[patch 29/29] ipw2200: batch non-user-requested scan result notifications

[Greg Kroah-Hartman <gregkh@suse.de>]

2.6.23-stable review patch.  If anyone has any objections, please let us
know.

------------------
From: Dan Williams <dcbw@redhat.com>

patch 0b5316769774d1dc2fdd702e095f9e6992af269a in mainline.

ipw2200 makes extensive use of background scanning when unassociated or
down.  Unfortunately, the firmware sends scan completed events many
times per second, which the driver pushes directly up to userspace.
This needlessly wakes up processes listening for wireless events many
times per second.  Batch together scan completed events for
non-user-requested scans and send them up to userspace every 4 seconds.
Scan completed events resulting from an SIOCSIWSCAN call are pushed up
without delay.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Cc: Tobias Powalowski <t.powa@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/net/wireless/ipw2200.c |   56 +++++++++++++++++++++++++++++++++--------
 drivers/net/wireless/ipw2200.h |    3 ++
 2 files changed, 49 insertions(+), 10 deletions(-)

--- a/drivers/net/wireless/ipw2200.c
+++ b/drivers/net/wireless/ipw2200.c
@@ -1740,8 +1740,10 @@ static int ipw_radio_kill_sw(struct ipw_
 	if (disable_radio) {
 		priv->status |= STATUS_RF_KILL_SW;
 
-		if (priv->workqueue)
+		if (priv->workqueue) {
 			cancel_delayed_work(&priv->request_scan);
+			cancel_delayed_work(&priv->scan_event);
+		}
 		queue_work(priv->workqueue, &priv->down);
 	} else {
 		priv->status &= ~STATUS_RF_KILL_SW;
@@ -1992,6 +1994,7 @@ static void ipw_irq_tasklet(struct ipw_p
 		wake_up_interruptible(&priv->wait_command_queue);
 		priv->status &= ~(STATUS_ASSOCIATED | STATUS_ASSOCIATING);
 		cancel_delayed_work(&priv->request_scan);
+		cancel_delayed_work(&priv->scan_event);
 		schedule_work(&priv->link_down);
 		queue_delayed_work(priv->workqueue, &priv->rf_kill, 2 * HZ);
 		handled |= IPW_INTA_BIT_RF_KILL_DONE;
@@ -4341,6 +4344,37 @@ static void ipw_handle_missed_beacon(str
 	IPW_DEBUG_NOTIF("Missed beacon: %d\n", missed_count);
 }
 
+static void ipw_scan_event(struct work_struct *work)
+{
+	union iwreq_data wrqu;
+
+	struct ipw_priv *priv =
+		container_of(work, struct ipw_priv, scan_event.work);
+
+	wrqu.data.length = 0;
+	wrqu.data.flags = 0;
+	wireless_send_event(priv->net_dev, SIOCGIWSCAN, &wrqu, NULL);
+}
+
+static void handle_scan_event(struct ipw_priv *priv)
+{
+	/* Only userspace-requested scan completion events go out immediately */
+	if (!priv->user_requested_scan) {
+		if (!delayed_work_pending(&priv->scan_event))
+			queue_delayed_work(priv->workqueue, &priv->scan_event,
+					 round_jiffies(msecs_to_jiffies(4000)));
+	} else {
+		union iwreq_data wrqu;
+
+		priv->user_requested_scan = 0;
+		cancel_delayed_work(&priv->scan_event);
+
+		wrqu.data.length = 0;
+		wrqu.data.flags = 0;
+		wireless_send_event(priv->net_dev, SIOCGIWSCAN, &wrqu, NULL);
+	}
+}
+
 /**
  * Handle host notification packet.
  * Called from interrupt routine
@@ -4702,14 +4736,8 @@ static void ipw_rx_notification(struct i
 			 * on how the scan was initiated. User space can just
 			 * sync on periodic scan to get fresh data...
 			 * Jean II */
-			if (x->status == SCAN_COMPLETED_STATUS_COMPLETE) {
-				union iwreq_data wrqu;
-
-				wrqu.data.length = 0;
-				wrqu.data.flags = 0;
-				wireless_send_event(priv->net_dev, SIOCGIWSCAN,
-						    &wrqu, NULL);
-			}
+			if (x->status == SCAN_COMPLETED_STATUS_COMPLETE)
+				handle_scan_event(priv);
 			break;
 		}
 
@@ -9472,6 +9500,10 @@ static int ipw_wx_set_scan(struct net_de
 	struct ipw_priv *priv = ieee80211_priv(dev);
 	struct iw_scan_req *req = (struct iw_scan_req *)extra;
 
+	mutex_lock(&priv->mutex);
+	priv->user_requested_scan = 1;
+	mutex_unlock(&priv->mutex);
+
 	if (wrqu->data.length == sizeof(struct iw_scan_req)) {
 		if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
 			ipw_request_direct_scan(priv, req->essid,
@@ -10647,6 +10679,7 @@ static void ipw_link_up(struct ipw_priv 
 	}
 
 	cancel_delayed_work(&priv->request_scan);
+	cancel_delayed_work(&priv->scan_event);
 	ipw_reset_stats(priv);
 	/* Ensure the rate is updated immediately */
 	priv->last_rate = ipw_get_current_rate(priv);
@@ -10684,7 +10717,8 @@ static void ipw_link_down(struct ipw_pri
 	if (!(priv->status & STATUS_EXIT_PENDING)) {
 		/* Queue up another scan... */
 		queue_delayed_work(priv->workqueue, &priv->request_scan, 0);
-	}
+	} else
+		cancel_delayed_work(&priv->scan_event);
 }
 
 static void ipw_bg_link_down(struct work_struct *work)
@@ -10714,6 +10748,7 @@ static int ipw_setup_deferred_work(struc
 	INIT_WORK(&priv->up, ipw_bg_up);
 	INIT_WORK(&priv->down, ipw_bg_down);
 	INIT_DELAYED_WORK(&priv->request_scan, ipw_request_scan);
+	INIT_DELAYED_WORK(&priv->scan_event, ipw_scan_event);
 	INIT_WORK(&priv->request_passive_scan, ipw_request_passive_scan);
 	INIT_DELAYED_WORK(&priv->gather_stats, ipw_bg_gather_stats);
 	INIT_WORK(&priv->abort_scan, ipw_bg_abort_scan);
@@ -11746,6 +11781,7 @@ static void ipw_pci_remove(struct pci_de
 	cancel_delayed_work(&priv->adhoc_check);
 	cancel_delayed_work(&priv->gather_stats);
 	cancel_delayed_work(&priv->request_scan);
+	cancel_delayed_work(&priv->scan_event);
 	cancel_delayed_work(&priv->rf_kill);
 	cancel_delayed_work(&priv->scan_check);
 	destroy_workqueue(priv->workqueue);
--- a/drivers/net/wireless/ipw2200.h
+++ b/drivers/net/wireless/ipw2200.h
@@ -1288,6 +1288,8 @@ struct ipw_priv {
 
 	struct iw_public_data wireless_data;
 
+	int user_requested_scan;
+
 	struct workqueue_struct *workqueue;
 
 	struct delayed_work adhoc_check;
@@ -1296,6 +1298,7 @@ struct ipw_priv {
 	struct work_struct system_config;
 	struct work_struct rx_replenish;
 	struct delayed_work request_scan;
+	struct delayed_work scan_event;
   	struct work_struct request_passive_scan;
 	struct work_struct adapter_restart;
 	struct delayed_work rf_kill;

-- 
-
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