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[PATCH] mac80211: fix virtual interface locking

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Florian Lohoff noticed a bug in mac80211: when bringing the
master interface down while other virtual interfaces are up
we call dev_close() under a spinlock which is not allowed.
This patch removes the sub_if_lock used by mac80211 in favour
of using an RCU list. All list manipulations are already done
under rtnl so are well protected against each other, and the
read-side locks we took in the RX and TX code are already in
RCU read-side critical sections.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Florian Lohoff <flo@rfc822.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Cc: Satyam Sharma <satyam@infradead.org>
Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg
2007-09-18 17:29:21 -04:00
committed by David S. Miller
parent ea49c359f3
commit 79010420cc
6 changed files with 58 additions and 65 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
net/mac80211/ieee80211_iface.c
View File

@@ -79,16 +79,15 @@ int ieee80211_if_add(struct net_device *dev, const char *name,
ieee80211_debugfs_add_netdev(sdata);
ieee80211_if_set_type(ndev, type);
write_lock_bh(&local->sub_if_lock);
/* we're under RTNL so all this is fine */
if (unlikely(local->reg_state == IEEE80211_DEV_UNREGISTERED)) {
write_unlock_bh(&local->sub_if_lock);
__ieee80211_if_del(local, sdata);
return -ENODEV;
}
list_add(&sdata->list, &local->sub_if_list);
list_add_tail_rcu(&sdata->list, &local->interfaces);
if (new_dev)
*new_dev = ndev;
write_unlock_bh(&local->sub_if_lock);
return 0;
@@ -226,22 +225,22 @@ void ieee80211_if_reinit(struct net_device *dev)
/* Remove all virtual interfaces that use this BSS
* as their sdata->bss */
struct ieee80211_sub_if_data *tsdata, *n;
LIST_HEAD(tmp_list);
write_lock_bh(&local->sub_if_lock);
list_for_each_entry_safe(tsdata, n, &local->sub_if_list, list) {
list_for_each_entry_safe(tsdata, n, &local->interfaces, list) {
if (tsdata != sdata && tsdata->bss == &sdata->u.ap) {
printk(KERN_DEBUG "%s: removing virtual "
"interface %s because its BSS interface"
" is being removed\n",
sdata->dev->name, tsdata->dev->name);
list_move_tail(&tsdata->list, &tmp_list);
list_del_rcu(&tsdata->list);
/*
* We have lots of time and can afford
* to sync for each interface
*/
synchronize_rcu();
__ieee80211_if_del(local, tsdata);
}
}
write_unlock_bh(&local->sub_if_lock);
list_for_each_entry_safe(tsdata, n, &tmp_list, list)
__ieee80211_if_del(local, tsdata);
kfree(sdata->u.ap.beacon_head);
kfree(sdata->u.ap.beacon_tail);
@@ -318,18 +317,16 @@ int ieee80211_if_remove(struct net_device *dev, const char *name, int id)
ASSERT_RTNL();
write_lock_bh(&local->sub_if_lock);
list_for_each_entry_safe(sdata, n, &local->sub_if_list, list) {
list_for_each_entry_safe(sdata, n, &local->interfaces, list) {
if ((sdata->type == id || id == -1) &&
strcmp(name, sdata->dev->name) == 0 &&
sdata->dev != local->mdev) {
list_del(&sdata->list);
write_unlock_bh(&local->sub_if_lock);
list_del_rcu(&sdata->list);
synchronize_rcu();
__ieee80211_if_del(local, sdata);
return 0;
}
}
write_unlock_bh(&local->sub_if_lock);
return -ENODEV;
}