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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 | ||
35 | struct p9_idpool { | |
36 | struct semaphore lock; | |
37 | struct idr pool; | |
38 | }; | |
39 | ||
40 | struct 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 | } | |
53 | EXPORT_SYMBOL(p9_idpool_create); | |
54 | ||
55 | void p9_idpool_destroy(struct p9_idpool *p) | |
56 | { | |
57 | idr_destroy(&p->pool); | |
58 | kfree(p); | |
59 | } | |
60 | EXPORT_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 | ||
70 | int p9_idpool_get(struct p9_idpool *p) | |
71 | { | |
72 | int i = 0; | |
73 | int error; | |
74 | ||
75 | retry: | |
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 | } | |
95 | EXPORT_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 | ||
105 | void 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 | } | |
114 | EXPORT_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 | */ | |
121 | int p9_idpool_check(int id, struct p9_idpool *p) | |
122 | { | |
123 | return idr_find(&p->pool, id) != NULL; | |
124 | } | |
125 | EXPORT_SYMBOL(p9_idpool_check); |