mac80211: use call_rcu() on sta deletion
mac80211 calls synchronize_rcu() on sta deletion,
which increase the roaming time significantly.
Convert it into a call_rcu() mechanism, in order
to avoid blocking. Since some of the cleanup
functions might sleep, schedule from the call_rcu
callback a new work that will do the actual cleanup.
In order to make sure the cleanup occurs before
the interface went down, flush local->workqueue
on ieee80211_do_stop().
Signed-off-by: Yoni Divinsky <yoni.divinsky@ti.com>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index d747da5..6f8a73c 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -793,11 +793,20 @@
flush_work(&sdata->work);
/*
* When we get here, the interface is marked down.
- * Call synchronize_rcu() to wait for the RX path
+ * Call rcu_barrier() to wait both for the RX path
* should it be using the interface and enqueuing
- * frames at this very time on another CPU.
+ * frames at this very time on another CPU, and
+ * for the sta free call_rcu callbacks.
*/
- synchronize_rcu();
+ rcu_barrier();
+
+ /*
+ * free_sta_rcu() enqueues a work for the actual
+ * sta cleanup, so we need to flush it while
+ * sdata is still valid.
+ */
+ flush_workqueue(local->workqueue);
+
skb_queue_purge(&sdata->skb_queue);
/*