1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice unmodified, this list of conditions, and the following
13 *    disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD: stable/11/sys/compat/linuxkpi/common/include/linux/spinlock.h 331756 2018-03-30 02:04:46Z emaste $
30 */
31#ifndef	_LINUX_SPINLOCK_H_
32#define	_LINUX_SPINLOCK_H_
33
34#include <sys/param.h>
35#include <sys/kernel.h>
36#include <sys/lock.h>
37#include <sys/mutex.h>
38#include <sys/kdb.h>
39
40#include <linux/compiler.h>
41#include <linux/rwlock.h>
42#include <linux/bottom_half.h>
43
44typedef struct {
45	struct mtx m;
46} spinlock_t;
47
48/*
49 * By defining CONFIG_SPIN_SKIP LinuxKPI spinlocks and asserts will be
50 * skipped during panic(). By default it is disabled due to
51 * performance reasons.
52 */
53#ifdef CONFIG_SPIN_SKIP
54#define	SPIN_SKIP(void)	unlikely(SCHEDULER_STOPPED() || kdb_active)
55#else
56#define	SPIN_SKIP(void) 0
57#endif
58
59#define	spin_lock(_l) do {			\
60	if (SPIN_SKIP())			\
61		break;				\
62	mtx_lock(&(_l)->m);			\
63	local_bh_disable();			\
64} while (0)
65
66#define	spin_lock_bh(_l) do {			\
67	spin_lock(_l);				\
68} while (0)
69
70#define	spin_lock_irq(_l) do {			\
71	spin_lock(_l);				\
72} while (0)
73
74#define	spin_unlock(_l)	do {			\
75	if (SPIN_SKIP())			\
76		break;				\
77	local_bh_enable();			\
78	mtx_unlock(&(_l)->m);			\
79} while (0)
80
81#define	spin_unlock_bh(_l) do {			\
82	spin_unlock(_l);			\
83} while (0)
84
85#define	spin_unlock_irq(_l) do {		\
86	spin_unlock(_l);			\
87} while (0)
88
89#define	spin_trylock(_l) ({			\
90	int __ret;				\
91	if (SPIN_SKIP()) {			\
92		__ret = 1;			\
93	} else {				\
94		__ret = mtx_trylock(&(_l)->m);	\
95		if (likely(__ret != 0))		\
96			local_bh_disable();	\
97	}					\
98	__ret;					\
99})
100
101#define	spin_trylock_irq(_l)			\
102	spin_trylock(_l)
103
104#define	spin_lock_nested(_l, _n) do {		\
105	if (SPIN_SKIP())			\
106		break;				\
107	mtx_lock_flags(&(_l)->m, MTX_DUPOK);	\
108	local_bh_disable();			\
109} while (0)
110
111#define	spin_lock_irqsave(_l, flags) do {	\
112	(flags) = 0;				\
113	spin_lock(_l);				\
114} while (0)
115
116#define	spin_lock_irqsave_nested(_l, flags, _n) do {	\
117	(flags) = 0;					\
118	spin_lock_nested(_l, _n);			\
119} while (0)
120
121#define	spin_unlock_irqrestore(_l, flags) do {		\
122	spin_unlock(_l);				\
123} while (0)
124
125#ifdef WITNESS_ALL
126/* NOTE: the maximum WITNESS name is 64 chars */
127#define	__spin_lock_name(name, file, line)		\
128	(((const char *){file ":" #line "-" name}) +	\
129	(sizeof(file) > 16 ? sizeof(file) - 16 : 0))
130#else
131#define	__spin_lock_name(name, file, line)	name
132#endif
133#define	_spin_lock_name(...)		__spin_lock_name(__VA_ARGS__)
134#define	spin_lock_name(name)		_spin_lock_name(name, __FILE__, __LINE__)
135
136#define	spin_lock_init(lock)	linux_spin_lock_init(lock, spin_lock_name("lnxspin"))
137
138static inline void
139linux_spin_lock_init(spinlock_t *lock, const char *name)
140{
141
142	memset(lock, 0, sizeof(*lock));
143	mtx_init(&lock->m, name, NULL, MTX_DEF | MTX_NOWITNESS);
144}
145
146static inline void
147spin_lock_destroy(spinlock_t *lock)
148{
149
150       mtx_destroy(&lock->m);
151}
152
153#define	DEFINE_SPINLOCK(lock)					\
154	spinlock_t lock;					\
155	MTX_SYSINIT(lock, &(lock).m, spin_lock_name("lnxspin"), MTX_DEF)
156
157#define	assert_spin_locked(_l) do {		\
158	if (SPIN_SKIP())			\
159		break;				\
160	mtx_assert(&(_l)->m, MA_OWNED);		\
161} while (0)
162
163#endif					/* _LINUX_SPINLOCK_H_ */
164