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authorDavid S. Miller <davem@davemloft.net>2008-08-18 21:03:15 -0700
committerDavid S. Miller <davem@davemloft.net>2008-08-18 21:06:19 -0700
commit4d8863a29c4755a0461cd31b6865026187d6c43a (patch)
tree502b355314b1ff2e6cef52bf3778aba3bdae80cd
parent25bfcd5a78a377ea4c54a3c21e44590e2fc478a6 (diff)
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 <davem@davemloft.net>
-rw-r--r--net/sched/sch_api.c13
-rw-r--r--net/sched/sch_generic.c6
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);
}
}

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