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authorJarek Poplawski <jarkao2@gmail.com>2008-08-22 06:24:05 -0400
committerDavid S. Miller <davem@davemloft.net>2008-08-22 06:31:39 -0400
commitf6e0b239a2657ea8cb67f0d83d0bfdbfd19a481b (patch)
tree9d6e3c97a81869fde3958cdbcf431ee3739f9b2c /net/sched
parent2540e0511ea17e25831be543cdf9381e6209950d (diff)
pkt_sched: Fix qdisc list locking
Since some qdiscs call qdisc_tree_decrease_qlen() (so qdisc_lookup()) without rtnl_lock(), adding and deleting from a qdisc list needs additional locking. This patch adds global spinlock qdisc_list_lock and wrapper functions for modifying the list. It is considered as a temporary solution until hfsc_dequeue(), netem_dequeue() and tbf_dequeue() (or qdisc_tree_decrease_qlen()) are redone. With feedback from Herbert Xu and David S. Miller. Signed-off-by: Jarek Poplawski <jarkao2@gmail.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
-rw-r--r--net/sched/sch_api.c44
-rw-r--r--net/sched/sch_generic.c5
2 files changed, 41 insertions, 8 deletions
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 45f442d7de47..e7fb9e0d21b4 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -199,19 +199,53 @@ struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
199 return NULL; 199 return NULL;
200} 200}
201 201
202/*
203 * This lock is needed until some qdiscs stop calling qdisc_tree_decrease_qlen()
204 * without rtnl_lock(); currently hfsc_dequeue(), netem_dequeue(), tbf_dequeue()
205 */
206static DEFINE_SPINLOCK(qdisc_list_lock);
207
208static void qdisc_list_add(struct Qdisc *q)
209{
210 if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
211 spin_lock_bh(&qdisc_list_lock);
212 list_add_tail(&q->list, &qdisc_root_sleeping(q)->list);
213 spin_unlock_bh(&qdisc_list_lock);
214 }
215}
216
217void qdisc_list_del(struct Qdisc *q)
218{
219 if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
220 spin_lock_bh(&qdisc_list_lock);
221 list_del(&q->list);
222 spin_unlock_bh(&qdisc_list_lock);
223 }
224}
225EXPORT_SYMBOL(qdisc_list_del);
226
202struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle) 227struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
203{ 228{
204 unsigned int i; 229 unsigned int i;
230 struct Qdisc *q;
231
232 spin_lock_bh(&qdisc_list_lock);
205 233
206 for (i = 0; i < dev->num_tx_queues; i++) { 234 for (i = 0; i < dev->num_tx_queues; i++) {
207 struct netdev_queue *txq = netdev_get_tx_queue(dev, i); 235 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
208 struct Qdisc *q, *txq_root = txq->qdisc_sleeping; 236 struct Qdisc *txq_root = txq->qdisc_sleeping;
209 237
210 q = qdisc_match_from_root(txq_root, handle); 238 q = qdisc_match_from_root(txq_root, handle);
211 if (q) 239 if (q)
212 return q; 240 goto unlock;
213 } 241 }
214 return qdisc_match_from_root(dev->rx_queue.qdisc_sleeping, handle); 242
243 q = qdisc_match_from_root(dev->rx_queue.qdisc_sleeping, handle);
244
245unlock:
246 spin_unlock_bh(&qdisc_list_lock);
247
248 return q;
215} 249}
216 250
217static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid) 251static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
@@ -810,8 +844,8 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
810 goto err_out3; 844 goto err_out3;
811 } 845 }
812 } 846 }
813 if ((parent != TC_H_ROOT) && !(sch->flags & TCQ_F_INGRESS)) 847
814 list_add_tail(&sch->list, &dev_queue->qdisc_sleeping->list); 848 qdisc_list_add(sch);
815 849
816 return sch; 850 return sch;
817 } 851 }
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index c3ed4d44fc14..5f0ade7806a7 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -526,10 +526,9 @@ void qdisc_destroy(struct Qdisc *qdisc)
526 !atomic_dec_and_test(&qdisc->refcnt)) 526 !atomic_dec_and_test(&qdisc->refcnt))
527 return; 527 return;
528 528
529 if (qdisc->parent)
530 list_del(&qdisc->list);
531
532#ifdef CONFIG_NET_SCHED 529#ifdef CONFIG_NET_SCHED
530 qdisc_list_del(qdisc);
531
533 qdisc_put_stab(qdisc->stab); 532 qdisc_put_stab(qdisc->stab);
534#endif 533#endif
535 gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est); 534 gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);