Bluetooth: Add hci_le_scan()

We are not supposed to block in start_discovery() because
start_discovery code is running in write() syscall context
and this would block the write operation on the mgmt socket.
This way, we cannot directly call hci_do_le_scan() to scan
LE devices in start_discovery(). To overcome this issue a
derefered work (hdev->le_scan) was created so we can properly
call hci_do_le_scan().

The helper function hci_le_scan() simply set LE scan parameters
and queue hdev->le_scan work. The work is queued on system_long_wq
since it can sleep for a few seconds in the worst case (timeout).

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

2 files changed, 41 insertions, 0 deletions

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 3e70872bffea..7107790817a5 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -126,6 +126,7 @@ struct le_scan_params {
         u8 type;
         u16 interval;
         u16 window;
+        int timeout;
 };
 
 #define NUM_REASSEMBLY 4
@@ -269,6 +270,9 @@ struct hci_dev {
 
         struct delayed_work     le_scan_disable;
 
+        struct work_struct      le_scan;
+        struct le_scan_params   le_scan_params;
+
         int (*open)(struct hci_dev *hdev);
         int (*close)(struct hci_dev *hdev);
         int (*flush)(struct hci_dev *hdev);
@@ -1033,5 +1037,7 @@ void hci_le_ltk_neg_reply(struct hci_conn *conn);
 
 int hci_do_inquiry(struct hci_dev *hdev, u8 length);
 int hci_cancel_inquiry(struct hci_dev *hdev);
+int hci_le_scan(struct hci_dev *hdev, u8 type, u16 interval, u16 window,
+                                                                int timeout);
 
 #endif /* __HCI_CORE_H */
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index ae86cdd80ac0..3d09f4b4ca68 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -735,6 +735,8 @@ static int hci_dev_do_close(struct hci_dev *hdev)
 {
         BT_DBG("%s %p", hdev->name, hdev);
 
+        cancel_work_sync(&hdev->le_scan);
+
         hci_req_cancel(hdev, ENODEV);
         hci_req_lock(hdev);
 
@@ -1668,6 +1670,37 @@ static void le_scan_disable_work(struct work_struct *work)
         hci_send_cmd(hdev, HCI_OP_LE_SET_SCAN_ENABLE, sizeof(cp), &cp);
 }
 
+static void le_scan_work(struct work_struct *work)
+{
+        struct hci_dev *hdev = container_of(work, struct hci_dev, le_scan);
+        struct le_scan_params *param = &hdev->le_scan_params;
+
+        BT_DBG("%s", hdev->name);
+
+        hci_do_le_scan(hdev, param->type, param->interval,
+                                        param->window, param->timeout);
+}
+
+int hci_le_scan(struct hci_dev *hdev, u8 type, u16 interval, u16 window,
+                                                                int timeout)
+{
+        struct le_scan_params *param = &hdev->le_scan_params;
+
+        BT_DBG("%s", hdev->name);
+
+        if (work_busy(&hdev->le_scan))
+                return -EINPROGRESS;
+
+        param->type = type;
+        param->interval = interval;
+        param->window = window;
+        param->timeout = timeout;
+
+        queue_work(system_long_wq, &hdev->le_scan);
+
+        return 0;
+}
+
 /* Register HCI device */
 int hci_register_dev(struct hci_dev *hdev)
 {
@@ -1754,6 +1787,8 @@ int hci_register_dev(struct hci_dev *hdev)
 
         atomic_set(&hdev->promisc, 0);
 
+        INIT_WORK(&hdev->le_scan, le_scan_work);
+
         INIT_DELAYED_WORK(&hdev->le_scan_disable, le_scan_disable_work);
 
         write_unlock(&hci_dev_list_lock);