mac80211: only cancel software-based scans on suspend

Otherwise the hardware scan handler could access an invalid scan request
structure.  The driver should cancel any pending hardware scans during
the suspend process anyway, so also add a warning if the hardware scan
is still pending when the device resumes.

Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/ieee80211_i.h

@@ -1186,6 +1186,12 @@ int __ieee80211_suspend(struct ieee80211_hw *hw);
 
 static inline int __ieee80211_resume(struct ieee80211_hw *hw)
 {
+	struct ieee80211_local *local = hw_to_local(hw);
+
+	WARN(test_bit(SCAN_HW_SCANNING, &local->scanning),
+		"%s: resume with hardware scan still in progress\n",
+		wiphy_name(hw->wiphy));
+
 	return ieee80211_reconfig(hw_to_local(hw));
 }
 #else

net/mac80211/pm.c

@@ -12,7 +12,8 @@ int __ieee80211_suspend(struct ieee80211_hw *hw)
 	struct ieee80211_sub_if_data *sdata;
 	struct sta_info *sta;
 
-	ieee80211_scan_cancel(local);
+	if (unlikely(test_bit(SCAN_SW_SCANNING, &local->scanning)))
+		ieee80211_scan_cancel(local);
 
 	ieee80211_stop_queues_by_reason(hw,
 			IEEE80211_QUEUE_STOP_REASON_SUSPEND);