pkt_sched: sch_api: Remove qdisc_list_lock

After implementing qdisc->ops->peek() there is no more calling
qdisc_tree_decrease_qlen() without rtnl_lock(), so qdisc_list_lock
added by commit: f6e0b239a2657ea8cb67f0d83d0bfdbfd19a481b "pkt_sched:
Fix qdisc list locking" can be removed.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 21 deletions

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 1ef25e6ee1f9..3fcfd4ef11d1 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -204,28 +204,16 @@ struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
         return NULL;
 }
 
-/*
- * This lock is needed until some qdiscs stop calling qdisc_tree_decrease_qlen()
- * without rtnl_lock(); currently hfsc_dequeue(), netem_dequeue(), tbf_dequeue()
- */
-static DEFINE_SPINLOCK(qdisc_list_lock);
-
 static void qdisc_list_add(struct Qdisc *q)
 {
-        if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
-                spin_lock_bh(&qdisc_list_lock);
+        if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS))
                 list_add_tail(&q->list, &qdisc_root_sleeping(q)->list);
-                spin_unlock_bh(&qdisc_list_lock);
-        }
 }
 
 void qdisc_list_del(struct Qdisc *q)
 {
-        if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
-                spin_lock_bh(&qdisc_list_lock);
+        if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS))
                 list_del(&q->list);
-                spin_unlock_bh(&qdisc_list_lock);
-        }
 }
 EXPORT_SYMBOL(qdisc_list_del);
 
@@ -234,22 +222,17 @@ struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
         unsigned int i;
         struct Qdisc *q;
 
-        spin_lock_bh(&qdisc_list_lock);
-
         for (i = 0; i < dev->num_tx_queues; i++) {
                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
                 struct Qdisc *txq_root = txq->qdisc_sleeping;
 
                 q = qdisc_match_from_root(txq_root, handle);
                 if (q)
-                        goto unlock;
+                        goto out;
         }
 
         q = qdisc_match_from_root(dev->rx_queue.qdisc_sleeping, handle);
-
-unlock:
-        spin_unlock_bh(&qdisc_list_lock);
-
+out:
         return q;
 }