USB: serial: drop extern keyword from function declarations

Drop the redundant extern keyword from function declarations in the
subsystem header file to improve readability (and make it easier to spot
the global variables).
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

include/linux/usb/serial.h

@@ -315,19 +315,19 @@ struct usb_serial_driver {
 #define to_usb_serial_driver(d) \
 	container_of(d, struct usb_serial_driver, driver)
 
-extern int usb_serial_register_drivers(struct usb_serial_driver *const serial_drivers[],
+int usb_serial_register_drivers(struct usb_serial_driver *const serial_drivers[],
 		const char *name, const struct usb_device_id *id_table);
-extern void usb_serial_deregister_drivers(struct usb_serial_driver *const serial_drivers[]);
-extern void usb_serial_port_softint(struct usb_serial_port *port);
+void usb_serial_deregister_drivers(struct usb_serial_driver *const serial_drivers[]);
+void usb_serial_port_softint(struct usb_serial_port *port);
 
-extern int usb_serial_suspend(struct usb_interface *intf, pm_message_t message);
-extern int usb_serial_resume(struct usb_interface *intf);
+int usb_serial_suspend(struct usb_interface *intf, pm_message_t message);
+int usb_serial_resume(struct usb_interface *intf);
 
 /* USB Serial console functions */
 #ifdef CONFIG_USB_SERIAL_CONSOLE
-extern void usb_serial_console_init(int minor);
-extern void usb_serial_console_exit(void);
-extern void usb_serial_console_disconnect(struct usb_serial *serial);
+void usb_serial_console_init(int minor);
+void usb_serial_console_exit(void);
+void usb_serial_console_disconnect(struct usb_serial *serial);
 #else
 static inline void usb_serial_console_init(int minor) { }
 static inline void usb_serial_console_exit(void) { }
@@ -335,40 +335,32 @@ static inline void usb_serial_console_disconnect(struct usb_serial *serial) {}
 #endif
 
 /* Functions needed by other parts of the usbserial core */
-extern struct usb_serial_port *usb_serial_port_get_by_minor(unsigned int minor);
-extern void usb_serial_put(struct usb_serial *serial);
-extern int usb_serial_generic_open(struct tty_struct *tty,
-	struct usb_serial_port *port);
-extern int usb_serial_generic_write_start(struct usb_serial_port *port,
-							gfp_t mem_flags);
-extern int usb_serial_generic_write(struct tty_struct *tty,
-	struct usb_serial_port *port, const unsigned char *buf, int count);
-extern void usb_serial_generic_close(struct usb_serial_port *port);
-extern int usb_serial_generic_resume(struct usb_serial *serial);
-extern int usb_serial_generic_write_room(struct tty_struct *tty);
-extern int usb_serial_generic_chars_in_buffer(struct tty_struct *tty);
-extern void usb_serial_generic_wait_until_sent(struct tty_struct *tty,
-								long timeout);
-extern void usb_serial_generic_read_bulk_callback(struct urb *urb);
-extern void usb_serial_generic_write_bulk_callback(struct urb *urb);
-extern void usb_serial_generic_throttle(struct tty_struct *tty);
-extern void usb_serial_generic_unthrottle(struct tty_struct *tty);
-extern int usb_serial_generic_tiocmiwait(struct tty_struct *tty,
-							unsigned long arg);
-extern int usb_serial_generic_get_icount(struct tty_struct *tty,
-					struct serial_icounter_struct *icount);
-extern int usb_serial_generic_register(void);
-extern void usb_serial_generic_deregister(void);
-extern int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
-						 gfp_t mem_flags);
-extern void usb_serial_generic_process_read_urb(struct urb *urb);
-extern int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
-						void *dest, size_t size);
+struct usb_serial_port *usb_serial_port_get_by_minor(unsigned int minor);
+void usb_serial_put(struct usb_serial *serial);
+int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port);
+int usb_serial_generic_write_start(struct usb_serial_port *port, gfp_t mem_flags);
+int usb_serial_generic_write(struct tty_struct *tty, struct usb_serial_port *port,
+		const unsigned char *buf, int count);
+void usb_serial_generic_close(struct usb_serial_port *port);
+int usb_serial_generic_resume(struct usb_serial *serial);
+int usb_serial_generic_write_room(struct tty_struct *tty);
+int usb_serial_generic_chars_in_buffer(struct tty_struct *tty);
+void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout);
+void usb_serial_generic_read_bulk_callback(struct urb *urb);
+void usb_serial_generic_write_bulk_callback(struct urb *urb);
+void usb_serial_generic_throttle(struct tty_struct *tty);
+void usb_serial_generic_unthrottle(struct tty_struct *tty);
+int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg);
+int usb_serial_generic_get_icount(struct tty_struct *tty, struct serial_icounter_struct *icount);
+int usb_serial_generic_register(void);
+void usb_serial_generic_deregister(void);
+int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port, gfp_t mem_flags);
+void usb_serial_generic_process_read_urb(struct urb *urb);
+int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port, void *dest, size_t size);
 
 #if defined(CONFIG_USB_SERIAL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
-extern int usb_serial_handle_sysrq_char(struct usb_serial_port *port,
-					unsigned int ch);
-extern int usb_serial_handle_break(struct usb_serial_port *port);
+int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch);
+int usb_serial_handle_break(struct usb_serial_port *port);
 #else
 static inline int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 {
@@ -380,13 +372,12 @@ static inline int usb_serial_handle_break(struct usb_serial_port *port)
 }
 #endif
 
-extern void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
-					 struct tty_struct *tty,
-					 unsigned int status);
+void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
+		struct tty_struct *tty, unsigned int status);
 
 
-extern int usb_serial_bus_register(struct usb_serial_driver *device);
-extern void usb_serial_bus_deregister(struct usb_serial_driver *device);
+int usb_serial_bus_register(struct usb_serial_driver *device);
+void usb_serial_bus_deregister(struct usb_serial_driver *device);
 
 extern struct bus_type usb_serial_bus_type;
 extern struct tty_driver *usb_serial_tty_driver;