wait.h revision 330861 
1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
6 * Copyright (c) 2017 Mark Johnston <markj@FreeBSD.org>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice unmodified, this list of conditions, and the following
14 *    disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * $FreeBSD: stable/11/sys/compat/linuxkpi/common/include/linux/wait.h 330861 2018-03-13 16:30:01Z hselasky $
31 */
32
33#ifndef _LINUX_WAIT_H_
34#define	_LINUX_WAIT_H_
35
36#include <linux/compiler.h>
37#include <linux/list.h>
38#include <linux/spinlock.h>
39
40#include <asm/atomic.h>
41
42#include <sys/param.h>
43#include <sys/systm.h>
44
45#define	SKIP_SLEEP() (SCHEDULER_STOPPED() || kdb_active)
46
47#define	might_sleep()							\
48	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "might_sleep()")
49
50struct wait_queue;
51struct wait_queue_head;
52
53typedef struct wait_queue wait_queue_t;
54typedef struct wait_queue_head wait_queue_head_t;
55
56typedef int wait_queue_func_t(wait_queue_t *, unsigned int, int, void *);
57
58/*
59 * Many API consumers directly reference these fields and those of
60 * wait_queue_head.
61 */
62struct wait_queue {
63	unsigned int flags;	/* always 0 */
64	void *private;
65	wait_queue_func_t *func;
66	struct list_head task_list;
67};
68
69struct wait_queue_head {
70	spinlock_t lock;
71	struct list_head task_list;
72};
73
74/*
75 * This function is referenced by at least one DRM driver, so it may not be
76 * renamed and furthermore must be the default wait queue callback.
77 */
78extern wait_queue_func_t autoremove_wake_function;
79extern wait_queue_func_t default_wake_function;
80
81#define	DEFINE_WAIT_FUNC(name, function)				\
82	wait_queue_t name = {						\
83		.private = current,					\
84		.func = function,					\
85		.task_list = LINUX_LIST_HEAD_INIT(name.task_list)	\
86	}
87
88#define	DEFINE_WAIT(name) \
89	DEFINE_WAIT_FUNC(name, autoremove_wake_function)
90
91#define	DECLARE_WAITQUEUE(name, task)					\
92	wait_queue_t name = {						\
93		.private = task,					\
94		.task_list = LINUX_LIST_HEAD_INIT(name.task_list)	\
95	}
96
97#define	DECLARE_WAIT_QUEUE_HEAD(name)					\
98	wait_queue_head_t name = {					\
99		.task_list = LINUX_LIST_HEAD_INIT(name.task_list),	\
100	};								\
101	MTX_SYSINIT(name, &(name).lock.m, spin_lock_name("wqhead"), MTX_DEF)
102
103#define	init_waitqueue_head(wqh) do {					\
104	mtx_init(&(wqh)->lock.m, spin_lock_name("wqhead"),		\
105	    NULL, MTX_DEF | MTX_NEW | MTX_NOWITNESS);			\
106	INIT_LIST_HEAD(&(wqh)->task_list);				\
107} while (0)
108
109void linux_wake_up(wait_queue_head_t *, unsigned int, int, bool);
110
111#define	wake_up(wqh)							\
112	linux_wake_up(wqh, TASK_NORMAL, 1, false)
113#define	wake_up_all(wqh)						\
114	linux_wake_up(wqh, TASK_NORMAL, 0, false)
115#define	wake_up_locked(wqh)						\
116	linux_wake_up(wqh, TASK_NORMAL, 1, true)
117#define	wake_up_all_locked(wqh)						\
118	linux_wake_up(wqh, TASK_NORMAL, 0, true)
119#define	wake_up_interruptible(wqh)					\
120	linux_wake_up(wqh, TASK_INTERRUPTIBLE, 1, false)
121#define	wake_up_interruptible_all(wqh)					\
122	linux_wake_up(wqh, TASK_INTERRUPTIBLE, 0, false)
123
124int linux_wait_event_common(wait_queue_head_t *, wait_queue_t *, int,
125    unsigned int, spinlock_t *);
126
127/*
128 * Returns -ERESTARTSYS for a signal, 0 if cond is false after timeout, 1 if
129 * cond is true after timeout, remaining jiffies (> 0) if cond is true before
130 * timeout.
131 */
132#define	__wait_event_common(wqh, cond, timeout, state, lock) ({	\
133	DEFINE_WAIT(__wq);					\
134	const int __timeout = ((int)(timeout)) < 1 ? 1 : (timeout);	\
135	int __start = ticks;					\
136	int __ret = 0;						\
137								\
138	for (;;) {						\
139		linux_prepare_to_wait(&(wqh), &__wq, state);	\
140		if (cond)					\
141			break;					\
142		__ret = linux_wait_event_common(&(wqh), &__wq,	\
143		    __timeout, state, lock);			\
144		if (__ret != 0)					\
145			break;					\
146	}							\
147	linux_finish_wait(&(wqh), &__wq);			\
148	if (__timeout != MAX_SCHEDULE_TIMEOUT) {		\
149		if (__ret == -EWOULDBLOCK)			\
150			__ret = !!(cond);			\
151		else if (__ret != -ERESTARTSYS) {		\
152			__ret = __timeout + __start - ticks;	\
153			/* range check return value */		\
154			if (__ret < 1)				\
155				__ret = 1;			\
156			else if (__ret > __timeout)		\
157				__ret = __timeout;		\
158		}						\
159	}							\
160	__ret;							\
161})
162
163#define	wait_event(wqh, cond) do {					\
164	(void) __wait_event_common(wqh, cond, MAX_SCHEDULE_TIMEOUT,	\
165	    TASK_UNINTERRUPTIBLE, NULL);				\
166} while (0)
167
168#define	wait_event_timeout(wqh, cond, timeout) ({			\
169	__wait_event_common(wqh, cond, timeout, TASK_UNINTERRUPTIBLE,	\
170	    NULL);							\
171})
172
173#define	wait_event_interruptible(wqh, cond) ({				\
174	__wait_event_common(wqh, cond, MAX_SCHEDULE_TIMEOUT,		\
175	    TASK_INTERRUPTIBLE, NULL);					\
176})
177
178#define	wait_event_interruptible_timeout(wqh, cond, timeout) ({		\
179	__wait_event_common(wqh, cond, timeout, TASK_INTERRUPTIBLE,	\
180	    NULL);							\
181})
182
183/*
184 * Wait queue is already locked.
185 */
186#define	wait_event_interruptible_locked(wqh, cond) ({			\
187	int __ret;							\
188									\
189	spin_unlock(&(wqh).lock);					\
190	__ret = __wait_event_common(wqh, cond, MAX_SCHEDULE_TIMEOUT,	\
191	    TASK_INTERRUPTIBLE, NULL);					\
192	spin_lock(&(wqh).lock);						\
193	__ret;								\
194})
195
196/*
197 * Hold the (locked) spinlock when testing the cond.
198 */
199#define	wait_event_interruptible_lock_irq(wqh, cond, lock) ({		\
200	__wait_event_common(wqh, cond, MAX_SCHEDULE_TIMEOUT,		\
201	    TASK_INTERRUPTIBLE, &(lock));				\
202})
203
204static inline void
205__add_wait_queue(wait_queue_head_t *wqh, wait_queue_t *wq)
206{
207	list_add(&wq->task_list, &wqh->task_list);
208}
209
210static inline void
211add_wait_queue(wait_queue_head_t *wqh, wait_queue_t *wq)
212{
213
214	spin_lock(&wqh->lock);
215	__add_wait_queue(wqh, wq);
216	spin_unlock(&wqh->lock);
217}
218
219static inline void
220__add_wait_queue_tail(wait_queue_head_t *wqh, wait_queue_t *wq)
221{
222	list_add_tail(&wq->task_list, &wqh->task_list);
223}
224
225static inline void
226__remove_wait_queue(wait_queue_head_t *wqh, wait_queue_t *wq)
227{
228	list_del(&wq->task_list);
229}
230
231static inline void
232remove_wait_queue(wait_queue_head_t *wqh, wait_queue_t *wq)
233{
234
235	spin_lock(&wqh->lock);
236	__remove_wait_queue(wqh, wq);
237	spin_unlock(&wqh->lock);
238}
239
240bool linux_waitqueue_active(wait_queue_head_t *);
241
242#define	waitqueue_active(wqh)		linux_waitqueue_active(wqh)
243
244void linux_prepare_to_wait(wait_queue_head_t *, wait_queue_t *, int);
245void linux_finish_wait(wait_queue_head_t *, wait_queue_t *);
246
247#define	prepare_to_wait(wqh, wq, state)	linux_prepare_to_wait(wqh, wq, state)
248#define	finish_wait(wqh, wq)		linux_finish_wait(wqh, wq)
249
250void linux_wake_up_bit(void *, int);
251int linux_wait_on_bit_timeout(unsigned long *, int, unsigned int, int);
252void linux_wake_up_atomic_t(atomic_t *);
253int linux_wait_on_atomic_t(atomic_t *, unsigned int);
254
255#define	wake_up_bit(word, bit)		linux_wake_up_bit(word, bit)
256#define	wait_on_bit(word, bit, state)					\
257	linux_wait_on_bit_timeout(word, bit, state, MAX_SCHEDULE_TIMEOUT)
258#define	wait_on_bit_timeout(word, bit, state, timeout)			\
259	linux_wait_on_bit_timeout(word, bit, state, timeout)
260#define	wake_up_atomic_t(a)		linux_wake_up_atomic_t(a)
261/*
262 * All existing callers have a cb that just schedule()s. To avoid adding
263 * complexity, just emulate that internally. The prototype is different so that
264 * callers must be manually modified; a cb that does something other than call
265 * schedule() will require special treatment.
266 */
267#define	wait_on_atomic_t(a, state)	linux_wait_on_atomic_t(a, state)
268
269struct task_struct;
270bool linux_wake_up_state(struct task_struct *, unsigned int);
271
272#define	wake_up_process(task)		linux_wake_up_state(task, TASK_NORMAL)
273#define	wake_up_state(task, state)	linux_wake_up_state(task, state)
274
275#endif /* _LINUX_WAIT_H_ */
276