[nrf fromtree] bluetooth: remove blocking operation in bt_conn_get_info

bt_conn_get_info API is used to retrieve connection-related
information. However, bt_conn_get_info sends the HCI command
BT_HCI_OP_READ_ENCRYPTION_KEY_SIZE to retrieve current
key_size, causing excessive blocking time.

Signed-off-by: Xiang Liu <[email protected]>
(cherry picked from commit 8e9fa6a)

Author: liuX10

subsys/bluetooth/host/classic/br.c

@@ -143,6 +143,10 @@ static bool br_sufficient_key_size(struct bt_conn *conn)
 	key_size = rp->key_size;
 	net_buf_unref(rsp);
 
+	if (conn->br.link_key) {
+		conn->br.link_key->enc_key_size = key_size;
+	}
+
 	LOG_DBG("Encryption key size is %u", key_size);
 
 	if (conn->sec_level == BT_SECURITY_L4) {

subsys/bluetooth/host/conn.c

@@ -2507,35 +2507,11 @@ uint8_t bt_conn_enc_key_size(const struct bt_conn *conn)
 		return 0;
 	}
 
-	if (IS_ENABLED(CONFIG_BT_CLASSIC) &&
-	    conn->type == BT_CONN_TYPE_BR) {
-		struct bt_hci_cp_read_encryption_key_size *cp;
-		struct bt_hci_rp_read_encryption_key_size *rp;
-		struct net_buf *buf;
-		struct net_buf *rsp;
-		uint8_t key_size;
-
-		buf = bt_hci_cmd_alloc(K_FOREVER);
-		if (!buf) {
-			return 0;
-		}
-
-		cp = net_buf_add(buf, sizeof(*cp));
-		cp->handle = sys_cpu_to_le16(conn->handle);
-
-		if (bt_hci_cmd_send_sync(BT_HCI_OP_READ_ENCRYPTION_KEY_SIZE,
-					buf, &rsp)) {
-			return 0;
-		}
-
-		rp = (void *)rsp->data;
-
-		key_size = rp->status ? 0 : rp->key_size;
-
-		net_buf_unref(rsp);
-
-		return key_size;
+#if defined(CONFIG_BT_CLASSIC)
+	if (conn->type == BT_CONN_TYPE_BR) {
+		return conn->br.link_key ? conn->br.link_key->enc_key_size : 0;
 	}
+#endif /* CONFIG_BT_CLASSIC */
 
 	if (IS_ENABLED(CONFIG_BT_SMP)) {
 		return conn->le.keys ? conn->le.keys->enc_size : 0;

subsys/bluetooth/host/hci_core.c

@@ -1077,9 +1077,16 @@ static void hci_disconn_complete(struct net_buf *buf)
 		 * If only for one connection session bond was set, clear keys
 		 * database row for this connection.
 		 */
-		if (conn->type == BT_CONN_TYPE_BR && conn->br.link_key != NULL &&
-		    atomic_test_and_clear_bit(conn->flags, BT_CONN_BR_NOBOND)) {
-			bt_keys_link_key_clear(conn->br.link_key);
+		if (conn->type == BT_CONN_TYPE_BR && conn->br.link_key != NULL) {
+			/*
+			 * If the connection link is paired but not bond, remove
+			 * the link key upon disconnection.
+			 */
+			if (atomic_test_and_clear_bit(conn->flags, BT_CONN_BR_NOBOND)) {
+				bt_keys_link_key_clear(conn->br.link_key);
+			}
+
+			conn->br.link_key->enc_key_size = 0;
 		}
 #endif
 		bt_conn_unref(conn);

subsys/bluetooth/host/keys.h

@@ -223,6 +223,7 @@ enum {
 
 struct bt_keys_link_key {
 	bt_addr_t addr;
+	uint8_t enc_key_size;
 	uint8_t storage_start[0] __aligned(sizeof(void *));
 	uint8_t flags;
 	uint8_t val[16];