util.c
3.26 KB
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
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
/*
* 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 <linux/slab.h>
#include <net/9p/9p.h>
/**
* struct p9_idpool - per-connection accounting for tag idpool
* @lock: protects the pool
* @pool: idr to allocate tag id from
*
*/
struct p9_idpool {
spinlock_t lock;
struct idr pool;
};
/**
* p9_idpool_create - create a new per-connection id 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);
/**
* p9_idpool_destroy - create a new per-connection id pool
* @p: idpool to destory
*/
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
*
* Bugs: 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 long 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;
P9_DPRINTK(P9_DEBUG_MUX, " id %d pool %p\n", i, p);
return i;
}
EXPORT_SYMBOL(p9_idpool_get);
/**
* p9_idpool_put - release numeric id from pool
* @id: numeric id which is being released
* @p: pool to release id into
*
* Bugs: 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 long flags;
P9_DPRINTK(P9_DEBUG_MUX, " id %d pool %p\n", id, p);
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 to check
*/
int p9_idpool_check(int id, struct p9_idpool *p)
{
return idr_find(&p->pool, id) != NULL;
}
EXPORT_SYMBOL(p9_idpool_check);