mgmt: Add supports of variable length parameter in mgmt_config

diff --git a/net/bluetooth/mgmt_config.c b/net/bluetooth/mgmt_config.c
index b30b571f8caf8..1e3cbeacb09b4 100644
--- a/net/bluetooth/mgmt_config.c
+++ b/net/bluetooth/mgmt_config.c
@@ -11,70 +11,96 @@ 
 #include "mgmt_util.h"
 #include "mgmt_config.h"
 
-#define HDEV_PARAM_U16(_param_code_, _param_name_) \
-{ \
-	{ cpu_to_le16(_param_code_), sizeof(__u16) }, \
-	{ cpu_to_le16(hdev->_param_name_) } \
-}
+#define HDEV_PARAM_U16(_param_name_) \
+	struct {\
+		struct mgmt_tlv entry; \
+		__le16 value; \
+	} __packed _param_name_
 
-#define HDEV_PARAM_U16_JIFFIES_TO_MSECS(_param_code_, _param_name_) \
-{ \
-	{ cpu_to_le16(_param_code_), sizeof(__u16) }, \
-	{ cpu_to_le16(jiffies_to_msecs(hdev->_param_name_)) } \
-}
+#define TLV_SET_U16(_param_code_, _param_name_) \
+	{ \
+		{ cpu_to_le16(_param_code_), sizeof(__u16) }, \
+		cpu_to_le16(hdev->_param_name_) \
+	}
+
+#define TLV_SET_U16_JIFFIES_TO_MSECS(_param_code_, _param_name_) \
+	{ \
+		{ cpu_to_le16(_param_code_), sizeof(__u16) }, \
+		cpu_to_le16(jiffies_to_msecs(hdev->_param_name_)) \
+	}
 
 int read_def_system_config(struct sock *sk, struct hci_dev *hdev, void *data,
 			   u16 data_len)
 {
-	struct {
-		struct mgmt_tlv entry;
-		union {
-			/* This is a simplification for now since all values
-			 * are 16 bits.  In the future, this code may need
-			 * refactoring to account for variable length values
-			 * and properly calculate the required buffer size.
-			 */
-			__le16 value;
-		};
-	} __packed params[] = {
+	int ret;
+	struct mgmt_rp_read_def_system_config {
 		/* Please see mgmt-api.txt for documentation of these values */
-		HDEV_PARAM_U16(0x0000, def_page_scan_type),
-		HDEV_PARAM_U16(0x0001, def_page_scan_int),
-		HDEV_PARAM_U16(0x0002, def_page_scan_window),
-		HDEV_PARAM_U16(0x0003, def_inq_scan_type),
-		HDEV_PARAM_U16(0x0004, def_inq_scan_int),
-		HDEV_PARAM_U16(0x0005, def_inq_scan_window),
-		HDEV_PARAM_U16(0x0006, def_br_lsto),
-		HDEV_PARAM_U16(0x0007, def_page_timeout),
-		HDEV_PARAM_U16(0x0008, sniff_min_interval),
-		HDEV_PARAM_U16(0x0009, sniff_max_interval),
-		HDEV_PARAM_U16(0x000a, le_adv_min_interval),
-		HDEV_PARAM_U16(0x000b, le_adv_max_interval),
-		HDEV_PARAM_U16(0x000c, def_multi_adv_rotation_duration),
-		HDEV_PARAM_U16(0x000d, le_scan_interval),
-		HDEV_PARAM_U16(0x000e, le_scan_window),
-		HDEV_PARAM_U16(0x000f, le_scan_int_suspend),
-		HDEV_PARAM_U16(0x0010, le_scan_window_suspend),
-		HDEV_PARAM_U16(0x0011, le_scan_int_discovery),
-		HDEV_PARAM_U16(0x0012, le_scan_window_discovery),
-		HDEV_PARAM_U16(0x0013, le_scan_int_adv_monitor),
-		HDEV_PARAM_U16(0x0014, le_scan_window_adv_monitor),
-		HDEV_PARAM_U16(0x0015, le_scan_int_connect),
-		HDEV_PARAM_U16(0x0016, le_scan_window_connect),
-		HDEV_PARAM_U16(0x0017, le_conn_min_interval),
-		HDEV_PARAM_U16(0x0018, le_conn_max_interval),
-		HDEV_PARAM_U16(0x0019, le_conn_latency),
-		HDEV_PARAM_U16(0x001a, le_supv_timeout),
-		HDEV_PARAM_U16_JIFFIES_TO_MSECS(0x001b,
-						def_le_autoconnect_timeout),
+		HDEV_PARAM_U16(def_page_scan_type);
+		HDEV_PARAM_U16(def_page_scan_int);
+		HDEV_PARAM_U16(def_page_scan_window);
+		HDEV_PARAM_U16(def_inq_scan_type);
+		HDEV_PARAM_U16(def_inq_scan_int);
+		HDEV_PARAM_U16(def_inq_scan_window);
+		HDEV_PARAM_U16(def_br_lsto);
+		HDEV_PARAM_U16(def_page_timeout);
+		HDEV_PARAM_U16(sniff_min_interval);
+		HDEV_PARAM_U16(sniff_max_interval);
+		HDEV_PARAM_U16(le_adv_min_interval);
+		HDEV_PARAM_U16(le_adv_max_interval);
+		HDEV_PARAM_U16(def_multi_adv_rotation_duration);
+		HDEV_PARAM_U16(le_scan_interval);
+		HDEV_PARAM_U16(le_scan_window);
+		HDEV_PARAM_U16(le_scan_int_suspend);
+		HDEV_PARAM_U16(le_scan_window_suspend);
+		HDEV_PARAM_U16(le_scan_int_discovery);
+		HDEV_PARAM_U16(le_scan_window_discovery);
+		HDEV_PARAM_U16(le_scan_int_adv_monitor);
+		HDEV_PARAM_U16(le_scan_window_adv_monitor);
+		HDEV_PARAM_U16(le_scan_int_connect);
+		HDEV_PARAM_U16(le_scan_window_connect);
+		HDEV_PARAM_U16(le_conn_min_interval);
+		HDEV_PARAM_U16(le_conn_max_interval);
+		HDEV_PARAM_U16(le_conn_latency);
+		HDEV_PARAM_U16(le_supv_timeout);
+		HDEV_PARAM_U16(def_le_autoconnect_timeout);
+	} __packed rp = {
+		TLV_SET_U16(0x0000, def_page_scan_type),
+		TLV_SET_U16(0x0001, def_page_scan_int),
+		TLV_SET_U16(0x0002, def_page_scan_window),
+		TLV_SET_U16(0x0003, def_inq_scan_type),
+		TLV_SET_U16(0x0004, def_inq_scan_int),
+		TLV_SET_U16(0x0005, def_inq_scan_window),
+		TLV_SET_U16(0x0006, def_br_lsto),
+		TLV_SET_U16(0x0007, def_page_timeout),
+		TLV_SET_U16(0x0008, sniff_min_interval),
+		TLV_SET_U16(0x0009, sniff_max_interval),
+		TLV_SET_U16(0x000a, le_adv_min_interval),
+		TLV_SET_U16(0x000b, le_adv_max_interval),
+		TLV_SET_U16(0x000c, def_multi_adv_rotation_duration),
+		TLV_SET_U16(0x000d, le_scan_interval),
+		TLV_SET_U16(0x000e, le_scan_window),
+		TLV_SET_U16(0x000f, le_scan_int_suspend),
+		TLV_SET_U16(0x0010, le_scan_window_suspend),
+		TLV_SET_U16(0x0011, le_scan_int_discovery),
+		TLV_SET_U16(0x0012, le_scan_window_discovery),
+		TLV_SET_U16(0x0013, le_scan_int_adv_monitor),
+		TLV_SET_U16(0x0014, le_scan_window_adv_monitor),
+		TLV_SET_U16(0x0015, le_scan_int_connect),
+		TLV_SET_U16(0x0016, le_scan_window_connect),
+		TLV_SET_U16(0x0017, le_conn_min_interval),
+		TLV_SET_U16(0x0018, le_conn_max_interval),
+		TLV_SET_U16(0x0019, le_conn_latency),
+		TLV_SET_U16(0x001a, le_supv_timeout),
+		TLV_SET_U16_JIFFIES_TO_MSECS(0x001b,
+					     def_le_autoconnect_timeout),
 	};
-	struct mgmt_rp_read_def_system_config *rp = (void *)params;
 
 	bt_dev_dbg(hdev, "sock %p", sk);
 
-	return mgmt_cmd_complete(sk, hdev->id,
-				 MGMT_OP_READ_DEF_SYSTEM_CONFIG,
-				 0, rp, sizeof(params));
+	ret = mgmt_cmd_complete(sk, hdev->id,
+				MGMT_OP_READ_DEF_SYSTEM_CONFIG,
+				0, &rp, sizeof(rp));
+	return ret;
 }
 
 #define TO_TLV(x)		((struct mgmt_tlv *)(x))