Re: [PATCH 3/6] mac80211: ieee80211_queue_stopped returns reasons

[Johannes Berg <johannes@sipsolutions.net>]

On Mon, 2013-04-08 at 12:57 -0700, Thomas Pedersen wrote:

> > That seems racy? Even asking whether it's stopped is racy though, what
> > are you even trying to accomplish?
> 
> Yeah, that's why I'd like to get the reason the first time.
> 
> _h_mesh_fwding() checks whether the outgoing queue is stopped, to
> avoid piling frames on the pending queue if the outgoing medium is
> busy. I guess the idea was to avoid queueing frames faster than the
> hardware could unload them. Maybe this doesn't actually happen, but we
> can be a little bit smarter about when to drop forwarded frames. Like
> if skbs are just being added to the outgoing queue, we probably
> shouldn't.

Technically I guess that can happen if your inbound link is better than
the outbound one? But it'll depend on the AC parameters etc. too.

However it seems that ieee80211_queue_stopped() is actually kinda broken
and should only return the 'driver-stopped' reason to start with. If you
fix that, it's probably good enough for you. I don't think in patch 4
you should drop frames for scanning, for example.

johannes