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/rwsem.h 331756 2018-03-30 02:04:46Z emaste $
30 */
31#ifndef	_LINUX_RWSEM_H_
32#define	_LINUX_RWSEM_H_
33
34#include <sys/param.h>
35#include <sys/lock.h>
36#include <sys/sx.h>
37#include <sys/libkern.h>
38#include <sys/kernel.h>
39
40struct rw_semaphore {
41	struct sx sx;
42};
43
44#define	down_write(_rw)			sx_xlock(&(_rw)->sx)
45#define	up_write(_rw)			sx_xunlock(&(_rw)->sx)
46#define	down_read(_rw)			sx_slock(&(_rw)->sx)
47#define	up_read(_rw)			sx_sunlock(&(_rw)->sx)
48#define	down_read_trylock(_rw)		!!sx_try_slock(&(_rw)->sx)
49#define	down_write_trylock(_rw)		!!sx_try_xlock(&(_rw)->sx)
50#define	down_write_killable(_rw)	linux_down_write_killable(_rw)
51#define	downgrade_write(_rw)		sx_downgrade(&(_rw)->sx)
52#define	down_read_nested(_rw, _sc)	down_read(_rw)
53#define	init_rwsem(_rw)			linux_init_rwsem(_rw, rwsem_name("lnxrwsem"))
54
55#ifdef WITNESS_ALL
56/* NOTE: the maximum WITNESS name is 64 chars */
57#define	__rwsem_name(name, file, line)		\
58	(((const char *){file ":" #line "-" name}) +	\
59	(sizeof(file) > 16 ? sizeof(file) - 16 : 0))
60#else
61#define	__rwsem_name(name, file, line)	name
62#endif
63#define	_rwsem_name(...)		__rwsem_name(__VA_ARGS__)
64#define	rwsem_name(name)		_rwsem_name(name, __FILE__, __LINE__)
65
66#define	DECLARE_RWSEM(name)						\
67struct rw_semaphore name;						\
68static void name##_rwsem_init(void *arg)				\
69{									\
70	linux_init_rwsem(&name, rwsem_name(#name));			\
71}									\
72SYSINIT(name, SI_SUB_LOCK, SI_ORDER_SECOND, name##_rwsem_init, NULL)
73
74static inline void
75linux_init_rwsem(struct rw_semaphore *rw, const char *name)
76{
77
78	memset(rw, 0, sizeof(*rw));
79	sx_init_flags(&rw->sx, name, SX_NOWITNESS);
80}
81
82extern int linux_down_write_killable(struct rw_semaphore *);
83
84#endif					/* _LINUX_RWSEM_H_ */
85