mac80211: improve powersave implementation

When you have multiple virtual interfaces the current
implementation requires setting them up properly from
userspace, which is undesirable when we want to default
to power save mode. Keep track of powersave requested
from userspace per managed mode interface, and only
enable powersave globally when exactly one managed mode
interface is active and has powersave turned on.

Second, only start the dynPS timer when PS is turned
on, and properly turn it off when PS is turned off.

Third, fix the scan_sdata abuse in the dynps code.

Finally, also reorder the code and refactor the code
that enables PS or the dynps timer instead of having
it copied in two places.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 142 insertions, 86 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 90267afa8e69..06d9a1d23252 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -446,6 +446,145 @@ void ieee80211_send_pspoll(struct ieee80211_local *local,
 	ieee80211_tx_skb(sdata, skb, 0);
 }
 
+void ieee80211_send_nullfunc(struct ieee80211_local *local,
+			     struct ieee80211_sub_if_data *sdata,
+			     int powersave)
+{
+	struct sk_buff *skb;
+	struct ieee80211_hdr *nullfunc;
+	__le16 fc;
+
+	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_STATION))
+		return;
+
+	skb = dev_alloc_skb(local->hw.extra_tx_headroom + 24);
+	if (!skb) {
+		printk(KERN_DEBUG "%s: failed to allocate buffer for nullfunc "
+		       "frame\n", sdata->dev->name);
+		return;
+	}
+	skb_reserve(skb, local->hw.extra_tx_headroom);
+
+	nullfunc = (struct ieee80211_hdr *) skb_put(skb, 24);
+	memset(nullfunc, 0, 24);
+	fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_NULLFUNC |
+			 IEEE80211_FCTL_TODS);
+	if (powersave)
+		fc |= cpu_to_le16(IEEE80211_FCTL_PM);
+	nullfunc->frame_control = fc;
+	memcpy(nullfunc->addr1, sdata->u.mgd.bssid, ETH_ALEN);
+	memcpy(nullfunc->addr2, sdata->dev->dev_addr, ETH_ALEN);
+	memcpy(nullfunc->addr3, sdata->u.mgd.bssid, ETH_ALEN);
+
+	ieee80211_tx_skb(sdata, skb, 0);
+}
+
+/* powersave */
+static void ieee80211_enable_ps(struct ieee80211_local *local,
+				struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_conf *conf = &local->hw.conf;
+
+	if (conf->dynamic_ps_timeout > 0 &&
+	    !(local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS)) {
+		mod_timer(&local->dynamic_ps_timer, jiffies +
+			  msecs_to_jiffies(conf->dynamic_ps_timeout));
+	} else {
+		if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
+			ieee80211_send_nullfunc(local, sdata, 1);
+		conf->flags |= IEEE80211_CONF_PS;
+		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+	}
+}
+
+static void ieee80211_change_ps(struct ieee80211_local *local)
+{
+	struct ieee80211_conf *conf = &local->hw.conf;
+
+	if (local->ps_sdata) {
+		if (!(local->ps_sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED))
+			return;
+
+		ieee80211_enable_ps(local, local->ps_sdata);
+	} else if (conf->flags & IEEE80211_CONF_PS) {
+		conf->flags &= ~IEEE80211_CONF_PS;
+		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+		del_timer_sync(&local->dynamic_ps_timer);
+		cancel_work_sync(&local->dynamic_ps_enable_work);
+	}
+}
+
+/* need to hold RTNL or interface lock */
+void ieee80211_recalc_ps(struct ieee80211_local *local)
+{
+	struct ieee80211_sub_if_data *sdata, *found = NULL;
+	int count = 0;
+
+	if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_PS)) {
+		local->ps_sdata = NULL;
+		return;
+	}
+
+	list_for_each_entry(sdata, &local->interfaces, list) {
+		if (!netif_running(sdata->dev))
+			continue;
+		if (sdata->vif.type != NL80211_IFTYPE_STATION)
+			continue;
+		found = sdata;
+		count++;
+	}
+
+	if (count == 1 && found->u.mgd.powersave)
+		local->ps_sdata = found;
+	else
+		local->ps_sdata = NULL;
+
+	ieee80211_change_ps(local);
+}
+
+void ieee80211_dynamic_ps_disable_work(struct work_struct *work)
+{
+	struct ieee80211_local *local =
+		container_of(work, struct ieee80211_local,
+			     dynamic_ps_disable_work);
+
+	if (local->hw.conf.flags & IEEE80211_CONF_PS) {
+		local->hw.conf.flags &= ~IEEE80211_CONF_PS;
+		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+	}
+
+	ieee80211_wake_queues_by_reason(&local->hw,
+					IEEE80211_QUEUE_STOP_REASON_PS);
+}
+
+void ieee80211_dynamic_ps_enable_work(struct work_struct *work)
+{
+	struct ieee80211_local *local =
+		container_of(work, struct ieee80211_local,
+			     dynamic_ps_enable_work);
+	struct ieee80211_sub_if_data *sdata = local->ps_sdata;
+
+	/* can only happen when PS was just disabled anyway */
+	if (!sdata)
+		return;
+
+	if (local->hw.conf.flags & IEEE80211_CONF_PS)
+		return;
+
+	if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
+		ieee80211_send_nullfunc(local, sdata, 1);
+
+	local->hw.conf.flags |= IEEE80211_CONF_PS;
+	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+}
+
+void ieee80211_dynamic_ps_timer(unsigned long data)
+{
+	struct ieee80211_local *local = (void *) data;
+
+	queue_work(local->hw.workqueue, &local->dynamic_ps_enable_work);
+}
+
 /* MLME */
 static void ieee80211_sta_wmm_params(struct ieee80211_local *local,
 				     struct ieee80211_if_managed *ifmgd,
@@ -721,19 +860,9 @@ static void ieee80211_set_associated(struct ieee80211_sub_if_data *sdata,
 	bss_info_changed |= BSS_CHANGED_BASIC_RATES;
 	ieee80211_bss_info_change_notify(sdata, bss_info_changed);
 
-	if (local->powersave) {
-		if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_DYNAMIC_PS) &&
-		    local->hw.conf.dynamic_ps_timeout > 0) {
-			mod_timer(&local->dynamic_ps_timer, jiffies +
-				  msecs_to_jiffies(
-					local->hw.conf.dynamic_ps_timeout));
-		} else {
-			if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)
-				ieee80211_send_nullfunc(local, sdata, 1);
-			conf->flags |= IEEE80211_CONF_PS;
-			ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
-		}
-	}
+	/* will be same as sdata */
+	if (local->ps_sdata)
+		ieee80211_enable_ps(local, sdata);
 
 	netif_tx_start_all_queues(sdata->dev);
 	netif_carrier_on(sdata->dev);
@@ -2195,76 +2324,3 @@ void ieee80211_mlme_notify_scan_completed(struct ieee80211_local *local)
 		ieee80211_restart_sta_timer(sdata);
 	rcu_read_unlock();
 }
-
-void ieee80211_dynamic_ps_disable_work(struct work_struct *work)
-{
-	struct ieee80211_local *local =
-		container_of(work, struct ieee80211_local,
-			     dynamic_ps_disable_work);
-
-	if (local->hw.conf.flags & IEEE80211_CONF_PS) {
-		local->hw.conf.flags &= ~IEEE80211_CONF_PS;
-		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
-	}
-
-	ieee80211_wake_queues_by_reason(&local->hw,
-					IEEE80211_QUEUE_STOP_REASON_PS);
-}
-
-void ieee80211_dynamic_ps_enable_work(struct work_struct *work)
-{
-	struct ieee80211_local *local =
-		container_of(work, struct ieee80211_local,
-			     dynamic_ps_enable_work);
-	/* XXX: using scan_sdata is completely broken! */
-	struct ieee80211_sub_if_data *sdata = local->scan_sdata;
-
-	if (local->hw.conf.flags & IEEE80211_CONF_PS)
-		return;
-
-	if (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK && sdata)
-		ieee80211_send_nullfunc(local, sdata, 1);
-
-	local->hw.conf.flags |= IEEE80211_CONF_PS;
-	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
-}
-
-void ieee80211_dynamic_ps_timer(unsigned long data)
-{
-	struct ieee80211_local *local = (void *) data;
-
-	queue_work(local->hw.workqueue, &local->dynamic_ps_enable_work);
-}
-
-void ieee80211_send_nullfunc(struct ieee80211_local *local,
-			     struct ieee80211_sub_if_data *sdata,
-			     int powersave)
-{
-	struct sk_buff *skb;
-	struct ieee80211_hdr *nullfunc;
-	__le16 fc;
-
-	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_STATION))
-		return;
-
-	skb = dev_alloc_skb(local->hw.extra_tx_headroom + 24);
-	if (!skb) {
-		printk(KERN_DEBUG "%s: failed to allocate buffer for nullfunc "
-		       "frame\n", sdata->dev->name);
-		return;
-	}
-	skb_reserve(skb, local->hw.extra_tx_headroom);
-
-	nullfunc = (struct ieee80211_hdr *) skb_put(skb, 24);
-	memset(nullfunc, 0, 24);
-	fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_NULLFUNC |
-			 IEEE80211_FCTL_TODS);
-	if (powersave)
-		fc |= cpu_to_le16(IEEE80211_FCTL_PM);
-	nullfunc->frame_control = fc;
-	memcpy(nullfunc->addr1, sdata->u.mgd.bssid, ETH_ALEN);
-	memcpy(nullfunc->addr2, sdata->dev->dev_addr, ETH_ALEN);
-	memcpy(nullfunc->addr3, sdata->u.mgd.bssid, ETH_ALEN);
-
-	ieee80211_tx_skb(sdata, skb, 0);
-}