Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: e3c92d19e54079e5ffc950adf8974c35eee0703e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
/*
 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef __XFS_SUPPORT_MRLOCK_H__
#define __XFS_SUPPORT_MRLOCK_H__

#include <linux/rwsem.h>

typedef struct {
	struct rw_semaphore	mr_lock;
#if defined(DEBUG) || defined(XFS_WARN)
	int			mr_writer;
#endif
} mrlock_t;

#if defined(DEBUG) || defined(XFS_WARN)
#define mrinit(mrp, name)	\
	do { (mrp)->mr_writer = 0; init_rwsem(&(mrp)->mr_lock); } while (0)
#else
#define mrinit(mrp, name)	\
	do { init_rwsem(&(mrp)->mr_lock); } while (0)
#endif

#define mrlock_init(mrp, t,n,s)	mrinit(mrp, n)
#define mrfree(mrp)		do { } while (0)

static inline void mraccess_nested(mrlock_t *mrp, int subclass)
{
	down_read_nested(&mrp->mr_lock, subclass);
}

static inline void mrupdate_nested(mrlock_t *mrp, int subclass)
{
	down_write_nested(&mrp->mr_lock, subclass);
#if defined(DEBUG) || defined(XFS_WARN)
	mrp->mr_writer = 1;
#endif
}

static inline int mrtryaccess(mrlock_t *mrp)
{
	return down_read_trylock(&mrp->mr_lock);
}

static inline int mrtryupdate(mrlock_t *mrp)
{
	if (!down_write_trylock(&mrp->mr_lock))
		return 0;
#if defined(DEBUG) || defined(XFS_WARN)
	mrp->mr_writer = 1;
#endif
	return 1;
}

static inline void mrunlock_excl(mrlock_t *mrp)
{
#if defined(DEBUG) || defined(XFS_WARN)
	mrp->mr_writer = 0;
#endif
	up_write(&mrp->mr_lock);
}

static inline void mrunlock_shared(mrlock_t *mrp)
{
	up_read(&mrp->mr_lock);
}

static inline void mrdemote(mrlock_t *mrp)
{
#if defined(DEBUG) || defined(XFS_WARN)
	mrp->mr_writer = 0;
#endif
	downgrade_write(&mrp->mr_lock);
}

#endif /* __XFS_SUPPORT_MRLOCK_H__ */