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Date: Mon, 21 Jan 2008 09:43:35 +0800
From: Dave Young <hidave.darkstar@...il.com>
To: Jarek Poplawski <jarkao2@...il.com>
Cc: Kay Sievers <kay.sievers@...y.org>,
Alan Stern <stern@...land.harvard.edu>,
Greg KH <gregkh@...e.de>, stefanr@...6.in-berlin.de,
David Brownell <david-b@...bell.net>,
Kernel development list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 7/7] driver-core : convert semaphore to mutex in struct
class
On Mon, Jan 21, 2008 at 09:30:21AM +0800, Dave Young wrote:
> On Sat, Jan 19, 2008 at 10:39:33AM +0100, Jarek Poplawski wrote:
> > Dave Young wrote, On 01/18/2008 10:07 AM:
> >
> > > On Jan 18, 2008 4:23 PM, Jarek Poplawski <jarkao2@...il.com> wrote:
> >
> > >> On Fri, Jan 18, 2008 at 03:48:02PM +0800, Dave Young wrote:
> >
> > ...
> >
> > >>> 1) Using CLASS_NORMAL/CLASS_PARENT/CLASS_CHILD will be enough.
> > >>> or
> > >>> 2) Simply add SINGLE_LEVEL_NESTING in class_device_add and other
> > >>> class_device functions because it is the only possible nest-lock place
> > >>> as I know.
> >
> >
> Althoug the class_device will be away soon, the patch is updated as following because the problem is clear and only several lines are changed. At least, it could be used for test.
>
>
> Convert the class semaphore to mutex.
> class_interface_register/unregister use class_device_* functions, so SINGLE_DEPTH_NESTING added for lockdep please in these functions.
>
> Signed-off-by: Dave Young <hidave.darkstar@...il.com>
>
Sorry for the dirty patch, please don't test the previous one.
I should have drink a cup of coffe before posting.
post the right one again.
---
Convert the class semaphore to mutex.
class_interface_register/unregister use class_device_* functions, so SINGLE_DEPTH_NESTING added for lockdep please in these functions.
Signed-off-by: Dave Young <hidave.darkstar@...il.com>
---
drivers/base/class.c | 38 +++++++++++++++++++-------------------
drivers/base/core.c | 18 ++++++++----------
include/linux/device.h | 3 ++-
3 files changed, 29 insertions(+), 30 deletions(-)
Index: linux-2.6.23/drivers/base/class.c
===================================================================
--- linux-2.6.23.orig/drivers/base/class.c 2008-01-21 09:36:43.000000000 +0800
+++ linux-2.6.23/drivers/base/class.c 2008-01-21 09:38:14.000000000 +0800
@@ -144,7 +144,7 @@
INIT_LIST_HEAD(&cls->devices);
INIT_LIST_HEAD(&cls->interfaces);
kset_init(&cls->class_dirs);
- init_MUTEX(&cls->sem);
+ mutex_init(&cls->mutex);
error = kobject_set_name(&cls->subsys.kobj, "%s", cls->name);
if (error)
return error;
@@ -617,13 +617,13 @@
kobject_uevent(&class_dev->kobj, KOBJ_ADD);
/* notify any interfaces this device is now here */
- down(&parent_class->sem);
+ mutex_lock_nested(&parent_class->mutex, SINGLE_DEPTH_NESTING);
list_add_tail(&class_dev->node, &parent_class->children);
list_for_each_entry(class_intf, &parent_class->interfaces, node) {
if (class_intf->add)
class_intf->add(class_dev, class_intf);
}
- up(&parent_class->sem);
+ mutex_unlock(&parent_class->mutex);
goto out1;
@@ -725,12 +725,12 @@
struct class_interface *class_intf;
if (parent_class) {
- down(&parent_class->sem);
+ mutex_lock_nested(&parent_class->mutex, SINGLE_DEPTH_NESTING);
list_del_init(&class_dev->node);
list_for_each_entry(class_intf, &parent_class->interfaces, node)
if (class_intf->remove)
class_intf->remove(class_dev, class_intf);
- up(&parent_class->sem);
+ mutex_unlock(&parent_class->mutex);
}
if (class_dev->dev) {
@@ -772,14 +772,14 @@
struct class_device *class_dev = NULL;
struct class_device *class_dev_tmp;
- down(&cls->sem);
+ mutex_lock_nested(&cls->mutex, SINGLE_DEPTH_NESTING);
list_for_each_entry(class_dev_tmp, &cls->children, node) {
if (class_dev_tmp->devt == devt) {
class_dev = class_dev_tmp;
break;
}
}
- up(&cls->sem);
+ mutex_unlock(&cls->mutex);
if (class_dev)
class_device_unregister(class_dev);
@@ -818,7 +818,7 @@
if (!class)
return -EINVAL;
- down(&class->sem);
+ mutex_lock(&class->mutex);
list_for_each_entry(dev, &class->devices, node) {
dev = get_device(dev);
if (dev) {
@@ -829,7 +829,7 @@
if (error)
break;
}
- up(&class->sem);
+ mutex_unlock(&class->mutex);
return error;
}
@@ -860,7 +860,7 @@
if (!class)
return NULL;
- down(&class->sem);
+ mutex_lock(&class->mutex);
list_for_each_entry(dev, &class->devices, node) {
dev = get_device(dev);
if (dev) {
@@ -872,7 +872,7 @@
} else
break;
}
- up(&class->sem);
+ mutex_unlock(&class->mutex);
return found ? dev : NULL;
}
@@ -898,7 +898,7 @@
if (!class)
return -EINVAL;
- down(&class->sem);
+ mutex_lock(&class->mutex);
list_for_each_entry(dev, &class->children, node) {
dev = class_device_get(dev);
if (dev) {
@@ -909,7 +909,7 @@
if (error)
break;
}
- up(&class->sem);
+ mutex_unlock(&class->mutex);
return error;
}
@@ -940,7 +940,7 @@
if (!class)
return NULL;
- down(&class->sem);
+ mutex_lock(&class->mutex);
list_for_each_entry(dev, &class->children, node) {
dev = class_device_get(dev);
if (dev) {
@@ -952,7 +952,7 @@
} else
break;
}
- up(&class->sem);
+ mutex_unlock(&class->mutex);
return found ? dev : NULL;
}
@@ -971,7 +971,7 @@
if (!parent)
return -EINVAL;
- down(&parent->sem);
+ mutex_lock(&parent->mutex);
list_add_tail(&class_intf->node, &parent->interfaces);
if (class_intf->add) {
list_for_each_entry(class_dev, &parent->children, node)
@@ -981,7 +981,7 @@
list_for_each_entry(dev, &parent->devices, node)
class_intf->add_dev(dev, class_intf);
}
- up(&parent->sem);
+ mutex_unlock(&parent->mutex);
return 0;
}
@@ -995,7 +995,7 @@
if (!parent)
return;
- down(&parent->sem);
+ mutex_lock(&parent->mutex);
list_del_init(&class_intf->node);
if (class_intf->remove) {
list_for_each_entry(class_dev, &parent->children, node)
@@ -1005,7 +1005,7 @@
list_for_each_entry(dev, &parent->devices, node)
class_intf->remove_dev(dev, class_intf);
}
- up(&parent->sem);
+ mutex_unlock(&parent->mutex);
class_put(parent);
}
Index: linux-2.6.23/drivers/base/core.c
===================================================================
--- linux-2.6.23.orig/drivers/base/core.c 2008-01-21 09:35:37.000000000 +0800
+++ linux-2.6.23/drivers/base/core.c 2008-01-21 09:36:47.000000000 +0800
@@ -19,8 +19,6 @@
#include <linux/kdev_t.h>
#include <linux/notifier.h>
-#include <asm/semaphore.h>
-
#include "base.h"
#include "power/power.h"
@@ -783,7 +781,7 @@
klist_add_tail(&dev->knode_parent, &parent->klist_children);
if (dev->class) {
- down(&dev->class->sem);
+ mutex_lock(&dev->class->mutex);
/* tie the class to the device */
list_add_tail(&dev->node, &dev->class->devices);
@@ -791,7 +789,7 @@
list_for_each_entry(class_intf, &dev->class->interfaces, node)
if (class_intf->add_dev)
class_intf->add_dev(dev, class_intf);
- up(&dev->class->sem);
+ mutex_unlock(&dev->class->mutex);
}
Done:
put_device(dev);
@@ -928,14 +926,14 @@
sysfs_remove_link(&dev->kobj, "device");
}
- down(&dev->class->sem);
+ mutex_lock(&dev->class->mutex);
/* notify any interfaces that the device is now gone */
list_for_each_entry(class_intf, &dev->class->interfaces, node)
if (class_intf->remove_dev)
class_intf->remove_dev(dev, class_intf);
/* remove the device from the class list */
list_del_init(&dev->node);
- up(&dev->class->sem);
+ mutex_unlock(&dev->class->mutex);
/* If we live in a parent class-directory, unreference it */
if (dev->kobj.parent->kset == &dev->class->class_dirs) {
@@ -946,7 +944,7 @@
* if we are the last child of our class, delete
* our class-directory at this parent
*/
- down(&dev->class->sem);
+ mutex_lock(&dev->class->mutex);
list_for_each_entry(d, &dev->class->devices, node) {
if (d == dev)
continue;
@@ -959,7 +957,7 @@
kobject_del(dev->kobj.parent);
kobject_put(dev->kobj.parent);
- up(&dev->class->sem);
+ mutex_unlock(&dev->class->mutex);
}
}
device_remove_file(dev, &uevent_attr);
@@ -1168,14 +1166,14 @@
struct device *dev = NULL;
struct device *dev_tmp;
- down(&class->sem);
+ mutex_lock(&class->mutex);
list_for_each_entry(dev_tmp, &class->devices, node) {
if (dev_tmp->devt == devt) {
dev = dev_tmp;
break;
}
}
- up(&class->sem);
+ mutex_unlock(&class->mutex);
if (dev)
device_unregister(dev);
Index: linux-2.6.23/include/linux/device.h
===================================================================
--- linux-2.6.23.orig/include/linux/device.h 2008-01-21 09:36:43.000000000 +0800
+++ linux-2.6.23/include/linux/device.h 2008-01-21 09:36:47.000000000 +0800
@@ -20,6 +20,7 @@
#include <linux/types.h>
#include <linux/module.h>
#include <linux/pm.h>
+ #include <linux/mutex.h>
#include <asm/semaphore.h>
#include <asm/atomic.h>
#include <asm/device.h>
@@ -180,7 +181,7 @@
struct list_head devices;
struct list_head interfaces;
struct kset class_dirs;
- struct semaphore sem; /* locks children, devices, interfaces */
+ struct mutex mutex; /* locks children, devices, interfaces */
struct class_attribute * class_attrs;
struct class_device_attribute * class_dev_attrs;
struct device_attribute * dev_attrs;
--
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