iwlwifi: rework iwl_scan_cancel_timeout

Since on timeout version of iwl_scan_cancel procedure we can sleep,
do not have to schedule abort_scan work to begin and perform scanning,
can do this directly. Also now, as we do not queue abort_scan from
restart work anymore, we can queue abort_scan to priv->workqueue.

Don't drop mutex when waiting for scan complete. Use STATUS_HW_SCAN bit
to check if scanning is currently pending, because STATUS_SCANNING will
be cleared only with priv->mutex taken.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi W Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-scan.c

@@ -126,7 +126,7 @@ static void iwl_do_scan_abort(struct iwl_priv *priv)
 int iwl_scan_cancel(struct iwl_priv *priv)
 {
 	IWL_DEBUG_SCAN(priv, "Queuing abort scan\n");
-	schedule_work(&priv->abort_scan);
+	queue_work(priv->workqueue, &priv->abort_scan);
 	return 0;
 }
 EXPORT_SYMBOL(iwl_scan_cancel);
@@ -135,25 +135,24 @@ EXPORT_SYMBOL(iwl_scan_cancel);
  * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
  * @ms: amount of time to wait (in milliseconds) for scan to abort
  *
- * NOTE: priv->mutex must be held before calling this function
  */
 int iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
 {
-	unsigned long now = jiffies;
-	int ret;
+	unsigned long timeout = jiffies + msecs_to_jiffies(ms);
+
+	lockdep_assert_held(&priv->mutex);
 
-	ret = iwl_scan_cancel(priv);
-	if (ret && ms) {
-		mutex_unlock(&priv->mutex);
-		while (!time_after(jiffies, now + msecs_to_jiffies(ms)) &&
-				test_bit(STATUS_SCANNING, &priv->status))
-			msleep(1);
-		mutex_lock(&priv->mutex);
+	IWL_DEBUG_SCAN(priv, "Scan cancel timeout\n");
 
-		return test_bit(STATUS_SCANNING, &priv->status);
+	iwl_do_scan_abort(priv);
+
+	while (time_before_eq(jiffies, timeout)) {
+		if (!test_bit(STATUS_SCAN_HW, &priv->status))
+			break;
+		msleep(20);
 	}
 
-	return ret;
+	return test_bit(STATUS_SCAN_HW, &priv->status);
 }
 EXPORT_SYMBOL(iwl_scan_cancel_timeout);