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Commit 1541f845 authored by Ivo Sieben's avatar Ivo Sieben Committed by Greg Kroah-Hartman
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tty: move global ldisc idle waitqueue to the individual ldisc 



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: default avatarIvo Sieben <meltedpianoman@gmail.com>
Acked-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3e62c413

drivers/tty/tty_ldisc.c

+4 −3
Original line number Original line Diff line number Diff line
@@ -28,7 +28,6 @@ 




static DEFINE_SPINLOCK(tty_ldisc_lock);

static DEFINE_SPINLOCK(tty_ldisc_lock);

static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait);

static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait);

static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_idle);

/* Line disc dispatch table */

/* Line disc dispatch table */

static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS];

static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS];
@@ -65,7 +64,7 @@ static void put_ldisc(struct tty_ldisc *ld) 
		return;

		return;

	}

	}

	local_irq_restore(flags);

	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;

	ld->ops = ldops;

	atomic_set(&ld->users, 1);

	atomic_set(&ld->users, 1);

	init_waitqueue_head(&ld->wq_idle);



	return ld;

	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)

static int tty_ldisc_wait_idle(struct tty_struct *tty, long timeout)

{

{

	long ret;

	long ret;

	ret = wait_event_timeout(tty_ldisc_idle,

	ret = wait_event_timeout(tty->ldisc->wq_idle,

			atomic_read(&tty->ldisc->users) == 1, timeout);

			atomic_read(&tty->ldisc->users) == 1, timeout);

	return ret > 0 ? 0 : -EBUSY;

	return ret > 0 ? 0 : -EBUSY;

}

}

include/linux/tty_ldisc.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -110,6 +110,7 @@ 
#include <linux/fs.h>

#include <linux/fs.h>

#include <linux/wait.h>

#include <linux/wait.h>

#include <linux/pps_kernel.h>

#include <linux/pps_kernel.h>

#include <linux/wait.h>





struct tty_ldisc_ops {

struct tty_ldisc_ops {

	int	magic;

	int	magic;
@@ -154,6 +155,7 @@ struct tty_ldisc_ops { 
struct tty_ldisc {

struct tty_ldisc {

	struct tty_ldisc_ops *ops;

	struct tty_ldisc_ops *ops;

	atomic_t users;

	atomic_t users;

	wait_queue_head_t wq_idle;

};

};





#define TTY_LDISC_MAGIC	0x5403

#define TTY_LDISC_MAGIC	0x5403