Messages in this thread Patch in this message | | | From | Grant Grundler <> | Subject | [PATCH] net: asix: fix modprobe "sysfs: cannot create duplicate filename" | Date | Mon, 6 Mar 2023 16:50:28 -0800 |
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"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: https://lore.kernel.org/netdev/20220623063649.GD23685@pengutronix.de/T/
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.
Reported-by: Anton Lundin <glance@acc.umu.se> Tested-by: Eizan Miyamoto <eizan@chromium.org> Signed-off-by: Grant Grundler <grundler@chromium.org> --- drivers/net/usb/asix_devices.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-)
diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c index 30e87389aefa1..f0a87b933062a 100644 --- a/drivers/net/usb/asix_devices.c +++ b/drivers/net/usb/asix_devices.c @@ -640,8 +640,9 @@ 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; @@ -653,7 +654,27 @@ 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); + goto mdio_regerr; + } + + priv->phydev = mdiobus_get_phy(priv->mdio, priv->phy_addr); + if (priv->phydev) + return 0; + + netdev_err(dev->net, "Could not find PHY\n"); + mdiobus_unregister(priv->mdio); +mdio_regerr: + mdiobus_free(priv->mdio); + return ret; +} + +static void ax88772_release_mdio(struct asix_common_private *priv) +{ + mdiobus_unregister(priv->mdio); + mdiobus_free(priv->mdio); } static int ax88772_init_phy(struct usbnet *dev) @@ -661,12 +682,6 @@ static int ax88772_init_phy(struct usbnet *dev) struct asix_common_private *priv = dev->driver_priv; int ret; - priv->phydev = mdiobus_get_phy(priv->mdio, priv->phy_addr); - if (!priv->phydev) { - netdev_err(dev->net, "Could not find PHY\n"); - return -ENODEV; - } - ret = phy_connect_direct(dev->net, priv->phydev, &asix_adjust_link, PHY_INTERFACE_MODE_INTERNAL); if (ret) { @@ -805,6 +820,7 @@ static void ax88772_unbind(struct usbnet *dev, struct usb_interface *intf) struct asix_common_private *priv = dev->driver_priv; phy_disconnect(priv->phydev); + ax88772_release_mdio(priv); asix_rx_fixup_common_free(dev->driver_priv); } -- 2.39.2
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