USB: usb-serial: Prepare for BKL push down

Take the lock in usb-serial instead. As it relies on the BKL internally
we can't push it any deeper yet.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 2138ba8aeb69..aea861e9173e 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -401,11 +401,13 @@ static int serial_ioctl (struct tty_struct *tty, struct file * file, unsigned in
         struct usb_serial_port *port = tty->driver_data;
         int retval = -ENODEV;
 
+        lock_kernel();
         if (!port)
                 goto exit;
 
         dbg("%s - port %d, cmd 0x%.4x", __FUNCTION__, port->number, cmd);
 
+        /* Caution - port->open_count is BKL protected */
         if (!port->open_count) {
                 dbg ("%s - port not open", __FUNCTION__);
                 goto exit;
@@ -416,8 +418,8 @@ static int serial_ioctl (struct tty_struct *tty, struct file * file, unsigned in
                 retval = port->serial->type->ioctl(port, file, cmd, arg);
         else
                 retval = -ENOIOCTLCMD;
-
 exit:
+        unlock_kernel();
         return retval;
 }
 
@@ -446,19 +448,24 @@ static void serial_break (struct tty_struct *tty, int break_state)
 {
         struct usb_serial_port *port = tty->driver_data;
 
-        if (!port)
+        lock_kernel();
+        if (!port) {
+                unlock_kernel();
                 return;
+        }
 
         dbg("%s - port %d", __FUNCTION__, port->number);
 
         if (!port->open_count) {
                 dbg("%s - port not open", __FUNCTION__);
+                unlock_kernel();
                 return;
         }
 
         /* pass on to the driver specific version of this function if it is available */
         if (port->serial->type->break_ctl)
                 port->serial->type->break_ctl(port, break_state);
+        unlock_kernel();
 }
 
 static int serial_read_proc (char *page, char **start, off_t off, int count, int *eof, void *data)