pkt_sched: No longer destroy qdiscs from RCU.

We can now kill them synchronously with all of the
previous dev_deactivate() cures.

This makes netdev destruction and shutdown saner as
the qdiscs hold references to the device.

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 19 deletions

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 757ab087adbf..84d25f2e6188 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -61,7 +61,6 @@ struct Qdisc
         struct gnet_stats_basic bstats;
         struct gnet_stats_queue qstats;
         struct gnet_stats_rate_est      rate_est;
-        struct rcu_head         q_rcu;
         int                     (*reshape_fail)(struct sk_buff *skb,
                                         struct Qdisc *q);
 
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 30b76aec723b..6f96b7bc0809 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -518,14 +518,19 @@ void qdisc_reset(struct Qdisc *qdisc)
 }
 EXPORT_SYMBOL(qdisc_reset);
 
-/* this is the rcu callback function to clean up a qdisc when there
- * are no further references to it */
+/* Under qdisc_lock(qdisc) and BH! */
 
-static void __qdisc_destroy(struct rcu_head *head)
+void qdisc_destroy(struct Qdisc *qdisc)
 {
-        struct Qdisc *qdisc = container_of(head, struct Qdisc, q_rcu);
         const struct Qdisc_ops  *ops = qdisc->ops;
 
+        if (qdisc->flags & TCQ_F_BUILTIN ||
+            !atomic_dec_and_test(&qdisc->refcnt))
+                return;
+
+        if (qdisc->parent)
+                list_del(&qdisc->list);
+
 #ifdef CONFIG_NET_SCHED
         qdisc_put_stab(qdisc->stab);
 #endif
@@ -542,20 +547,6 @@ static void __qdisc_destroy(struct rcu_head *head)
 
         kfree((char *) qdisc - qdisc->padded);
 }
-
-/* Under qdisc_lock(qdisc) and BH! */
-
-void qdisc_destroy(struct Qdisc *qdisc)
-{
-        if (qdisc->flags & TCQ_F_BUILTIN ||
-            !atomic_dec_and_test(&qdisc->refcnt))
-                return;
-
-        if (qdisc->parent)
-                list_del(&qdisc->list);
-
-        call_rcu(&qdisc->q_rcu, __qdisc_destroy);
-}
 EXPORT_SYMBOL(qdisc_destroy);
 
 static bool dev_all_qdisc_sleeping_noop(struct net_device *dev)