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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: | |
f6b1fe7c | 22 | * kobject is Copyright (c) 2002-2003 Patrick Mochel |
7063fbf2 JB |
23 | * |
24 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
25 | * | |
395cf969 | 26 | * Please see the file Documentation/filesystems/configfs/configfs.txt for |
7063fbf2 JB |
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 | ||
f6b1fe7c | 38 | static inline struct config_item *to_item(struct list_head *entry) |
7063fbf2 | 39 | { |
f6b1fe7c | 40 | return container_of(entry, struct config_item, ci_entry); |
7063fbf2 JB |
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 | */ | |
f6b1fe7c | 50 | void config_item_init(struct config_item *item) |
7063fbf2 JB |
51 | { |
52 | kref_init(&item->ci_kref); | |
53 | INIT_LIST_HEAD(&item->ci_entry); | |
54 | } | |
f6b1fe7c | 55 | EXPORT_SYMBOL(config_item_init); |
7063fbf2 JB |
56 | |
57 | /** | |
58 | * config_item_set_name - Set the name of an item | |
59 | * @item: item. | |
f6b1fe7c | 60 | * @fmt: The vsnprintf()'s format string. |
7063fbf2 JB |
61 | * |
62 | * If strlen(name) >= CONFIGFS_ITEM_NAME_LEN, then use a | |
63 | * dynamically allocated string that @item->ci_name points to. | |
64 | * Otherwise, use the static @item->ci_namebuf array. | |
65 | */ | |
f6b1fe7c | 66 | int config_item_set_name(struct config_item *item, const char *fmt, ...) |
7063fbf2 JB |
67 | { |
68 | int error = 0; | |
69 | int limit = CONFIGFS_ITEM_NAME_LEN; | |
70 | int need; | |
71 | va_list args; | |
f6b1fe7c | 72 | char *name; |
7063fbf2 JB |
73 | |
74 | /* | |
75 | * First, try the static array | |
76 | */ | |
f6b1fe7c FF |
77 | va_start(args, fmt); |
78 | need = vsnprintf(item->ci_namebuf, limit, fmt, args); | |
7063fbf2 JB |
79 | va_end(args); |
80 | if (need < limit) | |
81 | name = item->ci_namebuf; | |
82 | else { | |
83 | /* | |
84 | * Need more space? Allocate it and try again | |
85 | */ | |
86 | limit = need + 1; | |
f6b1fe7c | 87 | name = kmalloc(limit, GFP_KERNEL); |
7063fbf2 JB |
88 | if (!name) { |
89 | error = -ENOMEM; | |
90 | goto Done; | |
91 | } | |
f6b1fe7c FF |
92 | va_start(args, fmt); |
93 | need = vsnprintf(name, limit, fmt, args); | |
7063fbf2 JB |
94 | va_end(args); |
95 | ||
96 | /* Still? Give up. */ | |
97 | if (need >= limit) { | |
98 | kfree(name); | |
99 | error = -EFAULT; | |
100 | goto Done; | |
101 | } | |
102 | } | |
103 | ||
104 | /* Free the old name, if necessary. */ | |
105 | if (item->ci_name && item->ci_name != item->ci_namebuf) | |
106 | kfree(item->ci_name); | |
107 | ||
108 | /* Now, set the new name */ | |
109 | item->ci_name = name; | |
110 | Done: | |
111 | return error; | |
112 | } | |
7063fbf2 JB |
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 | ||
f6b1fe7c | 134 | struct config_item *config_item_get(struct config_item *item) |
7063fbf2 JB |
135 | { |
136 | if (item) | |
137 | kref_get(&item->ci_kref); | |
138 | return item; | |
139 | } | |
f6b1fe7c | 140 | EXPORT_SYMBOL(config_item_get); |
7063fbf2 | 141 | |
f6b1fe7c | 142 | static void config_item_cleanup(struct config_item *item) |
7063fbf2 | 143 | { |
f6b1fe7c FF |
144 | struct config_item_type *t = item->ci_type; |
145 | struct config_group *s = item->ci_group; | |
146 | struct config_item *parent = item->ci_parent; | |
7063fbf2 | 147 | |
f6b1fe7c | 148 | pr_debug("config_item %s: cleaning up\n", config_item_name(item)); |
7063fbf2 JB |
149 | if (item->ci_name != item->ci_namebuf) |
150 | kfree(item->ci_name); | |
151 | item->ci_name = NULL; | |
152 | if (t && t->ct_item_ops && t->ct_item_ops->release) | |
153 | t->ct_item_ops->release(item); | |
154 | if (s) | |
155 | config_group_put(s); | |
156 | if (parent) | |
157 | config_item_put(parent); | |
158 | } | |
159 | ||
160 | static void config_item_release(struct kref *kref) | |
161 | { | |
162 | config_item_cleanup(container_of(kref, struct config_item, ci_kref)); | |
163 | } | |
164 | ||
165 | /** | |
166 | * config_item_put - decrement refcount for item. | |
167 | * @item: item. | |
168 | * | |
169 | * Decrement the refcount, and if 0, call config_item_cleanup(). | |
170 | */ | |
f6b1fe7c | 171 | void config_item_put(struct config_item *item) |
7063fbf2 JB |
172 | { |
173 | if (item) | |
174 | kref_put(&item->ci_kref, config_item_release); | |
175 | } | |
f6b1fe7c | 176 | EXPORT_SYMBOL(config_item_put); |
7063fbf2 | 177 | |
7063fbf2 JB |
178 | /** |
179 | * config_group_init - initialize a group for use | |
f6b1fe7c | 180 | * @group: config_group |
7063fbf2 | 181 | */ |
7063fbf2 JB |
182 | void config_group_init(struct config_group *group) |
183 | { | |
184 | config_item_init(&group->cg_item); | |
185 | INIT_LIST_HEAD(&group->cg_children); | |
186 | } | |
f6b1fe7c | 187 | EXPORT_SYMBOL(config_group_init); |
7063fbf2 | 188 | |
7063fbf2 | 189 | /** |
3fe6c5ce | 190 | * config_group_find_item - search for item in group. |
7063fbf2 JB |
191 | * @group: group we're looking in. |
192 | * @name: item's name. | |
193 | * | |
3fe6c5ce SS |
194 | * Iterate over @group->cg_list, looking for a matching config_item. |
195 | * If matching item is found take a reference and return the item. | |
196 | * Caller must have locked group via @group->cg_subsys->su_mtx. | |
7063fbf2 | 197 | */ |
3fe6c5ce SS |
198 | struct config_item *config_group_find_item(struct config_group *group, |
199 | const char *name) | |
7063fbf2 | 200 | { |
f6b1fe7c FF |
201 | struct list_head *entry; |
202 | struct config_item *ret = NULL; | |
7063fbf2 | 203 | |
f6b1fe7c FF |
204 | list_for_each(entry, &group->cg_children) { |
205 | struct config_item *item = to_item(entry); | |
7063fbf2 | 206 | if (config_item_name(item) && |
3fe6c5ce | 207 | !strcmp(config_item_name(item), name)) { |
7063fbf2 JB |
208 | ret = config_item_get(item); |
209 | break; | |
210 | } | |
211 | } | |
212 | return ret; | |
213 | } | |
3fe6c5ce | 214 | EXPORT_SYMBOL(config_group_find_item); |