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1 | /* -*- mode: c; c-basic-offset: 8; -*- |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: |
3 | * |
4 | * item.c - library routines for handling generic config items |
5 | * |
6 | * This program is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU General Public |
8 | * License as published by the Free Software Foundation; either |
9 | * version 2 of the License, or (at your option) any later version. |
10 | * |
11 | * This program is distributed in the hope that it will be useful, |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 | * General Public License for more details. |
15 | * |
16 | * You should have received a copy of the GNU General Public |
17 | * License along with this program; if not, write to the |
18 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
19 | * Boston, MA 021110-1307, USA. |
20 | * |
21 | * Based on kobject: |
22 | * kobject is Copyright (c) 2002-2003 Patrick Mochel |
23 | * |
24 | * configfs Copyright (C) 2005 Oracle. All rights reserved. |
25 | * |
26 | * Please see the file Documentation/filesystems/configfs.txt for |
27 | * critical information about using the config_item interface. |
28 | */ |
29 | |
30 | #include <linux/string.h> |
31 | #include <linux/module.h> |
32 | #include <linux/stat.h> |
33 | #include <linux/slab.h> |
34 | |
35 | #include <linux/configfs.h> |
36 | |
37 | |
38 | static inline struct config_item * to_item(struct list_head * entry) |
39 | { |
40 | return container_of(entry,struct config_item,ci_entry); |
41 | } |
42 | |
43 | /* Evil kernel */ |
44 | static void config_item_release(struct kref *kref); |
45 | |
46 | /** |
47 | * config_item_init - initialize item. |
48 | * @item: item in question. |
49 | */ |
50 | void config_item_init(struct config_item * item) |
51 | { |
52 | kref_init(&item->ci_kref); |
53 | INIT_LIST_HEAD(&item->ci_entry); |
54 | } |
55 | |
56 | /** |
57 | * config_item_set_name - Set the name of an item |
58 | * @item: item. |
59 | * @name: name. |
60 | * |
61 | * If strlen(name) >= CONFIGFS_ITEM_NAME_LEN, then use a |
62 | * dynamically allocated string that @item->ci_name points to. |
63 | * Otherwise, use the static @item->ci_namebuf array. |
64 | */ |
65 | int config_item_set_name(struct config_item * item, const char * fmt, ...) |
66 | { |
67 | int error = 0; |
68 | int limit = CONFIGFS_ITEM_NAME_LEN; |
69 | int need; |
70 | va_list args; |
71 | char * name; |
72 | |
73 | /* |
74 | * First, try the static array |
75 | */ |
76 | va_start(args,fmt); |
77 | need = vsnprintf(item->ci_namebuf,limit,fmt,args); |
78 | va_end(args); |
79 | if (need < limit) |
80 | name = item->ci_namebuf; |
81 | else { |
82 | /* |
83 | * Need more space? Allocate it and try again |
84 | */ |
85 | limit = need + 1; |
86 | name = kmalloc(limit,GFP_KERNEL); |
87 | if (!name) { |
88 | error = -ENOMEM; |
89 | goto Done; |
90 | } |
91 | va_start(args,fmt); |
92 | need = vsnprintf(name,limit,fmt,args); |
93 | va_end(args); |
94 | |
95 | /* Still? Give up. */ |
96 | if (need >= limit) { |
97 | kfree(name); |
98 | error = -EFAULT; |
99 | goto Done; |
100 | } |
101 | } |
102 | |
103 | /* Free the old name, if necessary. */ |
104 | if (item->ci_name && item->ci_name != item->ci_namebuf) |
105 | kfree(item->ci_name); |
106 | |
107 | /* Now, set the new name */ |
108 | item->ci_name = name; |
109 | Done: |
110 | return error; |
111 | } |
112 | |
113 | EXPORT_SYMBOL(config_item_set_name); |
114 | |
115 | void config_item_init_type_name(struct config_item *item, |
116 | const char *name, |
117 | struct config_item_type *type) |
118 | { |
119 | config_item_set_name(item, name); |
120 | item->ci_type = type; |
121 | config_item_init(item); |
122 | } |
123 | EXPORT_SYMBOL(config_item_init_type_name); |
124 | |
125 | void config_group_init_type_name(struct config_group *group, const char *name, |
126 | struct config_item_type *type) |
127 | { |
128 | config_item_set_name(&group->cg_item, name); |
129 | group->cg_item.ci_type = type; |
130 | config_group_init(group); |
131 | } |
132 | EXPORT_SYMBOL(config_group_init_type_name); |
133 | |
134 | struct config_item * config_item_get(struct config_item * item) |
135 | { |
136 | if (item) |
137 | kref_get(&item->ci_kref); |
138 | return item; |
139 | } |
140 | |
141 | static void config_item_cleanup(struct config_item * item) |
142 | { |
143 | struct config_item_type * t = item->ci_type; |
144 | struct config_group * s = item->ci_group; |
145 | struct config_item * parent = item->ci_parent; |
146 | |
147 | pr_debug("config_item %s: cleaning up\n",config_item_name(item)); |
148 | if (item->ci_name != item->ci_namebuf) |
149 | kfree(item->ci_name); |
150 | item->ci_name = NULL; |
151 | if (t && t->ct_item_ops && t->ct_item_ops->release) |
152 | t->ct_item_ops->release(item); |
153 | if (s) |
154 | config_group_put(s); |
155 | if (parent) |
156 | config_item_put(parent); |
157 | } |
158 | |
159 | static void config_item_release(struct kref *kref) |
160 | { |
161 | config_item_cleanup(container_of(kref, struct config_item, ci_kref)); |
162 | } |
163 | |
164 | /** |
165 | * config_item_put - decrement refcount for item. |
166 | * @item: item. |
167 | * |
168 | * Decrement the refcount, and if 0, call config_item_cleanup(). |
169 | */ |
170 | void config_item_put(struct config_item * item) |
171 | { |
172 | if (item) |
173 | kref_put(&item->ci_kref, config_item_release); |
174 | } |
175 | |
176 | /** |
177 | * config_group_init - initialize a group for use |
178 | * @k: group |
179 | */ |
180 | void config_group_init(struct config_group *group) |
181 | { |
182 | config_item_init(&group->cg_item); |
183 | INIT_LIST_HEAD(&group->cg_children); |
184 | } |
185 | |
186 | /** |
187 | * config_group_find_item - search for item in group. |
188 | * @group: group we're looking in. |
189 | * @name: item's name. |
190 | * |
191 | * Iterate over @group->cg_list, looking for a matching config_item. |
192 | * If matching item is found take a reference and return the item. |
193 | * Caller must have locked group via @group->cg_subsys->su_mtx. |
194 | */ |
195 | struct config_item *config_group_find_item(struct config_group *group, |
196 | const char *name) |
197 | { |
198 | struct list_head * entry; |
199 | struct config_item * ret = NULL; |
200 | |
201 | list_for_each(entry,&group->cg_children) { |
202 | struct config_item * item = to_item(entry); |
203 | if (config_item_name(item) && |
204 | !strcmp(config_item_name(item), name)) { |
205 | ret = config_item_get(item); |
206 | break; |
207 | } |
208 | } |
209 | return ret; |
210 | } |
211 | |
212 | EXPORT_SYMBOL(config_item_init); |
213 | EXPORT_SYMBOL(config_group_init); |
214 | EXPORT_SYMBOL(config_item_get); |
215 | EXPORT_SYMBOL(config_item_put); |
216 | EXPORT_SYMBOL(config_group_find_item); |
217 |
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od-2011-09-04
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v2.6.34-rc5
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