1 files changed, 221 insertions, 83 deletions

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 74820656dc89..45731000eb8d 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -18,7 +18,6 @@
 #include <linux/if_arp.h>
 #include <linux/rtnetlink.h>
 #include <net/mac80211.h>
-#include <net/iw_handler.h>
 
 #include "ieee80211_i.h"
 #include "driver-ops.h"
@@ -265,7 +264,7 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 
 	mutex_lock(&local->scan_mtx);
 
-	if (WARN_ON(!local->hw_scanning && !local->sw_scanning)) {
+	if (WARN_ON(!local->scanning)) {
 		mutex_unlock(&local->scan_mtx);
 		return;
 	}
@@ -275,16 +274,15 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 		return;
 	}
 
-	if (local->hw_scanning)
+	if (test_bit(SCAN_HW_SCANNING, &local->scanning))
 		ieee80211_restore_scan_ies(local);
 
 	if (local->scan_req != &local->int_scan_req)
 		cfg80211_scan_done(local->scan_req, aborted);
 	local->scan_req = NULL;
 
-	was_hw_scan = local->hw_scanning;
-	local->hw_scanning = false;
-	local->sw_scanning = false;
+	was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
+	local->scanning = 0;
 	local->scan_channel = NULL;
 
 	/* we only have to protect scan_req and hw/sw scan */
@@ -366,17 +364,16 @@ static int ieee80211_start_sw_scan(struct ieee80211_local *local)
 			ieee80211_bss_info_change_notify(
 				sdata, BSS_CHANGED_BEACON_ENABLED);
 
-		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
-			if (sdata->u.mgd.associated) {
-				netif_tx_stop_all_queues(sdata->dev);
-				ieee80211_scan_ps_enable(sdata);
-			}
-		} else
+		/*
+		 * only handle non-STA interfaces here, STA interfaces
+		 * are handled in the scan state machine
+		 */
+		if (sdata->vif.type != NL80211_IFTYPE_STATION)
 			netif_tx_stop_all_queues(sdata->dev);
 	}
 	mutex_unlock(&local->iflist_mtx);
 
-	local->scan_state = SCAN_SET_CHANNEL;
+	local->next_scan_state = SCAN_DECISION;
 	local->scan_channel_idx = 0;
 
 	spin_lock_bh(&local->filter_lock);
@@ -434,9 +431,9 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 	}
 
 	if (local->ops->hw_scan)
-		local->hw_scanning = true;
+		__set_bit(SCAN_HW_SCANNING, &local->scanning);
 	else
-		local->sw_scanning = true;
+		__set_bit(SCAN_SW_SCANNING, &local->scanning);
 	/*
 	 * Kicking off the scan need not be protected,
 	 * only the scan variable stuff, since now
@@ -459,11 +456,9 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 	mutex_lock(&local->scan_mtx);
 
 	if (rc) {
-		if (local->ops->hw_scan) {
-			local->hw_scanning = false;
+		if (local->ops->hw_scan)
 			ieee80211_restore_scan_ies(local);
-		} else
-			local->sw_scanning = false;
+		local->scanning = 0;
 
 		ieee80211_recalc_idle(local);
 
@@ -474,13 +469,195 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
 	return rc;
 }
 
+static int ieee80211_scan_state_decision(struct ieee80211_local *local,
+					 unsigned long *next_delay)
+{
+	bool associated = false;
+	struct ieee80211_sub_if_data *sdata;
+
+	/* if no more bands/channels left, complete scan and advance to the idle state */
+	if (local->scan_channel_idx >= local->scan_req->n_channels) {
+		ieee80211_scan_completed(&local->hw, false);
+		return 1;
+	}
+
+	/* check if at least one STA interface is associated */
+	mutex_lock(&local->iflist_mtx);
+	list_for_each_entry(sdata, &local->interfaces, list) {
+		if (!netif_running(sdata->dev))
+			continue;
+
+		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+			if (sdata->u.mgd.associated) {
+				associated = true;
+				break;
+			}
+		}
+	}
+	mutex_unlock(&local->iflist_mtx);
+
+	if (local->scan_channel) {
+		/*
+		 * we're currently scanning a different channel, let's
+		 * switch back to the operating channel now if at least
+		 * one interface is associated. Otherwise just scan the
+		 * next channel
+		 */
+		if (associated)
+			local->next_scan_state = SCAN_ENTER_OPER_CHANNEL;
+		else
+			local->next_scan_state = SCAN_SET_CHANNEL;
+	} else {
+		/*
+		 * we're on the operating channel currently, let's
+		 * leave that channel now to scan another one
+		 */
+		local->next_scan_state = SCAN_LEAVE_OPER_CHANNEL;
+	}
+
+	*next_delay = 0;
+	return 0;
+}
+
+static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
+						    unsigned long *next_delay)
+{
+	struct ieee80211_sub_if_data *sdata;
+
+	/*
+	 * notify the AP about us leaving the channel and stop all STA interfaces
+	 */
+	mutex_lock(&local->iflist_mtx);
+	list_for_each_entry(sdata, &local->interfaces, list) {
+		if (!netif_running(sdata->dev))
+			continue;
+
+		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+			netif_tx_stop_all_queues(sdata->dev);
+			if (sdata->u.mgd.associated)
+				ieee80211_scan_ps_enable(sdata);
+		}
+	}
+	mutex_unlock(&local->iflist_mtx);
+
+	__set_bit(SCAN_OFF_CHANNEL, &local->scanning);
+
+	/* advance to the next channel to be scanned */
+	*next_delay = HZ / 10;
+	local->next_scan_state = SCAN_SET_CHANNEL;
+}
+
+static void ieee80211_scan_state_enter_oper_channel(struct ieee80211_local *local,
+						    unsigned long *next_delay)
+{
+	struct ieee80211_sub_if_data *sdata = local->scan_sdata;
+
+	/* switch back to the operating channel */
+	local->scan_channel = NULL;
+	ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+
+	/*
+	 * notify the AP about us being back and restart all STA interfaces
+	 */
+	mutex_lock(&local->iflist_mtx);
+	list_for_each_entry(sdata, &local->interfaces, list) {
+		if (!netif_running(sdata->dev))
+			continue;
+
+		/* Tell AP we're back */
+		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+			if (sdata->u.mgd.associated)
+				ieee80211_scan_ps_disable(sdata);
+			netif_tx_wake_all_queues(sdata->dev);
+		}
+	}
+	mutex_unlock(&local->iflist_mtx);
+
+	__clear_bit(SCAN_OFF_CHANNEL, &local->scanning);
+
+	*next_delay = HZ / 5;
+	local->next_scan_state = SCAN_DECISION;
+}
+
+static void ieee80211_scan_state_set_channel(struct ieee80211_local *local,
+					     unsigned long *next_delay)
+{
+	int skip;
+	struct ieee80211_channel *chan;
+	struct ieee80211_sub_if_data *sdata = local->scan_sdata;
+
+	skip = 0;
+	chan = local->scan_req->channels[local->scan_channel_idx];
+
+	if (chan->flags & IEEE80211_CHAN_DISABLED ||
+	    (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
+	     chan->flags & IEEE80211_CHAN_NO_IBSS))
+		skip = 1;
+
+	if (!skip) {
+		local->scan_channel = chan;
+		if (ieee80211_hw_config(local,
+					IEEE80211_CONF_CHANGE_CHANNEL))
+			skip = 1;
+	}
+
+	/* advance state machine to next channel/band */
+	local->scan_channel_idx++;
+
+	if (skip) {
+		/* if we skip this channel return to the decision state */
+		local->next_scan_state = SCAN_DECISION;
+		return;
+	}
+
+	/*
+	 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
+	 * (which unfortunately doesn't say _why_ step a) is done,
+	 * but it waits for the probe delay or until a frame is
+	 * received - and the received frame would update the NAV).
+	 * For now, we do not support waiting until a frame is
+	 * received.
+	 *
+	 * In any case, it is not necessary for a passive scan.
+	 */
+	if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
+	    !local->scan_req->n_ssids) {
+		*next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
+		local->next_scan_state = SCAN_DECISION;
+		return;
+	}
+
+	/* active scan, send probes */
+	*next_delay = IEEE80211_PROBE_DELAY;
+	local->next_scan_state = SCAN_SEND_PROBE;
+}
+
+static void ieee80211_scan_state_send_probe(struct ieee80211_local *local,
+					    unsigned long *next_delay)
+{
+	int i;
+	struct ieee80211_sub_if_data *sdata = local->scan_sdata;
+
+	for (i = 0; i < local->scan_req->n_ssids; i++)
+		ieee80211_send_probe_req(
+			sdata, NULL,
+			local->scan_req->ssids[i].ssid,
+			local->scan_req->ssids[i].ssid_len,
+			local->scan_req->ie, local->scan_req->ie_len);
+
+	/*
+	 * After sending probe requests, wait for probe responses
+	 * on the channel.
+	 */
+	*next_delay = IEEE80211_CHANNEL_TIME;
+	local->next_scan_state = SCAN_DECISION;
+}
+
 void ieee80211_scan_work(struct work_struct *work)
 {
 	struct ieee80211_local *local =
 		container_of(work, struct ieee80211_local, scan_work.work);
 	struct ieee80211_sub_if_data *sdata = local->scan_sdata;
-	struct ieee80211_channel *chan;
-	int skip, i;
 	unsigned long next_delay = 0;
 
 	mutex_lock(&local->scan_mtx);
@@ -489,7 +666,7 @@ void ieee80211_scan_work(struct work_struct *work)
 		return;
 	}
 
-	if (local->scan_req && !(local->sw_scanning || local->hw_scanning)) {
+	if (local->scan_req && !local->scanning) {
 		struct cfg80211_scan_request *req = local->scan_req;
 		int rc;
 
@@ -513,69 +690,30 @@ void ieee80211_scan_work(struct work_struct *work)
 		return;
 	}
 
-	switch (local->scan_state) {
-	case SCAN_SET_CHANNEL:
-		/* if no more bands/channels left, complete scan */
-		if (local->scan_channel_idx >= local->scan_req->n_channels) {
-			ieee80211_scan_completed(&local->hw, false);
-			return;
-		}
-		skip = 0;
-		chan = local->scan_req->channels[local->scan_channel_idx];
-
-		if (chan->flags & IEEE80211_CHAN_DISABLED ||
-		    (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
-		     chan->flags & IEEE80211_CHAN_NO_IBSS))
-			skip = 1;
-
-		if (!skip) {
-			local->scan_channel = chan;
-			if (ieee80211_hw_config(local,
-						IEEE80211_CONF_CHANGE_CHANNEL))
-				skip = 1;
-		}
-
-		/* advance state machine to next channel/band */
-		local->scan_channel_idx++;
-
-		if (skip)
+	/*
+	 * as long as no delay is required advance immediately
+	 * without scheduling a new work
+	 */
+	do {
+		switch (local->next_scan_state) {
+		case SCAN_DECISION:
+			if (ieee80211_scan_state_decision(local, &next_delay))
+				return;
 			break;
-
-		/*
-		 * Probe delay is used to update the NAV, cf. 11.1.3.2.2
-		 * (which unfortunately doesn't say _why_ step a) is done,
-		 * but it waits for the probe delay or until a frame is
-		 * received - and the received frame would update the NAV).
-		 * For now, we do not support waiting until a frame is
-		 * received.
-		 *
-		 * In any case, it is not necessary for a passive scan.
-		 */
-		if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN ||
-		    !local->scan_req->n_ssids) {
-			next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
+		case SCAN_SET_CHANNEL:
+			ieee80211_scan_state_set_channel(local, &next_delay);
+			break;
+		case SCAN_SEND_PROBE:
+			ieee80211_scan_state_send_probe(local, &next_delay);
+			break;
+		case SCAN_LEAVE_OPER_CHANNEL:
+			ieee80211_scan_state_leave_oper_channel(local, &next_delay);
+			break;
+		case SCAN_ENTER_OPER_CHANNEL:
+			ieee80211_scan_state_enter_oper_channel(local, &next_delay);
 			break;
 		}
-
-		next_delay = IEEE80211_PROBE_DELAY;
-		local->scan_state = SCAN_SEND_PROBE;
-		break;
-	case SCAN_SEND_PROBE:
-		for (i = 0; i < local->scan_req->n_ssids; i++)
-			ieee80211_send_probe_req(
-				sdata, NULL,
-				local->scan_req->ssids[i].ssid,
-				local->scan_req->ssids[i].ssid_len,
-				local->scan_req->ie, local->scan_req->ie_len);
-
-		/*
-		 * After sending probe requests, wait for probe responses
-		 * on the channel.
-		 */
-		next_delay = IEEE80211_CHANNEL_TIME;
-		local->scan_state = SCAN_SET_CHANNEL;
-		break;
-	}
+	} while (next_delay == 0);
 
 	queue_delayed_work(local->hw.workqueue, &local->scan_work,
 			   next_delay);
@@ -625,7 +763,7 @@ void ieee80211_scan_cancel(struct ieee80211_local *local)
 	 * queued -- mostly at suspend under RTNL.
 	 */
 	mutex_lock(&local->scan_mtx);
-	swscan = local->sw_scanning;
+	swscan = test_bit(SCAN_SW_SCANNING, &local->scanning);
 	mutex_unlock(&local->scan_mtx);
 
 	if (swscan)