mac80211: enable IEEE80211_CONF_PS only when associated

Also disable power save when disassociated. It makes no sense to have
power save enabled while disassociated.

iwlwifi seems to have this check in the driver, but it's better to do this
in mac80211 instead.

Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/wext.c b/net/mac80211/wext.c
index 1542804..f6640d0 100644
--- a/net/mac80211/wext.c
+++ b/net/mac80211/wext.c
@@ -830,25 +830,46 @@
 				    struct iw_param *wrq,
 				    char *extra)
 {
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 	struct ieee80211_conf *conf = &local->hw.conf;
+	int ret = 0;
+	bool ps;
+
+	if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		return -EINVAL;
 
 	if (wrq->disabled) {
-		conf->flags &= ~IEEE80211_CONF_PS;
-		return ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+		ps = false;
+		goto set;
 	}
 
 	switch (wrq->flags & IW_POWER_MODE) {
 	case IW_POWER_ON:       /* If not specified */
 	case IW_POWER_MODE:     /* If set all mask */
 	case IW_POWER_ALL_R:    /* If explicitely state all */
-		conf->flags |= IEEE80211_CONF_PS;
+		ps = true;
 		break;
 	default:                /* Otherwise we don't support it */
 		return -EINVAL;
 	}
 
-	return ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+	if (ps == local->powersave)
+		return ret;
+
+set:
+	local->powersave = ps;
+
+	if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) {
+		if (local->powersave)
+			conf->flags |= IEEE80211_CONF_PS;
+		else
+			conf->flags &= ~IEEE80211_CONF_PS;
+
+		ret = ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+	}
+
+	return ret;
 }
 
 static int ieee80211_ioctl_giwpower(struct net_device *dev,
@@ -857,9 +878,8 @@
 				    char *extra)
 {
 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
-	struct ieee80211_conf *conf = &local->hw.conf;
 
-	wrqu->power.disabled = !(conf->flags & IEEE80211_CONF_PS);
+	wrqu->power.disabled = !local->powersave;
 
 	return 0;
 }