mac80211: deinitialize ibss-internals after emptiness check

The check whether the IBSS is active and can be removed should be
performed before deinitializing the fields used for the check/search.
Otherwise, the configured BSS will not be found and removed properly.

To make it more clear for the future, rename sdata->u.ibss to the
local pointer ifibss which is used within the checks.

This behaviour was introduced by
f3209bea110cade12e2b133da8b8499689cb0e2e
("mac80211: fix IBSS teardown race")

Cc: stable@vger.kernel.org
Cc: Ignacy Gawedzki <i@lri.fr>
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ibss.c

@@ -1151,10 +1151,6 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
 
 	mutex_lock(&sdata->u.ibss.mtx);
 
-	sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
-	memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
-	sdata->u.ibss.ssid_len = 0;
-
 	active_ibss = ieee80211_sta_active_ibss(sdata);
 
 	if (!active_ibss && !is_zero_ether_addr(ifibss->bssid)) {
@@ -1175,6 +1171,10 @@ int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
 		}
 	}
 
+	ifibss->state = IEEE80211_IBSS_MLME_SEARCH;
+	memset(ifibss->bssid, 0, ETH_ALEN);
+	ifibss->ssid_len = 0;
+
 	sta_info_flush(sdata->local, sdata);
 
 	spin_lock_bh(&ifibss->incomplete_lock);