Bluetooth: Provide option to enable/disable debugfs information

The Bluetooth controllers can export extensive information about
internal states via debugfs. This patch provides an option to
choose if these information are provided or not.

For backwards compatibility with existing kernel configuration,
this option defaults to yes.

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

net/bluetooth/Kconfig

@@ -91,4 +91,12 @@ config BT_SELFTEST_SMP
 	  Run test cases for SMP cryptographic functionality, including both
 	  legacy SMP as well as the Secure Connections features.
 
+config BT_DEBUGFS
+	bool "Export Bluetooth internals in debugfs"
+	depends on BT && DEBUG_FS
+	default y
+	help
+	  Provide extensive information about internal Bluetooth states
+	  in debugfs.
+
 source "drivers/bluetooth/Kconfig"

net/bluetooth/Makefile

@@ -13,8 +13,9 @@ bluetooth_6lowpan-y := 6lowpan.o
 
 bluetooth-y := af_bluetooth.o hci_core.o hci_conn.o hci_event.o mgmt.o \
 	hci_sock.o hci_sysfs.o l2cap_core.o l2cap_sock.o smp.o sco.o lib.o \
-	a2mp.o amp.o ecc.o hci_request.o hci_debugfs.o
+	a2mp.o amp.o ecc.o hci_request.o
 
+bluetooth-$(CONFIG_BT_DEBUGFS) += hci_debugfs.o
 bluetooth-$(CONFIG_BT_SELFTEST) += selftest.o
 
 subdir-ccflags-y += -D__CHECK_ENDIAN__

net/bluetooth/hci_debugfs.h

@@ -20,7 +20,29 @@
    SOFTWARE IS DISCLAIMED.
 */
 
+#if IS_ENABLED(CONFIG_BT_DEBUGFS)
+
 void hci_debugfs_create_common(struct hci_dev *hdev);
 void hci_debugfs_create_bredr(struct hci_dev *hdev);
 void hci_debugfs_create_le(struct hci_dev *hdev);
 void hci_debugfs_create_conn(struct hci_conn *conn);
+
+#else
+
+static inline void hci_debugfs_create_common(struct hci_dev *hdev)
+{
+}
+
+static inline void hci_debugfs_create_bredr(struct hci_dev *hdev)
+{
+}
+
+static inline void hci_debugfs_create_le(struct hci_dev *hdev)
+{
+}
+
+static inline void hci_debugfs_create_conn(struct hci_conn *conn)
+{
+}
+
+#endif