mac80211: don't call bss_info_changed on p2p-device/monitor

Since the idle decision rework, mac80211 started calling
bss_info_changed() for the driver's monitor interface,
which causes a crash for iwlwifi, but drivers generally
don't expect this to happen. Therefore, avoid it.

While at it, also prevent calling it in such cases and
only print a warning. For the P2P Device interface the
idle will no longer be called (no channel context), so
also prevent that and warn on it.
Reported-by: Chaitanya <chaitanya.mgit@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/chan.c

@@ -137,7 +137,10 @@ static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
 
 	ieee80211_recalc_txpower(sdata);
 	sdata->vif.bss_conf.idle = false;
-	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
+
+	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
+	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
+		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
 
 	return 0;
 }
@@ -186,7 +189,10 @@ static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
 	rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
 
 	sdata->vif.bss_conf.idle = true;
-	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
+
+	if (sdata->vif.type != NL80211_IFTYPE_P2P_DEVICE &&
+	    sdata->vif.type != NL80211_IFTYPE_MONITOR)
+		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IDLE);
 
 	drv_unassign_vif_chanctx(local, sdata, ctx);
 

net/mac80211/driver-ops.h

@@ -207,13 +207,16 @@ static inline void drv_bss_info_changed(struct ieee80211_local *local,
 {
 	might_sleep();
 
-	WARN_ON_ONCE(changed & (BSS_CHANGED_BEACON |
-				BSS_CHANGED_BEACON_ENABLED) &&
-		     sdata->vif.type != NL80211_IFTYPE_AP &&
-		     sdata->vif.type != NL80211_IFTYPE_ADHOC &&
-		     sdata->vif.type != NL80211_IFTYPE_MESH_POINT);
-	WARN_ON_ONCE(sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE &&
-		     changed & ~BSS_CHANGED_IDLE);
+	if (WARN_ON_ONCE(changed & (BSS_CHANGED_BEACON |
+				    BSS_CHANGED_BEACON_ENABLED) &&
+			 sdata->vif.type != NL80211_IFTYPE_AP &&
+			 sdata->vif.type != NL80211_IFTYPE_ADHOC &&
+			 sdata->vif.type != NL80211_IFTYPE_MESH_POINT))
+		return;
+
+	if (WARN_ON_ONCE(sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE ||
+			 sdata->vif.type == NL80211_IFTYPE_MONITOR))
+		return;
 
 	check_sdata_in_driver(sdata);