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>
diff --git a/drivers/base/base.h b/drivers/base/base.h
index c035dc2..31dc0cd 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -44,7 +44,7 @@
* @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 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) \
diff --git a/drivers/base/class.c b/drivers/base/class.c
index 8900056..839d27c 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -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 @@
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 @@
* 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 @@
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 @@
if (error)
break;
}
- up(&class->p->class_sem);
+ mutex_unlock(&class->p->class_mutex);
return error;
}
@@ -329,7 +330,7 @@
*
* 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 @@
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 @@
} else
put_device(dev);
}
- up(&class->p->class_sem);
+ mutex_unlock(&class->p->class_mutex);
return found ? dev : NULL;
}
@@ -375,13 +376,13 @@
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 @@
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);
}
diff --git a/drivers/base/core.c b/drivers/base/core.c
index b90ae6f..c05b115 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -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 @@
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 @@
&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 @@
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 @@
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);