[PATCH 1/2] Add a new helper for sleepable BTM acquirements which is used by tty_write_message()
From: Jeff Liu <hidden>
Date: 2012-06-30 09:39:58
Also in:
linux-ext4, linux-fsdevel
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
This helper only used by tty_write_message(), it will sleep until BTM lock acquired. Signed-off-by: Jie Liu <redacted> --- drivers/tty/tty_mutex.c | 13 +++++++++++++ include/linux/tty.h | 1 + 2 files changed, 14 insertions(+), 0 deletions(-)
diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c
index 9ff986c..e638636 100644
--- a/drivers/tty/tty_mutex.c
+++ b/drivers/tty/tty_mutex.c@@ -30,3 +30,16 @@ void __lockfunc tty_unlock(void) mutex_unlock(&big_tty_mutex); } EXPORT_SYMBOL(tty_unlock); + +/* + * Wait until getting the big tty mutex. + * This function only used by tty_write_message(). + */ +void __lockfunc tty_lock_wait(void) +{ + while (!mutex_trylock(&big_tty_mutex)) { + set_current_state(TASK_UNINTERRUPTIBLE); + schedule(); + } +} +EXPORT_SYMBOL(tty_lock_wait);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 9f47ab5..5e01e0b 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h@@ -607,6 +607,7 @@ extern long vt_compat_ioctl(struct tty_struct *tty, /* functions for preparation of BKL removal */ extern void __lockfunc tty_lock(void) __acquires(tty_lock); extern void __lockfunc tty_unlock(void) __releases(tty_lock); +extern void __lockfunc tty_lock_wait(void) __acquires(tty_lock); /* * this shall be called only from where BTM is held (like close)
--
1.7.9