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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 destory |
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 = 0; |
91 | int error; |
92 | unsigned long flags; |
93 | |
94 | retry: |
95 | if (idr_pre_get(&p->pool, GFP_KERNEL) == 0) |
96 | return 0; |
97 | |
98 | spin_lock_irqsave(&p->lock, flags); |
99 | |
100 | /* no need to store exactly p, we just need something non-null */ |
101 | error = idr_get_new(&p->pool, p, &i); |
102 | spin_unlock_irqrestore(&p->lock, flags); |
103 | |
104 | if (error == -EAGAIN) |
105 | goto retry; |
106 | else if (error) |
107 | return -1; |
108 | |
109 | P9_DPRINTK(P9_DEBUG_MUX, " id %d pool %p\n", i, p); |
110 | return i; |
111 | } |
112 | EXPORT_SYMBOL(p9_idpool_get); |
113 | |
114 | /** |
115 | * p9_idpool_put - release numeric id from pool |
116 | * @id: numeric id which is being released |
117 | * @p: pool to release id into |
118 | * |
119 | * Bugs: This seems to be an awful generic function, should it be in idr.c with |
120 | * the lock included in struct idr? |
121 | */ |
122 | |
123 | void p9_idpool_put(int id, struct p9_idpool *p) |
124 | { |
125 | unsigned long flags; |
126 | |
127 | P9_DPRINTK(P9_DEBUG_MUX, " id %d pool %p\n", id, p); |
128 | |
129 | spin_lock_irqsave(&p->lock, flags); |
130 | idr_remove(&p->pool, id); |
131 | spin_unlock_irqrestore(&p->lock, flags); |
132 | } |
133 | EXPORT_SYMBOL(p9_idpool_put); |
134 | |
135 | /** |
136 | * p9_idpool_check - check if the specified id is available |
137 | * @id: id to check |
138 | * @p: pool to check |
139 | */ |
140 | |
141 | int p9_idpool_check(int id, struct p9_idpool *p) |
142 | { |
143 | return idr_find(&p->pool, id) != NULL; |
144 | } |
145 | EXPORT_SYMBOL(p9_idpool_check); |
146 | |
147 |
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