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Commit 0176beaf authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Ingo Molnar
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sched/wait: Introduce init_wait_entry() 



The partial initialization of wait_queue_t in prepare_to_wait_event() looks
ugly. This was done to shrink .text, but we can simply add the new helper
which does the full initialization and shrink the compiled code a bit more.

And. This way prepare_to_wait_event() can have more users. In particular we
are ready to remove the signal_pending_state() checks from wait_bit_action_f
helpers and change __wait_on_bit_lock() to use prepare_to_wait_event().

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160906140055.GA6167@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent eaf9ef52

include/linux/wait.h

+3 −6
Original line number Diff line number Diff line
@@ -248,6 +248,8 @@ wait_queue_head_t *bit_waitqueue(void *, int); 
	(!__builtin_constant_p(state) ||				\

		state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE)	\



extern void init_wait_entry(wait_queue_t *__wait, int flags);



/*

 * The below macro ___wait_event() has an explicit shadow of the __ret

 * variable when used from the wait_event_*() macros.
@@ -266,12 +268,7 @@ wait_queue_head_t *bit_waitqueue(void *, int); 
	wait_queue_t __wait;						\

	long __ret = ret;	/* explicit shadow */			\

									\

	INIT_LIST_HEAD(&__wait.task_list);				\

	if (exclusive)							\

		__wait.flags = WQ_FLAG_EXCLUSIVE;			\

	else								\

		__wait.flags = 0;					\

									\

	init_wait_entry(&__wait, exclusive ? WQ_FLAG_EXCLUSIVE : 0);	\

	for (;;) {							\

		long __int = prepare_to_wait_event(&wq, &__wait, state);\

									\

kernel/sched/wait.c

+9 −3
Original line number Diff line number Diff line
@@ -196,14 +196,20 @@ prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state) 
}

EXPORT_SYMBOL(prepare_to_wait_exclusive);



void init_wait_entry(wait_queue_t *wait, int flags)

{

	wait->flags = flags;

	wait->private = current;

	wait->func = autoremove_wake_function;

	INIT_LIST_HEAD(&wait->task_list);

}

EXPORT_SYMBOL(init_wait_entry);



long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state)

{

	unsigned long flags;

	long ret = 0;



	wait->private = current;

	wait->func = autoremove_wake_function;



	spin_lock_irqsave(&q->lock, flags);

	if (unlikely(signal_pending_state(state, current))) {

		/*