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Commit f75b1c60 authored by Dave Young's avatar Dave Young Committed by Greg Kroah-Hartman
Browse files

class: change internal semaphore to a mutex 



Now that the lockdep infrastructure in the class core is in place, we
should be able to properly change the internal class semaphore to be a
mutex.

David wrote the original patch, and Greg fixed it up to apply properly
due to all of the recent changes in this area.

From: Dave Young <hidave.darkstar@gmail.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent d2a3b914

drivers/base/base.h

+2 −2
Original line number Diff line number Diff line
@@ -44,7 +44,7 @@ struct driver_private { 
 * @class_devices - list of devices associated with this class

 * @class_interfaces - list of class_interfaces associated with this class

 * @class_dirs - "glue" directory for virtual devices associated with this class

 * @class_sem - semaphore to protect the children, devices, and interfaces lists.

 * @class_mutex - mutex to protect the children, devices, and interfaces lists.

 * @class - pointer back to the struct class that this structure is associated

 * with.

 *
@@ -57,7 +57,7 @@ struct class_private { 
	struct list_head class_devices;

	struct list_head class_interfaces;

	struct kset class_dirs;

	struct semaphore class_sem;

	struct mutex class_mutex;

	struct class *class;

};

#define to_class(obj)	\

drivers/base/class.c

+12 −11
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/err.h>

#include <linux/slab.h>

#include <linux/genhd.h>

#include <linux/mutex.h>

#include "base.h"



#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
@@ -147,7 +148,7 @@ int __class_register(struct class *cls, struct lock_class_key *key) 
	INIT_LIST_HEAD(&cp->class_devices);

	INIT_LIST_HEAD(&cp->class_interfaces);

	kset_init(&cp->class_dirs);

	init_MUTEX(&cp->class_sem);

	__mutex_init(&cp->class_mutex, "struct class mutex", key);

	error = kobject_set_name(&cp->class_subsys.kobj, "%s", cls->name);

	if (error) {

		kfree(cp);
@@ -281,7 +282,7 @@ char *make_class_name(const char *name, struct kobject *kobj) 
 * We check the return of @fn each time. If it returns anything

 * other than 0, we break out and return that value.

 *

 * Note, we hold class->class_sem in this function, so it can not be

 * Note, we hold class->class_mutex in this function, so it can not be

 * re-acquired in @fn, otherwise it will self-deadlocking. For

 * example, calls to add or remove class members would be verboten.

 */
@@ -293,7 +294,7 @@ int class_for_each_device(struct class *class, struct device *start, 


	if (!class)

		return -EINVAL;

	down(&class->p->class_sem);

	mutex_lock(&class->p->class_mutex);

	list_for_each_entry(dev, &class->p->class_devices, node) {

		if (start) {

			if (start == dev)
@@ -306,7 +307,7 @@ int class_for_each_device(struct class *class, struct device *start, 
		if (error)

			break;

	}

	up(&class->p->class_sem);

	mutex_unlock(&class->p->class_mutex);



	return error;

}
@@ -329,7 +330,7 @@ EXPORT_SYMBOL_GPL(class_for_each_device); 
 *

 * Note, you will need to drop the reference with put_device() after use.

 *

 * We hold class->class_sem in this function, so it can not be

 * We hold class->class_mutex in this function, so it can not be

 * re-acquired in @match, otherwise it will self-deadlocking. For

 * example, calls to add or remove class members would be verboten.

 */
@@ -343,7 +344,7 @@ struct device *class_find_device(struct class *class, struct device *start, 
	if (!class)

		return NULL;



	down(&class->p->class_sem);

	mutex_lock(&class->p->class_mutex);

	list_for_each_entry(dev, &class->p->class_devices, node) {

		if (start) {

			if (start == dev)
@@ -357,7 +358,7 @@ struct device *class_find_device(struct class *class, struct device *start, 
		} else

			put_device(dev);

	}

	up(&class->p->class_sem);

	mutex_unlock(&class->p->class_mutex);



	return found ? dev : NULL;

}
@@ -375,13 +376,13 @@ int class_interface_register(struct class_interface *class_intf) 
	if (!parent)

		return -EINVAL;



	down(&parent->p->class_sem);

	mutex_lock(&parent->p->class_mutex);

	list_add_tail(&class_intf->node, &parent->p->class_interfaces);

	if (class_intf->add_dev) {

		list_for_each_entry(dev, &parent->p->class_devices, node)

			class_intf->add_dev(dev, class_intf);

	}

	up(&parent->p->class_sem);

	mutex_unlock(&parent->p->class_mutex);



	return 0;

}
@@ -394,13 +395,13 @@ void class_interface_unregister(struct class_interface *class_intf) 
	if (!parent)

		return;



	down(&parent->p->class_sem);

	mutex_lock(&parent->p->class_mutex);

	list_del_init(&class_intf->node);

	if (class_intf->remove_dev) {

		list_for_each_entry(dev, &parent->p->class_devices, node)

			class_intf->remove_dev(dev, class_intf);

	}

	up(&parent->p->class_sem);

	mutex_unlock(&parent->p->class_mutex);



	class_put(parent);

}

drivers/base/core.c

+5 −4
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/genhd.h>

#include <linux/kallsyms.h>

#include <linux/semaphore.h>

#include <linux/mutex.h>



#include "base.h"

#include "power/power.h"
@@ -907,7 +908,7 @@ int device_add(struct device *dev) 
		klist_add_tail(&dev->knode_parent, &parent->klist_children);



	if (dev->class) {

		down(&dev->class->p->class_sem);

		mutex_lock(&dev->class->p->class_mutex);

		/* tie the class to the device */

		list_add_tail(&dev->node, &dev->class->p->class_devices);
@@ -916,7 +917,7 @@ int device_add(struct device *dev) 
				    &dev->class->p->class_interfaces, node)

			if (class_intf->add_dev)

				class_intf->add_dev(dev, class_intf);

		up(&dev->class->p->class_sem);

		mutex_unlock(&dev->class->p->class_mutex);

	}

 Done:

	put_device(dev);
@@ -1017,7 +1018,7 @@ void device_del(struct device *dev) 
	if (dev->class) {

		device_remove_class_symlinks(dev);



		down(&dev->class->p->class_sem);

		mutex_lock(&dev->class->p->class_mutex);

		/* notify any interfaces that the device is now gone */

		list_for_each_entry(class_intf,

				    &dev->class->p->class_interfaces, node)
@@ -1025,7 +1026,7 @@ void device_del(struct device *dev) 
				class_intf->remove_dev(dev, class_intf);

		/* remove the device from the class list */

		list_del_init(&dev->node);

		up(&dev->class->p->class_sem);

		mutex_unlock(&dev->class->p->class_mutex);

	}

	device_remove_file(dev, &uevent_attr);

	device_remove_attrs(dev);