2005-04-17 05:20:36 +07:00
|
|
|
/*
|
|
|
|
* sysfs.h - definitions for the device driver filesystem
|
|
|
|
*
|
|
|
|
* Copyright (c) 2001,2002 Patrick Mochel
|
|
|
|
* Copyright (c) 2004 Silicon Graphics, Inc.
|
2007-09-20 15:31:38 +07:00
|
|
|
* Copyright (c) 2007 SUSE Linux Products GmbH
|
|
|
|
* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
|
2005-04-17 05:20:36 +07:00
|
|
|
*
|
|
|
|
* Please see Documentation/filesystems/sysfs.txt for more information.
|
|
|
|
*/
|
|
|
|
|
|
|
|
#ifndef _SYSFS_H_
|
|
|
|
#define _SYSFS_H_
|
|
|
|
|
2013-11-24 21:54:58 +07:00
|
|
|
#include <linux/kernfs.h>
|
2006-08-15 12:43:17 +07:00
|
|
|
#include <linux/compiler.h>
|
2007-03-18 19:58:08 +07:00
|
|
|
#include <linux/errno.h>
|
2007-01-17 23:51:18 +07:00
|
|
|
#include <linux/list.h>
|
2010-02-12 06:21:53 +07:00
|
|
|
#include <linux/lockdep.h>
|
2010-08-11 21:01:02 +07:00
|
|
|
#include <linux/kobject_ns.h>
|
2013-07-15 06:05:59 +07:00
|
|
|
#include <linux/stat.h>
|
2011-07-27 06:09:06 +07:00
|
|
|
#include <linux/atomic.h>
|
2005-04-17 05:20:36 +07:00
|
|
|
|
|
|
|
struct kobject;
|
|
|
|
struct module;
|
2013-07-15 06:05:55 +07:00
|
|
|
struct bin_attribute;
|
2010-03-31 01:31:26 +07:00
|
|
|
enum kobj_ns_type;
|
2005-04-17 05:20:36 +07:00
|
|
|
|
|
|
|
struct attribute {
|
2007-09-20 14:05:10 +07:00
|
|
|
const char *name;
|
2011-07-24 10:10:46 +07:00
|
|
|
umode_t mode;
|
2010-02-12 06:21:53 +07:00
|
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
2012-05-15 00:30:03 +07:00
|
|
|
bool ignore_lockdep:1;
|
2010-02-12 06:21:53 +07:00
|
|
|
struct lock_class_key *key;
|
|
|
|
struct lock_class_key skey;
|
|
|
|
#endif
|
2005-04-17 05:20:36 +07:00
|
|
|
};
|
|
|
|
|
2010-02-12 19:35:32 +07:00
|
|
|
/**
|
|
|
|
* sysfs_attr_init - initialize a dynamically allocated sysfs attribute
|
|
|
|
* @attr: struct attribute to initialize
|
|
|
|
*
|
|
|
|
* Initialize a dynamically allocated struct attribute so we can
|
|
|
|
* make lockdep happy. This is a new requirement for attributes
|
|
|
|
* and initially this is only needed when lockdep is enabled.
|
|
|
|
* Lockdep gives a nice error when your attribute is added to
|
|
|
|
* sysfs if you don't have this.
|
|
|
|
*/
|
2010-02-12 06:21:53 +07:00
|
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
|
|
|
#define sysfs_attr_init(attr) \
|
|
|
|
do { \
|
|
|
|
static struct lock_class_key __key; \
|
|
|
|
\
|
|
|
|
(attr)->key = &__key; \
|
2013-08-22 07:47:05 +07:00
|
|
|
} while (0)
|
2010-02-12 06:21:53 +07:00
|
|
|
#else
|
2013-08-22 07:47:05 +07:00
|
|
|
#define sysfs_attr_init(attr) do {} while (0)
|
2010-02-12 06:21:53 +07:00
|
|
|
#endif
|
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
struct attribute_group {
|
2007-09-20 14:05:10 +07:00
|
|
|
const char *name;
|
2011-07-24 10:11:19 +07:00
|
|
|
umode_t (*is_visible)(struct kobject *,
|
2007-10-31 21:38:04 +07:00
|
|
|
struct attribute *, int);
|
2007-09-20 14:05:10 +07:00
|
|
|
struct attribute **attrs;
|
2013-07-15 06:05:55 +07:00
|
|
|
struct bin_attribute **bin_attrs;
|
2005-04-17 05:20:36 +07:00
|
|
|
};
|
|
|
|
|
|
|
|
/**
|
|
|
|
* Use these macros to make defining attributes easier. See include/linux/device.h
|
|
|
|
* for examples..
|
|
|
|
*/
|
|
|
|
|
2013-08-22 07:47:05 +07:00
|
|
|
#define __ATTR(_name, _mode, _show, _store) { \
|
2014-03-24 08:30:34 +07:00
|
|
|
.attr = {.name = __stringify(_name), \
|
|
|
|
.mode = VERIFY_OCTAL_PERMISSIONS(_mode) }, \
|
2013-07-15 06:06:00 +07:00
|
|
|
.show = _show, \
|
|
|
|
.store = _store, \
|
2005-04-17 05:20:36 +07:00
|
|
|
}
|
|
|
|
|
2013-07-15 06:06:00 +07:00
|
|
|
#define __ATTR_RO(_name) { \
|
|
|
|
.attr = { .name = __stringify(_name), .mode = S_IRUGO }, \
|
|
|
|
.show = _name##_show, \
|
2005-04-17 05:20:36 +07:00
|
|
|
}
|
|
|
|
|
2013-08-24 05:02:01 +07:00
|
|
|
#define __ATTR_WO(_name) { \
|
|
|
|
.attr = { .name = __stringify(_name), .mode = S_IWUSR }, \
|
|
|
|
.store = _name##_store, \
|
|
|
|
}
|
|
|
|
|
2013-07-15 06:06:00 +07:00
|
|
|
#define __ATTR_RW(_name) __ATTR(_name, (S_IWUSR | S_IRUGO), \
|
|
|
|
_name##_show, _name##_store)
|
2013-07-15 06:05:51 +07:00
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
#define __ATTR_NULL { .attr = { .name = NULL } }
|
2012-05-15 00:30:03 +07:00
|
|
|
|
|
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
|
|
|
#define __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) { \
|
|
|
|
.attr = {.name = __stringify(_name), .mode = _mode, \
|
|
|
|
.ignore_lockdep = true }, \
|
|
|
|
.show = _show, \
|
|
|
|
.store = _store, \
|
|
|
|
}
|
|
|
|
#else
|
|
|
|
#define __ATTR_IGNORE_LOCKDEP __ATTR
|
|
|
|
#endif
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2013-07-15 06:05:59 +07:00
|
|
|
#define __ATTRIBUTE_GROUPS(_name) \
|
|
|
|
static const struct attribute_group *_name##_groups[] = { \
|
|
|
|
&_name##_group, \
|
2013-07-15 06:05:52 +07:00
|
|
|
NULL, \
|
|
|
|
}
|
|
|
|
|
2013-07-15 06:05:59 +07:00
|
|
|
#define ATTRIBUTE_GROUPS(_name) \
|
|
|
|
static const struct attribute_group _name##_group = { \
|
|
|
|
.attrs = _name##_attrs, \
|
|
|
|
}; \
|
|
|
|
__ATTRIBUTE_GROUPS(_name)
|
|
|
|
|
2010-05-13 08:28:57 +07:00
|
|
|
struct file;
|
2005-04-17 05:20:36 +07:00
|
|
|
struct vm_area_struct;
|
|
|
|
|
|
|
|
struct bin_attribute {
|
|
|
|
struct attribute attr;
|
|
|
|
size_t size;
|
|
|
|
void *private;
|
2010-05-13 08:28:57 +07:00
|
|
|
ssize_t (*read)(struct file *, struct kobject *, struct bin_attribute *,
|
2007-06-09 12:57:22 +07:00
|
|
|
char *, loff_t, size_t);
|
2013-08-22 07:47:05 +07:00
|
|
|
ssize_t (*write)(struct file *, struct kobject *, struct bin_attribute *,
|
2007-06-09 12:57:22 +07:00
|
|
|
char *, loff_t, size_t);
|
2010-05-13 08:28:57 +07:00
|
|
|
int (*mmap)(struct file *, struct kobject *, struct bin_attribute *attr,
|
2005-04-17 05:20:36 +07:00
|
|
|
struct vm_area_struct *vma);
|
|
|
|
};
|
|
|
|
|
2010-02-12 19:35:32 +07:00
|
|
|
/**
|
|
|
|
* sysfs_bin_attr_init - initialize a dynamically allocated bin_attribute
|
|
|
|
* @attr: struct bin_attribute to initialize
|
|
|
|
*
|
|
|
|
* Initialize a dynamically allocated struct bin_attribute so we
|
|
|
|
* can make lockdep happy. This is a new requirement for
|
|
|
|
* attributes and initially this is only needed when lockdep is
|
|
|
|
* enabled. Lockdep gives a nice error when your attribute is
|
|
|
|
* added to sysfs if you don't have this.
|
|
|
|
*/
|
2010-03-01 16:38:36 +07:00
|
|
|
#define sysfs_bin_attr_init(bin_attr) sysfs_attr_init(&(bin_attr)->attr)
|
2010-02-12 06:21:53 +07:00
|
|
|
|
2013-07-15 06:05:59 +07:00
|
|
|
/* macros to create static binary attributes easier */
|
|
|
|
#define __BIN_ATTR(_name, _mode, _read, _write, _size) { \
|
|
|
|
.attr = { .name = __stringify(_name), .mode = _mode }, \
|
|
|
|
.read = _read, \
|
|
|
|
.write = _write, \
|
|
|
|
.size = _size, \
|
|
|
|
}
|
|
|
|
|
|
|
|
#define __BIN_ATTR_RO(_name, _size) { \
|
|
|
|
.attr = { .name = __stringify(_name), .mode = S_IRUGO }, \
|
|
|
|
.read = _name##_read, \
|
|
|
|
.size = _size, \
|
2013-07-15 06:05:53 +07:00
|
|
|
}
|
|
|
|
|
2013-07-15 06:05:59 +07:00
|
|
|
#define __BIN_ATTR_RW(_name, _size) __BIN_ATTR(_name, \
|
|
|
|
(S_IWUSR | S_IRUGO), _name##_read, \
|
2013-08-21 06:48:54 +07:00
|
|
|
_name##_write, _size)
|
2013-07-15 06:05:59 +07:00
|
|
|
|
|
|
|
#define __BIN_ATTR_NULL __ATTR_NULL
|
|
|
|
|
|
|
|
#define BIN_ATTR(_name, _mode, _read, _write, _size) \
|
|
|
|
struct bin_attribute bin_attr_##_name = __BIN_ATTR(_name, _mode, _read, \
|
|
|
|
_write, _size)
|
|
|
|
|
|
|
|
#define BIN_ATTR_RO(_name, _size) \
|
|
|
|
struct bin_attribute bin_attr_##_name = __BIN_ATTR_RO(_name, _size)
|
|
|
|
|
|
|
|
#define BIN_ATTR_RW(_name, _size) \
|
|
|
|
struct bin_attribute bin_attr_##_name = __BIN_ATTR_RW(_name, _size)
|
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
struct sysfs_ops {
|
2013-08-22 07:47:05 +07:00
|
|
|
ssize_t (*show)(struct kobject *, struct attribute *, char *);
|
|
|
|
ssize_t (*store)(struct kobject *, struct attribute *, const char *, size_t);
|
2005-04-17 05:20:36 +07:00
|
|
|
};
|
|
|
|
|
|
|
|
#ifdef CONFIG_SYSFS
|
|
|
|
|
2013-09-12 09:29:05 +07:00
|
|
|
int __must_check sysfs_create_dir_ns(struct kobject *kobj, const void *ns);
|
2007-09-20 14:05:10 +07:00
|
|
|
void sysfs_remove_dir(struct kobject *kobj);
|
2013-09-12 09:29:05 +07:00
|
|
|
int __must_check sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
|
|
|
|
const void *new_ns);
|
|
|
|
int __must_check sysfs_move_dir_ns(struct kobject *kobj,
|
|
|
|
struct kobject *new_parent_kobj,
|
|
|
|
const void *new_ns);
|
2005-04-19 11:57:32 +07:00
|
|
|
|
2013-09-12 09:29:04 +07:00
|
|
|
int __must_check sysfs_create_file_ns(struct kobject *kobj,
|
|
|
|
const struct attribute *attr,
|
|
|
|
const void *ns);
|
2010-01-05 18:48:01 +07:00
|
|
|
int __must_check sysfs_create_files(struct kobject *kobj,
|
|
|
|
const struct attribute **attr);
|
2010-07-02 21:54:05 +07:00
|
|
|
int __must_check sysfs_chmod_file(struct kobject *kobj,
|
2011-07-24 14:40:40 +07:00
|
|
|
const struct attribute *attr, umode_t mode);
|
2013-09-12 09:29:04 +07:00
|
|
|
void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
|
|
|
|
const void *ns);
|
kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers
Sometimes it's necessary to implement a node which wants to delete
nodes including itself. This isn't straightforward because of kernfs
active reference. While a file operation is in progress, an active
reference is held and kernfs_remove() waits for all such references to
drain before completing. For a self-deleting node, this is a deadlock
as kernfs_remove() ends up waiting for an active reference that itself
is sitting on top of.
This currently is worked around in the sysfs layer using
sysfs_schedule_callback() which makes such removals asynchronous.
While it works, it's rather cumbersome and inherently breaks
synchronicity of the operation - the file operation which triggered
the operation may complete before the removal is finished (or even
started) and the removal may fail asynchronously. If a removal
operation is immmediately followed by another operation which expects
the specific name to be available (e.g. removal followed by rename
onto the same name), there's no way to make the latter operation
reliable.
The thing is there's no inherent reason for this to be asynchrnous.
All that's necessary to do this synchronous is a dedicated operation
which drops its own active ref and deactivates self. This patch
implements kernfs_remove_self() and its wrappers in sysfs and driver
core. kernfs_remove_self() is to be called from one of the file
operations, drops the active ref the task is holding, removes the self
node, and restores active ref to the dead node so that the ref is
balanced afterwards. __kernfs_remove() is updated so that it takes an
early exit if the target node is already fully removed so that the
active ref restored by kernfs_remove_self() after removal doesn't
confuse the deactivation path.
This makes implementing self-deleting nodes very easy. The normal
removal path doesn't even need to be changed to use
kernfs_remove_self() for the self-deleting node. The method can
invoke kernfs_remove_self() on itself before proceeding the normal
removal path. kernfs_remove() invoked on the node by the normal
deletion path will simply be ignored.
This will replace sysfs_schedule_callback(). A subtle feature of
sysfs_schedule_callback() is that it collapses multiple invocations -
even if multiple removals are triggered, the removal callback is run
only once. An equivalent effect can be achieved by testing the return
value of kernfs_remove_self() - only the one which gets %true return
value should proceed with actual deletion. All other instances of
kernfs_remove_self() will wait till the enclosing kernfs operation
which invoked the winning instance of kernfs_remove_self() finishes
and then return %false. This trivially makes all users of
kernfs_remove_self() automatically show correct synchronous behavior
even when there are multiple concurrent operations - all "echo 1 >
delete" instances will finish only after the whole operation is
completed by one of the instances.
Note that manipulation of active ref is implemented in separate public
functions - kernfs_[un]break_active_protection().
kernfs_remove_self() is the only user at the moment but this will be
used to cater to more complex cases.
v2: For !CONFIG_SYSFS, dummy version kernfs_remove_self() was missing
and sysfs_remove_file_self() had incorrect return type. Fix it.
Reported by kbuild test bot.
v3: kernfs_[un]break_active_protection() separated out from
kernfs_remove_self() and exposed as public API.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-04 02:03:01 +07:00
|
|
|
bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr);
|
2010-01-05 18:48:01 +07:00
|
|
|
void sysfs_remove_files(struct kobject *kobj, const struct attribute **attr);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2006-08-15 12:43:17 +07:00
|
|
|
int __must_check sysfs_create_bin_file(struct kobject *kobj,
|
2009-12-18 20:34:20 +07:00
|
|
|
const struct bin_attribute *attr);
|
|
|
|
void sysfs_remove_bin_file(struct kobject *kobj,
|
|
|
|
const struct bin_attribute *attr);
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2007-09-20 14:05:10 +07:00
|
|
|
int __must_check sysfs_create_link(struct kobject *kobj, struct kobject *target,
|
|
|
|
const char *name);
|
2008-06-10 16:09:08 +07:00
|
|
|
int __must_check sysfs_create_link_nowarn(struct kobject *kobj,
|
|
|
|
struct kobject *target,
|
|
|
|
const char *name);
|
2007-09-20 14:05:10 +07:00
|
|
|
void sysfs_remove_link(struct kobject *kobj, const char *name);
|
|
|
|
|
2013-09-12 09:29:06 +07:00
|
|
|
int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *target,
|
|
|
|
const char *old_name, const char *new_name,
|
|
|
|
const void *new_ns);
|
2010-02-13 10:22:25 +07:00
|
|
|
|
2010-03-31 01:31:28 +07:00
|
|
|
void sysfs_delete_link(struct kobject *dir, struct kobject *targ,
|
|
|
|
const char *name);
|
|
|
|
|
2007-09-20 14:05:10 +07:00
|
|
|
int __must_check sysfs_create_group(struct kobject *kobj,
|
|
|
|
const struct attribute_group *grp);
|
2013-08-22 03:47:50 +07:00
|
|
|
int __must_check sysfs_create_groups(struct kobject *kobj,
|
|
|
|
const struct attribute_group **groups);
|
2008-03-21 08:47:52 +07:00
|
|
|
int sysfs_update_group(struct kobject *kobj,
|
|
|
|
const struct attribute_group *grp);
|
2007-09-20 14:05:10 +07:00
|
|
|
void sysfs_remove_group(struct kobject *kobj,
|
|
|
|
const struct attribute_group *grp);
|
2013-08-22 03:47:50 +07:00
|
|
|
void sysfs_remove_groups(struct kobject *kobj,
|
|
|
|
const struct attribute_group **groups);
|
2007-02-21 03:02:44 +07:00
|
|
|
int sysfs_add_file_to_group(struct kobject *kobj,
|
2007-09-20 14:05:10 +07:00
|
|
|
const struct attribute *attr, const char *group);
|
2007-02-21 03:02:44 +07:00
|
|
|
void sysfs_remove_file_from_group(struct kobject *kobj,
|
2007-09-20 14:05:10 +07:00
|
|
|
const struct attribute *attr, const char *group);
|
2010-09-26 04:34:22 +07:00
|
|
|
int sysfs_merge_group(struct kobject *kobj,
|
|
|
|
const struct attribute_group *grp);
|
|
|
|
void sysfs_unmerge_group(struct kobject *kobj,
|
|
|
|
const struct attribute_group *grp);
|
2013-01-26 03:51:13 +07:00
|
|
|
int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
|
|
|
|
struct kobject *target, const char *link_name);
|
|
|
|
void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
|
|
|
|
const char *link_name);
|
2007-02-21 03:02:44 +07:00
|
|
|
|
2008-09-26 06:45:13 +07:00
|
|
|
void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr);
|
2010-03-31 01:31:26 +07:00
|
|
|
|
2008-07-16 05:58:04 +07:00
|
|
|
int __must_check sysfs_init(void);
|
2006-08-15 12:43:23 +07:00
|
|
|
|
2014-02-08 01:32:07 +07:00
|
|
|
static inline void sysfs_enable_ns(struct kernfs_node *kn)
|
|
|
|
{
|
|
|
|
return kernfs_enable_ns(kn);
|
|
|
|
}
|
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
#else /* CONFIG_SYSFS */
|
|
|
|
|
2013-09-12 09:29:05 +07:00
|
|
|
static inline int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2007-09-20 14:05:10 +07:00
|
|
|
static inline void sysfs_remove_dir(struct kobject *kobj)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2013-09-12 09:29:05 +07:00
|
|
|
static inline int sysfs_rename_dir_ns(struct kobject *kobj,
|
|
|
|
const char *new_name, const void *new_ns)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
2008-07-04 08:05:28 +07:00
|
|
|
return 0;
|
2005-04-17 05:20:36 +07:00
|
|
|
}
|
|
|
|
|
2013-09-12 09:29:05 +07:00
|
|
|
static inline int sysfs_move_dir_ns(struct kobject *kobj,
|
|
|
|
struct kobject *new_parent_kobj,
|
|
|
|
const void *new_ns)
|
2006-11-20 23:07:51 +07:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2013-09-12 09:29:04 +07:00
|
|
|
static inline int sysfs_create_file_ns(struct kobject *kobj,
|
|
|
|
const struct attribute *attr,
|
|
|
|
const void *ns)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-01-05 18:48:01 +07:00
|
|
|
static inline int sysfs_create_files(struct kobject *kobj,
|
|
|
|
const struct attribute **attr)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2007-09-20 14:05:10 +07:00
|
|
|
static inline int sysfs_chmod_file(struct kobject *kobj,
|
2011-07-24 14:40:40 +07:00
|
|
|
const struct attribute *attr, umode_t mode)
|
2005-04-19 11:57:32 +07:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
2005-04-17 05:20:36 +07:00
|
|
|
|
2013-09-12 09:29:04 +07:00
|
|
|
static inline void sysfs_remove_file_ns(struct kobject *kobj,
|
|
|
|
const struct attribute *attr,
|
|
|
|
const void *ns)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers
Sometimes it's necessary to implement a node which wants to delete
nodes including itself. This isn't straightforward because of kernfs
active reference. While a file operation is in progress, an active
reference is held and kernfs_remove() waits for all such references to
drain before completing. For a self-deleting node, this is a deadlock
as kernfs_remove() ends up waiting for an active reference that itself
is sitting on top of.
This currently is worked around in the sysfs layer using
sysfs_schedule_callback() which makes such removals asynchronous.
While it works, it's rather cumbersome and inherently breaks
synchronicity of the operation - the file operation which triggered
the operation may complete before the removal is finished (or even
started) and the removal may fail asynchronously. If a removal
operation is immmediately followed by another operation which expects
the specific name to be available (e.g. removal followed by rename
onto the same name), there's no way to make the latter operation
reliable.
The thing is there's no inherent reason for this to be asynchrnous.
All that's necessary to do this synchronous is a dedicated operation
which drops its own active ref and deactivates self. This patch
implements kernfs_remove_self() and its wrappers in sysfs and driver
core. kernfs_remove_self() is to be called from one of the file
operations, drops the active ref the task is holding, removes the self
node, and restores active ref to the dead node so that the ref is
balanced afterwards. __kernfs_remove() is updated so that it takes an
early exit if the target node is already fully removed so that the
active ref restored by kernfs_remove_self() after removal doesn't
confuse the deactivation path.
This makes implementing self-deleting nodes very easy. The normal
removal path doesn't even need to be changed to use
kernfs_remove_self() for the self-deleting node. The method can
invoke kernfs_remove_self() on itself before proceeding the normal
removal path. kernfs_remove() invoked on the node by the normal
deletion path will simply be ignored.
This will replace sysfs_schedule_callback(). A subtle feature of
sysfs_schedule_callback() is that it collapses multiple invocations -
even if multiple removals are triggered, the removal callback is run
only once. An equivalent effect can be achieved by testing the return
value of kernfs_remove_self() - only the one which gets %true return
value should proceed with actual deletion. All other instances of
kernfs_remove_self() will wait till the enclosing kernfs operation
which invoked the winning instance of kernfs_remove_self() finishes
and then return %false. This trivially makes all users of
kernfs_remove_self() automatically show correct synchronous behavior
even when there are multiple concurrent operations - all "echo 1 >
delete" instances will finish only after the whole operation is
completed by one of the instances.
Note that manipulation of active ref is implemented in separate public
functions - kernfs_[un]break_active_protection().
kernfs_remove_self() is the only user at the moment but this will be
used to cater to more complex cases.
v2: For !CONFIG_SYSFS, dummy version kernfs_remove_self() was missing
and sysfs_remove_file_self() had incorrect return type. Fix it.
Reported by kbuild test bot.
v3: kernfs_[un]break_active_protection() separated out from
kernfs_remove_self() and exposed as public API.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-04 02:03:01 +07:00
|
|
|
static inline bool sysfs_remove_file_self(struct kobject *kobj,
|
|
|
|
const struct attribute *attr)
|
|
|
|
{
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
|
2010-01-05 18:48:01 +07:00
|
|
|
static inline void sysfs_remove_files(struct kobject *kobj,
|
|
|
|
const struct attribute **attr)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2007-09-20 14:05:10 +07:00
|
|
|
static inline int sysfs_create_bin_file(struct kobject *kobj,
|
2009-12-18 20:34:20 +07:00
|
|
|
const struct bin_attribute *attr)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2008-02-20 08:39:02 +07:00
|
|
|
static inline void sysfs_remove_bin_file(struct kobject *kobj,
|
2009-12-18 20:34:20 +07:00
|
|
|
const struct bin_attribute *attr)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2007-09-20 14:05:10 +07:00
|
|
|
static inline int sysfs_create_link(struct kobject *kobj,
|
|
|
|
struct kobject *target, const char *name)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2008-06-10 16:09:08 +07:00
|
|
|
static inline int sysfs_create_link_nowarn(struct kobject *kobj,
|
|
|
|
struct kobject *target,
|
|
|
|
const char *name)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2007-09-20 14:05:10 +07:00
|
|
|
static inline void sysfs_remove_link(struct kobject *kobj, const char *name)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2013-09-12 09:29:06 +07:00
|
|
|
static inline int sysfs_rename_link_ns(struct kobject *k, struct kobject *t,
|
|
|
|
const char *old_name,
|
|
|
|
const char *new_name, const void *ns)
|
2010-02-13 10:22:25 +07:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-03-31 01:31:28 +07:00
|
|
|
static inline void sysfs_delete_link(struct kobject *k, struct kobject *t,
|
|
|
|
const char *name)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2007-09-20 14:05:10 +07:00
|
|
|
static inline int sysfs_create_group(struct kobject *kobj,
|
|
|
|
const struct attribute_group *grp)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2013-08-28 07:24:49 +07:00
|
|
|
static inline int sysfs_create_groups(struct kobject *kobj,
|
|
|
|
const struct attribute_group **groups)
|
|
|
|
{
|
2013-08-28 23:51:41 +07:00
|
|
|
return 0;
|
2013-08-28 07:24:49 +07:00
|
|
|
}
|
|
|
|
|
2008-04-30 23:01:17 +07:00
|
|
|
static inline int sysfs_update_group(struct kobject *kobj,
|
|
|
|
const struct attribute_group *grp)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2007-09-20 14:05:10 +07:00
|
|
|
static inline void sysfs_remove_group(struct kobject *kobj,
|
|
|
|
const struct attribute_group *grp)
|
2005-04-17 05:20:36 +07:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2013-08-28 07:24:49 +07:00
|
|
|
static inline void sysfs_remove_groups(struct kobject *kobj,
|
|
|
|
const struct attribute_group **groups)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2007-02-21 03:02:44 +07:00
|
|
|
static inline int sysfs_add_file_to_group(struct kobject *kobj,
|
|
|
|
const struct attribute *attr, const char *group)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void sysfs_remove_file_from_group(struct kobject *kobj,
|
2007-03-01 19:40:21 +07:00
|
|
|
const struct attribute *attr, const char *group)
|
2007-02-21 03:02:44 +07:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2010-09-26 04:34:22 +07:00
|
|
|
static inline int sysfs_merge_group(struct kobject *kobj,
|
|
|
|
const struct attribute_group *grp)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void sysfs_unmerge_group(struct kobject *kobj,
|
|
|
|
const struct attribute_group *grp)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2013-01-26 03:51:13 +07:00
|
|
|
static inline int sysfs_add_link_to_group(struct kobject *kobj,
|
|
|
|
const char *group_name, struct kobject *target,
|
|
|
|
const char *link_name)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void sysfs_remove_link_from_group(struct kobject *kobj,
|
|
|
|
const char *group_name, const char *link_name)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2008-09-26 06:45:13 +07:00
|
|
|
static inline void sysfs_notify(struct kobject *kobj, const char *dir,
|
|
|
|
const char *attr)
|
2006-03-20 13:53:53 +07:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2006-08-15 12:43:23 +07:00
|
|
|
static inline int __must_check sysfs_init(void)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2014-02-08 01:32:07 +07:00
|
|
|
static inline void sysfs_enable_ns(struct kernfs_node *kn)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
#endif /* CONFIG_SYSFS */
|
|
|
|
|
2013-09-12 09:29:04 +07:00
|
|
|
static inline int __must_check sysfs_create_file(struct kobject *kobj,
|
|
|
|
const struct attribute *attr)
|
|
|
|
{
|
|
|
|
return sysfs_create_file_ns(kobj, attr, NULL);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void sysfs_remove_file(struct kobject *kobj,
|
|
|
|
const struct attribute *attr)
|
|
|
|
{
|
|
|
|
return sysfs_remove_file_ns(kobj, attr, NULL);
|
|
|
|
}
|
|
|
|
|
2013-09-12 09:29:06 +07:00
|
|
|
static inline int sysfs_rename_link(struct kobject *kobj, struct kobject *target,
|
|
|
|
const char *old_name, const char *new_name)
|
|
|
|
{
|
|
|
|
return sysfs_rename_link_ns(kobj, target, old_name, new_name, NULL);
|
|
|
|
}
|
|
|
|
|
2013-12-12 02:11:53 +07:00
|
|
|
static inline void sysfs_notify_dirent(struct kernfs_node *kn)
|
2013-11-29 02:54:30 +07:00
|
|
|
{
|
2013-12-12 02:11:53 +07:00
|
|
|
kernfs_notify(kn);
|
2013-11-29 02:54:30 +07:00
|
|
|
}
|
|
|
|
|
2013-12-12 02:11:53 +07:00
|
|
|
static inline struct kernfs_node *sysfs_get_dirent(struct kernfs_node *parent,
|
|
|
|
const unsigned char *name)
|
2013-09-12 10:19:13 +07:00
|
|
|
{
|
2013-12-12 02:11:53 +07:00
|
|
|
return kernfs_find_and_get(parent, name);
|
2013-09-12 10:19:13 +07:00
|
|
|
}
|
|
|
|
|
2013-12-12 02:11:53 +07:00
|
|
|
static inline struct kernfs_node *sysfs_get(struct kernfs_node *kn)
|
2013-11-29 02:54:27 +07:00
|
|
|
{
|
2013-12-12 02:11:53 +07:00
|
|
|
kernfs_get(kn);
|
|
|
|
return kn;
|
2013-11-29 02:54:30 +07:00
|
|
|
}
|
|
|
|
|
2013-12-12 02:11:53 +07:00
|
|
|
static inline void sysfs_put(struct kernfs_node *kn)
|
2013-11-29 02:54:30 +07:00
|
|
|
{
|
2013-12-12 02:11:53 +07:00
|
|
|
kernfs_put(kn);
|
2013-11-29 02:54:27 +07:00
|
|
|
}
|
|
|
|
|
2005-04-17 05:20:36 +07:00
|
|
|
#endif /* _SYSFS_H_ */
|