Commit 568aafc6 authored by Alan Cox's avatar Alan Cox Committed by Greg Kroah-Hartman
Browse files

tty: tty_port: Add a kref object to the tty port 



Users of tty port need a way to refcount ports when hotplugging is
involved.

Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 338818fd

drivers/char/tty_port.c

+18 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ void tty_port_init(struct tty_port *port) 
	spin_lock_init(&port->lock);

	port->close_delay = (50 * HZ) / 100;

	port->closing_wait = (3000 * HZ) / 100;

	kref_init(&port->kref);

}

EXPORT_SYMBOL(tty_port_init);
@@ -56,6 +57,23 @@ void tty_port_free_xmit_buf(struct tty_port *port) 
}

EXPORT_SYMBOL(tty_port_free_xmit_buf);



static void tty_port_destructor(struct kref *kref)

{

	struct tty_port *port = container_of(kref, struct tty_port, kref);

	if (port->xmit_buf)

		free_page((unsigned long)port->xmit_buf);

	if (port->ops->destruct)

		port->ops->destruct(port);

	else

		kfree(port);

}



void tty_port_put(struct tty_port *port)

{

	if (port)

		kref_put(&port->kref, tty_port_destructor);

}

EXPORT_SYMBOL(tty_port_put);



/**

 *	tty_port_tty_get	-	get a tty reference

include/linux/tty.h

+12 −0
Original line number Diff line number Diff line
@@ -199,6 +199,8 @@ struct tty_port_operations { 
        /* 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);

	/* Called on the final put of a port */

	void (*destruct)(struct tty_port *port);

};

	

struct tty_port {
@@ -219,6 +221,7 @@ struct tty_port { 
	int			drain_delay;	/* Set to zero if no pure time

						   based drain is needed else

						   set to size of fifo */

	struct kref		kref;		/* Ref counter */

};



/*
@@ -461,6 +464,15 @@ extern int tty_write_lock(struct tty_struct *tty, int ndelay); 
extern void tty_port_init(struct tty_port *port);

extern int tty_port_alloc_xmit_buf(struct tty_port *port);

extern void tty_port_free_xmit_buf(struct tty_port *port);

extern void tty_port_put(struct tty_port *port);



extern inline struct tty_port *tty_port_get(struct tty_port *port)

{

	if (port)

		kref_get(&port->kref);

	return port;

}



extern struct tty_struct *tty_port_tty_get(struct tty_port *port);

extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);

extern int tty_port_carrier_raised(struct tty_port *port);