tty: Fix USB kref leak

The sysrq code acquired a kref leak. Fix it by passing the tty separately
from the caller (thus effectively using the callers kref which all the
callers hold anyway)
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/usb/serial/ftdi_sio.c

@@ -2121,7 +2121,7 @@ static void ftdi_process_read(struct work_struct *work)
 				/* Note that the error flag is duplicated for
 				   every character received since we don't know
 				   which character it applied to */
-				if (!usb_serial_handle_sysrq_char(port,
+				if (!usb_serial_handle_sysrq_char(tty, port,
 						data[packet_offset + i]))
 					tty_insert_flip_char(tty,
 						data[packet_offset + i],

drivers/usb/serial/generic.c

@@ -432,7 +432,7 @@ static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
 	else {
 		/* Push data to tty */
 		for (i = 0; i < urb->actual_length; i++, ch++) {
-			if (!usb_serial_handle_sysrq_char(port, *ch))
+			if (!usb_serial_handle_sysrq_char(tty, port, *ch))
 				tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 		}
 	}
@@ -534,11 +534,12 @@ void usb_serial_generic_unthrottle(struct tty_struct *tty)
 	}
 }
 
-int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
+int usb_serial_handle_sysrq_char(struct tty_struct *tty,
+			struct usb_serial_port *port, unsigned int ch)
 {
 	if (port->sysrq && port->console) {
 		if (ch && time_before(jiffies, port->sysrq)) {
-			handle_sysrq(ch, tty_port_tty_get(&port->port));
+			handle_sysrq(ch, tty);
 			port->sysrq = 0;
 			return 1;
 		}

drivers/usb/serial/pl2303.c

@@ -1038,7 +1038,7 @@ static void pl2303_read_bulk_callback(struct urb *urb)
 		if (line_status & UART_OVERRUN_ERROR)
 			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 		for (i = 0; i < urb->actual_length; ++i)
-			if (!usb_serial_handle_sysrq_char(port, data[i]))
+			if (!usb_serial_handle_sysrq_char(tty, port, data[i]))
 				tty_insert_flip_char(tty, data[i], tty_flag);
 		tty_flip_buffer_push(tty);
 	}

include/linux/usb/serial.h

@@ -317,7 +317,8 @@ extern int usb_serial_generic_register(int debug);
 extern void usb_serial_generic_deregister(void);
 extern void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
 						 gfp_t mem_flags);
-extern int usb_serial_handle_sysrq_char(struct usb_serial_port *port,
+extern int usb_serial_handle_sysrq_char(struct tty_struct *tty,
+					struct usb_serial_port *port,
 					unsigned int ch);
 extern int usb_serial_handle_break(struct usb_serial_port *port);