1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/usb/serial/usb-serial.h b/drivers/usb/serial/usb-serial.h
index 238a5a871ed6..d7d27c3385b3 100644
--- a/drivers/usb/serial/usb-serial.h
+++ b/drivers/usb/serial/usb-serial.h
@@ -16,6 +16,7 @@
 
 #include <linux/config.h>
 #include <linux/kref.h>
+#include <asm/semaphore.h>
 
 #define SERIAL_TTY_MAJOR        188     /* Nice legal number now */
 #define SERIAL_TTY_MINORS       255     /* loads of devices :) */
@@ -30,6 +31,8 @@
  * @serial: pointer back to the struct usb_serial owner of this port.
  * @tty: pointer to the corresponding tty for this port.
  * @lock: spinlock to grab when updating portions of this structure.
+ * @sem: semaphore used to synchronize serial_open() and serial_close()
+ *      access for this port.
  * @number: the number of the port (the minor number).
  * @interrupt_in_buffer: pointer to the interrupt in buffer for this port.
  * @interrupt_in_urb: pointer to the interrupt in struct urb for this port.
@@ -60,6 +63,7 @@ struct usb_serial_port {
         struct usb_serial *     serial;
         struct tty_struct *     tty;
         spinlock_t              lock;
+        struct semaphore        sem;
         unsigned char           number;
 
         unsigned char *         interrupt_in_buffer;