From 10cf6595ebba3ea12233b7ff459fa68798d7ff21 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Tue, 3 Aug 2004 19:23:36 -0700 Subject: [PATCH] [PKT_SCHED]: Fix locking in __qdisc_destroy rcu-callback Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/sched/sch_api.c | 10 +++++----- net/sched/sch_generic.c | 24 ++++++++++++------------ 2 files changed, 17 insertions(+), 17 deletions(-) diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 6498c34c54947..5d601c2cf4818 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -812,18 +812,18 @@ static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb) continue; if (idx > s_idx) s_q_idx = 0; - read_lock(&qdisc_tree_lock); + read_lock_bh(&qdisc_tree_lock); for (q = dev->qdisc_list, q_idx = 0; q; q = q->next, q_idx++) { if (q_idx < s_q_idx) continue; if (tc_fill_qdisc(skb, q, 0, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWQDISC) <= 0) { - read_unlock(&qdisc_tree_lock); + read_unlock_bh(&qdisc_tree_lock); goto done; } } - read_unlock(&qdisc_tree_lock); + read_unlock_bh(&qdisc_tree_lock); } done: @@ -1033,7 +1033,7 @@ static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb) s_t = cb->args[0]; - read_lock(&qdisc_tree_lock); + read_lock_bh(&qdisc_tree_lock); for (q=dev->qdisc_list, t=0; q; q = q->next, t++) { if (t < s_t) continue; if (!q->ops->cl_ops) continue; @@ -1052,7 +1052,7 @@ static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb) if (arg.w.stop) break; } - read_unlock(&qdisc_tree_lock); + read_unlock_bh(&qdisc_tree_lock); cb->args[0] = t; diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index ece985b6dc25e..34c75b5020b2c 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -45,10 +45,11 @@ The idea is the following: - enqueue, dequeue are serialized via top level device spinlock dev->queue_lock. - - tree walking is protected by read_lock(qdisc_tree_lock) + - tree walking is protected by read_lock_bh(qdisc_tree_lock) and this lock is used only in process context. - - updates to tree are made only under rtnl semaphore, - hence this lock may be made without local bh disabling. + - updates to tree are made under rtnl semaphore or + from softirq context (__qdisc_destroy rcu-callback) + hence this lock needs local bh disabling. qdisc_tree_lock must be grabbed BEFORE dev->queue_lock! */ @@ -56,14 +57,14 @@ rwlock_t qdisc_tree_lock = RW_LOCK_UNLOCKED; void qdisc_lock_tree(struct net_device *dev) { - write_lock(&qdisc_tree_lock); + write_lock_bh(&qdisc_tree_lock); spin_lock_bh(&dev->queue_lock); } void qdisc_unlock_tree(struct net_device *dev) { spin_unlock_bh(&dev->queue_lock); - write_unlock(&qdisc_tree_lock); + write_unlock_bh(&qdisc_tree_lock); } /* @@ -431,10 +432,12 @@ static void __qdisc_destroy(struct rcu_head *head) #ifdef CONFIG_NET_ESTIMATOR qdisc_kill_estimator(&qdisc->stats); #endif + write_lock(&qdisc_tree_lock); if (ops->reset) ops->reset(qdisc); if (ops->destroy) ops->destroy(qdisc); + write_unlock(&qdisc_tree_lock); module_put(ops->owner); if (!(qdisc->flags&TCQ_F_BUILTIN)) @@ -459,12 +462,9 @@ void qdisc_destroy(struct Qdisc *qdisc) } } } - call_rcu(&qdisc->q_rcu, __qdisc_destroy); - } - void dev_activate(struct net_device *dev) { /* No queueing discipline is attached to device; @@ -482,17 +482,17 @@ void dev_activate(struct net_device *dev) return; } - write_lock(&qdisc_tree_lock); + write_lock_bh(&qdisc_tree_lock); qdisc->next = dev->qdisc_list; dev->qdisc_list = qdisc; - write_unlock(&qdisc_tree_lock); + write_unlock_bh(&qdisc_tree_lock); } else { qdisc = &noqueue_qdisc; } - write_lock(&qdisc_tree_lock); + write_lock_bh(&qdisc_tree_lock); dev->qdisc_sleeping = qdisc; - write_unlock(&qdisc_tree_lock); + write_unlock_bh(&qdisc_tree_lock); } spin_lock_bh(&dev->queue_lock); -- 2.53.0