_restart in resume path

[Alexander Couzens]

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 <lynxis@fe80.eu>
---
 drivers/net/usb/asix_devices.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index 3d4f7959dabb..b1b3d8f7e67d 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -642,10 +642,12 @@ static void ax88772_restore_phy(struct usbnet *dev)
 				     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;
 	}
-- 
2.18.0

Re: [PATCH] net: usb: asix: replace mii_nway_restart in resume path

[David Miller]

From: Alexander Couzens <lynxis@fe80.eu>
Date: Tue, 17 Jul 2018 13:17:09 +0200

> 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 <lynxis@fe80.eu>

Applied and queued up for -stable, thank you.