wifi: cfg80211: use wiphy work for socket owner autodisconnect

wifi: cfg80211: use wiphy work for socket owner autodisconnect

nl80211_netlink_notify() walks the cfg80211 wireless device list when a
NETLINK_GENERIC socket is released. If the socket owns a connection, the
notifier queues the embedded wdev->disconnect_wk work item.

That work is a plain work_struct today. NETDEV_GOING_DOWN cancels it, but a
NETLINK_URELEASE notifier that already observed conn_owner_nlportid can
queue it after that cancel returns. _cfg80211_unregister_wdev() then
removes the wdev from the list and waits for RCU readers, but
synchronize_net() does not drain work queued by such a reader.

Make the autodisconnect work a wiphy_work instead. The callback already
needs the wiphy mutex, and wiphy_work runs under that mutex. This lets
teardown cancel pending autodisconnect work while holding the mutex,
without a cancel_work_sync() vs. worker locking concern.

Also cancel the wiphy work after list_del_rcu() and synchronize_net(). Any
NETLINK_URELEASE notifier that had already reached the wdev list has then
either queued the work and it is removed, or can no longer find the wdev.

Fixes: bd2522b16884 ("cfg80211: NL80211_ATTR_SOCKET_OWNER support for CMD_CONNECT")
Suggested-by: Johannes Berg <johannes@sipsolutions.net>
Assisted-by: Codex:gpt-5.5
Signed-off-by: Cen Zhang <zzzccc427@gmail.com>
Link: https://patch.msgid.link/20260706152418.779226-1-zzzccc427@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>