Linux kernel mirror (for testing)
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1/*
2 * net/9p/util.c
3 *
4 * This file contains some helper functions
5 *
6 * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
7 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
8 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to:
21 * Free Software Foundation
22 * 51 Franklin Street, Fifth Floor
23 * Boston, MA 02111-1301 USA
24 *
25 */
26
27#include <linux/module.h>
28#include <linux/errno.h>
29#include <linux/fs.h>
30#include <linux/sched.h>
31#include <linux/parser.h>
32#include <linux/idr.h>
33#include <net/9p/9p.h>
34
35struct p9_idpool {
36 struct semaphore lock;
37 struct idr pool;
38};
39
40struct p9_idpool *p9_idpool_create(void)
41{
42 struct p9_idpool *p;
43
44 p = kmalloc(sizeof(struct p9_idpool), GFP_KERNEL);
45 if (!p)
46 return ERR_PTR(-ENOMEM);
47
48 init_MUTEX(&p->lock);
49 idr_init(&p->pool);
50
51 return p;
52}
53EXPORT_SYMBOL(p9_idpool_create);
54
55void p9_idpool_destroy(struct p9_idpool *p)
56{
57 idr_destroy(&p->pool);
58 kfree(p);
59}
60EXPORT_SYMBOL(p9_idpool_destroy);
61
62/**
63 * p9_idpool_get - allocate numeric id from pool
64 * @p - pool to allocate from
65 *
66 * XXX - This seems to be an awful generic function, should it be in idr.c with
67 * the lock included in struct idr?
68 */
69
70int p9_idpool_get(struct p9_idpool *p)
71{
72 int i = 0;
73 int error;
74
75retry:
76 if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
77 return 0;
78
79 if (down_interruptible(&p->lock) == -EINTR) {
80 P9_EPRINTK(KERN_WARNING, "Interrupted while locking\n");
81 return -1;
82 }
83
84 /* no need to store exactly p, we just need something non-null */
85 error = idr_get_new(&p->pool, p, &i);
86 up(&p->lock);
87
88 if (error == -EAGAIN)
89 goto retry;
90 else if (error)
91 return -1;
92
93 return i;
94}
95EXPORT_SYMBOL(p9_idpool_get);
96
97/**
98 * p9_idpool_put - release numeric id from pool
99 * @p - pool to allocate from
100 *
101 * XXX - This seems to be an awful generic function, should it be in idr.c with
102 * the lock included in struct idr?
103 */
104
105void p9_idpool_put(int id, struct p9_idpool *p)
106{
107 if (down_interruptible(&p->lock) == -EINTR) {
108 P9_EPRINTK(KERN_WARNING, "Interrupted while locking\n");
109 return;
110 }
111 idr_remove(&p->pool, id);
112 up(&p->lock);
113}
114EXPORT_SYMBOL(p9_idpool_put);
115
116/**
117 * p9_idpool_check - check if the specified id is available
118 * @id - id to check
119 * @p - pool
120 */
121int p9_idpool_check(int id, struct p9_idpool *p)
122{
123 return idr_find(&p->pool, id) != NULL;
124}
125EXPORT_SYMBOL(p9_idpool_check);