Commit 72099304 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

Revert "sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()" 



This reverts commit d1ba277e.

As reported by Stephen, this patch breaks linux-next as a ppc patch
suddenly (after 2 years) started using this old api call.  So revert it
for now, it will go away in 3.15-rc2 when we can change the PPC call to
the new api.

Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b7ce40cf

drivers/base/core.c

+33 −0
Original line number Diff line number Diff line
@@ -614,6 +614,39 @@ void device_remove_bin_file(struct device *dev, 
}

EXPORT_SYMBOL_GPL(device_remove_bin_file);



/**

 * device_schedule_callback_owner - helper to schedule a callback for a device

 * @dev: device.

 * @func: callback function to invoke later.

 * @owner: module owning the callback routine

 *

 * Attribute methods must not unregister themselves or their parent device

 * (which would amount to the same thing).  Attempts to do so will deadlock,

 * since unregistration is mutually exclusive with driver callbacks.

 *

 * Instead methods can call this routine, which will attempt to allocate

 * and schedule a workqueue request to call back @func with @dev as its

 * argument in the workqueue's process context.  @dev will be pinned until

 * @func returns.

 *

 * This routine is usually called via the inline device_schedule_callback(),

 * which automatically sets @owner to THIS_MODULE.

 *

 * Returns 0 if the request was submitted, -ENOMEM if storage could not

 * be allocated, -ENODEV if a reference to @owner isn't available.

 *

 * NOTE: This routine won't work if CONFIG_SYSFS isn't set!  It uses an

 * underlying sysfs routine (since it is intended for use by attribute

 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.

 */

int device_schedule_callback_owner(struct device *dev,

		void (*func)(struct device *), struct module *owner)

{

	return sysfs_schedule_callback(&dev->kobj,

			(void (*)(void *)) func, dev, owner);

}

EXPORT_SYMBOL_GPL(device_schedule_callback_owner);



static void klist_children_get(struct klist_node *n)

{

	struct device_private *p = to_device_private_parent(n);

fs/sysfs/file.c

+92 −0
Original line number Diff line number Diff line
@@ -453,3 +453,95 @@ void sysfs_remove_bin_file(struct kobject *kobj, 
	kernfs_remove_by_name(kobj->sd, attr->attr.name);

}

EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);



struct sysfs_schedule_callback_struct {

	struct list_head	workq_list;

	struct kobject		*kobj;

	void			(*func)(void *);

	void			*data;

	struct module		*owner;

	struct work_struct	work;

};



static struct workqueue_struct *sysfs_workqueue;

static DEFINE_MUTEX(sysfs_workq_mutex);

static LIST_HEAD(sysfs_workq);

static void sysfs_schedule_callback_work(struct work_struct *work)

{

	struct sysfs_schedule_callback_struct *ss = container_of(work,

			struct sysfs_schedule_callback_struct, work);



	(ss->func)(ss->data);

	kobject_put(ss->kobj);

	module_put(ss->owner);

	mutex_lock(&sysfs_workq_mutex);

	list_del(&ss->workq_list);

	mutex_unlock(&sysfs_workq_mutex);

	kfree(ss);

}



/**

 * sysfs_schedule_callback - helper to schedule a callback for a kobject

 * @kobj: object we're acting for.

 * @func: callback function to invoke later.

 * @data: argument to pass to @func.

 * @owner: module owning the callback code

 *

 * sysfs attribute methods must not unregister themselves or their parent

 * kobject (which would amount to the same thing).  Attempts to do so will

 * deadlock, since unregistration is mutually exclusive with driver

 * callbacks.

 *

 * Instead methods can call this routine, which will attempt to allocate

 * and schedule a workqueue request to call back @func with @data as its

 * argument in the workqueue's process context.  @kobj will be pinned

 * until @func returns.

 *

 * Returns 0 if the request was submitted, -ENOMEM if storage could not

 * be allocated, -ENODEV if a reference to @owner isn't available,

 * -EAGAIN if a callback has already been scheduled for @kobj.

 */

int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),

		void *data, struct module *owner)

{

	struct sysfs_schedule_callback_struct *ss, *tmp;



	if (!try_module_get(owner))

		return -ENODEV;



	mutex_lock(&sysfs_workq_mutex);

	list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list)

		if (ss->kobj == kobj) {

			module_put(owner);

			mutex_unlock(&sysfs_workq_mutex);

			return -EAGAIN;

		}

	mutex_unlock(&sysfs_workq_mutex);



	if (sysfs_workqueue == NULL) {

		sysfs_workqueue = create_singlethread_workqueue("sysfsd");

		if (sysfs_workqueue == NULL) {

			module_put(owner);

			return -ENOMEM;

		}

	}



	ss = kmalloc(sizeof(*ss), GFP_KERNEL);

	if (!ss) {

		module_put(owner);

		return -ENOMEM;

	}

	kobject_get(kobj);

	ss->kobj = kobj;

	ss->func = func;

	ss->data = data;

	ss->owner = owner;

	INIT_WORK(&ss->work, sysfs_schedule_callback_work);

	INIT_LIST_HEAD(&ss->workq_list);

	mutex_lock(&sysfs_workq_mutex);

	list_add_tail(&ss->workq_list, &sysfs_workq);

	mutex_unlock(&sysfs_workq_mutex);

	queue_work(sysfs_workqueue, &ss->work);

	return 0;

}

EXPORT_SYMBOL_GPL(sysfs_schedule_callback);

include/linux/device.h

+10 −1
Original line number Diff line number Diff line
@@ -566,6 +566,12 @@ extern int __must_check device_create_bin_file(struct device *dev, 
					const struct bin_attribute *attr);

extern void device_remove_bin_file(struct device *dev,

				   const struct bin_attribute *attr);

extern int device_schedule_callback_owner(struct device *dev,

		void (*func)(struct device *dev), struct module *owner);



/* This is a macro to avoid include problems with THIS_MODULE */

#define device_schedule_callback(dev, func)			\

	device_schedule_callback_owner(dev, func, THIS_MODULE)



/* device resource management */

typedef void (*dr_release_t)(struct device *dev, void *res);
@@ -925,7 +931,10 @@ extern int device_online(struct device *dev); 
extern struct device *__root_device_register(const char *name,

					     struct module *owner);



/* This is a macro to avoid include problems with THIS_MODULE */

/*

 * This is a macro to avoid include problems with THIS_MODULE,

 * just as per what is done for device_schedule_callback() above.

 */

#define root_device_register(name) \

	__root_device_register(name, THIS_MODULE)

include/linux/sysfs.h

+9 −0
Original line number Diff line number Diff line
@@ -178,6 +178,9 @@ struct sysfs_ops { 


#ifdef CONFIG_SYSFS



int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),

			    void *data, struct module *owner);



int __must_check sysfs_create_dir_ns(struct kobject *kobj, const void *ns);

void sysfs_remove_dir(struct kobject *kobj);

int __must_check sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
@@ -251,6 +254,12 @@ static inline void sysfs_enable_ns(struct kernfs_node *kn) 


#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_ns(struct kobject *kobj, const void *ns)

{

	return 0;

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