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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

9
net/mac80211/rx.c
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@@ -1383,8 +1383,9 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
}
/*
* key references are protected using RCU and this requires that
* we are in a read-site RCU section during receive processing
* key references and virtual interfaces are protected using RCU
* and this requires that we are in a read-side RCU section during
* receive processing
*/
rcu_read_lock();
@@ -1439,8 +1440,7 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
bssid = ieee80211_get_bssid(hdr, skb->len - radiotap_len);
read_lock(&local->sub_if_lock);
list_for_each_entry(sdata, &local->sub_if_list, list) {
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
rx.flags |= IEEE80211_TXRXD_RXRA_MATCH;
if (!netif_running(sdata->dev))
@@ -1493,7 +1493,6 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
&rx, sta);
} else
dev_kfree_skb(skb);
read_unlock(&local->sub_if_lock);
end:
rcu_read_unlock();