mac80211: optimise roaming time again
The last fixes re-added the RCU synchronize penalty
on roaming to fix the races. Split up sta_info_flush()
now to get rid of that again, and let managed mode
(and only it) delay the actual destruction.
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 604b4aa..12341ef 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -775,8 +775,10 @@
* This is relevant only in WDS mode, in all other modes we've
* already removed all stations when disconnecting or similar,
* so warn otherwise.
+ *
+ * We call sta_info_flush_cleanup() later, to combine RCU waits.
*/
- flushed = sta_info_flush(sdata);
+ flushed = sta_info_flush_defer(sdata);
WARN_ON_ONCE((sdata->vif.type != NL80211_IFTYPE_WDS && flushed > 0) ||
(sdata->vif.type == NL80211_IFTYPE_WDS && flushed != 1));
@@ -861,11 +863,14 @@
cancel_work_sync(&sdata->work);
/*
* When we get here, the interface is marked down.
- * Call synchronize_rcu() to wait for the RX path
- * should it be using the interface and enqueuing
- * frames at this very time on another CPU.
+ * sta_info_flush_cleanup() calls rcu_barrier to
+ * wait for the station call_rcu() calls to complete,
+ * here we require it to wait for the RX path in case
+ * it is using the interface and enqueuing frames at
+ * this very time on another CPU.
*/
- synchronize_rcu();
+ sta_info_flush_cleanup(sdata);
+
skb_queue_purge(&sdata->skb_queue);
/*