From 5fb662297b8a4bdadd60371c34b760efca948ebc Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Sat, 2 Aug 2008 20:02:43 -0700 Subject: pkt_sched: Use qdisc_lock() on already sampled root qdisc. Based upon a bug report by Jeff Kirsher. Don't use qdisc_root_lock() in these cases as the root qdisc could have been changed, and we'd thus lock the wrong object. Tested by Emil S Tantilov who confirms that this seems to fix the problem. Signed-off-by: David S. Miller --- net/sched/sch_generic.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'net/sched/sch_generic.c') diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 9c9cd4d94890..7cf83b37459d 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -29,7 +29,7 @@ /* Main transmission queue. */ /* Modifications to data participating in scheduling must be protected with - * qdisc_root_lock(qdisc) spinlock. + * qdisc_lock(qdisc) spinlock. * * The idea is the following: * - enqueue, dequeue are serialized via qdisc root lock @@ -126,7 +126,7 @@ static inline int qdisc_restart(struct Qdisc *q) if (unlikely((skb = dequeue_skb(q)) == NULL)) return 0; - root_lock = qdisc_root_lock(q); + root_lock = qdisc_lock(q); /* And release qdisc */ spin_unlock(root_lock); @@ -507,7 +507,7 @@ errout: } EXPORT_SYMBOL(qdisc_create_dflt); -/* Under qdisc_root_lock(qdisc) and BH! */ +/* Under qdisc_lock(qdisc) and BH! */ void qdisc_reset(struct Qdisc *qdisc) { @@ -543,7 +543,7 @@ static void __qdisc_destroy(struct rcu_head *head) kfree((char *) qdisc - qdisc->padded); } -/* Under qdisc_root_lock(qdisc) and BH! */ +/* Under qdisc_lock(qdisc) and BH! */ void qdisc_destroy(struct Qdisc *qdisc) { @@ -659,7 +659,7 @@ static bool some_qdisc_is_running(struct net_device *dev, int lock) dev_queue = netdev_get_tx_queue(dev, i); q = dev_queue->qdisc; - root_lock = qdisc_root_lock(q); + root_lock = qdisc_lock(q); if (lock) spin_lock_bh(root_lock); @@ -735,7 +735,7 @@ static void shutdown_scheduler_queue(struct net_device *dev, struct Qdisc *qdisc_default = _qdisc_default; if (qdisc) { - spinlock_t *root_lock = qdisc_root_lock(qdisc); + spinlock_t *root_lock = qdisc_lock(qdisc); dev_queue->qdisc = qdisc_default; dev_queue->qdisc_sleeping = qdisc_default; -- cgit v1.2.3