iwlwifi: mvm: add D0i3 ref/unref for scan

Take a reference when starting to scan and release it on completion.
Note that if the scan is cancelled/aborted, a completion will still be
sent up.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Eliad Peller <eliadx.peller@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/mvm/mac80211.c

@@ -1442,11 +1442,17 @@ static int iwl_mvm_mac_hw_scan(struct ieee80211_hw *hw,
 
 	mutex_lock(&mvm->mutex);
 
-	if (mvm->scan_status == IWL_MVM_SCAN_NONE)
-		ret = iwl_mvm_scan_request(mvm, vif, req);
-	else
+	if (mvm->scan_status != IWL_MVM_SCAN_NONE) {
 		ret = -EBUSY;
+		goto out;
+	}
 
+	iwl_mvm_ref(mvm, IWL_MVM_REF_SCAN);
+
+	ret = iwl_mvm_scan_request(mvm, vif, req);
+	if (ret)
+		iwl_mvm_unref(mvm, IWL_MVM_REF_SCAN);
+out:
 	mutex_unlock(&mvm->mutex);
 
 	return ret;

drivers/net/wireless/iwlwifi/mvm/mvm.h

@@ -241,6 +241,7 @@ enum iwl_mvm_smps_type_request {
 
 enum iwl_mvm_ref_type {
 	IWL_MVM_REF_UCODE_DOWN,
+	IWL_MVM_REF_SCAN,
 
 	IWL_MVM_REF_COUNT,
 };

drivers/net/wireless/iwlwifi/mvm/scan.c

@@ -407,6 +407,8 @@ int iwl_mvm_rx_scan_complete(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
 	mvm->scan_status = IWL_MVM_SCAN_NONE;
 	ieee80211_scan_completed(mvm->hw, notif->status != SCAN_COMP_STATUS_OK);
 
+	iwl_mvm_unref(mvm, IWL_MVM_REF_SCAN);
+
 	return 0;
 }
 
@@ -475,6 +477,7 @@ void iwl_mvm_cancel_scan(struct iwl_mvm *mvm)
 
 	if (iwl_mvm_is_radio_killed(mvm)) {
 		ieee80211_scan_completed(mvm->hw, true);
+		iwl_mvm_unref(mvm, IWL_MVM_REF_SCAN);
 		mvm->scan_status = IWL_MVM_SCAN_NONE;
 		return;
 	}