Commit b3212fe2 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Peter Zijlstra
Browse files

sched/swait: Prepare usage in completions 



As a preparation to use simple wait queues for completions:

  - Provide swake_up_all_locked() to support complete_all()
  - Make __prepare_to_swait() public available

This is done to enable the usage of complete() within truly atomic contexts
on a PREEMPT_RT enabled kernel.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200321113242.228481202@linutronix.de
parent e5d4d175

kernel/sched/sched.h

+3 −0
Original line number Diff line number Diff line
@@ -2492,3 +2492,6 @@ static inline bool is_per_cpu_kthread(struct task_struct *p) 
	return true;

}

#endif



void swake_up_all_locked(struct swait_queue_head *q);

void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);

kernel/sched/swait.c

+14 −1
Original line number Diff line number Diff line
@@ -32,6 +32,19 @@ void swake_up_locked(struct swait_queue_head *q) 
}

EXPORT_SYMBOL(swake_up_locked);



/*

 * Wake up all waiters. This is an interface which is solely exposed for

 * completions and not for general usage.

 *

 * It is intentionally different from swake_up_all() to allow usage from

 * hard interrupt context and interrupt disabled regions.

 */

void swake_up_all_locked(struct swait_queue_head *q)

{

	while (!list_empty(&q->task_list))

		swake_up_locked(q);

}



void swake_up_one(struct swait_queue_head *q)

{

	unsigned long flags;
@@ -69,7 +82,7 @@ void swake_up_all(struct swait_queue_head *q) 
}

EXPORT_SYMBOL(swake_up_all);



static void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait)

void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait)

{

	wait->task = current;

	if (list_empty(&wait->task_list))

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