net/mac80211,rcu: convert call_rcu(work_free_rcu) to kfree_rcu()

The rcu callback work_free_rcu() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(work_free_rcu).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

net/mac80211/work.c

@@ -65,17 +65,9 @@ static void run_again(struct ieee80211_local *local,
 		mod_timer(&local->work_timer, timeout);
 }
 
-static void work_free_rcu(struct rcu_head *head)
-{
-	struct ieee80211_work *wk =
-		container_of(head, struct ieee80211_work, rcu_head);
-
-	kfree(wk);
-}
-
 void free_work(struct ieee80211_work *wk)
 {
-	call_rcu(&wk->rcu_head, work_free_rcu);
+	kfree_rcu(wk, rcu_head);
 }
 
 static int ieee80211_compatible_rates(const u8 *supp_rates, int supp_rates_len,