diff options
| author | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-19 11:54:39 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-19 11:54:39 -0700 |
| commit | 804b908adfcffe3831621acb6c8a776585983d2a (patch) | |
| tree | 9664d4395ae8e590e50c568225ea88435383ed99 /net/sched/sch_generic.c | |
| parent | 1b3e4c706c19dec10b11dac1b23071e3e4b262ad (diff) | |
| parent | ce0e32e65f70337e0732c97499b643205fa8ea31 (diff) | |
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
* 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6:
[NET]: Fix possible dev_deactivate race condition
[INET]: Justification for local port range robustness.
[PACKET]: Kill unused pg_vec_endpage() function
[NET]: QoS/Sched as menuconfig
[NET]: Fix bug in sk_filter race cures.
[PATCH] mac80211: make ieee802_11_parse_elems return void
Diffstat (limited to 'net/sched/sch_generic.c')
| -rw-r--r-- | net/sched/sch_generic.c | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index e01d57692c9..fa1a6f45dc4 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -556,6 +556,7 @@ void dev_deactivate(struct net_device *dev) { struct Qdisc *qdisc; struct sk_buff *skb; + int running; spin_lock_bh(&dev->queue_lock); qdisc = dev->qdisc; @@ -571,12 +572,31 @@ void dev_deactivate(struct net_device *dev) dev_watchdog_down(dev); - /* Wait for outstanding dev_queue_xmit calls. */ + /* Wait for outstanding qdisc-less dev_queue_xmit calls. */ synchronize_rcu(); /* Wait for outstanding qdisc_run calls. */ - while (test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state)) - yield(); + do { + while (test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state)) + yield(); + + /* + * Double-check inside queue lock to ensure that all effects + * of the queue run are visible when we return. + */ + spin_lock_bh(&dev->queue_lock); + running = test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state); + spin_unlock_bh(&dev->queue_lock); + + /* + * The running flag should never be set at this point because + * we've already set dev->qdisc to noop_qdisc *inside* the same + * pair of spin locks. That is, if any qdisc_run starts after + * our initial test it should see the noop_qdisc and then + * clear the RUNNING bit before dropping the queue lock. So + * if it is set here then we've found a bug. + */ + } while (WARN_ON_ONCE(running)); } void dev_init_scheduler(struct net_device *dev) |