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linux-2.6/include/linux/sysfs.h
Eric W. Biederman 487505c257 sysfs: Implement support for tagged files in sysfs.
Looking up files in sysfs is hard to understand and analyize because we
currently allow placing untagged files in tagged directories.  In the
implementation of that we have two subtly different meanings of NULL.
NULL meaning there is no tag on a directory entry and NULL meaning
we don't care which namespace the lookup is performed for.  This
multiple uses of NULL have resulted in subtle bugs (since fixed)
in the code.

Currently it is only the bonding driver that needs to have an untagged
file in a tagged directory.

To untagle this mess I am adding support for tagged files to sysfs.
Modifying the bonding driver to implement bonding_masters as a tagged
file.  Registering bonding_masters once for each network namespace.
Then I am removing support for untagged entries in tagged sysfs
directories.

Resulting in code that is much easier to reason about.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-10-19 19:24:14 -04:00

347 lines
8.9 KiB
C

/*
* sysfs.h - definitions for the device driver filesystem
*
* Copyright (c) 2001,2002 Patrick Mochel
* Copyright (c) 2004 Silicon Graphics, Inc.
* Copyright (c) 2007 SUSE Linux Products GmbH
* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
*
* Please see Documentation/filesystems/sysfs.txt for more information.
*/
#ifndef _SYSFS_H_
#define _SYSFS_H_
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/kobject_ns.h>
#include <linux/atomic.h>
struct kobject;
struct module;
enum kobj_ns_type;
struct attribute {
const char *name;
mode_t mode;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lock_class_key *key;
struct lock_class_key skey;
#endif
};
/**
* 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.
*/
#ifdef CONFIG_DEBUG_LOCK_ALLOC
#define sysfs_attr_init(attr) \
do { \
static struct lock_class_key __key; \
\
(attr)->key = &__key; \
} while(0)
#else
#define sysfs_attr_init(attr) do {} while(0)
#endif
struct attribute_group {
const char *name;
mode_t (*is_visible)(struct kobject *,
struct attribute *, int);
struct attribute **attrs;
};
/**
* Use these macros to make defining attributes easier. See include/linux/device.h
* for examples..
*/
#define __ATTR(_name,_mode,_show,_store) { \
.attr = {.name = __stringify(_name), .mode = _mode }, \
.show = _show, \
.store = _store, \
}
#define __ATTR_RO(_name) { \
.attr = { .name = __stringify(_name), .mode = 0444 }, \
.show = _name##_show, \
}
#define __ATTR_NULL { .attr = { .name = NULL } }
#define attr_name(_attr) (_attr).attr.name
struct file;
struct vm_area_struct;
struct bin_attribute {
struct attribute attr;
size_t size;
void *private;
ssize_t (*read)(struct file *, struct kobject *, struct bin_attribute *,
char *, loff_t, size_t);
ssize_t (*write)(struct file *,struct kobject *, struct bin_attribute *,
char *, loff_t, size_t);
int (*mmap)(struct file *, struct kobject *, struct bin_attribute *attr,
struct vm_area_struct *vma);
};
/**
* 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.
*/
#define sysfs_bin_attr_init(bin_attr) sysfs_attr_init(&(bin_attr)->attr)
struct sysfs_ops {
ssize_t (*show)(struct kobject *, struct attribute *,char *);
ssize_t (*store)(struct kobject *,struct attribute *,const char *, size_t);
const void *(*namespace)(struct kobject *, const struct attribute *);
};
struct sysfs_dirent;
#ifdef CONFIG_SYSFS
int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
void *data, struct module *owner);
int __must_check sysfs_create_dir(struct kobject *kobj);
void sysfs_remove_dir(struct kobject *kobj);
int __must_check sysfs_rename_dir(struct kobject *kobj, const char *new_name);
int __must_check sysfs_move_dir(struct kobject *kobj,
struct kobject *new_parent_kobj);
int __must_check sysfs_create_file(struct kobject *kobj,
const struct attribute *attr);
int __must_check sysfs_create_files(struct kobject *kobj,
const struct attribute **attr);
int __must_check sysfs_chmod_file(struct kobject *kobj,
const struct attribute *attr, mode_t mode);
void sysfs_remove_file(struct kobject *kobj, const struct attribute *attr);
void sysfs_remove_files(struct kobject *kobj, const struct attribute **attr);
int __must_check sysfs_create_bin_file(struct kobject *kobj,
const struct bin_attribute *attr);
void sysfs_remove_bin_file(struct kobject *kobj,
const struct bin_attribute *attr);
int __must_check sysfs_create_link(struct kobject *kobj, struct kobject *target,
const char *name);
int __must_check sysfs_create_link_nowarn(struct kobject *kobj,
struct kobject *target,
const char *name);
void sysfs_remove_link(struct kobject *kobj, const char *name);
int sysfs_rename_link(struct kobject *kobj, struct kobject *target,
const char *old_name, const char *new_name);
void sysfs_delete_link(struct kobject *dir, struct kobject *targ,
const char *name);
int __must_check sysfs_create_group(struct kobject *kobj,
const struct attribute_group *grp);
int sysfs_update_group(struct kobject *kobj,
const struct attribute_group *grp);
void sysfs_remove_group(struct kobject *kobj,
const struct attribute_group *grp);
int sysfs_add_file_to_group(struct kobject *kobj,
const struct attribute *attr, const char *group);
void sysfs_remove_file_from_group(struct kobject *kobj,
const struct attribute *attr, const char *group);
int sysfs_merge_group(struct kobject *kobj,
const struct attribute_group *grp);
void sysfs_unmerge_group(struct kobject *kobj,
const struct attribute_group *grp);
void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr);
void sysfs_notify_dirent(struct sysfs_dirent *sd);
struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
const void *ns,
const unsigned char *name);
struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd);
void sysfs_put(struct sysfs_dirent *sd);
int __must_check sysfs_init(void);
#else /* CONFIG_SYSFS */
static inline int sysfs_schedule_callback(struct kobject *kobj,
void (*func)(void *), void *data, struct module *owner)
{
return -ENOSYS;
}
static inline int sysfs_create_dir(struct kobject *kobj)
{
return 0;
}
static inline void sysfs_remove_dir(struct kobject *kobj)
{
}
static inline int sysfs_rename_dir(struct kobject *kobj, const char *new_name)
{
return 0;
}
static inline int sysfs_move_dir(struct kobject *kobj,
struct kobject *new_parent_kobj)
{
return 0;
}
static inline int sysfs_create_file(struct kobject *kobj,
const struct attribute *attr)
{
return 0;
}
static inline int sysfs_create_files(struct kobject *kobj,
const struct attribute **attr)
{
return 0;
}
static inline int sysfs_chmod_file(struct kobject *kobj,
const struct attribute *attr, mode_t mode)
{
return 0;
}
static inline void sysfs_remove_file(struct kobject *kobj,
const struct attribute *attr)
{
}
static inline void sysfs_remove_files(struct kobject *kobj,
const struct attribute **attr)
{
}
static inline int sysfs_create_bin_file(struct kobject *kobj,
const struct bin_attribute *attr)
{
return 0;
}
static inline void sysfs_remove_bin_file(struct kobject *kobj,
const struct bin_attribute *attr)
{
}
static inline int sysfs_create_link(struct kobject *kobj,
struct kobject *target, const char *name)
{
return 0;
}
static inline int sysfs_create_link_nowarn(struct kobject *kobj,
struct kobject *target,
const char *name)
{
return 0;
}
static inline void sysfs_remove_link(struct kobject *kobj, const char *name)
{
}
static inline int sysfs_rename_link(struct kobject *k, struct kobject *t,
const char *old_name, const char *new_name)
{
return 0;
}
static inline void sysfs_delete_link(struct kobject *k, struct kobject *t,
const char *name)
{
}
static inline int sysfs_create_group(struct kobject *kobj,
const struct attribute_group *grp)
{
return 0;
}
static inline int sysfs_update_group(struct kobject *kobj,
const struct attribute_group *grp)
{
return 0;
}
static inline void sysfs_remove_group(struct kobject *kobj,
const struct attribute_group *grp)
{
}
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,
const struct attribute *attr, const char *group)
{
}
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)
{
}
static inline void sysfs_notify(struct kobject *kobj, const char *dir,
const char *attr)
{
}
static inline void sysfs_notify_dirent(struct sysfs_dirent *sd)
{
}
static inline
struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
const void *ns,
const unsigned char *name)
{
return NULL;
}
static inline struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
{
return NULL;
}
static inline void sysfs_put(struct sysfs_dirent *sd)
{
}
static inline int __must_check sysfs_init(void)
{
return 0;
}
#endif /* CONFIG_SYSFS */
#endif /* _SYSFS_H_ */