aboutsummaryrefslogtreecommitdiffstats
path: root/net/9p/util.c
blob: ef7215565d881de05e00c7214623f3a8fa759b8f (plain) (blame)
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
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
/*
 *  net/9p/util.c
 *
 *  This file contains some helper functions
 *
 *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will 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 to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/parser.h>
#include <linux/idr.h>
#include <net/9p/9p.h>

struct p9_idpool {
	spinlock_t lock;
	struct idr pool;
};

struct p9_idpool *p9_idpool_create(void)
{
	struct p9_idpool *p;

	p = kmalloc(sizeof(struct p9_idpool), GFP_KERNEL);
	if (!p)
		return ERR_PTR(-ENOMEM);

	spin_lock_init(&p->lock);
	idr_init(&p->pool);

	return p;
}
EXPORT_SYMBOL(p9_idpool_create);

void p9_idpool_destroy(struct p9_idpool *p)
{
	idr_destroy(&p->pool);
	kfree(p);
}
EXPORT_SYMBOL(p9_idpool_destroy);

/**
 * p9_idpool_get - allocate numeric id from pool
 * @p - pool to allocate from
 *
 * XXX - This seems to be an awful generic function, should it be in idr.c with
 *            the lock included in struct idr?
 */

int p9_idpool_get(struct p9_idpool *p)
{
	int i = 0;
	int error;
	unsigned int flags;

retry:
	if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
		return 0;

	spin_lock_irqsave(&p->lock, flags);

	/* no need to store exactly p, we just need something non-null */
	error = idr_get_new(&p->pool, p, &i);
	spin_unlock_irqrestore(&p->lock, flags);

	if (error == -EAGAIN)
		goto retry;
	else if (error)
		return -1;

	return i;
}
EXPORT_SYMBOL(p9_idpool_get);

/**
 * p9_idpool_put - release numeric id from pool
 * @p - pool to allocate from
 *
 * XXX - This seems to be an awful generic function, should it be in idr.c with
 *            the lock included in struct idr?
 */

void p9_idpool_put(int id, struct p9_idpool *p)
{
	unsigned int flags;
	spin_lock_irqsave(&p->lock, flags);
	idr_remove(&p->pool, id);
	spin_unlock_irqrestore(&p->lock, flags);
}
EXPORT_SYMBOL(p9_idpool_put);

/**
 * p9_idpool_check - check if the specified id is available
 * @id - id to check
 * @p - pool
 */
int p9_idpool_check(int id, struct p9_idpool *p)
{
	return idr_find(&p->pool, id) != NULL;
}
EXPORT_SYMBOL(p9_idpool_check);