mac80211: simplify station/aggregation code

A number of places use RCU locking for accessing
the station list, even though they do not need
to. Use mutex locking instead to prepare for the
locking changes I want to make. The mlme code is
also using a WLAN_STA_DISASSOC flag that has the
same meaning as WLAN_STA_BLOCK_BA, so use that.

While doing so, combine places where we loop
over stations twice, and optimise away some of
the loops by checking if the hardware supports
aggregation at all first.

Also fix a more theoretical race condition: right
now we could resume, set up an aggregation session,
and right after tear it down again due to the code
that is needed for hardware reconfiguration here.
Also mark add a comment to that code marking it as
a workaround.

Finally, remove a pointless aggregation disabling
loop when an interface is stopped, directly after
that we remove all stations from it which will also
disable all aggregation sessions that may still be
active, and does so in a race-free way unlike the
current loop that doesn't block new sessions.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 1 insertions, 9 deletions

diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index d1b6664a253..9b9f21be0ff 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -239,17 +239,9 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 	    sdata->vif.type != NL80211_IFTYPE_AP)
 		return -EINVAL;
 
-	if (test_sta_flags(sta, WLAN_STA_DISASSOC)) {
-#ifdef CONFIG_MAC80211_HT_DEBUG
-		printk(KERN_DEBUG "Disassociation is in progress. "
-		       "Denying BA session request\n");
-#endif
-		return -EINVAL;
-	}
-
 	if (test_sta_flags(sta, WLAN_STA_BLOCK_BA)) {
 #ifdef CONFIG_MAC80211_HT_DEBUG
-		printk(KERN_DEBUG "Suspend in progress. "
+		printk(KERN_DEBUG "BA sessions blocked. "
 		       "Denying BA session request\n");
 #endif
 		return -EINVAL;