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tty: move global ldisc idle waitqueue to the individual ldisc

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The global wait_queue that is used for line discipline idle handling is
moved to a separate wait_queue for each line instance. This prevents
unnecessary blocking on one line, because of idle handling on another
line.

Signed-off-by: Ivo Sieben <meltedpianoman@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ivo Sieben 2012-05-03 14:37:43 +02:00 committed by Greg Kroah-Hartman
parent 3e62c413fb
commit 1541f845d1
2 changed files with 6 additions and 3 deletions
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7
drivers/tty/tty_ldisc.c
View file

@ -28,7 +28,6 @@
static DEFINE_SPINLOCK(tty_ldisc_lock);
static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait);
static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_idle);
/* Line disc dispatch table */
static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS];
@ -65,7 +64,7 @@ static void put_ldisc(struct tty_ldisc *ld)
return;
}
local_irq_restore(flags);
wake_up(&tty_ldisc_idle);
wake_up(&ld->wq_idle);
}
/**
@ -200,6 +199,8 @@ static struct tty_ldisc *tty_ldisc_get(int disc)
ld->ops = ldops;
atomic_set(&ld->users, 1);
init_waitqueue_head(&ld->wq_idle);
return ld;
}
@ -538,7 +539,7 @@ static void tty_ldisc_flush_works(struct tty_struct *tty)
static int tty_ldisc_wait_idle(struct tty_struct *tty, long timeout)
{
long ret;
ret = wait_event_timeout(tty_ldisc_idle,
ret = wait_event_timeout(tty->ldisc->wq_idle,
atomic_read(&tty->ldisc->users) == 1, timeout);
return ret > 0 ? 0 : -EBUSY;
}

2
include/linux/tty_ldisc.h
View file

@ -110,6 +110,7 @@
#include <linux/fs.h>
#include <linux/wait.h>
#include <linux/pps_kernel.h>
#include <linux/wait.h>
struct tty_ldisc_ops {
int magic;
@ -154,6 +155,7 @@ struct tty_ldisc_ops {
struct tty_ldisc {
struct tty_ldisc_ops *ops;
atomic_t users;
wait_queue_head_t wq_idle;
};
#define TTY_LDISC_MAGIC 0x5403