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Diffstat (limited to 'net/9p/util.c')
-rw-r--r-- | net/9p/util.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/net/9p/util.c b/net/9p/util.c new file mode 100644 index 000000000000..22077b79395d --- /dev/null +++ b/net/9p/util.c | |||
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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); | ||