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192 lines
4.7 KiB
192 lines
4.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* -*- mode: c; c-basic-offset: 8; -*- |
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* vim: noexpandtab sw=8 ts=8 sts=0: |
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* |
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* item.c - library routines for handling generic config items |
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* |
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* Based on kobject: |
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* kobject is Copyright (c) 2002-2003 Patrick Mochel |
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* |
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* configfs Copyright (C) 2005 Oracle. All rights reserved. |
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* |
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* Please see the file Documentation/filesystems/configfs.rst for |
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* critical information about using the config_item interface. |
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*/ |
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#include <linux/string.h> |
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#include <linux/module.h> |
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#include <linux/stat.h> |
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#include <linux/slab.h> |
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#include <linux/configfs.h> |
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static inline struct config_item *to_item(struct list_head *entry) |
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{ |
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return container_of(entry, struct config_item, ci_entry); |
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} |
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/* Evil kernel */ |
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static void config_item_release(struct kref *kref); |
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/** |
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* config_item_init - initialize item. |
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* @item: item in question. |
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*/ |
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static void config_item_init(struct config_item *item) |
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{ |
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kref_init(&item->ci_kref); |
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INIT_LIST_HEAD(&item->ci_entry); |
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} |
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/** |
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* config_item_set_name - Set the name of an item |
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* @item: item. |
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* @fmt: The vsnprintf()'s format string. |
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* |
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* If strlen(name) >= CONFIGFS_ITEM_NAME_LEN, then use a |
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* dynamically allocated string that @item->ci_name points to. |
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* Otherwise, use the static @item->ci_namebuf array. |
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*/ |
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int config_item_set_name(struct config_item *item, const char *fmt, ...) |
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{ |
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int limit = CONFIGFS_ITEM_NAME_LEN; |
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int need; |
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va_list args; |
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char *name; |
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/* |
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* First, try the static array |
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*/ |
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va_start(args, fmt); |
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need = vsnprintf(item->ci_namebuf, limit, fmt, args); |
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va_end(args); |
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if (need < limit) |
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name = item->ci_namebuf; |
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else { |
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va_start(args, fmt); |
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name = kvasprintf(GFP_KERNEL, fmt, args); |
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va_end(args); |
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if (!name) |
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return -EFAULT; |
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} |
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/* Free the old name, if necessary. */ |
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if (item->ci_name && item->ci_name != item->ci_namebuf) |
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kfree(item->ci_name); |
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/* Now, set the new name */ |
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item->ci_name = name; |
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return 0; |
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} |
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EXPORT_SYMBOL(config_item_set_name); |
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void config_item_init_type_name(struct config_item *item, |
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const char *name, |
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const struct config_item_type *type) |
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{ |
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config_item_set_name(item, "%s", name); |
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item->ci_type = type; |
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config_item_init(item); |
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} |
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EXPORT_SYMBOL(config_item_init_type_name); |
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void config_group_init_type_name(struct config_group *group, const char *name, |
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const struct config_item_type *type) |
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{ |
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config_item_set_name(&group->cg_item, "%s", name); |
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group->cg_item.ci_type = type; |
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config_group_init(group); |
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} |
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EXPORT_SYMBOL(config_group_init_type_name); |
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struct config_item *config_item_get(struct config_item *item) |
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{ |
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if (item) |
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kref_get(&item->ci_kref); |
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return item; |
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} |
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EXPORT_SYMBOL(config_item_get); |
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struct config_item *config_item_get_unless_zero(struct config_item *item) |
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{ |
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if (item && kref_get_unless_zero(&item->ci_kref)) |
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return item; |
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return NULL; |
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} |
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EXPORT_SYMBOL(config_item_get_unless_zero); |
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static void config_item_cleanup(struct config_item *item) |
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{ |
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const struct config_item_type *t = item->ci_type; |
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struct config_group *s = item->ci_group; |
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struct config_item *parent = item->ci_parent; |
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pr_debug("config_item %s: cleaning up\n", config_item_name(item)); |
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if (item->ci_name != item->ci_namebuf) |
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kfree(item->ci_name); |
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item->ci_name = NULL; |
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if (t && t->ct_item_ops && t->ct_item_ops->release) |
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t->ct_item_ops->release(item); |
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if (s) |
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config_group_put(s); |
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if (parent) |
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config_item_put(parent); |
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} |
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static void config_item_release(struct kref *kref) |
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{ |
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config_item_cleanup(container_of(kref, struct config_item, ci_kref)); |
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} |
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/** |
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* config_item_put - decrement refcount for item. |
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* @item: item. |
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* |
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* Decrement the refcount, and if 0, call config_item_cleanup(). |
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*/ |
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void config_item_put(struct config_item *item) |
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{ |
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if (item) |
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kref_put(&item->ci_kref, config_item_release); |
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} |
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EXPORT_SYMBOL(config_item_put); |
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/** |
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* config_group_init - initialize a group for use |
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* @group: config_group |
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*/ |
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void config_group_init(struct config_group *group) |
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{ |
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config_item_init(&group->cg_item); |
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INIT_LIST_HEAD(&group->cg_children); |
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INIT_LIST_HEAD(&group->default_groups); |
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} |
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EXPORT_SYMBOL(config_group_init); |
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/** |
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* config_group_find_item - search for item in group. |
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* @group: group we're looking in. |
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* @name: item's name. |
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* |
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* Iterate over @group->cg_list, looking for a matching config_item. |
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* If matching item is found take a reference and return the item. |
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* Caller must have locked group via @group->cg_subsys->su_mtx. |
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*/ |
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struct config_item *config_group_find_item(struct config_group *group, |
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const char *name) |
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{ |
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struct list_head *entry; |
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struct config_item *ret = NULL; |
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list_for_each(entry, &group->cg_children) { |
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struct config_item *item = to_item(entry); |
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if (config_item_name(item) && |
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!strcmp(config_item_name(item), name)) { |
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ret = config_item_get(item); |
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break; |
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} |
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} |
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return ret; |
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} |
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EXPORT_SYMBOL(config_group_find_item);
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