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

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
......@@ -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) \
......
......@@ -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);
}
......
......@@ -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);
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment