From be1bc2889a4db4961ef69f47fb471ecae9f23ade Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 1 Jun 2010 22:53:05 +0200 Subject: tty: introduce wait_event_interruptible_tty Calling wait_event_interruptible implicitly releases the BKL when it sleeps, but we need to do this explcitly when we have converted it to a mutex. Signed-off-by: Arnd Bergmann Cc: Alan Cox Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) (limited to 'include') diff --git a/include/linux/tty.h b/include/linux/tty.h index 6ead6b60c743..955d72ea71c0 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -607,5 +607,47 @@ static inline void tty_unlock(void) __releases(kernel_lock) } #define tty_locked() (kernel_locked()) +/* + * wait_event_interruptible_tty -- wait for a condition with the tty lock held + * + * The condition we are waiting for might take a long time to + * become true, or might depend on another thread taking the + * BTM. In either case, we need to drop the BTM to guarantee + * forward progress. This is a leftover from the conversion + * from the BKL and should eventually get removed as the BTM + * falls out of use. + * + * Do not use in new code. + */ +#define wait_event_interruptible_tty(wq, condition) \ +({ \ + int __ret = 0; \ + if (!(condition)) { \ + __wait_event_interruptible_tty(wq, condition, __ret); \ + } \ + __ret; \ +}) + +#define __wait_event_interruptible_tty(wq, condition, ret) \ +do { \ + DEFINE_WAIT(__wait); \ + \ + for (;;) { \ + prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \ + if (condition) \ + break; \ + if (!signal_pending(current)) { \ + tty_unlock(); \ + schedule(); \ + tty_lock(); \ + continue; \ + } \ + ret = -ERESTARTSYS; \ + break; \ + } \ + finish_wait(&wq, &__wait); \ +} while (0) + + #endif /* __KERNEL__ */ #endif -- cgit v1.2.3