From 50816c48997af857d4bab3dca1aba90339705e96 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 5 Mar 2017 10:33:16 +0100 Subject: [PATCH] sched/wait: Standardize internal naming of wait-queue entries So the various wait-queue entry variables in include/linux/wait.h and kernel/sched/wait.c are named in a colorfully inconsistent way: wait_queue_entry_t *wait wait_queue_entry_t *__wait (even in plain C code!) wait_queue_entry_t *q (!) wait_queue_entry_t *new (making anyone who knows C++ cringe) wait_queue_entry_t *old I think part of the reason for the inconsistency is the constant apparent confusion about what a wait queue 'head' versus 'entry' is. ( Some of the documentation talks about a 'wait descriptor', which is the wait-queue entry itself - further adding to the confusion. ) The most common name is 'wait', but that in itself is somewhat ambiguous as well, as it does not really make it clear whether it's a wait-queue entry or head. To improve all this name the wait-queue entry structure parameters and variables consistently and push through this naming into all the wait.h and wait.c code: struct wait_queue_entry *wq_entry The 'wq_' prefix makes it easy to grep for, and we also use the opportunity to move away from the typedef to a plain 'struct' naming: in the kernel we typically reserve typedefs for cases where a C structure is really small and somewhat opaque - such as pte_t. wait-queue entries are neither small nor opaque, so use the more standard 'struct xxx_entry' list management code nomenclature instead. ( We don't touch external users, and we preserve the typedef as well for actual wait-queue users, to reduce unnecessary churn. ) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/wait.h | 84 ++++++++++++++++++++++---------------------- kernel/sched/wait.c | 98 ++++++++++++++++++++++++++-------------------------- 2 files changed, 91 insertions(+), 91 deletions(-) diff --git a/include/linux/wait.h b/include/linux/wait.h index 5889f0c..77fdea8 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -11,8 +11,9 @@ #include typedef struct wait_queue_entry wait_queue_entry_t; -typedef int (*wait_queue_func_t)(wait_queue_entry_t *wait, unsigned mode, int flags, void *key); -int default_wake_function(wait_queue_entry_t *wait, unsigned mode, int flags, void *key); + +typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key); +int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key); /* wait_queue_entry::flags */ #define WQ_FLAG_EXCLUSIVE 0x01 @@ -37,7 +38,7 @@ struct wait_bit_key { struct wait_bit_queue { struct wait_bit_key key; - wait_queue_entry_t wait; + struct wait_queue_entry wait; }; struct __wait_queue_head { @@ -58,7 +59,7 @@ struct task_struct; .task_list = { NULL, NULL } } #define DECLARE_WAITQUEUE(name, tsk) \ - wait_queue_entry_t name = __WAITQUEUE_INITIALIZER(name, tsk) + struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk) #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ @@ -91,19 +92,19 @@ extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct # define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name) #endif -static inline void init_waitqueue_entry(wait_queue_entry_t *q, struct task_struct *p) +static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p) { - q->flags = 0; - q->private = p; - q->func = default_wake_function; + wq_entry->flags = 0; + wq_entry->private = p; + wq_entry->func = default_wake_function; } static inline void -init_waitqueue_func_entry(wait_queue_entry_t *q, wait_queue_func_t func) +init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func) { - q->flags = 0; - q->private = NULL; - q->func = func; + wq_entry->flags = 0; + wq_entry->private = NULL; + wq_entry->func = func; } /** @@ -162,42 +163,41 @@ static inline bool wq_has_sleeper(wait_queue_head_t *wq) return waitqueue_active(wq); } -extern void add_wait_queue(wait_queue_head_t *q, wait_queue_entry_t *wait); -extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait); -extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_entry_t *wait); +extern void add_wait_queue(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); +extern void add_wait_queue_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); +extern void remove_wait_queue(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); -static inline void __add_wait_queue(wait_queue_head_t *head, wait_queue_entry_t *new) +static inline void __add_wait_queue(wait_queue_head_t *head, struct wait_queue_entry *wq_entry) { - list_add(&new->task_list, &head->task_list); + list_add(&wq_entry->task_list, &head->task_list); } /* * Used for wake-one threads: */ static inline void -__add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait) +__add_wait_queue_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry) { - wait->flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue(q, wait); + wq_entry->flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue(q, wq_entry); } -static inline void __add_wait_queue_entry_tail(wait_queue_head_t *head, - wait_queue_entry_t *new) +static inline void __add_wait_queue_entry_tail(wait_queue_head_t *head, struct wait_queue_entry *wq_entry) { - list_add_tail(&new->task_list, &head->task_list); + list_add_tail(&wq_entry->task_list, &head->task_list); } static inline void -__add_wait_queue_entry_tail_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait) +__add_wait_queue_entry_tail_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry) { - wait->flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue_entry_tail(q, wait); + wq_entry->flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue_entry_tail(q, wq_entry); } static inline void -__remove_wait_queue(wait_queue_head_t *head, wait_queue_entry_t *old) +__remove_wait_queue(wait_queue_head_t *head, struct wait_queue_entry *wq_entry) { - list_del(&old->task_list); + list_del(&wq_entry->task_list); } typedef int wait_bit_action_f(struct wait_bit_key *, int mode); @@ -252,7 +252,7 @@ wait_queue_head_t *bit_waitqueue(void *, int); (!__builtin_constant_p(state) || \ state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \ -extern void init_wait_entry(wait_queue_entry_t *__wait, int flags); +extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags); /* * The below macro ___wait_event() has an explicit shadow of the __ret @@ -269,12 +269,12 @@ extern void init_wait_entry(wait_queue_entry_t *__wait, int flags); #define ___wait_event(wq, condition, state, exclusive, ret, cmd) \ ({ \ __label__ __out; \ - wait_queue_entry_t __wait; \ + struct wait_queue_entry __wq_entry; \ long __ret = ret; /* explicit shadow */ \ \ - init_wait_entry(&__wait, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \ + init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0);\ for (;;) { \ - long __int = prepare_to_wait_event(&wq, &__wait, state);\ + long __int = prepare_to_wait_event(&wq, &__wq_entry, state);\ \ if (condition) \ break; \ @@ -286,7 +286,7 @@ extern void init_wait_entry(wait_queue_entry_t *__wait, int flags); \ cmd; \ } \ - finish_wait(&wq, &__wait); \ + finish_wait(&wq, &__wq_entry); \ __out: __ret; \ }) @@ -970,17 +970,17 @@ do { \ /* * Waitqueues which are removed from the waitqueue_head at wakeup time */ -void prepare_to_wait(wait_queue_head_t *q, wait_queue_entry_t *wait, int state); -void prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait, int state); -long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_entry_t *wait, int state); -void finish_wait(wait_queue_head_t *q, wait_queue_entry_t *wait); -long wait_woken(wait_queue_entry_t *wait, unsigned mode, long timeout); -int woken_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key); -int autoremove_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key); -int wake_bit_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key); +void prepare_to_wait(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state); +void prepare_to_wait_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state); +long prepare_to_wait_event(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state); +void finish_wait(wait_queue_head_t *q, struct wait_queue_entry *wq_entry); +long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout); +int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); +int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); +int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); #define DEFINE_WAIT_FUNC(name, function) \ - wait_queue_entry_t name = { \ + struct wait_queue_entry name = { \ .private = current, \ .func = function, \ .task_list = LIST_HEAD_INIT((name).task_list), \ diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 301ea02..c37b314 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -21,34 +21,34 @@ void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct lock_c EXPORT_SYMBOL(__init_waitqueue_head); -void add_wait_queue(wait_queue_head_t *q, wait_queue_entry_t *wait) +void add_wait_queue(wait_queue_head_t *q, struct wait_queue_entry *wq_entry) { unsigned long flags; - wait->flags &= ~WQ_FLAG_EXCLUSIVE; + wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE; spin_lock_irqsave(&q->lock, flags); - __add_wait_queue(q, wait); + __add_wait_queue_entry_tail(q, wq_entry); spin_unlock_irqrestore(&q->lock, flags); } EXPORT_SYMBOL(add_wait_queue); -void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait) +void add_wait_queue_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry) { unsigned long flags; - wait->flags |= WQ_FLAG_EXCLUSIVE; + wq_entry->flags |= WQ_FLAG_EXCLUSIVE; spin_lock_irqsave(&q->lock, flags); - __add_wait_queue_entry_tail(q, wait); + __add_wait_queue_entry_tail(q, wq_entry); spin_unlock_irqrestore(&q->lock, flags); } EXPORT_SYMBOL(add_wait_queue_exclusive); -void remove_wait_queue(wait_queue_head_t *q, wait_queue_entry_t *wait) +void remove_wait_queue(wait_queue_head_t *q, struct wait_queue_entry *wq_entry) { unsigned long flags; spin_lock_irqsave(&q->lock, flags); - __remove_wait_queue(q, wait); + __remove_wait_queue(q, wq_entry); spin_unlock_irqrestore(&q->lock, flags); } EXPORT_SYMBOL(remove_wait_queue); @@ -170,43 +170,43 @@ EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ * loads to move into the critical region). */ void -prepare_to_wait(wait_queue_head_t *q, wait_queue_entry_t *wait, int state) +prepare_to_wait(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state) { unsigned long flags; - wait->flags &= ~WQ_FLAG_EXCLUSIVE; + wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE; spin_lock_irqsave(&q->lock, flags); - if (list_empty(&wait->task_list)) - __add_wait_queue(q, wait); + if (list_empty(&wq_entry->task_list)) + __add_wait_queue(q, wq_entry); set_current_state(state); spin_unlock_irqrestore(&q->lock, flags); } EXPORT_SYMBOL(prepare_to_wait); void -prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_entry_t *wait, int state) +prepare_to_wait_exclusive(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state) { unsigned long flags; - wait->flags |= WQ_FLAG_EXCLUSIVE; + wq_entry->flags |= WQ_FLAG_EXCLUSIVE; spin_lock_irqsave(&q->lock, flags); - if (list_empty(&wait->task_list)) - __add_wait_queue_entry_tail(q, wait); + if (list_empty(&wq_entry->task_list)) + __add_wait_queue_entry_tail(q, wq_entry); set_current_state(state); spin_unlock_irqrestore(&q->lock, flags); } EXPORT_SYMBOL(prepare_to_wait_exclusive); -void init_wait_entry(wait_queue_entry_t *wait, int flags) +void init_wait_entry(struct wait_queue_entry *wq_entry, int flags) { - wait->flags = flags; - wait->private = current; - wait->func = autoremove_wake_function; - INIT_LIST_HEAD(&wait->task_list); + wq_entry->flags = flags; + wq_entry->private = current; + wq_entry->func = autoremove_wake_function; + INIT_LIST_HEAD(&wq_entry->task_list); } EXPORT_SYMBOL(init_wait_entry); -long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_entry_t *wait, int state) +long prepare_to_wait_event(wait_queue_head_t *q, struct wait_queue_entry *wq_entry, int state) { unsigned long flags; long ret = 0; @@ -225,14 +225,14 @@ long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_entry_t *wait, int s * can't see us, it should wake up another exclusive waiter if * we fail. */ - list_del_init(&wait->task_list); + list_del_init(&wq_entry->task_list); ret = -ERESTARTSYS; } else { - if (list_empty(&wait->task_list)) { - if (wait->flags & WQ_FLAG_EXCLUSIVE) - __add_wait_queue_entry_tail(q, wait); + if (list_empty(&wq_entry->task_list)) { + if (wq_entry->flags & WQ_FLAG_EXCLUSIVE) + __add_wait_queue_entry_tail(q, wq_entry); else - __add_wait_queue(q, wait); + __add_wait_queue(q, wq_entry); } set_current_state(state); } @@ -284,13 +284,13 @@ EXPORT_SYMBOL(do_wait_intr_irq); /** * finish_wait - clean up after waiting in a queue * @q: waitqueue waited on - * @wait: wait descriptor + * @wq_entry: wait descriptor * * Sets current thread back to running state and removes * the wait descriptor from the given waitqueue if still * queued. */ -void finish_wait(wait_queue_head_t *q, wait_queue_entry_t *wait) +void finish_wait(wait_queue_head_t *q, struct wait_queue_entry *wq_entry) { unsigned long flags; @@ -308,20 +308,20 @@ void finish_wait(wait_queue_head_t *q, wait_queue_entry_t *wait) * have _one_ other CPU that looks at or modifies * the list). */ - if (!list_empty_careful(&wait->task_list)) { + if (!list_empty_careful(&wq_entry->task_list)) { spin_lock_irqsave(&q->lock, flags); - list_del_init(&wait->task_list); + list_del_init(&wq_entry->task_list); spin_unlock_irqrestore(&q->lock, flags); } } EXPORT_SYMBOL(finish_wait); -int autoremove_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) +int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key) { - int ret = default_wake_function(wait, mode, sync, key); + int ret = default_wake_function(wq_entry, mode, sync, key); if (ret) - list_del_init(&wait->task_list); + list_del_init(&wq_entry->task_list); return ret; } EXPORT_SYMBOL(autoremove_wake_function); @@ -341,17 +341,17 @@ static inline bool is_kthread_should_stop(void) * * p->state = mode; condition = true; * smp_mb(); // A smp_wmb(); // C - * if (!wait->flags & WQ_FLAG_WOKEN) wait->flags |= WQ_FLAG_WOKEN; + * if (!wq_entry->flags & WQ_FLAG_WOKEN) wq_entry->flags |= WQ_FLAG_WOKEN; * schedule() try_to_wake_up(); * p->state = TASK_RUNNING; ~~~~~~~~~~~~~~~~~~ - * wait->flags &= ~WQ_FLAG_WOKEN; condition = true; + * wq_entry->flags &= ~WQ_FLAG_WOKEN; condition = true; * smp_mb() // B smp_wmb(); // C - * wait->flags |= WQ_FLAG_WOKEN; + * wq_entry->flags |= WQ_FLAG_WOKEN; * } * remove_wait_queue(&wq, &wait); * */ -long wait_woken(wait_queue_entry_t *wait, unsigned mode, long timeout) +long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout) { set_current_state(mode); /* A */ /* @@ -359,7 +359,7 @@ long wait_woken(wait_queue_entry_t *wait, unsigned mode, long timeout) * woken_wake_function() such that if we observe WQ_FLAG_WOKEN we must * also observe all state before the wakeup. */ - if (!(wait->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop()) + if (!(wq_entry->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop()) timeout = schedule_timeout(timeout); __set_current_state(TASK_RUNNING); @@ -369,13 +369,13 @@ long wait_woken(wait_queue_entry_t *wait, unsigned mode, long timeout) * condition being true _OR_ WQ_FLAG_WOKEN such that we will not miss * an event. */ - smp_store_mb(wait->flags, wait->flags & ~WQ_FLAG_WOKEN); /* B */ + smp_store_mb(wq_entry->flags, wq_entry->flags & ~WQ_FLAG_WOKEN); /* B */ return timeout; } EXPORT_SYMBOL(wait_woken); -int woken_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) +int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key) { /* * Although this function is called under waitqueue lock, LOCK @@ -385,24 +385,24 @@ int woken_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void * and is paired with smp_store_mb() in wait_woken(). */ smp_wmb(); /* C */ - wait->flags |= WQ_FLAG_WOKEN; + wq_entry->flags |= WQ_FLAG_WOKEN; - return default_wake_function(wait, mode, sync, key); + return default_wake_function(wq_entry, mode, sync, key); } EXPORT_SYMBOL(woken_wake_function); -int wake_bit_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *arg) +int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *arg) { struct wait_bit_key *key = arg; struct wait_bit_queue *wait_bit - = container_of(wait, struct wait_bit_queue, wait); + = container_of(wq_entry, struct wait_bit_queue, wait); if (wait_bit->key.flags != key->flags || wait_bit->key.bit_nr != key->bit_nr || test_bit(key->bit_nr, key->flags)) return 0; else - return autoremove_wake_function(wait, mode, sync, key); + return autoremove_wake_function(wq_entry, mode, sync, key); } EXPORT_SYMBOL(wake_bit_function); @@ -534,19 +534,19 @@ static inline wait_queue_head_t *atomic_t_waitqueue(atomic_t *p) return bit_waitqueue(p, 0); } -static int wake_atomic_t_function(wait_queue_entry_t *wait, unsigned mode, int sync, +static int wake_atomic_t_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *arg) { struct wait_bit_key *key = arg; struct wait_bit_queue *wait_bit - = container_of(wait, struct wait_bit_queue, wait); + = container_of(wq_entry, struct wait_bit_queue, wait); atomic_t *val = key->flags; if (wait_bit->key.flags != key->flags || wait_bit->key.bit_nr != key->bit_nr || atomic_read(val) != 0) return 0; - return autoremove_wake_function(wait, mode, sync, key); + return autoremove_wake_function(wq_entry, mode, sync, key); } /* -- 2.7.4