mac80211: split ieee80211_key_alloc/free

In order to RCU-ify sta_info, we need to be able to allocate
a key without linking it to an sdata/sta structure (because
allocation cannot be done in an rcu critical section). This
patch splits up ieee80211_key_alloc() and updates all users
appropriately.

While at it, this patch fixes a number of race conditions
such as finally making key replacement atomic, unfortunately
at the expense of more complex code.

Note that this patch documents /existing/ bugs with sta info
and key interaction, there is currently a race condition
when a sta info is freed without holding the RTNL. This will
finally be fixed by a followup patch.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index c6c0df4bbd2c..e384e6632d97 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -312,7 +312,7 @@ void sta_info_free(struct sta_info *sta)
 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
 
         ieee80211_key_free(sta->key);
-        sta->key = NULL;
+        WARN_ON(sta->key);
 
         if (local->ops->sta_notify) {
                 struct ieee80211_sub_if_data *sdata;