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 * $FreeBSD$
30 */
31#ifndef	_LINUX_SPINLOCK_H_
32#define	_LINUX_SPINLOCK_H_
33
34#include <asm/atomic.h>
35#include <sys/param.h>
36#include <sys/kernel.h>
37#include <sys/lock.h>
38#include <sys/mutex.h>
39#include <sys/kdb.h>
40
41#include <linux/compiler.h>
42#include <linux/rwlock.h>
43#include <linux/bottom_half.h>
44
45typedef struct {
46	struct mtx m;
47} spinlock_t;
48
49/*
50 * By defining CONFIG_SPIN_SKIP LinuxKPI spinlocks and asserts will be
51 * skipped during panic(). By default it is disabled due to
52 * performance reasons.
53 */
54#ifdef CONFIG_SPIN_SKIP
55#define	SPIN_SKIP(void)	unlikely(SCHEDULER_STOPPED() || kdb_active)
56#else
57#define	SPIN_SKIP(void) 0
58#endif
59
60#define	spin_lock(_l) do {			\
61	if (SPIN_SKIP())			\
62		break;				\
63	mtx_lock(&(_l)->m);			\
64	local_bh_disable();			\
65} while (0)
66
67#define	spin_lock_bh(_l) do {			\
68	spin_lock(_l);				\
69} while (0)
70
71#define	spin_lock_irq(_l) do {			\
72	spin_lock(_l);				\
73} while (0)
74
75#define	spin_unlock(_l)	do {			\
76	if (SPIN_SKIP())			\
77		break;				\
78	local_bh_enable();			\
79	mtx_unlock(&(_l)->m);			\
80} while (0)
81
82#define	spin_unlock_bh(_l) do {			\
83	spin_unlock(_l);			\
84} while (0)
85
86#define	spin_unlock_irq(_l) do {		\
87	spin_unlock(_l);			\
88} while (0)
89
90#define	spin_trylock(_l) ({			\
91	int __ret;				\
92	if (SPIN_SKIP()) {			\
93		__ret = 1;			\
94	} else {				\
95		__ret = mtx_trylock(&(_l)->m);	\
96		if (likely(__ret != 0))		\
97			local_bh_disable();	\
98	}					\
99	__ret;					\
100})
101
102#define	spin_trylock_irq(_l)			\
103	spin_trylock(_l)
104
105#define	spin_lock_nested(_l, _n) do {		\
106	if (SPIN_SKIP())			\
107		break;				\
108	mtx_lock_flags(&(_l)->m, MTX_DUPOK);	\
109	local_bh_disable();			\
110} while (0)
111
112#define	spin_lock_irqsave(_l, flags) do {	\
113	(flags) = 0;				\
114	spin_lock(_l);				\
115} while (0)
116
117#define	spin_lock_irqsave_nested(_l, flags, _n) do {	\
118	(flags) = 0;					\
119	spin_lock_nested(_l, _n);			\
120} while (0)
121
122#define	spin_unlock_irqrestore(_l, flags) do {		\
123	spin_unlock(_l);				\
124} while (0)
125
126#ifdef WITNESS_ALL
127/* NOTE: the maximum WITNESS name is 64 chars */
128#define	__spin_lock_name(name, file, line)		\
129	(((const char *){file ":" #line "-" name}) +	\
130	(sizeof(file) > 16 ? sizeof(file) - 16 : 0))
131#else
132#define	__spin_lock_name(name, file, line)	name
133#endif
134#define	_spin_lock_name(...)		__spin_lock_name(__VA_ARGS__)
135#define	spin_lock_name(name)		_spin_lock_name(name, __FILE__, __LINE__)
136
137#define	spin_lock_init(lock)	linux_spin_lock_init(lock, spin_lock_name("lnxspin"))
138
139static inline void
140linux_spin_lock_init(spinlock_t *lock, const char *name)
141{
142
143	memset(lock, 0, sizeof(*lock));
144	mtx_init(&lock->m, name, NULL, MTX_DEF | MTX_NOWITNESS);
145}
146
147static inline void
148spin_lock_destroy(spinlock_t *lock)
149{
150
151       mtx_destroy(&lock->m);
152}
153
154#define	DEFINE_SPINLOCK(lock)					\
155	spinlock_t lock;					\
156	MTX_SYSINIT(lock, &(lock).m, spin_lock_name("lnxspin"), MTX_DEF)
157
158#define	assert_spin_locked(_l) do {		\
159	if (SPIN_SKIP())			\
160		break;				\
161	mtx_assert(&(_l)->m, MA_OWNED);		\
162} while (0)
163
164static inline int
165atomic_dec_and_lock_irqsave(atomic_t *cnt, spinlock_t *lock,
166    unsigned long flags)
167{
168	spin_lock_irqsave(lock, flags);
169	if (atomic_dec_and_test(cnt))
170		return 1;
171	spin_unlock_irqrestore(lock, flags);
172	return 0;
173}
174
175#endif					/* _LINUX_SPINLOCK_H_ */
176