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      1 /*	$NetBSD: mutex.h,v 1.17 2021/12/19 11:33:31 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _LINUX_MUTEX_H_
     33 #define _LINUX_MUTEX_H_
     34 
     35 #include <sys/mutex.h>
     36 
     37 #include <lib/libkern/libkern.h> /* KASSERT */
     38 
     39 #include <asm/processor.h>
     40 
     41 #include <linux/list.h>
     42 #include <linux/spinlock.h>
     43 
     44 struct mutex {
     45 	kmutex_t mtx_lock;
     46 };
     47 
     48 struct lock_class_key {
     49 };
     50 
     51 /* Name collision.  Pooh.  */
     52 static inline void
     53 linux_mutex_init(struct mutex *mutex)
     54 {
     55 	mutex_init(&mutex->mtx_lock, MUTEX_DEFAULT, IPL_NONE);
     56 }
     57 
     58 /* Lockdep stuff.  */
     59 static inline void
     60 __mutex_init(struct mutex *mutex, const char *name __unused,
     61     struct lock_class_key *key __unused)
     62 {
     63 	linux_mutex_init(mutex);
     64 }
     65 
     66 /* Another name collision.  */
     67 static inline void
     68 linux_mutex_destroy(struct mutex *mutex)
     69 {
     70 	mutex_destroy(&mutex->mtx_lock);
     71 }
     72 
     73 static inline void
     74 mutex_lock(struct mutex *mutex)
     75 {
     76 	mutex_enter(&mutex->mtx_lock);
     77 }
     78 
     79 static inline int
     80 mutex_lock_interruptible(struct mutex *mutex)
     81 {
     82 	mutex_enter(&mutex->mtx_lock); /* XXX */
     83 	return 0;
     84 }
     85 
     86 static inline int
     87 mutex_trylock(struct mutex *mutex)
     88 {
     89 	return mutex_tryenter(&mutex->mtx_lock);
     90 }
     91 
     92 static inline void
     93 mutex_unlock(struct mutex *mutex)
     94 {
     95 	mutex_exit(&mutex->mtx_lock);
     96 }
     97 
     98 static inline bool
     99 mutex_is_locked(struct mutex *mutex)
    100 {
    101 	return mutex_owned(&mutex->mtx_lock);
    102 }
    103 
    104 static inline void
    105 mutex_lock_nest_lock(struct mutex *mutex, struct mutex *already)
    106 {
    107 
    108 	KASSERT(mutex_is_locked(already));
    109 	mutex_lock(mutex);
    110 }
    111 
    112 static inline void
    113 mutex_lock_nested(struct mutex *mutex, unsigned subclass __unused)
    114 {
    115 	mutex_lock(mutex);
    116 }
    117 
    118 static inline int
    119 mutex_lock_interruptible_nested(struct mutex *mutex,
    120     unsigned subclass __unused)
    121 {
    122 	return mutex_lock_interruptible(mutex);
    123 }
    124 
    125 /*
    126  * `recursive locking is bad, do not use this ever.'
    127  * -- linux/scripts/checkpath.pl
    128  */
    129 static inline enum {
    130 	MUTEX_TRYLOCK_FAILED,
    131 	MUTEX_TRYLOCK_SUCCESS,
    132 	MUTEX_TRYLOCK_RECURSIVE,
    133 }
    134 mutex_trylock_recursive(struct mutex *mutex)
    135 {
    136 	if (mutex_owned(&mutex->mtx_lock))
    137 		return MUTEX_TRYLOCK_RECURSIVE;
    138 	else if (mutex_tryenter(&mutex->mtx_lock))
    139 		return MUTEX_TRYLOCK_SUCCESS;
    140 	else
    141 		return MUTEX_TRYLOCK_FAILED;
    142 }
    143 
    144 #endif  /* _LINUX_MUTEX_H_ */
    145