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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: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Dave Young 2008-05-28 09:28:39 -07:00 committed by Greg Kroah-Hartman
parent d2a3b9146e
commit f75b1c60fc
3 changed files with 19 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/base/base.h
View File

@ -44,7 +44,7 @@ struct driver_private {
* @class_devices - list of devices associated with this class * @class_devices - list of devices associated with this class
* @class_interfaces - list of class_interfaces 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_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 * @class - pointer back to the struct class that this structure is associated
* with. * with.
* *
@ -57,7 +57,7 @@ struct class_private {
struct list_head class_devices; struct list_head class_devices;
struct list_head class_interfaces; struct list_head class_interfaces;
struct kset class_dirs; struct kset class_dirs;
struct semaphore class_sem; struct mutex class_mutex;
struct class *class; struct class *class;
}; };
#define to_class(obj) \ #define to_class(obj) \

23
drivers/base/class.c
View File

@ -18,6 +18,7 @@
#include <linux/err.h> #include <linux/err.h>
#include <linux/slab.h> #include <linux/slab.h>
#include <linux/genhd.h> #include <linux/genhd.h>
#include <linux/mutex.h>
#include "base.h" #include "base.h"
#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr) #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_devices);
INIT_LIST_HEAD(&cp->class_interfaces); INIT_LIST_HEAD(&cp->class_interfaces);
kset_init(&cp->class_dirs); 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); error = kobject_set_name(&cp->class_subsys.kobj, "%s", cls->name);
if (error) { if (error) {
kfree(cp); 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 * We check the return of @fn each time. If it returns anything
* other than 0, we break out and return that value. * 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 * re-acquired in @fn, otherwise it will self-deadlocking. For
* example, calls to add or remove class members would be verboten. * 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) if (!class)
return -EINVAL; return -EINVAL;
down(&class->p->class_sem); mutex_lock(&class->p->class_mutex);
list_for_each_entry(dev, &class->p->class_devices, node) { list_for_each_entry(dev, &class->p->class_devices, node) {
if (start) { if (start) {
if (start == dev) if (start == dev)
@ -306,7 +307,7 @@ int class_for_each_device(struct class *class, struct device *start,
if (error) if (error)
break; break;
} }
up(&class->p->class_sem); mutex_unlock(&class->p->class_mutex);
return error; 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. * 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 * re-acquired in @match, otherwise it will self-deadlocking. For
* example, calls to add or remove class members would be verboten. * 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) if (!class)
return NULL; return NULL;
down(&class->p->class_sem); mutex_lock(&class->p->class_mutex);
list_for_each_entry(dev, &class->p->class_devices, node) { list_for_each_entry(dev, &class->p->class_devices, node) {
if (start) { if (start) {
if (start == dev) if (start == dev)
@ -357,7 +358,7 @@ struct device *class_find_device(struct class *class, struct device *start,
} else } else
put_device(dev); put_device(dev);
} }
up(&class->p->class_sem); mutex_unlock(&class->p->class_mutex);
return found ? dev : NULL; return found ? dev : NULL;
} }
@ -375,13 +376,13 @@ int class_interface_register(struct class_interface *class_intf)
if (!parent) if (!parent)
return -EINVAL; return -EINVAL;
down(&parent->p->class_sem); mutex_lock(&parent->p->class_mutex);
list_add_tail(&class_intf->node, &parent->p->class_interfaces); list_add_tail(&class_intf->node, &parent->p->class_interfaces);
if (class_intf->add_dev) { if (class_intf->add_dev) {
list_for_each_entry(dev, &parent->p->class_devices, node) list_for_each_entry(dev, &parent->p->class_devices, node)
class_intf->add_dev(dev, class_intf); class_intf->add_dev(dev, class_intf);
} }
up(&parent->p->class_sem); mutex_unlock(&parent->p->class_mutex);
return 0; return 0;
} }
@ -394,13 +395,13 @@ void class_interface_unregister(struct class_interface *class_intf)
if (!parent) if (!parent)
return; return;
down(&parent->p->class_sem); mutex_lock(&parent->p->class_mutex);
list_del_init(&class_intf->node); list_del_init(&class_intf->node);
if (class_intf->remove_dev) { if (class_intf->remove_dev) {
list_for_each_entry(dev, &parent->p->class_devices, node) list_for_each_entry(dev, &parent->p->class_devices, node)
class_intf->remove_dev(dev, class_intf); class_intf->remove_dev(dev, class_intf);
} }
up(&parent->p->class_sem); mutex_unlock(&parent->p->class_mutex);
class_put(parent); class_put(parent);
} }

9
drivers/base/core.c
View File

@ -21,6 +21,7 @@
#include <linux/genhd.h> #include <linux/genhd.h>
#include <linux/kallsyms.h> #include <linux/kallsyms.h>
#include <linux/semaphore.h> #include <linux/semaphore.h>
#include <linux/mutex.h>
#include "base.h" #include "base.h"
#include "power/power.h" #include "power/power.h"
@ -907,7 +908,7 @@ int device_add(struct device *dev)
klist_add_tail(&dev->knode_parent, &parent->klist_children); klist_add_tail(&dev->knode_parent, &parent->klist_children);
if (dev->class) { if (dev->class) {
down(&dev->class->p->class_sem); mutex_lock(&dev->class->p->class_mutex);
/* tie the class to the device */ /* tie the class to the device */
list_add_tail(&dev->node, &dev->class->p->class_devices); 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) &dev->class->p->class_interfaces, node)
if (class_intf->add_dev) if (class_intf->add_dev)
class_intf->add_dev(dev, class_intf); class_intf->add_dev(dev, class_intf);
up(&dev->class->p->class_sem); mutex_unlock(&dev->class->p->class_mutex);
} }
Done: Done:
put_device(dev); put_device(dev);
@ -1017,7 +1018,7 @@ void device_del(struct device *dev)
if (dev->class) { if (dev->class) {
device_remove_class_symlinks(dev); 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 */ /* notify any interfaces that the device is now gone */
list_for_each_entry(class_intf, list_for_each_entry(class_intf,
&dev->class->p->class_interfaces, node) &dev->class->p->class_interfaces, node)
@ -1025,7 +1026,7 @@ void device_del(struct device *dev)
class_intf->remove_dev(dev, class_intf); class_intf->remove_dev(dev, class_intf);
/* remove the device from the class list */ /* remove the device from the class list */
list_del_init(&dev->node); 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_file(dev, &uevent_attr);
device_remove_attrs(dev); device_remove_attrs(dev);