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

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

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Cox 2009-11-30 13:17:14 +00:00 committed by Greg Kroah-Hartman
parent 338818fd80
commit 568aafc627
2 changed files with 30 additions and 0 deletions
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18
drivers/char/tty_port.c
View File

@ -29,6 +29,7 @@ void tty_port_init(struct tty_port *port)
spin_lock_init(&port->lock); spin_lock_init(&port->lock);
port->close_delay = (50 * HZ) / 100; port->close_delay = (50 * HZ) / 100;
port->closing_wait = (3000 * HZ) / 100; port->closing_wait = (3000 * HZ) / 100;
kref_init(&port->kref);
} }
EXPORT_SYMBOL(tty_port_init); 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); 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 * tty_port_tty_get - get a tty reference

12
include/linux/tty.h
View File

@ -199,6 +199,8 @@ struct tty_port_operations {
/* FIXME: long term getting the tty argument *out* of this would be /* FIXME: long term getting the tty argument *out* of this would be
good for consoles */ good for consoles */
int (*activate)(struct tty_port *port, struct tty_struct *tty); 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 { struct tty_port {
@ -219,6 +221,7 @@ struct tty_port {
int drain_delay; /* Set to zero if no pure time int drain_delay; /* Set to zero if no pure time
based drain is needed else based drain is needed else
set to size of fifo */ 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 void tty_port_init(struct tty_port *port);
extern int tty_port_alloc_xmit_buf(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_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 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 void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
extern int tty_port_carrier_raised(struct tty_port *port); extern int tty_port_carrier_raised(struct tty_port *port);