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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 <linux/slab.h> | |
34 | #include <net/9p/9p.h> | |
35 | ||
36 | /** | |
37 | * struct p9_idpool - per-connection accounting for tag idpool | |
38 | * @lock: protects the pool | |
39 | * @pool: idr to allocate tag id from | |
40 | * | |
41 | */ | |
42 | ||
43 | struct p9_idpool { | |
44 | spinlock_t lock; | |
45 | struct idr pool; | |
46 | }; | |
47 | ||
48 | /** | |
49 | * p9_idpool_create - create a new per-connection id pool | |
50 | * | |
51 | */ | |
52 | ||
53 | struct p9_idpool *p9_idpool_create(void) | |
54 | { | |
55 | struct p9_idpool *p; | |
56 | ||
57 | p = kmalloc(sizeof(struct p9_idpool), GFP_KERNEL); | |
58 | if (!p) | |
59 | return ERR_PTR(-ENOMEM); | |
60 | ||
61 | spin_lock_init(&p->lock); | |
62 | idr_init(&p->pool); | |
63 | ||
64 | return p; | |
65 | } | |
66 | EXPORT_SYMBOL(p9_idpool_create); | |
67 | ||
68 | /** | |
69 | * p9_idpool_destroy - create a new per-connection id pool | |
70 | * @p: idpool to destroy | |
71 | */ | |
72 | ||
73 | void p9_idpool_destroy(struct p9_idpool *p) | |
74 | { | |
75 | idr_destroy(&p->pool); | |
76 | kfree(p); | |
77 | } | |
78 | EXPORT_SYMBOL(p9_idpool_destroy); | |
79 | ||
80 | /** | |
81 | * p9_idpool_get - allocate numeric id from pool | |
82 | * @p: pool to allocate from | |
83 | * | |
84 | * Bugs: This seems to be an awful generic function, should it be in idr.c with | |
85 | * the lock included in struct idr? | |
86 | */ | |
87 | ||
88 | int p9_idpool_get(struct p9_idpool *p) | |
89 | { | |
90 | int i; | |
91 | unsigned long flags; | |
92 | ||
93 | idr_preload(GFP_NOFS); | |
94 | spin_lock_irqsave(&p->lock, flags); | |
95 | ||
96 | /* no need to store exactly p, we just need something non-null */ | |
97 | i = idr_alloc(&p->pool, p, 0, 0, GFP_NOWAIT); | |
98 | ||
99 | spin_unlock_irqrestore(&p->lock, flags); | |
100 | idr_preload_end(); | |
101 | if (i < 0) | |
102 | return -1; | |
103 | ||
104 | p9_debug(P9_DEBUG_MUX, " id %d pool %p\n", i, p); | |
105 | return i; | |
106 | } | |
107 | EXPORT_SYMBOL(p9_idpool_get); | |
108 | ||
109 | /** | |
110 | * p9_idpool_put - release numeric id from pool | |
111 | * @id: numeric id which is being released | |
112 | * @p: pool to release id into | |
113 | * | |
114 | * Bugs: This seems to be an awful generic function, should it be in idr.c with | |
115 | * the lock included in struct idr? | |
116 | */ | |
117 | ||
118 | void p9_idpool_put(int id, struct p9_idpool *p) | |
119 | { | |
120 | unsigned long flags; | |
121 | ||
122 | p9_debug(P9_DEBUG_MUX, " id %d pool %p\n", id, p); | |
123 | ||
124 | spin_lock_irqsave(&p->lock, flags); | |
125 | idr_remove(&p->pool, id); | |
126 | spin_unlock_irqrestore(&p->lock, flags); | |
127 | } | |
128 | EXPORT_SYMBOL(p9_idpool_put); | |
129 | ||
130 | /** | |
131 | * p9_idpool_check - check if the specified id is available | |
132 | * @id: id to check | |
133 | * @p: pool to check | |
134 | */ | |
135 | ||
136 | int p9_idpool_check(int id, struct p9_idpool *p) | |
137 | { | |
138 | return idr_find(&p->pool, id) != NULL; | |
139 | } | |
140 | EXPORT_SYMBOL(p9_idpool_check); | |
141 |