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>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index a470e1123a55..c88f161f8118 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -287,6 +287,7 @@ struct sta_ampdu_mlme {
 struct sta_info {
         /* General information, mostly static */
         struct list_head list;
+        struct rcu_head rcu_head;
         struct sta_info __rcu *hnext;
         struct ieee80211_local *local;
         struct ieee80211_sub_if_data *sdata;
@@ -297,6 +298,7 @@ struct sta_info {
         spinlock_t lock;
 
         struct work_struct drv_unblock_wk;
+        struct work_struct free_sta_wk;
 
         u16 listen_interval;