From: Grant Grundler grundler@chromium.org
[ Upstream commit 8eac0095de355ee31e1b014f79f83d2cd62a2d04 ]
"modprobe asix ; rmmod asix ; modprobe asix" fails with: sysfs: cannot create duplicate filename \ '/devices/virtual/mdio_bus/usb-003:004'
Issue was originally reported by Anton Lundin on 2022-06-22 (link below).
Chrome OS team hit the same issue in Feb, 2023 when trying to find work arounds for other issues with AX88172 devices.
The use of devm_mdiobus_register() with usbnet devices results in the MDIO data being associated with the USB device. When the asix driver is unloaded, the USB device continues to exist and the corresponding "mdiobus_unregister()" is NOT called until the USB device is unplugged or unauthorized. So the next "modprobe asix" will fail because the MDIO phy sysfs attributes still exist.
The 'easy' (from a design PoV) fix is to use the non-devm variants of mdiobus_* functions and explicitly manage this use in the asix_bind and asix_unbind function calls. I've not explored trying to fix usbnet initialization so devm_* stuff will work.
Fixes: e532a096be0e5 ("net: usb: asix: ax88772: add phylib support") Reported-by: Anton Lundin glance@acc.umu.se Link: https://lore.kernel.org/netdev/20220623063649.GD23685@pengutronix.de/T/ Tested-by: Eizan Miyamoto eizan@chromium.org Signed-off-by: Grant Grundler grundler@chromium.org Link: https://lore.kernel.org/r/20230321170539.732147-1-grundler@chromium.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/usb/asix_devices.c | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-)
diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c index 743cbf5d662c9..f7cff58fe0449 100644 --- a/drivers/net/usb/asix_devices.c +++ b/drivers/net/usb/asix_devices.c @@ -666,8 +666,9 @@ static int asix_resume(struct usb_interface *intf) static int ax88772_init_mdio(struct usbnet *dev) { struct asix_common_private *priv = dev->driver_priv; + int ret;
- priv->mdio = devm_mdiobus_alloc(&dev->udev->dev); + priv->mdio = mdiobus_alloc(); if (!priv->mdio) return -ENOMEM;
@@ -679,7 +680,20 @@ static int ax88772_init_mdio(struct usbnet *dev) snprintf(priv->mdio->id, MII_BUS_ID_SIZE, "usb-%03d:%03d", dev->udev->bus->busnum, dev->udev->devnum);
- return devm_mdiobus_register(&dev->udev->dev, priv->mdio); + ret = mdiobus_register(priv->mdio); + if (ret) { + netdev_err(dev->net, "Could not register MDIO bus (err %d)\n", ret); + mdiobus_free(priv->mdio); + priv->mdio = NULL; + } + + return ret; +} + +static void ax88772_mdio_unregister(struct asix_common_private *priv) +{ + mdiobus_unregister(priv->mdio); + mdiobus_free(priv->mdio); }
static int ax88772_init_phy(struct usbnet *dev) @@ -896,16 +910,23 @@ static int ax88772_bind(struct usbnet *dev, struct usb_interface *intf)
ret = ax88772_init_mdio(dev); if (ret) - return ret; + goto mdio_err;
ret = ax88772_phylink_setup(dev); if (ret) - return ret; + goto phylink_err;
ret = ax88772_init_phy(dev); if (ret) - phylink_destroy(priv->phylink); + goto initphy_err;
+ return 0; + +initphy_err: + phylink_destroy(priv->phylink); +phylink_err: + ax88772_mdio_unregister(priv); +mdio_err: return ret; }
@@ -926,6 +947,7 @@ static void ax88772_unbind(struct usbnet *dev, struct usb_interface *intf) phylink_disconnect_phy(priv->phylink); rtnl_unlock(); phylink_destroy(priv->phylink); + ax88772_mdio_unregister(priv); asix_rx_fixup_common_free(dev->driver_priv); }