linux/kernel/sched/swait.c
Peter Zijlstra b3dae109fa sched/swait: Rename to exclusive
Since swait basically implemented exclusive waits only, make sure
the API reflects that.

  $ git grep -l -e "\<swake_up\>"
		-e "\<swait_event[^ (]*"
		-e "\<prepare_to_swait\>" | while read file;
    do
	sed -i -e 's/\<swake_up\>/&_one/g'
	       -e 's/\<swait_event[^ (]*/&_exclusive/g'
	       -e 's/\<prepare_to_swait\>/&_exclusive/g' $file;
    done

With a few manual touch-ups.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: bigeasy@linutronix.de
Cc: oleg@redhat.com
Cc: paulmck@linux.vnet.ibm.com
Cc: pbonzini@redhat.com
Link: https://lkml.kernel.org/r/20180612083909.261946548@infradead.org
2018-06-20 11:35:56 +02:00

133 lines
3.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* <linux/swait.h> (simple wait queues ) implementation:
*/
#include "sched.h"
void __init_swait_queue_head(struct swait_queue_head *q, const char *name,
struct lock_class_key *key)
{
raw_spin_lock_init(&q->lock);
lockdep_set_class_and_name(&q->lock, key, name);
INIT_LIST_HEAD(&q->task_list);
}
EXPORT_SYMBOL(__init_swait_queue_head);
/*
* The thing about the wake_up_state() return value; I think we can ignore it.
*
* If for some reason it would return 0, that means the previously waiting
* task is already running, so it will observe condition true (or has already).
*/
void swake_up_locked(struct swait_queue_head *q)
{
struct swait_queue *curr;
if (list_empty(&q->task_list))
return;
curr = list_first_entry(&q->task_list, typeof(*curr), task_list);
wake_up_process(curr->task);
list_del_init(&curr->task_list);
}
EXPORT_SYMBOL(swake_up_locked);
void swake_up_one(struct swait_queue_head *q)
{
unsigned long flags;
raw_spin_lock_irqsave(&q->lock, flags);
swake_up_locked(q);
raw_spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL(swake_up_one);
/*
* Does not allow usage from IRQ disabled, since we must be able to
* release IRQs to guarantee bounded hold time.
*/
void swake_up_all(struct swait_queue_head *q)
{
struct swait_queue *curr;
LIST_HEAD(tmp);
raw_spin_lock_irq(&q->lock);
list_splice_init(&q->task_list, &tmp);
while (!list_empty(&tmp)) {
curr = list_first_entry(&tmp, typeof(*curr), task_list);
wake_up_state(curr->task, TASK_NORMAL);
list_del_init(&curr->task_list);
if (list_empty(&tmp))
break;
raw_spin_unlock_irq(&q->lock);
raw_spin_lock_irq(&q->lock);
}
raw_spin_unlock_irq(&q->lock);
}
EXPORT_SYMBOL(swake_up_all);
static void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait)
{
wait->task = current;
if (list_empty(&wait->task_list))
list_add_tail(&wait->task_list, &q->task_list);
}
void prepare_to_swait_exclusive(struct swait_queue_head *q, struct swait_queue *wait, int state)
{
unsigned long flags;
raw_spin_lock_irqsave(&q->lock, flags);
__prepare_to_swait(q, wait);
set_current_state(state);
raw_spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL(prepare_to_swait_exclusive);
long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait, int state)
{
unsigned long flags;
long ret = 0;
raw_spin_lock_irqsave(&q->lock, flags);
if (unlikely(signal_pending_state(state, current))) {
/*
* See prepare_to_wait_event(). TL;DR, subsequent swake_up_one()
* must not see us.
*/
list_del_init(&wait->task_list);
ret = -ERESTARTSYS;
} else {
__prepare_to_swait(q, wait);
set_current_state(state);
}
raw_spin_unlock_irqrestore(&q->lock, flags);
return ret;
}
EXPORT_SYMBOL(prepare_to_swait_event);
void __finish_swait(struct swait_queue_head *q, struct swait_queue *wait)
{
__set_current_state(TASK_RUNNING);
if (!list_empty(&wait->task_list))
list_del_init(&wait->task_list);
}
void finish_swait(struct swait_queue_head *q, struct swait_queue *wait)
{
unsigned long flags;
__set_current_state(TASK_RUNNING);
if (!list_empty_careful(&wait->task_list)) {
raw_spin_lock_irqsave(&q->lock, flags);
list_del_init(&wait->task_list);
raw_spin_unlock_irqrestore(&q->lock, flags);
}
}
EXPORT_SYMBOL(finish_swait);