From d2a08ea03830ba2bf5a5379a480e50963cba99a6 Mon Sep 17 00:00:00 2001 From: Kuen-Han Tsai Date: Mon, 9 Mar 2026 20:04:49 +0800 Subject: [PATCH] Revert "usb: gadget: u_ether: Add auto-cleanup helper for freeing net_device" commit 46662d3a1ad40282ba9f753cccc6f909ec4468cc upstream. This reverts commit 0c0981126b99288ed354d3d414c8a5fd42ac9e25. This commit is being reverted as part of a series-wide revert. By deferring the net_device allocation to the bind() phase, a single function instance will spawn multiple network devices if it is symlinked to multiple USB configurations. This causes regressions for userspace tools (like the postmarketOS DHCP daemon) that rely on reading the interface name (e.g., "usb0") from configfs. Currently, configfs returns the template "usb%d", causing the userspace network setup to fail. Crucially, because this patch breaks the 1:1 mapping between the function instance and the network device, this naming issue cannot simply be patched. Configfs only exposes a single 'ifname' attribute per instance, making it impossible to accurately report the actual interface name when multiple underlying network devices can exist for that single instance. All configurations tied to the same function instance are meant to share a single network device. Revert this change to restore the 1:1 mapping by allocating the network device at the instance level (alloc_inst). Reported-by: David Heidelberg Closes: https://lore.kernel.org/linux-usb/70b558ea-a12e-4170-9b8e-c951131249af@ixit.cz/ Fixes: 56a512a9b410 ("usb: gadget: f_ncm: align net_device lifecycle with bind/unbind") Cc: stable Signed-off-by: Kuen-Han Tsai Link: https://patch.msgid.link/20260309-f-ncm-revert-v2-4-ea2afbc7d9b2@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/u_ether.c | 15 --------------- drivers/usb/gadget/function/u_ether.h | 2 -- 2 files changed, 17 deletions(-) diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c index 6c32665538cc..745ed2c212e3 100644 --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -1125,21 +1125,6 @@ void gether_cleanup(struct eth_dev *dev) } EXPORT_SYMBOL_GPL(gether_cleanup); -void gether_unregister_free_netdev(struct net_device *net) -{ - if (!net) - return; - - struct eth_dev *dev = netdev_priv(net); - - if (net->reg_state == NETREG_REGISTERED) { - unregister_netdev(net); - flush_work(&dev->work); - } - free_netdev(net); -} -EXPORT_SYMBOL_GPL(gether_unregister_free_netdev); - /** * gether_connect - notify network layer that USB link is active * @link: the USB link, set up with endpoints, descriptors matching diff --git a/drivers/usb/gadget/function/u_ether.h b/drivers/usb/gadget/function/u_ether.h index a212a8ec5eb1..63a0240df4d7 100644 --- a/drivers/usb/gadget/function/u_ether.h +++ b/drivers/usb/gadget/function/u_ether.h @@ -283,8 +283,6 @@ int gether_get_ifname(struct net_device *net, char *name, int len); int gether_set_ifname(struct net_device *net, const char *name, int len); void gether_cleanup(struct eth_dev *dev); -void gether_unregister_free_netdev(struct net_device *net); -DEFINE_FREE(free_gether_netdev, struct net_device *, gether_unregister_free_netdev(_T)); void gether_setup_opts_default(struct gether_opts *opts, const char *name); void gether_apply_opts(struct net_device *net, struct gether_opts *opts);