Bluetooth: Convert link keys list to use RCU

This patch converts the hdev->link_keys list to be protected through
RCU, thereby eliminating the need to hold the hdev lock while accessing
the list.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 54680fd..bd0a801 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3324,8 +3324,8 @@
 	 */
 	if (key->type == HCI_LK_DEBUG_COMBINATION &&
 	    !test_bit(HCI_KEEP_DEBUG_KEYS, &hdev->dev_flags)) {
-		list_del(&key->list);
-		kfree(key);
+		list_del_rcu(&key->list);
+		kfree_rcu(key, rcu);
 	} else if (conn) {
 		if (persistent)
 			clear_bit(HCI_CONN_FLUSH_KEY, &conn->flags);