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/*-
* Copyright (c) 2004 John Baldwin <jhb@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _SYS_SLEEPQUEUE_H_
#define _SYS_SLEEPQUEUE_H_
/*
* Sleep queue interface. Sleep/wakeup and condition variables use a sleep
* queue for the queue of threads blocked on a sleep channel.
*
* A thread calls sleepq_lock() to lock the sleep queue chain associated
* with a given wait channel. A thread can then call call sleepq_add() to
* add themself onto a sleep queue and call one of the sleepq_wait()
* functions to actually go to sleep. If a thread needs to abort a sleep
* operation it should call sleepq_release() to unlock the associated sleep
* queue chain lock. If the thread also needs to remove itself from a queue
* it just enqueued itself on, it can use sleepq_remove() instead.
*
* If the thread only wishes to sleep for a limited amount of time, it can
* call sleepq_set_timeout() after sleepq_add() to setup a timeout. It
* should then use one of the sleepq_timedwait() functions to block.
*
* If the thread wants to the sleep to be interruptible by signals, it can
* call sleepq_catch_signals() after sleepq_add(). It should then use
* one of the sleepq_wait_sig() functions to block. After the thread has
* been resumed, it should call sleepq_calc_signal_retval() to determine
* if it should return EINTR or ERESTART passing in the value returned from
* the earlier call to sleepq_catch_signals().
*
* A thread is normally resumed from a sleep queue by either the
* sleepq_signal() or sleepq_broadcast() functions. Sleepq_signal() wakes
* the thread with the highest priority that is sleeping on the specified
* wait channel. Sleepq_broadcast() wakes all threads that are sleeping
* on the specified wait channel. A thread sleeping in an interruptible
* sleep can be interrupted by calling sleepq_abort(). A thread can also
* be removed from a specified sleep queue using the sleepq_remove()
* function. Note that the sleep queue chain must first be locked via
* sleepq_lock() when calling sleepq_signal() and sleepq_broadcast().
*
* Each thread allocates a sleep queue at thread creation via sleepq_alloc()
* and releases it at thread destruction via sleepq_free(). Note that
* a sleep queue is not tied to a specific thread and that the sleep queue
* released at thread destruction may not be the same sleep queue that the
* thread allocated when it was created.
*
* XXX: Some other parts of the kernel such as ithread sleeping may end up
* using this interface as well (death to TDI_IWAIT!)
*/
struct mtx;
struct sleepqueue;
struct thread;
#ifdef _KERNEL
#define SLEEPQ_TYPE 0x0ff /* Mask of sleep queue types. */
#define SLEEPQ_MSLEEP 0x00 /* Used by msleep/wakeup. */
#define SLEEPQ_CONDVAR 0x01 /* Used for a cv. */
#define SLEEPQ_INTERRUPTIBLE 0x100 /* Sleep is interruptible. */
void init_sleepqueues(void);
void sleepq_abort(struct thread *td);
void sleepq_add(void *, struct mtx *, const char *, int);
struct sleepqueue *sleepq_alloc(void);
void sleepq_broadcast(void *, int, int);
int sleepq_calc_signal_retval(int sig);
int sleepq_catch_signals(void *wchan);
void sleepq_free(struct sleepqueue *);
void sleepq_lock(void *);
struct sleepqueue *sleepq_lookup(void *);
void sleepq_release(void *);
void sleepq_remove(struct thread *, void *);
void sleepq_signal(void *, int, int);
void sleepq_set_timeout(void *wchan, int timo);
int sleepq_timedwait(void *wchan);
int sleepq_timedwait_sig(void *wchan, int signal_caught);
void sleepq_wait(void *);
int sleepq_wait_sig(void *wchan);
#endif /* _KERNEL */
#endif /* !_SYS_SLEEPQUEUE_H_ */
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