iwlwifi: unify scan start checks

Rather than duplicating all the checks and even
in case of errors accepting the scan request
from mac80211, we can push the checks to the
caller and in all error cases reject the scan
request right away (rather than accepting and
then saying it was aborted).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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>
diff --git a/drivers/net/wireless/iwlwifi/iwl-scan.c b/drivers/net/wireless/iwlwifi/iwl-scan.c
index 7727f09..6bd14bc 100644
--- a/drivers/net/wireless/iwlwifi/iwl-scan.c
+++ b/drivers/net/wireless/iwlwifi/iwl-scan.c
@@ -324,19 +324,68 @@
 }
 EXPORT_SYMBOL(iwl_init_scan_params);
 
-static int iwl_scan_initiate(struct iwl_priv *priv, struct ieee80211_vif *vif)
+static int __must_check iwl_scan_initiate(struct iwl_priv *priv,
+					  struct ieee80211_vif *vif,
+					  bool internal,
+					  enum nl80211_band band)
 {
-	lockdep_assert_held(&priv->mutex);
+	int ret;
 
-	IWL_DEBUG_INFO(priv, "Starting scan...\n");
-	set_bit(STATUS_SCANNING, &priv->status);
-	priv->is_internal_short_scan = false;
-	priv->scan_start = jiffies;
+	lockdep_assert_held(&priv->mutex);
 
 	if (WARN_ON(!priv->cfg->ops->utils->request_scan))
 		return -EOPNOTSUPP;
 
-	priv->cfg->ops->utils->request_scan(priv, vif);
+	cancel_delayed_work(&priv->scan_check);
+
+	if (!iwl_is_ready(priv)) {
+		IWL_WARN(priv, "request scan called when driver not ready.\n");
+		return -EIO;
+	}
+
+	if (test_bit(STATUS_SCAN_HW, &priv->status)) {
+		IWL_DEBUG_INFO(priv,
+			"Multiple concurrent scan requests in parallel.\n");
+		return -EBUSY;
+	}
+
+	if (test_bit(STATUS_EXIT_PENDING, &priv->status)) {
+		IWL_DEBUG_SCAN(priv, "Aborting scan due to device shutdown\n");
+		return -EIO;
+	}
+
+	if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
+		IWL_DEBUG_HC(priv, "Scan request while abort pending.\n");
+		return -EBUSY;
+	}
+
+	if (iwl_is_rfkill(priv)) {
+		IWL_DEBUG_HC(priv, "Aborting scan due to RF Kill activation\n");
+		return -EIO;
+	}
+
+	if (!test_bit(STATUS_READY, &priv->status)) {
+		IWL_DEBUG_HC(priv, "Scan request while uninitialized.\n");
+		return -EBUSY;
+	}
+
+	IWL_DEBUG_INFO(priv, "Starting %sscan...\n",
+			internal ? "internal short " : "");
+
+	set_bit(STATUS_SCANNING, &priv->status);
+	priv->is_internal_short_scan = internal;
+	priv->scan_start = jiffies;
+	priv->scan_band = band;
+
+	ret = priv->cfg->ops->utils->request_scan(priv, vif);
+	if (ret) {
+		clear_bit(STATUS_SCANNING, &priv->status);
+		priv->is_internal_short_scan = false;
+		return ret;
+	}
+
+	queue_delayed_work(priv->workqueue, &priv->scan_check,
+			   IWL_SCAN_CHECK_WATCHDOG);
 
 	return 0;
 }
@@ -355,12 +404,6 @@
 
 	mutex_lock(&priv->mutex);
 
-	if (!iwl_is_ready_rf(priv)) {
-		ret = -EIO;
-		IWL_DEBUG_MAC80211(priv, "leave - not ready or exit pending\n");
-		goto out_unlock;
-	}
-
 	if (test_bit(STATUS_SCANNING, &priv->status) &&
 	    !priv->is_internal_short_scan) {
 		IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
@@ -368,14 +411,7 @@
 		goto out_unlock;
 	}
 
-	if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
-		IWL_DEBUG_SCAN(priv, "Scan request while abort pending\n");
-		ret = -EAGAIN;
-		goto out_unlock;
-	}
-
 	/* mac80211 will only ask for one band at a time */
-	priv->scan_band = req->channels[0]->band;
 	priv->scan_request = req;
 	priv->scan_vif = vif;
 
@@ -386,7 +422,8 @@
 	if (priv->is_internal_short_scan)
 		ret = 0;
 	else
-		ret = iwl_scan_initiate(priv, vif);
+		ret = iwl_scan_initiate(priv, vif, false,
+					req->channels[0]->band);
 
 	IWL_DEBUG_MAC80211(priv, "leave\n");
 
@@ -418,31 +455,13 @@
 		goto unlock;
 	}
 
-	if (!iwl_is_ready_rf(priv)) {
-		IWL_DEBUG_SCAN(priv, "not ready or exit pending\n");
-		goto unlock;
-	}
-
 	if (test_bit(STATUS_SCANNING, &priv->status)) {
 		IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
 		goto unlock;
 	}
 
-	if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
-		IWL_DEBUG_SCAN(priv, "Scan request while abort pending\n");
-		goto unlock;
-	}
-
-	priv->scan_band = priv->band;
-
-	IWL_DEBUG_SCAN(priv, "Start internal short scan...\n");
-	set_bit(STATUS_SCANNING, &priv->status);
-	priv->is_internal_short_scan = true;
-
-	if (WARN_ON(!priv->cfg->ops->utils->request_scan))
-		goto unlock;
-
-	priv->cfg->ops->utils->request_scan(priv, NULL);
+	if (iwl_scan_initiate(priv, NULL, true, priv->band))
+		IWL_DEBUG_SCAN(priv, "failed to start internal short scan\n");
  unlock:
 	mutex_unlock(&priv->mutex);
 }
@@ -536,7 +555,6 @@
 	struct iwl_priv *priv =
 	    container_of(work, struct iwl_priv, scan_completed);
 	bool internal = false;
-	bool scan_completed = false;
 	struct iwl_rxon_context *ctx;
 
 	IWL_DEBUG_SCAN(priv, "SCAN complete scan\n");
@@ -549,16 +567,27 @@
 		IWL_DEBUG_SCAN(priv, "internal short scan completed\n");
 		internal = true;
 	} else if (priv->scan_request) {
-		scan_completed = true;
 		priv->scan_request = NULL;
 		priv->scan_vif = NULL;
+		ieee80211_scan_completed(priv->hw, false);
 	}
 
 	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 		goto out;
 
-	if (internal && priv->scan_request)
-		iwl_scan_initiate(priv, priv->scan_vif);
+	if (internal && priv->scan_request) {
+		int err = iwl_scan_initiate(priv, priv->scan_vif, false,
+					priv->scan_request->channels[0]->band);
+
+		if (err) {
+			IWL_DEBUG_SCAN(priv,
+				"failed to initiate pending scan: %d\n", err);
+			priv->scan_request = NULL;
+			priv->scan_vif = NULL;
+			ieee80211_scan_completed(priv->hw, true);
+		} else
+			goto out;
+	}
 
 	/* Since setting the TXPOWER may have been deferred while
 	 * performing the scan, fire one off */
@@ -571,19 +600,11 @@
 	for_each_context(priv, ctx)
 		iwlcore_commit_rxon(priv, ctx);
 
- out:
 	if (priv->cfg->ops->hcmd->set_pan_params)
 		priv->cfg->ops->hcmd->set_pan_params(priv);
 
+ out:
 	mutex_unlock(&priv->mutex);
-
-	/*
-	 * Do not hold mutex here since this will cause mac80211 to call
-	 * into driver again into functions that will attempt to take
-	 * mutex.
-	 */
-	if (scan_completed)
-		ieee80211_scan_completed(priv->hw, false);
 }
 
 void iwl_setup_scan_deferred_work(struct iwl_priv *priv)