2005-04-17 05:20:36 +07:00
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/*
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* kobject.h - generic kernel object infrastructure.
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*
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2007-09-28 04:48:53 +07:00
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* Copyright (c) 2002-2003 Patrick Mochel
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* Copyright (c) 2002-2003 Open Source Development Labs
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2008-01-25 12:27:06 +07:00
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* Copyright (c) 2006-2008 Greg Kroah-Hartman <greg@kroah.com>
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* Copyright (c) 2006-2008 Novell Inc.
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2005-04-17 05:20:36 +07:00
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*
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* This file is released under the GPLv2.
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*
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* Please read Documentation/kobject.txt before using the kobject
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* interface, ESPECIALLY the parts about reference counts and object
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2008-01-25 12:27:06 +07:00
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* destructors.
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2005-04-17 05:20:36 +07:00
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*/
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#ifndef _KOBJECT_H_
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#define _KOBJECT_H_
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/sysfs.h>
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2006-08-15 12:43:17 +07:00
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#include <linux/compiler.h>
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2005-04-17 05:20:36 +07:00
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#include <linux/spinlock.h>
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#include <linux/kref.h>
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2010-08-11 21:01:02 +07:00
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#include <linux/kobject_ns.h>
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2005-04-17 05:20:36 +07:00
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#include <linux/kernel.h>
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2006-03-20 13:53:53 +07:00
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#include <linux/wait.h>
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2011-07-27 06:09:06 +07:00
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#include <linux/atomic.h>
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2013-06-27 21:06:14 +07:00
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#include <linux/workqueue.h>
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2005-04-17 05:20:36 +07:00
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2005-11-16 15:00:00 +07:00
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#define UEVENT_HELPER_PATH_LEN 256
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2007-08-14 20:15:12 +07:00
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#define UEVENT_NUM_ENVP 32 /* number of env pointers */
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#define UEVENT_BUFFER_SIZE 2048 /* buffer for the variables */
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2005-11-11 11:33:52 +07:00
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2014-04-11 04:09:31 +07:00
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#ifdef CONFIG_UEVENT_HELPER
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2005-11-11 11:33:52 +07:00
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/* path to the userspace helper executed on an event */
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2005-11-16 15:00:00 +07:00
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extern char uevent_helper[];
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2014-04-11 04:09:31 +07:00
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#endif
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2005-11-11 11:33:52 +07:00
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2005-11-16 15:00:00 +07:00
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/* counter to tag the uevent, read only except for the kobject core */
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extern u64 uevent_seqnum;
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2005-04-17 05:20:36 +07:00
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2007-07-09 03:29:26 +07:00
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/*
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* The actions here must match the index to the string array
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* in lib/kobject_uevent.c
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*
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* Do not add new actions here without checking with the driver-core
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* maintainers. Action strings are not meant to express subsystem
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* or device specific properties. In most cases you want to send a
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* kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
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* specific variables added to the event environment.
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*/
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2005-11-11 11:33:52 +07:00
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enum kobject_action {
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2007-07-09 03:29:26 +07:00
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KOBJ_ADD,
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KOBJ_REMOVE,
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KOBJ_CHANGE,
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KOBJ_MOVE,
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KOBJ_ONLINE,
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KOBJ_OFFLINE,
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KOBJ_MAX
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2005-11-11 11:33:52 +07:00
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};
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2005-04-17 05:20:36 +07:00
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struct kobject {
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2007-12-20 08:09:39 +07:00
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const char *name;
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2005-04-17 05:20:36 +07:00
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struct list_head entry;
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2008-01-25 12:27:06 +07:00
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struct kobject *parent;
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struct kset *kset;
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struct kobj_type *ktype;
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2013-12-12 02:11:53 +07:00
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struct kernfs_node *sd;
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2008-06-02 17:07:25 +07:00
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struct kref kref;
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2013-06-27 21:06:14 +07:00
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#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
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struct delayed_work release;
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#endif
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2007-12-19 07:40:42 +07:00
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unsigned int state_initialized:1;
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unsigned int state_in_sysfs:1;
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unsigned int state_add_uevent_sent:1;
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unsigned int state_remove_uevent_sent:1;
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2009-03-01 20:10:49 +07:00
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unsigned int uevent_suppress:1;
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2005-04-17 05:20:36 +07:00
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};
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2011-11-01 07:11:33 +07:00
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extern __printf(2, 3)
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int kobject_set_name(struct kobject *kobj, const char *name, ...);
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2015-07-18 06:23:42 +07:00
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extern __printf(2, 0)
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int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
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va_list vargs);
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2005-04-17 05:20:36 +07:00
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2008-01-25 12:27:06 +07:00
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static inline const char *kobject_name(const struct kobject *kobj)
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2005-04-17 05:20:36 +07:00
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{
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2007-12-20 08:09:39 +07:00
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return kobj->name;
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2005-04-17 05:20:36 +07:00
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}
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2007-12-18 13:05:35 +07:00
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extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
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2011-11-01 07:11:33 +07:00
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extern __printf(3, 4) __must_check
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int kobject_add(struct kobject *kobj, struct kobject *parent,
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const char *fmt, ...);
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extern __printf(4, 5) __must_check
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int kobject_init_and_add(struct kobject *kobj,
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struct kobj_type *ktype, struct kobject *parent,
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const char *fmt, ...);
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2007-12-04 12:31:08 +07:00
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2008-01-25 12:27:06 +07:00
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extern void kobject_del(struct kobject *kobj);
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2005-04-17 05:20:36 +07:00
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2007-11-06 13:24:43 +07:00
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extern struct kobject * __must_check kobject_create(void);
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2007-11-06 04:16:15 +07:00
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extern struct kobject * __must_check kobject_create_and_add(const char *name,
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struct kobject *parent);
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2006-08-15 12:43:17 +07:00
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extern int __must_check kobject_rename(struct kobject *, const char *new_name);
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2006-11-20 23:07:51 +07:00
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extern int __must_check kobject_move(struct kobject *, struct kobject *);
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2005-04-17 05:20:36 +07:00
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2008-01-25 12:27:06 +07:00
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extern struct kobject *kobject_get(struct kobject *kobj);
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extern void kobject_put(struct kobject *kobj);
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2005-04-17 05:20:36 +07:00
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2013-09-12 09:29:05 +07:00
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extern const void *kobject_namespace(struct kobject *kobj);
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2008-01-25 12:27:06 +07:00
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extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
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2005-04-17 05:20:36 +07:00
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struct kobj_type {
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2008-01-25 12:27:06 +07:00
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void (*release)(struct kobject *kobj);
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2010-01-19 08:58:23 +07:00
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const struct sysfs_ops *sysfs_ops;
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2008-01-25 12:27:06 +07:00
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struct attribute **default_attrs;
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2010-03-31 01:31:25 +07:00
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const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
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const void *(*namespace)(struct kobject *kobj);
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2005-04-17 05:20:36 +07:00
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};
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2007-08-14 20:15:12 +07:00
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struct kobj_uevent_env {
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kobject: don't block for each kobject_uevent
Currently kobject_uevent has somewhat unpredictable semantics. The
point is, since it may call a usermode helper and wait for it to execute
(UMH_WAIT_EXEC), it is impossible to say for sure what lock dependencies
it will introduce for the caller - strictly speaking it depends on what
fs the binary is located on and the set of locks fork may take. There
are quite a few kobject_uevent's users that do not take this into
account and call it with various mutexes taken, e.g. rtnl_mutex,
net_mutex, which might potentially lead to a deadlock.
Since there is actually no reason to wait for the usermode helper to
execute there, let's make kobject_uevent start the helper asynchronously
with the aid of the UMH_NO_WAIT flag.
Personally, I'm interested in this, because I really want kobject_uevent
to be called under the slab_mutex in the slub implementation as it used
to be some time ago, because it greatly simplifies synchronization and
automatically fixes a kmemcg-related race. However, there was a
deadlock detected on an attempt to call kobject_uevent under the
slab_mutex (see https://lkml.org/lkml/2012/1/14/45), which was reported
to be fixed by releasing the slab_mutex for kobject_uevent.
Unfortunately, there was no information about who exactly blocked on the
slab_mutex causing the usermode helper to stall, neither have I managed
to find this out or reproduce the issue.
BTW, this is not the first attempt to make kobject_uevent use
UMH_NO_WAIT. Previous one was made by commit f520360d93cd ("kobject:
don't block for each kobject_uevent"), but it was wrong (it passed
arguments allocated on stack to async thread) so it was reverted in
05f54c13cd0c ("Revert "kobject: don't block for each kobject_uevent".").
It targeted on speeding up the boot process though.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Greg KH <greg@kroah.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-04 04:48:21 +07:00
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char *argv[3];
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2007-08-14 20:15:12 +07:00
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char *envp[UEVENT_NUM_ENVP];
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int envp_idx;
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char buf[UEVENT_BUFFER_SIZE];
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int buflen;
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};
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2007-07-27 23:36:26 +07:00
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struct kset_uevent_ops {
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2009-12-31 20:52:51 +07:00
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int (* const filter)(struct kset *kset, struct kobject *kobj);
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const char *(* const name)(struct kset *kset, struct kobject *kobj);
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int (* const uevent)(struct kset *kset, struct kobject *kobj,
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2007-08-14 20:15:12 +07:00
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struct kobj_uevent_env *env);
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2007-07-27 23:36:26 +07:00
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};
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2005-04-17 05:20:36 +07:00
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2007-11-02 19:47:53 +07:00
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struct kobj_attribute {
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struct attribute attr;
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ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
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char *buf);
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ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
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const char *buf, size_t count);
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};
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2010-01-19 08:58:23 +07:00
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extern const struct sysfs_ops kobj_sysfs_ops;
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2007-11-02 19:47:53 +07:00
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2010-03-31 01:31:25 +07:00
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struct sock;
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2010-05-04 04:23:15 +07:00
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2007-09-28 04:48:53 +07:00
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/**
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* struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
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2005-04-17 05:20:36 +07:00
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*
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2007-09-28 04:48:53 +07:00
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* A kset defines a group of kobjects. They can be individually
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* different "types" but overall these kobjects all want to be grouped
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* together and operated on in the same manner. ksets are used to
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* define the attribute callbacks and other common events that happen to
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* a kobject.
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2005-04-17 05:20:36 +07:00
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*
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2007-09-28 04:48:53 +07:00
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* @list: the list of all kobjects for this kset
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* @list_lock: a lock for iterating over the kobjects
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* @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
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* @uevent_ops: the set of uevent operations for this kset. These are
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* called whenever a kobject has something happen to it so that the kset
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* can add new environment variables, or filter out the uevents if so
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* desired.
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2005-04-17 05:20:36 +07:00
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*/
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struct kset {
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2008-01-25 12:27:06 +07:00
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struct list_head list;
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spinlock_t list_lock;
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struct kobject kobj;
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2009-12-31 20:52:51 +07:00
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const struct kset_uevent_ops *uevent_ops;
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2005-04-17 05:20:36 +07:00
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};
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2008-01-25 12:27:06 +07:00
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extern void kset_init(struct kset *kset);
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extern int __must_check kset_register(struct kset *kset);
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extern void kset_unregister(struct kset *kset);
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2007-09-28 04:48:53 +07:00
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extern struct kset * __must_check kset_create_and_add(const char *name,
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2009-12-31 20:52:51 +07:00
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const struct kset_uevent_ops *u,
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2007-09-28 04:48:53 +07:00
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struct kobject *parent_kobj);
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2005-04-17 05:20:36 +07:00
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2008-01-25 12:27:06 +07:00
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static inline struct kset *to_kset(struct kobject *kobj)
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2005-04-17 05:20:36 +07:00
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{
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2008-01-25 12:27:06 +07:00
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return kobj ? container_of(kobj, struct kset, kobj) : NULL;
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2005-04-17 05:20:36 +07:00
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}
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2008-01-25 12:27:06 +07:00
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static inline struct kset *kset_get(struct kset *k)
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2005-04-17 05:20:36 +07:00
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{
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return k ? to_kset(kobject_get(&k->kobj)) : NULL;
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}
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2008-01-25 12:27:06 +07:00
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static inline void kset_put(struct kset *k)
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2005-04-17 05:20:36 +07:00
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{
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kobject_put(&k->kobj);
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}
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2007-10-16 23:11:44 +07:00
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static inline struct kobj_type *get_ktype(struct kobject *kobj)
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2005-04-17 05:20:36 +07:00
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{
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2007-10-16 23:11:44 +07:00
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return kobj->ktype;
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2005-04-17 05:20:36 +07:00
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}
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2008-01-25 12:27:06 +07:00
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extern struct kobject *kset_find_obj(struct kset *, const char *);
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2005-04-17 05:20:36 +07:00
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2007-11-07 01:36:58 +07:00
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/* The global /sys/kernel/ kobject for people to chain off of */
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extern struct kobject *kernel_kobj;
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2008-07-24 11:27:39 +07:00
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/* The global /sys/kernel/mm/ kobject for people to chain off of */
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extern struct kobject *mm_kobj;
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2007-11-01 22:29:06 +07:00
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/* The global /sys/hypervisor/ kobject for people to chain off of */
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extern struct kobject *hypervisor_kobj;
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2007-11-28 02:28:26 +07:00
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/* The global /sys/power/ kobject for people to chain off of */
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extern struct kobject *power_kobj;
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2007-11-06 04:16:15 +07:00
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/* The global /sys/firmware/ kobject for people to chain off of */
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extern struct kobject *firmware_kobj;
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2005-04-17 05:20:36 +07:00
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2006-12-20 04:01:27 +07:00
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int kobject_uevent(struct kobject *kobj, enum kobject_action action);
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int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
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2006-11-20 23:07:51 +07:00
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char *envp[]);
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2005-11-11 11:33:52 +07:00
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2011-11-01 07:11:33 +07:00
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__printf(2, 3)
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int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
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2007-08-13 01:43:55 +07:00
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int kobject_action_type(const char *buf, size_t count,
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enum kobject_action *type);
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2005-04-17 05:20:36 +07:00
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#endif /* _KOBJECT_H_ */
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