From 4d8863a29c4755a0461cd31b6865026187d6c43a Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 18 Aug 2008 21:03:15 -0700 Subject: [PATCH] pkt_sched: Don't hold qdisc lock over qdisc_destroy(). Based upon reports by Denys Fedoryshchenko, and feedback and help from Jarek Poplawski and Herbert Xu. We always either: 1) Never made an external reference to this qdisc. or 2) Did a dev_deactivate() which purged all asynchronous references. So do not lock the qdisc when we call qdisc_destroy(), it's illegal anyways as when we drop the lock this is free'd memory. Signed-off-by: David S. Miller --- net/sched/sch_api.c | 13 ++----------- net/sched/sch_generic.c | 6 ------ 2 files changed, 2 insertions(+), 17 deletions(-) diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 7d7070b1eebd..d91a2338877c 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -638,11 +638,8 @@ static void notify_and_destroy(struct sk_buff *skb, struct nlmsghdr *n, u32 clid if (new || old) qdisc_notify(skb, n, clid, old, new); - if (old) { - sch_tree_lock(old); + if (old) qdisc_destroy(old); - sch_tree_unlock(old); - } } /* Graft qdisc "new" to class "classid" of qdisc "parent" or @@ -1092,16 +1089,10 @@ create_n_graft: graft: if (1) { - spinlock_t *root_lock; - err = qdisc_graft(dev, p, skb, n, clid, q, NULL); if (err) { - if (q) { - root_lock = qdisc_root_lock(q); - spin_lock_bh(root_lock); + if (q) qdisc_destroy(q); - spin_unlock_bh(root_lock); - } return err; } } diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 6f96b7bc0809..c3ed4d44fc14 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -518,8 +518,6 @@ void qdisc_reset(struct Qdisc *qdisc) } EXPORT_SYMBOL(qdisc_reset); -/* Under qdisc_lock(qdisc) and BH! */ - void qdisc_destroy(struct Qdisc *qdisc) { const struct Qdisc_ops *ops = qdisc->ops; @@ -712,14 +710,10 @@ static void shutdown_scheduler_queue(struct net_device *dev, struct Qdisc *qdisc_default = _qdisc_default; if (qdisc) { - spinlock_t *root_lock = qdisc_lock(qdisc); - dev_queue->qdisc = qdisc_default; dev_queue->qdisc_sleeping = qdisc_default; - spin_lock_bh(root_lock); qdisc_destroy(qdisc); - spin_unlock_bh(root_lock); } }