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Subject[PATCH 12/68] TTY: srmcons, convert to use tty_port
Date
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: Jiri Slaby <jslaby@suse.cz>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
---
arch/alpha/kernel/srmcons.c | 32 +++++++++++++++++---------------
1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/arch/alpha/kernel/srmcons.c b/arch/alpha/kernel/srmcons.c
index 2c89ce5c..3ea8094 100644
--- a/arch/alpha/kernel/srmcons.c
+++ b/arch/alpha/kernel/srmcons.c
@@ -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) {
--
1.7.9.2



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