On 11 March 2014 14:16, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > On Tue, 2014-03-11 at 08:46 +0100, Michal Kazior wrote: > >> Self-NACK. > > Heh. > >> I totally missed how ieee80211_remove_interfaces() works. It removes >> all interfaces from the list in one go before each is actually >> stopped. This means refcount computes 0. IOW If you unload a driver >> with multiple interfaces running you get a nice general protection >> fault (multiple ieee80211_free_chanctx calls). > > Ok, that seems like a problem :) > >> I'm planning on adding `struct list_head` to sdata and chanctx to be >> able to iterate over assigned (and reserved, in the future) chanctx. >> What do you think? Do you have other ideas? > > I guess that seems reasonable - not sure why you'd want the reserved > one? Some of the maintenance there might be tricky? For multi-vif we need to be able to track list of interfaces that have a reservation. This is needed for example for chandef calculation (e.g. to see if you can start a new vif on given chanctx that is part of a reservation already, etc). It's also necessary so you can synchronize CSA across interfaces with the chanctx reservation that happen "in place" when you're out of max_num_different_channels. In that case you must unassign all interfaces, free chanctx, create new chanctx, and then assign the reservation interfaces. Actually I think there's also one thing that might benefit from chanctx-vif list tracking: ieee80211_recalc_chanctx_chantype(). It seems to complain with WARN_ON splat when I reload driver when more than 1 vif is running because it doesn't find a non-NULL `compat` chandef (rightfully so as local->interfaces is empty at that point due to ieee80211_remove_interfaces). Michał -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
