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328970de | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
fa60ce2c | 2 | /* |
7063fbf2 JB |
3 | * item.c - library routines for handling generic config items |
4 | * | |
7063fbf2 | 5 | * Based on kobject: |
f6b1fe7c | 6 | * kobject is Copyright (c) 2002-2003 Patrick Mochel |
7063fbf2 JB |
7 | * |
8 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
9 | * | |
98264991 | 10 | * Please see the file Documentation/filesystems/configfs.rst for |
7063fbf2 JB |
11 | * critical information about using the config_item interface. |
12 | */ | |
13 | ||
14 | #include <linux/string.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/stat.h> | |
17 | #include <linux/slab.h> | |
18 | ||
19 | #include <linux/configfs.h> | |
20 | ||
21 | ||
f6b1fe7c | 22 | static inline struct config_item *to_item(struct list_head *entry) |
7063fbf2 | 23 | { |
f6b1fe7c | 24 | return container_of(entry, struct config_item, ci_entry); |
7063fbf2 JB |
25 | } |
26 | ||
27 | /* Evil kernel */ | |
28 | static void config_item_release(struct kref *kref); | |
29 | ||
30 | /** | |
31 | * config_item_init - initialize item. | |
32 | * @item: item in question. | |
33 | */ | |
5286d20c | 34 | static void config_item_init(struct config_item *item) |
7063fbf2 JB |
35 | { |
36 | kref_init(&item->ci_kref); | |
37 | INIT_LIST_HEAD(&item->ci_entry); | |
38 | } | |
39 | ||
40 | /** | |
41 | * config_item_set_name - Set the name of an item | |
42 | * @item: item. | |
f6b1fe7c | 43 | * @fmt: The vsnprintf()'s format string. |
7063fbf2 JB |
44 | * |
45 | * If strlen(name) >= CONFIGFS_ITEM_NAME_LEN, then use a | |
46 | * dynamically allocated string that @item->ci_name points to. | |
47 | * Otherwise, use the static @item->ci_namebuf array. | |
48 | */ | |
f6b1fe7c | 49 | int config_item_set_name(struct config_item *item, const char *fmt, ...) |
7063fbf2 | 50 | { |
7063fbf2 JB |
51 | int limit = CONFIGFS_ITEM_NAME_LEN; |
52 | int need; | |
53 | va_list args; | |
f6b1fe7c | 54 | char *name; |
7063fbf2 JB |
55 | |
56 | /* | |
57 | * First, try the static array | |
58 | */ | |
f6b1fe7c FF |
59 | va_start(args, fmt); |
60 | need = vsnprintf(item->ci_namebuf, limit, fmt, args); | |
7063fbf2 JB |
61 | va_end(args); |
62 | if (need < limit) | |
63 | name = item->ci_namebuf; | |
64 | else { | |
f6b1fe7c | 65 | va_start(args, fmt); |
707c6235 | 66 | name = kvasprintf(GFP_KERNEL, fmt, args); |
7063fbf2 | 67 | va_end(args); |
707c6235 BVA |
68 | if (!name) |
69 | return -EFAULT; | |
7063fbf2 JB |
70 | } |
71 | ||
72 | /* Free the old name, if necessary. */ | |
73 | if (item->ci_name && item->ci_name != item->ci_namebuf) | |
74 | kfree(item->ci_name); | |
75 | ||
76 | /* Now, set the new name */ | |
77 | item->ci_name = name; | |
707c6235 | 78 | return 0; |
7063fbf2 | 79 | } |
7063fbf2 JB |
80 | EXPORT_SYMBOL(config_item_set_name); |
81 | ||
82 | void config_item_init_type_name(struct config_item *item, | |
83 | const char *name, | |
aa293583 | 84 | const struct config_item_type *type) |
7063fbf2 | 85 | { |
3958b792 | 86 | config_item_set_name(item, "%s", name); |
7063fbf2 JB |
87 | item->ci_type = type; |
88 | config_item_init(item); | |
89 | } | |
90 | EXPORT_SYMBOL(config_item_init_type_name); | |
91 | ||
92 | void config_group_init_type_name(struct config_group *group, const char *name, | |
aa293583 | 93 | const struct config_item_type *type) |
7063fbf2 | 94 | { |
3958b792 | 95 | config_item_set_name(&group->cg_item, "%s", name); |
7063fbf2 JB |
96 | group->cg_item.ci_type = type; |
97 | config_group_init(group); | |
98 | } | |
99 | EXPORT_SYMBOL(config_group_init_type_name); | |
100 | ||
f6b1fe7c | 101 | struct config_item *config_item_get(struct config_item *item) |
7063fbf2 JB |
102 | { |
103 | if (item) | |
104 | kref_get(&item->ci_kref); | |
105 | return item; | |
106 | } | |
f6b1fe7c | 107 | EXPORT_SYMBOL(config_item_get); |
7063fbf2 | 108 | |
19e72d3a BVA |
109 | struct config_item *config_item_get_unless_zero(struct config_item *item) |
110 | { | |
111 | if (item && kref_get_unless_zero(&item->ci_kref)) | |
112 | return item; | |
113 | return NULL; | |
114 | } | |
115 | EXPORT_SYMBOL(config_item_get_unless_zero); | |
116 | ||
f6b1fe7c | 117 | static void config_item_cleanup(struct config_item *item) |
7063fbf2 | 118 | { |
aa293583 | 119 | const struct config_item_type *t = item->ci_type; |
f6b1fe7c FF |
120 | struct config_group *s = item->ci_group; |
121 | struct config_item *parent = item->ci_parent; | |
7063fbf2 | 122 | |
f6b1fe7c | 123 | pr_debug("config_item %s: cleaning up\n", config_item_name(item)); |
7063fbf2 JB |
124 | if (item->ci_name != item->ci_namebuf) |
125 | kfree(item->ci_name); | |
126 | item->ci_name = NULL; | |
127 | if (t && t->ct_item_ops && t->ct_item_ops->release) | |
128 | t->ct_item_ops->release(item); | |
129 | if (s) | |
130 | config_group_put(s); | |
131 | if (parent) | |
132 | config_item_put(parent); | |
133 | } | |
134 | ||
135 | static void config_item_release(struct kref *kref) | |
136 | { | |
137 | config_item_cleanup(container_of(kref, struct config_item, ci_kref)); | |
138 | } | |
139 | ||
140 | /** | |
141 | * config_item_put - decrement refcount for item. | |
142 | * @item: item. | |
143 | * | |
144 | * Decrement the refcount, and if 0, call config_item_cleanup(). | |
145 | */ | |
f6b1fe7c | 146 | void config_item_put(struct config_item *item) |
7063fbf2 JB |
147 | { |
148 | if (item) | |
149 | kref_put(&item->ci_kref, config_item_release); | |
150 | } | |
f6b1fe7c | 151 | EXPORT_SYMBOL(config_item_put); |
7063fbf2 | 152 | |
7063fbf2 JB |
153 | /** |
154 | * config_group_init - initialize a group for use | |
f6b1fe7c | 155 | * @group: config_group |
7063fbf2 | 156 | */ |
7063fbf2 JB |
157 | void config_group_init(struct config_group *group) |
158 | { | |
159 | config_item_init(&group->cg_item); | |
160 | INIT_LIST_HEAD(&group->cg_children); | |
1ae1602d | 161 | INIT_LIST_HEAD(&group->default_groups); |
7063fbf2 | 162 | } |
f6b1fe7c | 163 | EXPORT_SYMBOL(config_group_init); |
7063fbf2 | 164 | |
7063fbf2 | 165 | /** |
3fe6c5ce | 166 | * config_group_find_item - search for item in group. |
7063fbf2 JB |
167 | * @group: group we're looking in. |
168 | * @name: item's name. | |
169 | * | |
3fe6c5ce SS |
170 | * Iterate over @group->cg_list, looking for a matching config_item. |
171 | * If matching item is found take a reference and return the item. | |
172 | * Caller must have locked group via @group->cg_subsys->su_mtx. | |
7063fbf2 | 173 | */ |
3fe6c5ce SS |
174 | struct config_item *config_group_find_item(struct config_group *group, |
175 | const char *name) | |
7063fbf2 | 176 | { |
f6b1fe7c FF |
177 | struct list_head *entry; |
178 | struct config_item *ret = NULL; | |
7063fbf2 | 179 | |
f6b1fe7c FF |
180 | list_for_each(entry, &group->cg_children) { |
181 | struct config_item *item = to_item(entry); | |
7063fbf2 | 182 | if (config_item_name(item) && |
3fe6c5ce | 183 | !strcmp(config_item_name(item), name)) { |
7063fbf2 JB |
184 | ret = config_item_get(item); |
185 | break; | |
186 | } | |
187 | } | |
188 | return ret; | |
189 | } | |
3fe6c5ce | 190 | EXPORT_SYMBOL(config_group_find_item); |