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@xxxxxxxxxxxxx>
---
include/net/bluetooth/hci_core.h | 12 ++++++++++++
net/bluetooth/hci_core.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+), 0 deletions(-)
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index d157762..8da5eac 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -126,6 +126,13 @@ struct adv_entry {
u8 bdaddr_type;
};
+struct le_scan_params {
+ u8 type;
+ u16 interval;
+ u16 window;
+ int timeout;
+};
+
#define NUM_REASSEMBLY 4
struct hci_dev {
struct list_head list;
@@ -268,6 +275,9 @@ struct hci_dev {
wait_queue_head_t le_scan_wait_q;
u8 le_scan_result;
+ 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);
@@ -1027,5 +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 22abc37..d77e586 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -779,6 +779,7 @@ static int hci_dev_do_close(struct hci_dev *hdev)
if (test_and_clear_bit(HCI_SERVICE_CACHE, &hdev->dev_flags))
cancel_delayed_work(&hdev->service_cache);
+ cancel_work_sync(&hdev->le_scan);
cancel_delayed_work_sync(&hdev->le_scan_disable);
hci_dev_lock(hdev);
@@ -1646,6 +1647,37 @@ static void le_scan_disable_work(struct work_struct *work)
send_le_scan_enable_cmd(hdev, 0);
}
+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 *params = &hdev->le_scan_params;
+
+ BT_DBG("%s", hdev->name);
+
+ hci_do_le_scan(hdev, params->type, params->interval,
+ params->window, params->timeout);
+}
+
+int hci_le_scan(struct hci_dev *hdev, u8 type, u16 interval, u16 window,
+ int timeout)
+{
+ struct le_scan_params *params = &hdev->le_scan_params;
+
+ BT_DBG("%s", hdev->name);
+
+ if (work_busy(&hdev->le_scan))
+ return -EINPROGRESS;
+
+ params->type = type;
+ params->interval = interval;
+ params->window = window;
+ params->timeout = timeout;
+
+ queue_work(system_long_wq, &hdev->le_scan);
+
+ return 0;
+}
+
/* Register HCI device */
int hci_register_dev(struct hci_dev *hdev)
{
@@ -1731,6 +1763,8 @@ 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);
init_waitqueue_head(&hdev->le_scan_wait_q);
--
1.7.8.4
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