Commit 54089d4c authored by Jiri Slaby's avatar Jiri Slaby Committed by Greg Kroah-Hartman
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TTY: srmcons, convert to use tty_port 



This is needed because the tty buffer will become a tty_port member
later. That will help us to wipe out most of the races and checks for
the tty pointer in hot paths.

Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ee024d49

arch/alpha/kernel/srmcons.c

+17 −15
Original line number Diff line number Diff line
@@ -30,9 +30,8 @@ static int srm_is_registered_console = 0; 
#define MAX_SRM_CONSOLE_DEVICES 1	/* only support 1 console device */



struct srmcons_private {

	struct tty_struct *tty;

	struct tty_port port;

	struct timer_list timer;

	spinlock_t lock;

} srmcons_singleton;



typedef union _srmcons_result {
@@ -68,20 +67,21 @@ static void 
srmcons_receive_chars(unsigned long data)

{

	struct srmcons_private *srmconsp = (struct srmcons_private *)data;

	struct tty_port *port = &srmconsp->port;

	unsigned long flags;

	int incr = 10;



	local_irq_save(flags);

	if (spin_trylock(&srmcons_callback_lock)) {

		if (!srmcons_do_receive_chars(srmconsp->tty))

		if (!srmcons_do_receive_chars(port->tty))

			incr = 100;

		spin_unlock(&srmcons_callback_lock);

	} 



	spin_lock(&srmconsp->lock);

	if (srmconsp->tty)

	spin_lock(&port->lock);

	if (port->tty)

		mod_timer(&srmconsp->timer, jiffies + incr);

	spin_unlock(&srmconsp->lock);

	spin_unlock(&port->lock);



	local_irq_restore(flags);

}
@@ -157,18 +157,19 @@ static int 
srmcons_open(struct tty_struct *tty, struct file *filp)

{

	struct srmcons_private *srmconsp = &srmcons_singleton;

	struct tty_port *port = &srmconsp->port;

	unsigned long flags;



	spin_lock_irqsave(&srmconsp->lock, flags);

	spin_lock_irqsave(&port->lock, flags);



	if (!srmconsp->tty) {

	if (!port->tty) {

		tty->driver_data = srmconsp;



		srmconsp->tty = tty;

		tty->port = port;

		port->tty = tty; /* XXX proper refcounting */

		mod_timer(&srmconsp->timer, jiffies + 10);

	}



	spin_unlock_irqrestore(&srmconsp->lock, flags);

	spin_unlock_irqrestore(&port->lock, flags);



	return 0;

}
@@ -177,16 +178,17 @@ static void 
srmcons_close(struct tty_struct *tty, struct file *filp)

{

	struct srmcons_private *srmconsp = tty->driver_data;

	struct tty_port *port = &srmconsp->port;

	unsigned long flags;



	spin_lock_irqsave(&srmconsp->lock, flags);

	spin_lock_irqsave(&port->lock, flags);



	if (tty->count == 1) {

		srmconsp->tty = NULL;

		port->tty = NULL;

		del_timer(&srmconsp->timer);

	}



	spin_unlock_irqrestore(&srmconsp->lock, flags);

	spin_unlock_irqrestore(&port->lock, flags);

}
@@ -203,7 +205,7 @@ static const struct tty_operations srmcons_ops = { 
static int __init

srmcons_init(void)

{

	spin_lock_init(&srmcons_singleton.lock);

	tty_port_init(&srmcons_singleton.port);

	setup_timer(&srmcons_singleton.timer, srmcons_receive_chars,

			(unsigned long)&srmcons_singleton);

	if (srm_is_registered_console) {

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