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2055da9738
So I've noticed a number of instances where it was not obvious from the
code whether ->task_list was for a wait-queue head or a wait-queue entry.
Furthermore, there's a number of wait-queue users where the lists are
not for 'tasks' but other entities (poll tables, etc.), in which case
the 'task_list' name is actively confusing.
To clear this all up, name the wait-queue head and entry list structure
fields unambiguously:
struct wait_queue_head::task_list => ::head
struct wait_queue_entry::task_list => ::entry
For example, this code:
rqw->wait.task_list.next != &wait->task_list
... is was pretty unclear (to me) what it's doing, while now it's written this way:
rqw->wait.head.next != &wait->entry
... which makes it pretty clear that we are iterating a list until we see the head.
Other examples are:
list_for_each_entry_safe(pos, next, &x->task_list, task_list) {
list_for_each_entry(wq, &fence->wait.task_list, task_list) {
... where it's unclear (to me) what we are iterating, and during review it's
hard to tell whether it's trying to walk a wait-queue entry (which would be
a bug), while now it's written as:
list_for_each_entry_safe(pos, next, &x->head, entry) {
list_for_each_entry(wq, &fence->wait.head, entry) {
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
969 lines
34 KiB
C
969 lines
34 KiB
C
#ifndef _LINUX_WAIT_H
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#define _LINUX_WAIT_H
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/*
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* Linux wait queue related types and methods
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*/
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#include <linux/list.h>
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#include <linux/stddef.h>
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#include <linux/spinlock.h>
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#include <asm/current.h>
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#include <uapi/linux/wait.h>
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typedef struct wait_queue_entry wait_queue_entry_t;
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typedef int (*wait_queue_func_t)(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
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int default_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int flags, void *key);
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/* wait_queue_entry::flags */
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#define WQ_FLAG_EXCLUSIVE 0x01
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#define WQ_FLAG_WOKEN 0x02
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/*
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* A single wait-queue entry structure:
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*/
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struct wait_queue_entry {
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unsigned int flags;
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void *private;
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wait_queue_func_t func;
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struct list_head entry;
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};
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struct wait_queue_head {
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spinlock_t lock;
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struct list_head head;
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};
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typedef struct wait_queue_head wait_queue_head_t;
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struct task_struct;
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/*
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* Macros for declaration and initialisaton of the datatypes
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*/
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#define __WAITQUEUE_INITIALIZER(name, tsk) { \
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.private = tsk, \
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.func = default_wake_function, \
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.entry = { NULL, NULL } }
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#define DECLARE_WAITQUEUE(name, tsk) \
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struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk)
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#define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \
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.lock = __SPIN_LOCK_UNLOCKED(name.lock), \
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.head = { &(name).head, &(name).head } }
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#define DECLARE_WAIT_QUEUE_HEAD(name) \
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struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name)
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extern void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, struct lock_class_key *);
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#define init_waitqueue_head(wq_head) \
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do { \
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static struct lock_class_key __key; \
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\
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__init_waitqueue_head((wq_head), #wq_head, &__key); \
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} while (0)
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#ifdef CONFIG_LOCKDEP
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# define __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) \
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({ init_waitqueue_head(&name); name; })
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# define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) \
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struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
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#else
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# define DECLARE_WAIT_QUEUE_HEAD_ONSTACK(name) DECLARE_WAIT_QUEUE_HEAD(name)
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#endif
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static inline void init_waitqueue_entry(struct wait_queue_entry *wq_entry, struct task_struct *p)
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{
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wq_entry->flags = 0;
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wq_entry->private = p;
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wq_entry->func = default_wake_function;
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}
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static inline void
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init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t func)
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{
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wq_entry->flags = 0;
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wq_entry->private = NULL;
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wq_entry->func = func;
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}
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/**
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* waitqueue_active -- locklessly test for waiters on the queue
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* @wq_head: the waitqueue to test for waiters
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*
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* returns true if the wait list is not empty
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*
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* NOTE: this function is lockless and requires care, incorrect usage _will_
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* lead to sporadic and non-obvious failure.
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*
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* Use either while holding wait_queue_head::lock or when used for wakeups
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* with an extra smp_mb() like:
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*
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* CPU0 - waker CPU1 - waiter
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*
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* for (;;) {
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* @cond = true; prepare_to_wait(&wq_head, &wait, state);
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* smp_mb(); // smp_mb() from set_current_state()
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* if (waitqueue_active(wq_head)) if (@cond)
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* wake_up(wq_head); break;
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* schedule();
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* }
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* finish_wait(&wq_head, &wait);
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*
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* Because without the explicit smp_mb() it's possible for the
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* waitqueue_active() load to get hoisted over the @cond store such that we'll
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* observe an empty wait list while the waiter might not observe @cond.
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*
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* Also note that this 'optimization' trades a spin_lock() for an smp_mb(),
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* which (when the lock is uncontended) are of roughly equal cost.
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*/
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static inline int waitqueue_active(struct wait_queue_head *wq_head)
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{
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return !list_empty(&wq_head->head);
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}
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/**
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* wq_has_sleeper - check if there are any waiting processes
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* @wq_head: wait queue head
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*
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* Returns true if wq_head has waiting processes
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*
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* Please refer to the comment for waitqueue_active.
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*/
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static inline bool wq_has_sleeper(struct wait_queue_head *wq_head)
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{
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/*
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* We need to be sure we are in sync with the
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* add_wait_queue modifications to the wait queue.
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*
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* This memory barrier should be paired with one on the
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* waiting side.
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*/
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smp_mb();
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return waitqueue_active(wq_head);
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}
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extern void add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
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extern void add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
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extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry);
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static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
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{
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list_add(&wq_entry->entry, &wq_head->head);
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}
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/*
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* Used for wake-one threads:
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*/
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static inline void
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__add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
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{
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wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
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__add_wait_queue(wq_head, wq_entry);
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}
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static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
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{
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list_add_tail(&wq_entry->entry, &wq_head->head);
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}
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static inline void
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__add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
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{
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wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
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__add_wait_queue_entry_tail(wq_head, wq_entry);
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}
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static inline void
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__remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry)
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{
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list_del(&wq_entry->entry);
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}
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void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
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void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
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void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
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void __wake_up_locked(struct wait_queue_head *wq_head, unsigned int mode, int nr);
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void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr);
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#define wake_up(x) __wake_up(x, TASK_NORMAL, 1, NULL)
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#define wake_up_nr(x, nr) __wake_up(x, TASK_NORMAL, nr, NULL)
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#define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL)
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#define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1)
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#define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0)
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#define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL)
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#define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
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#define wake_up_interruptible_all(x) __wake_up(x, TASK_INTERRUPTIBLE, 0, NULL)
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#define wake_up_interruptible_sync(x) __wake_up_sync((x), TASK_INTERRUPTIBLE, 1)
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/*
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* Wakeup macros to be used to report events to the targets.
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*/
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#define wake_up_poll(x, m) \
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__wake_up(x, TASK_NORMAL, 1, (void *) (m))
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#define wake_up_locked_poll(x, m) \
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__wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
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#define wake_up_interruptible_poll(x, m) \
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__wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
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#define wake_up_interruptible_sync_poll(x, m) \
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__wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
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#define ___wait_cond_timeout(condition) \
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({ \
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bool __cond = (condition); \
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if (__cond && !__ret) \
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__ret = 1; \
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__cond || !__ret; \
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})
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#define ___wait_is_interruptible(state) \
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(!__builtin_constant_p(state) || \
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state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \
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extern void init_wait_entry(struct wait_queue_entry *wq_entry, int flags);
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/*
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* The below macro ___wait_event() has an explicit shadow of the __ret
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* variable when used from the wait_event_*() macros.
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*
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* This is so that both can use the ___wait_cond_timeout() construct
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* to wrap the condition.
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*
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* The type inconsistency of the wait_event_*() __ret variable is also
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* on purpose; we use long where we can return timeout values and int
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* otherwise.
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*/
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#define ___wait_event(wq_head, condition, state, exclusive, ret, cmd) \
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({ \
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__label__ __out; \
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struct wait_queue_entry __wq_entry; \
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long __ret = ret; /* explicit shadow */ \
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\
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init_wait_entry(&__wq_entry, exclusive ? WQ_FLAG_EXCLUSIVE : 0); \
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for (;;) { \
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long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\
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\
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if (condition) \
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break; \
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\
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if (___wait_is_interruptible(state) && __int) { \
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__ret = __int; \
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goto __out; \
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} \
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\
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cmd; \
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} \
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finish_wait(&wq_head, &__wq_entry); \
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__out: __ret; \
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})
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#define __wait_event(wq_head, condition) \
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(void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
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schedule())
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/**
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* wait_event - sleep until a condition gets true
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* @wq_head: the waitqueue to wait on
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* @condition: a C expression for the event to wait for
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*
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* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
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* @condition evaluates to true. The @condition is checked each time
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* the waitqueue @wq_head is woken up.
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*
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* wake_up() has to be called after changing any variable that could
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* change the result of the wait condition.
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*/
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#define wait_event(wq_head, condition) \
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do { \
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might_sleep(); \
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if (condition) \
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break; \
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__wait_event(wq_head, condition); \
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} while (0)
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#define __io_wait_event(wq_head, condition) \
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(void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
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io_schedule())
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/*
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* io_wait_event() -- like wait_event() but with io_schedule()
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*/
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#define io_wait_event(wq_head, condition) \
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do { \
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might_sleep(); \
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if (condition) \
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break; \
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__io_wait_event(wq_head, condition); \
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} while (0)
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#define __wait_event_freezable(wq_head, condition) \
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___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
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schedule(); try_to_freeze())
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/**
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* wait_event_freezable - sleep (or freeze) until a condition gets true
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* @wq_head: the waitqueue to wait on
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* @condition: a C expression for the event to wait for
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*
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* The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
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* to system load) until the @condition evaluates to true. The
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* @condition is checked each time the waitqueue @wq_head is woken up.
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*
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* wake_up() has to be called after changing any variable that could
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* change the result of the wait condition.
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*/
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#define wait_event_freezable(wq_head, condition) \
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({ \
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int __ret = 0; \
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might_sleep(); \
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if (!(condition)) \
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__ret = __wait_event_freezable(wq_head, condition); \
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__ret; \
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})
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#define __wait_event_timeout(wq_head, condition, timeout) \
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___wait_event(wq_head, ___wait_cond_timeout(condition), \
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TASK_UNINTERRUPTIBLE, 0, timeout, \
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__ret = schedule_timeout(__ret))
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/**
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* wait_event_timeout - sleep until a condition gets true or a timeout elapses
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* @wq_head: the waitqueue to wait on
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* @condition: a C expression for the event to wait for
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* @timeout: timeout, in jiffies
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*
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* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
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* @condition evaluates to true. The @condition is checked each time
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* the waitqueue @wq_head is woken up.
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*
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* wake_up() has to be called after changing any variable that could
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* change the result of the wait condition.
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*
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* Returns:
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* 0 if the @condition evaluated to %false after the @timeout elapsed,
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* 1 if the @condition evaluated to %true after the @timeout elapsed,
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* or the remaining jiffies (at least 1) if the @condition evaluated
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* to %true before the @timeout elapsed.
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*/
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#define wait_event_timeout(wq_head, condition, timeout) \
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({ \
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long __ret = timeout; \
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might_sleep(); \
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if (!___wait_cond_timeout(condition)) \
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__ret = __wait_event_timeout(wq_head, condition, timeout); \
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__ret; \
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})
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#define __wait_event_freezable_timeout(wq_head, condition, timeout) \
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___wait_event(wq_head, ___wait_cond_timeout(condition), \
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TASK_INTERRUPTIBLE, 0, timeout, \
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__ret = schedule_timeout(__ret); try_to_freeze())
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/*
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* like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
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* increasing load and is freezable.
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*/
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#define wait_event_freezable_timeout(wq_head, condition, timeout) \
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({ \
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long __ret = timeout; \
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might_sleep(); \
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if (!___wait_cond_timeout(condition)) \
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__ret = __wait_event_freezable_timeout(wq_head, condition, timeout); \
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__ret; \
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})
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#define __wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \
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(void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 1, 0, \
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cmd1; schedule(); cmd2)
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/*
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* Just like wait_event_cmd(), except it sets exclusive flag
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*/
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#define wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2) \
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do { \
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if (condition) \
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break; \
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__wait_event_exclusive_cmd(wq_head, condition, cmd1, cmd2); \
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} while (0)
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#define __wait_event_cmd(wq_head, condition, cmd1, cmd2) \
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(void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
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cmd1; schedule(); cmd2)
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/**
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* wait_event_cmd - sleep until a condition gets true
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* @wq_head: the waitqueue to wait on
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* @condition: a C expression for the event to wait for
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* @cmd1: the command will be executed before sleep
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* @cmd2: the command will be executed after sleep
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*
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* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
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* @condition evaluates to true. The @condition is checked each time
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* the waitqueue @wq_head is woken up.
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*
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* wake_up() has to be called after changing any variable that could
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* change the result of the wait condition.
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*/
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#define wait_event_cmd(wq_head, condition, cmd1, cmd2) \
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do { \
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if (condition) \
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break; \
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__wait_event_cmd(wq_head, condition, cmd1, cmd2); \
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} while (0)
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#define __wait_event_interruptible(wq_head, condition) \
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___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
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schedule())
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/**
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* wait_event_interruptible - sleep until a condition gets true
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* @wq_head: the waitqueue to wait on
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* @condition: a C expression for the event to wait for
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*
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* The process is put to sleep (TASK_INTERRUPTIBLE) until the
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* @condition evaluates to true or a signal is received.
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* The @condition is checked each time the waitqueue @wq_head is woken up.
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|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible(wq_head, condition) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_interruptible(wq_head, condition); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_interruptible_timeout(wq_head, condition, timeout) \
|
|
___wait_event(wq_head, ___wait_cond_timeout(condition), \
|
|
TASK_INTERRUPTIBLE, 0, timeout, \
|
|
__ret = schedule_timeout(__ret))
|
|
|
|
/**
|
|
* wait_event_interruptible_timeout - sleep until a condition gets true or a timeout elapses
|
|
* @wq_head: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @timeout: timeout, in jiffies
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq_head is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* Returns:
|
|
* 0 if the @condition evaluated to %false after the @timeout elapsed,
|
|
* 1 if the @condition evaluated to %true after the @timeout elapsed,
|
|
* the remaining jiffies (at least 1) if the @condition evaluated
|
|
* to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
|
|
* interrupted by a signal.
|
|
*/
|
|
#define wait_event_interruptible_timeout(wq_head, condition, timeout) \
|
|
({ \
|
|
long __ret = timeout; \
|
|
might_sleep(); \
|
|
if (!___wait_cond_timeout(condition)) \
|
|
__ret = __wait_event_interruptible_timeout(wq_head, \
|
|
condition, timeout); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_hrtimeout(wq_head, condition, timeout, state) \
|
|
({ \
|
|
int __ret = 0; \
|
|
struct hrtimer_sleeper __t; \
|
|
\
|
|
hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); \
|
|
hrtimer_init_sleeper(&__t, current); \
|
|
if ((timeout) != KTIME_MAX) \
|
|
hrtimer_start_range_ns(&__t.timer, timeout, \
|
|
current->timer_slack_ns, \
|
|
HRTIMER_MODE_REL); \
|
|
\
|
|
__ret = ___wait_event(wq_head, condition, state, 0, 0, \
|
|
if (!__t.task) { \
|
|
__ret = -ETIME; \
|
|
break; \
|
|
} \
|
|
schedule()); \
|
|
\
|
|
hrtimer_cancel(&__t.timer); \
|
|
destroy_hrtimer_on_stack(&__t.timer); \
|
|
__ret; \
|
|
})
|
|
|
|
/**
|
|
* wait_event_hrtimeout - sleep until a condition gets true or a timeout elapses
|
|
* @wq_head: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @timeout: timeout, as a ktime_t
|
|
*
|
|
* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq_head is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function returns 0 if @condition became true, or -ETIME if the timeout
|
|
* elapsed.
|
|
*/
|
|
#define wait_event_hrtimeout(wq_head, condition, timeout) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_hrtimeout(wq_head, condition, timeout, \
|
|
TASK_UNINTERRUPTIBLE); \
|
|
__ret; \
|
|
})
|
|
|
|
/**
|
|
* wait_event_interruptible_hrtimeout - sleep until a condition gets true or a timeout elapses
|
|
* @wq_head: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @timeout: timeout, as a ktime_t
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq_head is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function returns 0 if @condition became true, -ERESTARTSYS if it was
|
|
* interrupted by a signal, or -ETIME if the timeout elapsed.
|
|
*/
|
|
#define wait_event_interruptible_hrtimeout(wq, condition, timeout) \
|
|
({ \
|
|
long __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_hrtimeout(wq, condition, timeout, \
|
|
TASK_INTERRUPTIBLE); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_interruptible_exclusive(wq, condition) \
|
|
___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
|
|
schedule())
|
|
|
|
#define wait_event_interruptible_exclusive(wq, condition) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_interruptible_exclusive(wq, condition); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_killable_exclusive(wq, condition) \
|
|
___wait_event(wq, condition, TASK_KILLABLE, 1, 0, \
|
|
schedule())
|
|
|
|
#define wait_event_killable_exclusive(wq, condition) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_killable_exclusive(wq, condition); \
|
|
__ret; \
|
|
})
|
|
|
|
|
|
#define __wait_event_freezable_exclusive(wq, condition) \
|
|
___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
|
|
schedule(); try_to_freeze())
|
|
|
|
#define wait_event_freezable_exclusive(wq, condition) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_freezable_exclusive(wq, condition); \
|
|
__ret; \
|
|
})
|
|
|
|
extern int do_wait_intr(wait_queue_head_t *, wait_queue_entry_t *);
|
|
extern int do_wait_intr_irq(wait_queue_head_t *, wait_queue_entry_t *);
|
|
|
|
#define __wait_event_interruptible_locked(wq, condition, exclusive, fn) \
|
|
({ \
|
|
int __ret; \
|
|
DEFINE_WAIT(__wait); \
|
|
if (exclusive) \
|
|
__wait.flags |= WQ_FLAG_EXCLUSIVE; \
|
|
do { \
|
|
__ret = fn(&(wq), &__wait); \
|
|
if (__ret) \
|
|
break; \
|
|
} while (!(condition)); \
|
|
__remove_wait_queue(&(wq), &__wait); \
|
|
__set_current_state(TASK_RUNNING); \
|
|
__ret; \
|
|
})
|
|
|
|
|
|
/**
|
|
* wait_event_interruptible_locked - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* It must be called with wq.lock being held. This spinlock is
|
|
* unlocked while sleeping but @condition testing is done while lock
|
|
* is held and when this macro exits the lock is held.
|
|
*
|
|
* The lock is locked/unlocked using spin_lock()/spin_unlock()
|
|
* functions which must match the way they are locked/unlocked outside
|
|
* of this macro.
|
|
*
|
|
* wake_up_locked() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_locked(wq, condition) \
|
|
((condition) \
|
|
? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr))
|
|
|
|
/**
|
|
* wait_event_interruptible_locked_irq - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* It must be called with wq.lock being held. This spinlock is
|
|
* unlocked while sleeping but @condition testing is done while lock
|
|
* is held and when this macro exits the lock is held.
|
|
*
|
|
* The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
|
|
* functions which must match the way they are locked/unlocked outside
|
|
* of this macro.
|
|
*
|
|
* wake_up_locked() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_locked_irq(wq, condition) \
|
|
((condition) \
|
|
? 0 : __wait_event_interruptible_locked(wq, condition, 0, do_wait_intr_irq))
|
|
|
|
/**
|
|
* wait_event_interruptible_exclusive_locked - sleep exclusively until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* It must be called with wq.lock being held. This spinlock is
|
|
* unlocked while sleeping but @condition testing is done while lock
|
|
* is held and when this macro exits the lock is held.
|
|
*
|
|
* The lock is locked/unlocked using spin_lock()/spin_unlock()
|
|
* functions which must match the way they are locked/unlocked outside
|
|
* of this macro.
|
|
*
|
|
* The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
|
|
* set thus when other process waits process on the list if this
|
|
* process is awaken further processes are not considered.
|
|
*
|
|
* wake_up_locked() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_exclusive_locked(wq, condition) \
|
|
((condition) \
|
|
? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr))
|
|
|
|
/**
|
|
* wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* It must be called with wq.lock being held. This spinlock is
|
|
* unlocked while sleeping but @condition testing is done while lock
|
|
* is held and when this macro exits the lock is held.
|
|
*
|
|
* The lock is locked/unlocked using spin_lock_irq()/spin_unlock_irq()
|
|
* functions which must match the way they are locked/unlocked outside
|
|
* of this macro.
|
|
*
|
|
* The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag
|
|
* set thus when other process waits process on the list if this
|
|
* process is awaken further processes are not considered.
|
|
*
|
|
* wake_up_locked() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_exclusive_locked_irq(wq, condition) \
|
|
((condition) \
|
|
? 0 : __wait_event_interruptible_locked(wq, condition, 1, do_wait_intr_irq))
|
|
|
|
|
|
#define __wait_event_killable(wq, condition) \
|
|
___wait_event(wq, condition, TASK_KILLABLE, 0, 0, schedule())
|
|
|
|
/**
|
|
* wait_event_killable - sleep until a condition gets true
|
|
* @wq: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
*
|
|
* The process is put to sleep (TASK_KILLABLE) until the
|
|
* @condition evaluates to true or a signal is received.
|
|
* The @condition is checked each time the waitqueue @wq is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* The function will return -ERESTARTSYS if it was interrupted by a
|
|
* signal and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_killable(wq_head, condition) \
|
|
({ \
|
|
int __ret = 0; \
|
|
might_sleep(); \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_killable(wq_head, condition); \
|
|
__ret; \
|
|
})
|
|
|
|
|
|
#define __wait_event_lock_irq(wq_head, condition, lock, cmd) \
|
|
(void)___wait_event(wq_head, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
|
|
spin_unlock_irq(&lock); \
|
|
cmd; \
|
|
schedule(); \
|
|
spin_lock_irq(&lock))
|
|
|
|
/**
|
|
* wait_event_lock_irq_cmd - sleep until a condition gets true. The
|
|
* condition is checked under the lock. This
|
|
* is expected to be called with the lock
|
|
* taken.
|
|
* @wq_head: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @lock: a locked spinlock_t, which will be released before cmd
|
|
* and schedule() and reacquired afterwards.
|
|
* @cmd: a command which is invoked outside the critical section before
|
|
* sleep
|
|
*
|
|
* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
|
|
* @condition evaluates to true. The @condition is checked each time
|
|
* the waitqueue @wq_head is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* This is supposed to be called while holding the lock. The lock is
|
|
* dropped before invoking the cmd and going to sleep and is reacquired
|
|
* afterwards.
|
|
*/
|
|
#define wait_event_lock_irq_cmd(wq_head, condition, lock, cmd) \
|
|
do { \
|
|
if (condition) \
|
|
break; \
|
|
__wait_event_lock_irq(wq_head, condition, lock, cmd); \
|
|
} while (0)
|
|
|
|
/**
|
|
* wait_event_lock_irq - sleep until a condition gets true. The
|
|
* condition is checked under the lock. This
|
|
* is expected to be called with the lock
|
|
* taken.
|
|
* @wq_head: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @lock: a locked spinlock_t, which will be released before schedule()
|
|
* and reacquired afterwards.
|
|
*
|
|
* The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
|
|
* @condition evaluates to true. The @condition is checked each time
|
|
* the waitqueue @wq_head is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* This is supposed to be called while holding the lock. The lock is
|
|
* dropped before going to sleep and is reacquired afterwards.
|
|
*/
|
|
#define wait_event_lock_irq(wq_head, condition, lock) \
|
|
do { \
|
|
if (condition) \
|
|
break; \
|
|
__wait_event_lock_irq(wq_head, condition, lock, ); \
|
|
} while (0)
|
|
|
|
|
|
#define __wait_event_interruptible_lock_irq(wq_head, condition, lock, cmd) \
|
|
___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
|
|
spin_unlock_irq(&lock); \
|
|
cmd; \
|
|
schedule(); \
|
|
spin_lock_irq(&lock))
|
|
|
|
/**
|
|
* wait_event_interruptible_lock_irq_cmd - sleep until a condition gets true.
|
|
* The condition is checked under the lock. This is expected to
|
|
* be called with the lock taken.
|
|
* @wq_head: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @lock: a locked spinlock_t, which will be released before cmd and
|
|
* schedule() and reacquired afterwards.
|
|
* @cmd: a command which is invoked outside the critical section before
|
|
* sleep
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or a signal is received. The @condition is
|
|
* checked each time the waitqueue @wq_head is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* This is supposed to be called while holding the lock. The lock is
|
|
* dropped before invoking the cmd and going to sleep and is reacquired
|
|
* afterwards.
|
|
*
|
|
* The macro will return -ERESTARTSYS if it was interrupted by a signal
|
|
* and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_lock_irq_cmd(wq_head, condition, lock, cmd) \
|
|
({ \
|
|
int __ret = 0; \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_interruptible_lock_irq(wq_head, \
|
|
condition, lock, cmd); \
|
|
__ret; \
|
|
})
|
|
|
|
/**
|
|
* wait_event_interruptible_lock_irq - sleep until a condition gets true.
|
|
* The condition is checked under the lock. This is expected
|
|
* to be called with the lock taken.
|
|
* @wq_head: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @lock: a locked spinlock_t, which will be released before schedule()
|
|
* and reacquired afterwards.
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or signal is received. The @condition is
|
|
* checked each time the waitqueue @wq_head is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* This is supposed to be called while holding the lock. The lock is
|
|
* dropped before going to sleep and is reacquired afterwards.
|
|
*
|
|
* The macro will return -ERESTARTSYS if it was interrupted by a signal
|
|
* and 0 if @condition evaluated to true.
|
|
*/
|
|
#define wait_event_interruptible_lock_irq(wq_head, condition, lock) \
|
|
({ \
|
|
int __ret = 0; \
|
|
if (!(condition)) \
|
|
__ret = __wait_event_interruptible_lock_irq(wq_head, \
|
|
condition, lock,); \
|
|
__ret; \
|
|
})
|
|
|
|
#define __wait_event_interruptible_lock_irq_timeout(wq_head, condition, \
|
|
lock, timeout) \
|
|
___wait_event(wq_head, ___wait_cond_timeout(condition), \
|
|
TASK_INTERRUPTIBLE, 0, timeout, \
|
|
spin_unlock_irq(&lock); \
|
|
__ret = schedule_timeout(__ret); \
|
|
spin_lock_irq(&lock));
|
|
|
|
/**
|
|
* wait_event_interruptible_lock_irq_timeout - sleep until a condition gets
|
|
* true or a timeout elapses. The condition is checked under
|
|
* the lock. This is expected to be called with the lock taken.
|
|
* @wq_head: the waitqueue to wait on
|
|
* @condition: a C expression for the event to wait for
|
|
* @lock: a locked spinlock_t, which will be released before schedule()
|
|
* and reacquired afterwards.
|
|
* @timeout: timeout, in jiffies
|
|
*
|
|
* The process is put to sleep (TASK_INTERRUPTIBLE) until the
|
|
* @condition evaluates to true or signal is received. The @condition is
|
|
* checked each time the waitqueue @wq_head is woken up.
|
|
*
|
|
* wake_up() has to be called after changing any variable that could
|
|
* change the result of the wait condition.
|
|
*
|
|
* This is supposed to be called while holding the lock. The lock is
|
|
* dropped before going to sleep and is reacquired afterwards.
|
|
*
|
|
* The function returns 0 if the @timeout elapsed, -ERESTARTSYS if it
|
|
* was interrupted by a signal, and the remaining jiffies otherwise
|
|
* if the condition evaluated to true before the timeout elapsed.
|
|
*/
|
|
#define wait_event_interruptible_lock_irq_timeout(wq_head, condition, lock, \
|
|
timeout) \
|
|
({ \
|
|
long __ret = timeout; \
|
|
if (!___wait_cond_timeout(condition)) \
|
|
__ret = __wait_event_interruptible_lock_irq_timeout( \
|
|
wq_head, condition, lock, timeout); \
|
|
__ret; \
|
|
})
|
|
|
|
/*
|
|
* Waitqueues which are removed from the waitqueue_head at wakeup time
|
|
*/
|
|
void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
|
|
void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
|
|
long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state);
|
|
void finish_wait(struct wait_queue_head *wq_head, 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);
|
|
|
|
#define DEFINE_WAIT_FUNC(name, function) \
|
|
struct wait_queue_entry name = { \
|
|
.private = current, \
|
|
.func = function, \
|
|
.entry = LIST_HEAD_INIT((name).entry), \
|
|
}
|
|
|
|
#define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function)
|
|
|
|
#define init_wait(wait) \
|
|
do { \
|
|
(wait)->private = current; \
|
|
(wait)->func = autoremove_wake_function; \
|
|
INIT_LIST_HEAD(&(wait)->entry); \
|
|
(wait)->flags = 0; \
|
|
} while (0)
|
|
|
|
#endif /* _LINUX_WAIT_H */
|