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Message-ID: <20080121013021.GB2832@darkstar.te-china.tietoenator.com>
Date: Mon, 21 Jan 2008 09:30:21 +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 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>
---
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 2008-01-17 15:19:05.000000000 +0800
+++ linux-2.6.23/drivers/base/class.c 2008-01-18 15:56:00.000000000 +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 2008-01-17 15:19:05.000000000 +0800
+++ linux-2.6.23/drivers/base/core.c 2008-01-18 11:30:51.000000000 +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"
@@ -590,6 +588,7 @@
spin_lock(&dev->class->class_dirs.list_lock);
list_for_each_entry(k, &dev->class->class_dirs.list, entry)
if (k->parent == parent_kobj) {
+ printk("hidave : get reference of k\n");
kobj = kobject_get(k);
break;
}
@@ -783,7 +782,7 @@
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 +790,7 @@
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 +927,14 @@
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 +945,7 @@
* 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 +958,7 @@
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 +1167,14 @@
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);
@@ -1320,10 +1319,8 @@
pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
new_parent ? new_parent->bus_id : "<NULL>");
error = kobject_move(&dev->kobj, new_parent_kobj);
- if (error) {
- put_device(new_parent);
- goto out;
- }
+ if (error)
+ goto out_put_new_parent;
old_parent = dev->parent;
dev->parent = new_parent;
if (old_parent)
@@ -1331,7 +1328,7 @@
if (new_parent)
klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
if (!dev->class)
- goto out_put;
+ goto out_put_old;
error = device_move_class_links(dev, old_parent, new_parent);
if (error) {
/* We ignore errors on cleanup since we're hosed anyway... */
@@ -1343,11 +1340,15 @@
klist_add_tail(&dev->knode_parent,
&old_parent->klist_children);
}
- put_device(new_parent);
- goto out;
+ goto out_put_new;
}
-out_put:
+out_put_old:
put_device(old_parent);
+out_put_new:
+ if (new_parent)
+ put_device(new_parent);
+ else
+ kobject_put(new_parent_kobj);
out:
put_device(dev);
return error;
Index: linux-2.6.23/include/linux/device.h
===================================================================
--- linux-2.6.23.orig/include/linux/device.h 2008-01-17 15:19:05.000000000 +0800
+++ linux-2.6.23/include/linux/device.h 2008-01-17 17:45:34.000000000 +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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