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sched, wait: Use wrapper functions 

epoll should not touch flags in wait_queue_t. This patch introduces a new
function __add_wait_queue_exclusive(), for the users, who use wait queue as a
LIFO queue.

__add_wait_queue_tail_exclusive() is introduced too instead of
add_wait_queue_exclusive_locked(). remove_wait_queue_locked() is removed, as
it is a duplicate of __remove_wait_queue(), disliked by users, and with less
users.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: <containers@lists.linux-foundation.org>
LKML-Reference: <1273214006-2979-1-git-send-email-xiaosuo@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
hifive-unleashed-5.1
Changli Gao 2010-05-07 14:33:26 +08:00 committed by Ingo Molnar
parent af507ae8a0
commit a93d2f1744
4 changed files with 18 additions and 25 deletions
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3
fs/eventpoll.c
View File

@ -1140,8 +1140,7 @@ retry:
* ep_poll_callback() when events will become available.
*/
init_waitqueue_entry(&wait, current);
wait.flags |= WQ_FLAG_EXCLUSIVE;
__add_wait_queue(&ep->wq, &wait);
__add_wait_queue_exclusive(&ep->wq, &wait);
for (;;) {
/*

35
include/linux/wait.h
View File

@ -127,12 +127,26 @@ static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new)
/*
* Used for wake-one threads:
*/
static inline void __add_wait_queue_exclusive(wait_queue_head_t *q,
wait_queue_t *wait)
{
wait->flags |= WQ_FLAG_EXCLUSIVE;
__add_wait_queue(q, wait);
}
static inline void __add_wait_queue_tail(wait_queue_head_t *head,
wait_queue_t *new)
wait_queue_t *new)
{
list_add_tail(&new->task_list, &head->task_list);
}
static inline void __add_wait_queue_tail_exclusive(wait_queue_head_t *q,
wait_queue_t *wait)
{
wait->flags |= WQ_FLAG_EXCLUSIVE;
__add_wait_queue_tail(q, wait);
}
static inline void __remove_wait_queue(wait_queue_head_t *head,
wait_queue_t *old)
{
@ -403,25 +417,6 @@ do { \
__ret; \
})
/*
* Must be called with the spinlock in the wait_queue_head_t held.
*/
static inline void add_wait_queue_exclusive_locked(wait_queue_head_t *q,
wait_queue_t * wait)
{
wait->flags |= WQ_FLAG_EXCLUSIVE;
__add_wait_queue_tail(q, wait);
}
/*
* Must be called with the spinlock in the wait_queue_head_t held.
*/
static inline void remove_wait_queue_locked(wait_queue_head_t *q,
wait_queue_t * wait)
{
__remove_wait_queue(q, wait);
}
/*
* These are the old interfaces to sleep waiting for an event.
* They are racy. DO NOT use them, use the wait_event* interfaces above.

2
kernel/cgroup.c
View File

@ -3010,7 +3010,7 @@ static int cgroup_event_wake(wait_queue_t *wait, unsigned mode,
unsigned long flags = (unsigned long)key;
if (flags & POLLHUP) {
remove_wait_queue_locked(event->wqh, &event->wait);
__remove_wait_queue(event->wqh, &event->wait);
spin_lock(&cgrp->event_list_lock);
list_del(&event->list);
spin_unlock(&cgrp->event_list_lock);

3
kernel/sched.c
View File

@ -3983,8 +3983,7 @@ do_wait_for_common(struct completion *x, long timeout, int state)
if (!x->done) {
DECLARE_WAITQUEUE(wait, current);
wait.flags |= WQ_FLAG_EXCLUSIVE;
__add_wait_queue_tail(&x->wait, &wait);
__add_wait_queue_tail_exclusive(&x->wait, &wait);
do {
if (signal_pending_state(state, current)) {
timeout = -ERESTARTSYS;