Bluetooth: Run all background scan updates through req_workqueue

Instead of firing off a simple async request queue all background scan
updates through req_workqueue and use hci_req_sync() there to ensure
that no two updates overlap with each other.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci_core.h

@@ -327,6 +327,8 @@ struct hci_dev {
 	struct work_struct	cmd_work;
 	struct work_struct	tx_work;
 
+	struct work_struct	bg_scan_update;
+
 	struct sk_buff_head	rx_q;
 	struct sk_buff_head	raw_q;
 	struct sk_buff_head	cmd_q;

net/bluetooth/hci_request.c

@@ -731,28 +731,6 @@ void __hci_update_background_scan(struct hci_request *req)
 	}
 }
 
-static void update_background_scan_complete(struct hci_dev *hdev, u8 status,
-					    u16 opcode)
-{
-	if (status)
-		BT_DBG("HCI request failed to update background scanning: "
-		       "status 0x%2.2x", status);
-}
-
-void hci_update_background_scan(struct hci_dev *hdev)
-{
-	int err;
-	struct hci_request req;
-
-	hci_req_init(&req, hdev);
-
-	__hci_update_background_scan(&req);
-
-	err = hci_req_run(&req, update_background_scan_complete);
-	if (err && err != -ENODATA)
-		BT_ERR("Failed to run HCI request: err %d", err);
-}
-
 void __hci_abort_conn(struct hci_request *req, struct hci_conn *conn,
 		      u8 reason)
 {
@@ -846,10 +824,27 @@ int hci_abort_conn(struct hci_conn *conn, u8 reason)
 	return 0;
 }
 
+static void update_bg_scan(struct hci_request *req, unsigned long opt)
+{
+	hci_dev_lock(req->hdev);
+	__hci_update_background_scan(req);
+	hci_dev_unlock(req->hdev);
+}
+
+static void bg_scan_update(struct work_struct *work)
+{
+	struct hci_dev *hdev = container_of(work, struct hci_dev,
+					    bg_scan_update);
+
+	hci_req_sync(hdev, update_bg_scan, 0, HCI_CMD_TIMEOUT);
+}
+
 void hci_request_setup(struct hci_dev *hdev)
 {
+	INIT_WORK(&hdev->bg_scan_update, bg_scan_update);
 }
 
 void hci_request_cancel_all(struct hci_dev *hdev)
 {
+	cancel_work_sync(&hdev->bg_scan_update);
 }

net/bluetooth/hci_request.h

@@ -64,12 +64,16 @@ void __hci_update_page_scan(struct hci_request *req);
 int hci_update_random_address(struct hci_request *req, bool require_privacy,
 			      u8 *own_addr_type);
 
-void hci_update_background_scan(struct hci_dev *hdev);
 void __hci_update_background_scan(struct hci_request *req);
 
 int hci_abort_conn(struct hci_conn *conn, u8 reason);
 void __hci_abort_conn(struct hci_request *req, struct hci_conn *conn,
 		      u8 reason);
 
+static inline void hci_update_background_scan(struct hci_dev *hdev)
+{
+	queue_work(hdev->req_workqueue, &hdev->bg_scan_update);
+}
+
 void hci_request_setup(struct hci_dev *hdev);
 void hci_request_cancel_all(struct hci_dev *hdev);

net/bluetooth/mgmt.c

@@ -2510,8 +2510,8 @@ static void le_enable_complete(struct hci_dev *hdev, u8 status, u16 opcode)
 		hci_req_init(&req, hdev);
 		update_adv_data(&req);
 		update_scan_rsp_data(&req);
-		__hci_update_background_scan(&req);
 		hci_req_run(&req, NULL);
+		hci_update_background_scan(hdev);
 	}
 
 unlock: