diff --git a/fs/eventpoll.c b/fs/eventpoll.c index bd056a5..e9b3ebe 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_ex(&ep->wq, &wait); for (;;) { /* diff --git a/include/linux/list.h b/include/linux/list.h index 8392884..3622d90 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -573,6 +573,11 @@ static inline int hlist_unhashed(const struct hlist_node *h) return !h->pprev; } +static inline int hlist_unhashed_careful(const struct hlist_node *h) +{ + return !h->pprev && !h->next; +} + static inline int hlist_empty(const struct hlist_head *h) { return !h->first; diff --git a/include/linux/wait.h b/include/linux/wait.h index a48e16b..5f42123 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -30,11 +30,9 @@ typedef int (*wait_queue_func_t)(wait_queue_t *wait, unsigned mode, int flags, v int default_wake_function(wait_queue_t *wait, unsigned mode, int flags, void *key); struct __wait_queue { - unsigned int flags; -#define WQ_FLAG_EXCLUSIVE 0x01 void *private; wait_queue_func_t func; - struct list_head task_list; + struct hlist_node task_list; }; struct wait_bit_key { @@ -49,7 +47,8 @@ struct wait_bit_queue { struct __wait_queue_head { spinlock_t lock; - struct list_head task_list; + struct hlist_head task_list; + struct hlist_head task_list_ex; }; typedef struct __wait_queue_head wait_queue_head_t; @@ -69,7 +68,8 @@ struct task_struct; #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ - .task_list = { &(name).task_list, &(name).task_list } } + .task_list = HLIST_HEAD_INIT, \ + .task_list_ex = HLIST_HEAD_INIT } #define DECLARE_WAIT_QUEUE_HEAD(name) \ wait_queue_head_t name = __WAIT_QUEUE_HEAD_INITIALIZER(name) @@ -97,7 +97,6 @@ extern void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *) static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p) { - q->flags = 0; q->private = p; q->func = default_wake_function; } @@ -105,14 +104,13 @@ static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p) static inline void init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func) { - q->flags = 0; q->private = NULL; q->func = func; } static inline int waitqueue_active(wait_queue_head_t *q) { - return !list_empty(&q->task_list); + return !hlist_empty(&q->task_list) || !hlist_empty(&q->task_list_ex); } extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait); @@ -121,22 +119,22 @@ extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait); static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_t *new) { - list_add(&new->task_list, &head->task_list); + hlist_add_head(&new->task_list, &head->task_list); } /* * Used for wake-one threads: */ -static inline void __add_wait_queue_tail(wait_queue_head_t *head, +static inline void __add_wait_queue_ex(wait_queue_head_t *head, wait_queue_t *new) { - list_add_tail(&new->task_list, &head->task_list); + hlist_add_head(&new->task_list, &head->task_list_ex); } static inline void __remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old) { - list_del(&old->task_list); + hlist_del(&old->task_list); } void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key); @@ -409,8 +407,7 @@ do { \ 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); + __add_wait_queue_ex(q, wait); } /* @@ -449,7 +446,7 @@ int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key); wait_queue_t name = { \ .private = current, \ .func = function, \ - .task_list = LIST_HEAD_INIT((name).task_list), \ + .task_list = { NULL, NULL }, \ } #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function) @@ -460,8 +457,7 @@ int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key); .wait = { \ .private = current, \ .func = wake_bit_function, \ - .task_list = \ - LIST_HEAD_INIT((name).wait.task_list), \ + .task_list = { NULL, NULL }, \ }, \ } @@ -469,7 +465,7 @@ int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key); do { \ (wait)->private = current; \ (wait)->func = autoremove_wake_function; \ - INIT_LIST_HEAD(&(wait)->task_list); \ + INIT_HLIST_NODE(&(wait)->task_list); \ } while (0) /** diff --git a/kernel/sched.c b/kernel/sched.c index be5ab70..813fd44 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3901,13 +3901,14 @@ EXPORT_SYMBOL(default_wake_function); static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, int nr_exclusive, int wake_flags, void *key) { - wait_queue_t *curr, *next; + wait_queue_t *curr; + struct hlist_node *pos, *n; - list_for_each_entry_safe(curr, next, &q->task_list, task_list) { - unsigned flags = curr->flags; + hlist_for_each_entry_safe(curr, pos, n, &q->task_list, task_list) + curr->func(curr, mode, wake_flags, key); - if (curr->func(curr, mode, wake_flags, key) && - (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) + hlist_for_each_entry_safe(curr, pos, n, &q->task_list_ex, task_list) { + if (curr->func(curr, mode, wake_flags, key) && !--nr_exclusive) break; } } diff --git a/kernel/wait.c b/kernel/wait.c index c4bd3d8..b4278f0 100644 --- a/kernel/wait.c +++ b/kernel/wait.c @@ -14,7 +14,8 @@ void __init_waitqueue_head(wait_queue_head_t *q, struct lock_class_key *key) { spin_lock_init(&q->lock); lockdep_set_class(&q->lock, key); - INIT_LIST_HEAD(&q->task_list); + INIT_HLIST_HEAD(&q->task_list); + INIT_HLIST_HEAD(&q->task_list_ex); } EXPORT_SYMBOL(__init_waitqueue_head); @@ -23,7 +24,6 @@ void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait) { unsigned long flags; - wait->flags &= ~WQ_FLAG_EXCLUSIVE; spin_lock_irqsave(&q->lock, flags); __add_wait_queue(q, wait); spin_unlock_irqrestore(&q->lock, flags); @@ -34,9 +34,8 @@ void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait) { unsigned long flags; - wait->flags |= WQ_FLAG_EXCLUSIVE; spin_lock_irqsave(&q->lock, flags); - __add_wait_queue_tail(q, wait); + __add_wait_queue_ex(q, wait); spin_unlock_irqrestore(&q->lock, flags); } EXPORT_SYMBOL(add_wait_queue_exclusive); @@ -69,9 +68,8 @@ prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state) { unsigned long flags; - wait->flags &= ~WQ_FLAG_EXCLUSIVE; spin_lock_irqsave(&q->lock, flags); - if (list_empty(&wait->task_list)) + if (hlist_unhashed(&wait->task_list)) __add_wait_queue(q, wait); set_current_state(state); spin_unlock_irqrestore(&q->lock, flags); @@ -83,10 +81,9 @@ prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state) { unsigned long flags; - wait->flags |= WQ_FLAG_EXCLUSIVE; spin_lock_irqsave(&q->lock, flags); - if (list_empty(&wait->task_list)) - __add_wait_queue_tail(q, wait); + if (hlist_unhashed(&wait->task_list)) + __add_wait_queue_ex(q, wait); set_current_state(state); spin_unlock_irqrestore(&q->lock, flags); } @@ -119,9 +116,9 @@ void finish_wait(wait_queue_head_t *q, wait_queue_t *wait) * have _one_ other CPU that looks at or modifies * the list). */ - if (!list_empty_careful(&wait->task_list)) { + if (!hlist_unhashed_careful(&wait->task_list)) { spin_lock_irqsave(&q->lock, flags); - list_del_init(&wait->task_list); + hlist_del_init(&wait->task_list); spin_unlock_irqrestore(&q->lock, flags); } } @@ -152,8 +149,8 @@ void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait, __set_current_state(TASK_RUNNING); spin_lock_irqsave(&q->lock, flags); - if (!list_empty(&wait->task_list)) - list_del_init(&wait->task_list); + if (!hlist_unhashed(&wait->task_list)) + hlist_del_init(&wait->task_list); else if (waitqueue_active(q)) __wake_up_locked_key(q, mode, key); spin_unlock_irqrestore(&q->lock, flags); @@ -165,7 +162,7 @@ int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void * int ret = default_wake_function(wait, mode, sync, key); if (ret) - list_del_init(&wait->task_list); + hlist_del_init(&wait->task_list); return ret; } EXPORT_SYMBOL(autoremove_wake_function);