mac80211: track scheduled scan virtual interface

Instead of tracking whether or not we're in a
scheduled scan, track the virtual interface
(sdata) in an RCU-protected pointer to make it
usable from RX to check the MAC address.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/main.c

@@ -322,7 +322,8 @@ static void ieee80211_restart_work(struct work_struct *work)
 
 	mutex_lock(&local->mtx);
 	WARN(test_bit(SCAN_HW_SCANNING, &local->scanning) ||
-	     local->sched_scanning,
+	     rcu_dereference_protected(local->sched_scan_sdata,
+				       lockdep_is_held(&local->mtx)),
 		"%s called with hardware scan in progress\n", __func__);
 	mutex_unlock(&local->mtx);