net: dcb: flush lingering app table entries for unregistered devices
If I'm not mistaken (and I don't think I am), the way in which the dcbnl_ops work is that drivers call dcb_ieee_setapp() and this populates the application table with dynamically allocated struct dcb_app_type entries that are kept in the module-global dcb_app_list. However, nobody keeps exact track of these entries, and although dcb_ieee_delapp() is supposed to remove them, nobody does so when the interface goes away (example: driver unbinds from device). So the dcb_app_list will contain lingering entries with an ifindex that no longer matches any device in dcb_app_lookup(). Reclaim the lost memory by listening for the NETDEV_UNREGISTER event and flushing the app table entries of interfaces that are now gone. In fact something like this used to be done as part of the initial commit (blamed below), but it was done in dcbnl_exit() -> dcb_flushapp(), essentially at module_exit time. That became dead code after commit 7a6b6f51 ("DCB: fix kconfig option") which essentially merged "tristate config DCB" and "bool config DCBNL" into a single "bool config DCB", so net/dcb/dcbnl.c could not be built as a module anymore. Commit 36b9ad80 ("net/dcb: make dcbnl.c explicitly non-modular") recognized this and deleted dcbnl_exit() and dcb_flushapp() altogether, leaving us with the version we have today. Since flushing application table entries can and should be done as soon as the netdevice disappears, fundamentally the commit that is to blame is the one that introduced the design of this API. Fixes: 9ab933ab ("dcbnl: add appliction tlv handlers") Signed-off-by:Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: