tty_port: add "tty_port_open" helper
For the moment this just moves the USB logic over and fixes the 'what if
we open and hangup at the same time' race noticed by Oliver Neukum.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/tty.h b/include/linux/tty.h
index f0f43d0..6352ac2 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -190,9 +190,15 @@
/* Control the DTR line */
void (*dtr_rts)(struct tty_port *port, int raise);
/* Called when the last close completes or a hangup finishes
- IFF the port was initialized. Do not use to free resources */
+ IFF the port was initialized. Do not use to free resources. Called
+ under the port mutex to serialize against activate/shutdowns */
void (*shutdown)(struct tty_port *port);
void (*drop)(struct tty_port *port);
+ /* Called under the port mutex from tty_port_open, serialized using
+ the port mutex */
+ /* FIXME: long term getting the tty argument *out* of this would be
+ good for consoles */
+ int (*activate)(struct tty_port *port, struct tty_struct *tty);
};
struct tty_port {
@@ -467,6 +473,8 @@
extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
extern void tty_port_close(struct tty_port *port,
struct tty_struct *tty, struct file *filp);
+extern int tty_port_open(struct tty_port *port,
+ struct tty_struct *tty, struct file *filp);
extern inline int tty_port_users(struct tty_port *port)
{
return port->count + port->blocked_open;