netdev - Re: [REGRESSION] mac80211: IBSS vif queue stopped when started after 11s vif

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Date:   Wed, 29 Mar 2017 13:53:06 +0200
From:   Johannes Berg <johannes@...solutions.net>
To:     Sven Eckelmann <sven.eckelmann@...nmesh.com>
Cc:     linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        Michal Kazior <michal.kazior@...to.com>
Subject: Re: [REGRESSION] mac80211: IBSS vif queue stopped when started
 after 11s vif


>     if (local->ops->wake_tx_queue)
>     		return;
> 
> evaluates to true. The rest rest of the function is therefore always
> skipped for ath9k.

Ahh, yes, ok.

> Removing this is enough to fix the problem. And now you will propably
> say "hey, this is not my code". And this is the reason why I have now
> CC'ed the author of 80a83cfc434b ("mac80211: skip netdev queue
> control with software queuing"). This change in
> ieee80211_propagate_queue_wake is basically breaking 
> the (delayed) startup of the ibss netdev queue [1] when the device
> was offchan during the ieee80211_do_open of the ibss interface.
> 
> Not sure whether removing it in ieee80211_propagate_queue_wake will
> have other odd side effects with software queuing. Maybe Michal
> Kazior can tell us if it is safe to remove it.

No, it's the other way around.

Michal's patches correctly added a test for this to
__ieee80211_stop_queue(), the only missing thing is that this test
should also be in ieee80211_do_open() like this:

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 40813dd3301c..5bb0c5012819 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -718,7 +718,8 @@ int ieee80211_do_open(struct wireless_dev *wdev, bool coming_up)
 	ieee80211_recalc_ps(local);
 
 	if (sdata->vif.type == NL80211_IFTYPE_MONITOR ||
-	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
+	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
+	    local->ops->wake_tx_queue) {
 		/* XXX: for AP_VLAN, actually track AP queues */
 		netif_tx_start_all_queues(dev);
 	} else if (dev) {

johannes