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328970de | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
7063fbf2 JB |
2 | /* -*- mode: c; c-basic-offset: 8; -*- |
3 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
4 | * | |
5 | * item.c - library routines for handling generic config items | |
6 | * | |
7063fbf2 | 7 | * Based on kobject: |
f6b1fe7c | 8 | * kobject is Copyright (c) 2002-2003 Patrick Mochel |
7063fbf2 JB |
9 | * |
10 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
11 | * | |
395cf969 | 12 | * Please see the file Documentation/filesystems/configfs/configfs.txt for |
7063fbf2 JB |
13 | * critical information about using the config_item interface. |
14 | */ | |
15 | ||
16 | #include <linux/string.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/stat.h> | |
19 | #include <linux/slab.h> | |
20 | ||
21 | #include <linux/configfs.h> | |
22 | ||
23 | ||
f6b1fe7c | 24 | static inline struct config_item *to_item(struct list_head *entry) |
7063fbf2 | 25 | { |
f6b1fe7c | 26 | return container_of(entry, struct config_item, ci_entry); |
7063fbf2 JB |
27 | } |
28 | ||
29 | /* Evil kernel */ | |
30 | static void config_item_release(struct kref *kref); | |
31 | ||
32 | /** | |
33 | * config_item_init - initialize item. | |
34 | * @item: item in question. | |
35 | */ | |
5286d20c | 36 | static void config_item_init(struct config_item *item) |
7063fbf2 JB |
37 | { |
38 | kref_init(&item->ci_kref); | |
39 | INIT_LIST_HEAD(&item->ci_entry); | |
40 | } | |
41 | ||
42 | /** | |
43 | * config_item_set_name - Set the name of an item | |
44 | * @item: item. | |
f6b1fe7c | 45 | * @fmt: The vsnprintf()'s format string. |
7063fbf2 JB |
46 | * |
47 | * If strlen(name) >= CONFIGFS_ITEM_NAME_LEN, then use a | |
48 | * dynamically allocated string that @item->ci_name points to. | |
49 | * Otherwise, use the static @item->ci_namebuf array. | |
50 | */ | |
f6b1fe7c | 51 | int config_item_set_name(struct config_item *item, const char *fmt, ...) |
7063fbf2 | 52 | { |
7063fbf2 JB |
53 | int limit = CONFIGFS_ITEM_NAME_LEN; |
54 | int need; | |
55 | va_list args; | |
f6b1fe7c | 56 | char *name; |
7063fbf2 JB |
57 | |
58 | /* | |
59 | * First, try the static array | |
60 | */ | |
f6b1fe7c FF |
61 | va_start(args, fmt); |
62 | need = vsnprintf(item->ci_namebuf, limit, fmt, args); | |
7063fbf2 JB |
63 | va_end(args); |
64 | if (need < limit) | |
65 | name = item->ci_namebuf; | |
66 | else { | |
f6b1fe7c | 67 | va_start(args, fmt); |
707c6235 | 68 | name = kvasprintf(GFP_KERNEL, fmt, args); |
7063fbf2 | 69 | va_end(args); |
707c6235 BVA |
70 | if (!name) |
71 | return -EFAULT; | |
7063fbf2 JB |
72 | } |
73 | ||
74 | /* Free the old name, if necessary. */ | |
75 | if (item->ci_name && item->ci_name != item->ci_namebuf) | |
76 | kfree(item->ci_name); | |
77 | ||
78 | /* Now, set the new name */ | |
79 | item->ci_name = name; | |
707c6235 | 80 | return 0; |
7063fbf2 | 81 | } |
7063fbf2 JB |
82 | EXPORT_SYMBOL(config_item_set_name); |
83 | ||
84 | void config_item_init_type_name(struct config_item *item, | |
85 | const char *name, | |
aa293583 | 86 | const struct config_item_type *type) |
7063fbf2 | 87 | { |
3958b792 | 88 | config_item_set_name(item, "%s", name); |
7063fbf2 JB |
89 | item->ci_type = type; |
90 | config_item_init(item); | |
91 | } | |
92 | EXPORT_SYMBOL(config_item_init_type_name); | |
93 | ||
94 | void config_group_init_type_name(struct config_group *group, const char *name, | |
aa293583 | 95 | const struct config_item_type *type) |
7063fbf2 | 96 | { |
3958b792 | 97 | config_item_set_name(&group->cg_item, "%s", name); |
7063fbf2 JB |
98 | group->cg_item.ci_type = type; |
99 | config_group_init(group); | |
100 | } | |
101 | EXPORT_SYMBOL(config_group_init_type_name); | |
102 | ||
f6b1fe7c | 103 | struct config_item *config_item_get(struct config_item *item) |
7063fbf2 JB |
104 | { |
105 | if (item) | |
106 | kref_get(&item->ci_kref); | |
107 | return item; | |
108 | } | |
f6b1fe7c | 109 | EXPORT_SYMBOL(config_item_get); |
7063fbf2 | 110 | |
19e72d3a BVA |
111 | struct config_item *config_item_get_unless_zero(struct config_item *item) |
112 | { | |
113 | if (item && kref_get_unless_zero(&item->ci_kref)) | |
114 | return item; | |
115 | return NULL; | |
116 | } | |
117 | EXPORT_SYMBOL(config_item_get_unless_zero); | |
118 | ||
f6b1fe7c | 119 | static void config_item_cleanup(struct config_item *item) |
7063fbf2 | 120 | { |
aa293583 | 121 | const struct config_item_type *t = item->ci_type; |
f6b1fe7c FF |
122 | struct config_group *s = item->ci_group; |
123 | struct config_item *parent = item->ci_parent; | |
7063fbf2 | 124 | |
f6b1fe7c | 125 | pr_debug("config_item %s: cleaning up\n", config_item_name(item)); |
7063fbf2 JB |
126 | if (item->ci_name != item->ci_namebuf) |
127 | kfree(item->ci_name); | |
128 | item->ci_name = NULL; | |
129 | if (t && t->ct_item_ops && t->ct_item_ops->release) | |
130 | t->ct_item_ops->release(item); | |
131 | if (s) | |
132 | config_group_put(s); | |
133 | if (parent) | |
134 | config_item_put(parent); | |
135 | } | |
136 | ||
137 | static void config_item_release(struct kref *kref) | |
138 | { | |
139 | config_item_cleanup(container_of(kref, struct config_item, ci_kref)); | |
140 | } | |
141 | ||
142 | /** | |
143 | * config_item_put - decrement refcount for item. | |
144 | * @item: item. | |
145 | * | |
146 | * Decrement the refcount, and if 0, call config_item_cleanup(). | |
147 | */ | |
f6b1fe7c | 148 | void config_item_put(struct config_item *item) |
7063fbf2 JB |
149 | { |
150 | if (item) | |
151 | kref_put(&item->ci_kref, config_item_release); | |
152 | } | |
f6b1fe7c | 153 | EXPORT_SYMBOL(config_item_put); |
7063fbf2 | 154 | |
7063fbf2 JB |
155 | /** |
156 | * config_group_init - initialize a group for use | |
f6b1fe7c | 157 | * @group: config_group |
7063fbf2 | 158 | */ |
7063fbf2 JB |
159 | void config_group_init(struct config_group *group) |
160 | { | |
161 | config_item_init(&group->cg_item); | |
162 | INIT_LIST_HEAD(&group->cg_children); | |
1ae1602d | 163 | INIT_LIST_HEAD(&group->default_groups); |
7063fbf2 | 164 | } |
f6b1fe7c | 165 | EXPORT_SYMBOL(config_group_init); |
7063fbf2 | 166 | |
7063fbf2 | 167 | /** |
3fe6c5ce | 168 | * config_group_find_item - search for item in group. |
7063fbf2 JB |
169 | * @group: group we're looking in. |
170 | * @name: item's name. | |
171 | * | |
3fe6c5ce SS |
172 | * Iterate over @group->cg_list, looking for a matching config_item. |
173 | * If matching item is found take a reference and return the item. | |
174 | * Caller must have locked group via @group->cg_subsys->su_mtx. | |
7063fbf2 | 175 | */ |
3fe6c5ce SS |
176 | struct config_item *config_group_find_item(struct config_group *group, |
177 | const char *name) | |
7063fbf2 | 178 | { |
f6b1fe7c FF |
179 | struct list_head *entry; |
180 | struct config_item *ret = NULL; | |
7063fbf2 | 181 | |
f6b1fe7c FF |
182 | list_for_each(entry, &group->cg_children) { |
183 | struct config_item *item = to_item(entry); | |
7063fbf2 | 184 | if (config_item_name(item) && |
3fe6c5ce | 185 | !strcmp(config_item_name(item), name)) { |
7063fbf2 JB |
186 | ret = config_item_get(item); |
187 | break; | |
188 | } | |
189 | } | |
190 | return ret; | |
191 | } | |
3fe6c5ce | 192 | EXPORT_SYMBOL(config_group_find_item); |