Bluetooth: Add timeout for LE connection attempts

LE connection attempts do not have a controller side timeout in the same
way as BR/EDR has (in form of the page timeout). Since we always do
scanning before initiating connections the attempts are always expected
to succeed in some reasonable time.

This patch adds a timer which forces a cancellation of the connection
attempt within 20 seconds if it has not been successful by then. This
way we e.g. ensure that mgmt_pair_device times out eventually and gives
an error response.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci.h

@@ -183,6 +183,7 @@ enum {
 #define HCI_ACL_TX_TIMEOUT	msecs_to_jiffies(45000)	/* 45 seconds */
 #define HCI_AUTO_OFF_TIMEOUT	msecs_to_jiffies(2000)	/* 2 seconds */
 #define HCI_POWER_OFF_TIMEOUT	msecs_to_jiffies(5000)	/* 5 seconds */
+#define HCI_LE_CONN_TIMEOUT	msecs_to_jiffies(20000)	/* 20 seconds */
 
 /* HCI data types */
 #define HCI_COMMAND_PKT		0x01

include/net/bluetooth/hci_core.h

@@ -375,6 +375,7 @@ struct hci_conn {
 	struct delayed_work disc_work;
 	struct delayed_work auto_accept_work;
 	struct delayed_work idle_work;
+	struct delayed_work le_conn_timeout;
 
 	struct device	dev;