From a93d2f1744206827ccf416e2cdc5018aa503314e Mon Sep 17 00:00:00 2001 From: Changli Gao Date: Fri, 7 May 2010 14:33:26 +0800 Subject: [PATCH] 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 Signed-off-by: Peter Zijlstra Cc: Alexander Viro Cc: Paul Menage Cc: Li Zefan Cc: Davide Libenzi Cc: LKML-Reference: <1273214006-2979-1-git-send-email-xiaosuo@gmail.com> Signed-off-by: Ingo Molnar --- fs/eventpoll.c | 3 +-- include/linux/wait.h | 35 +++++++++++++++-------------------- kernel/cgroup.c | 2 +- kernel/sched.c | 3 +-- 4 files changed, 18 insertions(+), 25 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index bd056a5..3817149 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -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 (;;) { /* diff --git a/include/linux/wait.h b/include/linux/wait.h index a48e16b..76d96d0 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -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) { @@ -404,25 +418,6 @@ do { \ }) /* - * 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. * We plan to remove these interfaces. diff --git a/kernel/cgroup.c b/kernel/cgroup.c index e2769e1..4a07d05 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -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); diff --git a/kernel/sched.c b/kernel/sched.c index 39aa9c7..b531d79 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -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; -- 1.8.2.3