| Message ID | 20230308202159.2419227-1-grundler@chromium.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [PATCHv3,net,1/2] net: asix: fix modprobe "sysfs: cannot create duplicate filename" | expand |
Wed, Mar 08, 2023 at 09:21:58PM CET, grundler@chromium.org wrote: >"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 14:16 UTC: > >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: e532a096be0e ("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> Reviewed-by: Jiri Pirko <jiri@nvidia.com>
diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c index 743cbf5d662c..538c84909913 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) @@ -690,6 +704,7 @@ static int ax88772_init_phy(struct usbnet *dev) priv->phydev = mdiobus_get_phy(priv->mdio, priv->phy_addr); if (!priv->phydev) { netdev_err(dev->net, "Could not find PHY\n"); + ax88772_mdio_unregister(priv); return -ENODEV; } @@ -926,6 +941,7 @@ 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); }
"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 14:16 UTC: 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: e532a096be0e ("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> --- drivers/net/usb/asix_devices.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) V3: rebase against netdev/net.git remove "TEST" prefix in subject line added Link: tag for Reported-by tag V2: moved mdiobus_get_phy() call back into ax88772_init_phy() (Lukas Wunner is entirely correct this patch is much easier to backport without this patch hunk.) Added "Fixes:" tag per request from Florian Fainelli