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 #ifndef _LINUXKPI_LINUX_RWSEM_H_
30 #define _LINUXKPI_LINUX_RWSEM_H_
31
32 #include <sys/param.h>
33 #include <sys/lock.h>
34 #include <sys/sx.h>
35 #include <sys/libkern.h>
36 #include <sys/kernel.h>
37
38 struct rw_semaphore {
39 struct sx sx;
40 };
41
42 #define down_write(_rw) sx_xlock(&(_rw)->sx)
43 #define up_write(_rw) sx_xunlock(&(_rw)->sx)
44 #define down_read(_rw) sx_slock(&(_rw)->sx)
45 #define up_read(_rw) sx_sunlock(&(_rw)->sx)
46 #define down_read_trylock(_rw) !!sx_try_slock(&(_rw)->sx)
47 #define down_read_killable(_rw) linux_down_read_killable(_rw)
48 #define down_write_trylock(_rw) !!sx_try_xlock(&(_rw)->sx)
49 #define down_write_killable(_rw) linux_down_write_killable(_rw)
50 #define downgrade_write(_rw) sx_downgrade(&(_rw)->sx)
51 #define down_read_nested(_rw, _sc) down_read(_rw)
52 #define init_rwsem(_rw) linux_init_rwsem(_rw, rwsem_name("lnxrwsem"))
53 #define down_write_nest_lock(sem, _rw) down_write(_rw)
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) \
67 struct rw_semaphore name; \
68 static void name##_rwsem_init(void *arg) \
69 { \
70 linux_init_rwsem(&name, rwsem_name(#name)); \
71 } \
72 SYSINIT(name, SI_SUB_LOCK, SI_ORDER_SECOND, name##_rwsem_init, NULL)
73
74 static inline void
linux_init_rwsem(struct rw_semaphore * rw,const char * name)75 linux_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
82 extern int linux_down_read_killable(struct rw_semaphore *);
83 extern int linux_down_write_killable(struct rw_semaphore *);
84
85 #endif /* _LINUXKPI_LINUX_RWSEM_H_ */
86