[RFC 5/9] tty: make ldisc_mutex nest under tty_lock

From: Arnd Bergmann
Date: Tue Mar 30 2010 - 16:57:12 EST


Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/char/tty_io.c | 2 +-
drivers/char/tty_ldisc.c | 10 +++++-----
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 91cc978..aeab6cb 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1279,7 +1279,7 @@ static int tty_reopen(struct tty_struct *tty)
tty->count++;
tty->driver = driver; /* N.B. why do this every time?? */

- mutex_lock(&tty->ldisc_mutex);
+ mutex_lock_tty_on(&tty->ldisc_mutex);
WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
mutex_unlock(&tty->ldisc_mutex);

diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c
index af5b4a7..946ac05 100644
--- a/drivers/char/tty_ldisc.c
+++ b/drivers/char/tty_ldisc.c
@@ -580,7 +580,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)

tty_wait_until_sent(tty, 0);

- mutex_lock(&tty->ldisc_mutex);
+ mutex_lock_tty_off(&tty->ldisc_mutex);

/*
* We could be midstream of another ldisc change which has
@@ -591,7 +591,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
mutex_unlock(&tty->ldisc_mutex);
wait_event(tty_ldisc_wait,
test_bit(TTY_LDISC_CHANGING, &tty->flags) == 0);
- mutex_lock(&tty->ldisc_mutex);
+ mutex_lock_tty_off(&tty->ldisc_mutex);
}

tty_lock();
@@ -632,7 +632,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)

flush_scheduled_work();

- mutex_lock(&tty->ldisc_mutex);
+ mutex_lock_tty_off(&tty->ldisc_mutex);
tty_lock();
if (test_bit(TTY_HUPPED, &tty->flags)) {
/* We were raced by the hangup method. It will have stomped
@@ -779,7 +779,7 @@ void tty_ldisc_hangup(struct tty_struct *tty)
*
* Avoid racing set_ldisc or tty_ldisc_release
*/
- mutex_lock(&tty->ldisc_mutex);
+ mutex_lock_tty_on(&tty->ldisc_mutex);
tty_ldisc_halt(tty);
/* At this point we have a closed ldisc and we want to
reopen it. We could defer this to the next open but
@@ -854,7 +854,7 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty)
tty_ldisc_halt(tty);
flush_scheduled_work();

- mutex_lock(&tty->ldisc_mutex);
+ mutex_lock_tty_on(&tty->ldisc_mutex);
/*
* Now kill off the ldisc
*/
--
1.7.0

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