Re: [PATCH] sysdev: remove global sysdev drivers list

From: Akinobu Mita
Date: Sun Aug 19 2007 - 04:03:35 EST

On Mon, Aug 13, 2007 at 09:43:31AM +0200, Cornelia Huck wrote:
> On Sun, 12 Aug 2007 13:44:07 +0900,
> Akinobu Mita <akinobu.mita@xxxxxxxxx> wrote:
>
> > No one uses sysdev_drivers. Because no one calls sysdev_driver_register
> > with NULL class.
> >
> > And it is difficult to imagine that someone want to implement a global
> > sysdev driver which is called with all sys_device on any kind of
> > sysdev_class.
> >
> > So this patch removes global sysdev_drivers list.
>
> This makes sense, I guess, especially since it simplyfies the code.
>
> Some minor comments below.

Yes. All your comments are oviously correct.
Please check updated patch.

From: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Subject: [PATCH] sysdev: remove global sysdev drivers list

No one uses sysdev_drivers. Because no one calls sysdev_driver_register
with NULL class.

And it is difficult to imagine that someone want to implement a global
sysdev driver which is called with all sys_device on any kind of
sysdev_class.

So this patch removes global sysdev_drivers list and update comments
for this change.

Cc: Tejun Heo <htejun@xxxxxxxxx>
Cc: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>

---
drivers/base/sys.c | 71 ++++++++++-------------------------------------------
1 file changed, 14 insertions(+), 57 deletions(-)

Index: 2.6-git/drivers/base/sys.c
===================================================================
--- 2.6-git.orig/drivers/base/sys.c
+++ 2.6-git/drivers/base/sys.c
@@ -153,25 +153,22 @@ void sysdev_class_unregister(struct sysd
EXPORT_SYMBOL_GPL(sysdev_class_register);
EXPORT_SYMBOL_GPL(sysdev_class_unregister);

-
-static LIST_HEAD(sysdev_drivers);
static DEFINE_MUTEX(sysdev_drivers_lock);

/**
* sysdev_driver_register - Register auxillary driver
- * @cls: Device class driver belongs to.
+ * @cls: Device class driver belongs to.
* @drv: Driver.
*
- * If @cls is valid, then @drv is inserted into @cls->drivers to be
+ * @drv is inserted into @cls->drivers to be
* called on each operation on devices of that class. The refcount
* of @cls is incremented.
- * Otherwise, @drv is inserted into sysdev_drivers, and called for
- * each device.
*/

-int sysdev_driver_register(struct sysdev_class * cls,
- struct sysdev_driver * drv)
+int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv)
{
+ int err = 0;
+
mutex_lock(&sysdev_drivers_lock);
if (cls && kset_get(&cls->kset)) {
list_add_tail(&drv->entry, &cls->drivers);
@@ -182,10 +179,13 @@ int sysdev_driver_register(struct sysdev
list_for_each_entry(dev, &cls->kset.list, kobj.entry)
drv->add(dev);
}
- } else
- list_add_tail(&drv->entry, &sysdev_drivers);
+ } else {
+ err = -EINVAL;
+ printk(KERN_ERR "%s: invalid device class\n", __FUNCTION__);
+ WARN_ON(1);
+ }
mutex_unlock(&sysdev_drivers_lock);
- return 0;
+ return err;
}


@@ -251,12 +251,6 @@ int sysdev_register(struct sys_device *
* code that should have called us.
*/

- /* Notify global drivers */
- list_for_each_entry(drv, &sysdev_drivers, entry) {
- if (drv->add)
- drv->add(sysdev);
- }
-
/* Notify class auxillary drivers */
list_for_each_entry(drv, &cls->drivers, entry) {
if (drv->add)
@@ -272,11 +266,6 @@ void sysdev_unregister(struct sys_device
struct sysdev_driver * drv;

mutex_lock(&sysdev_drivers_lock);
- list_for_each_entry(drv, &sysdev_drivers, entry) {
- if (drv->remove)
- drv->remove(sysdev);
- }
-
list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
if (drv->remove)
drv->remove(sysdev);
@@ -293,7 +282,7 @@ void sysdev_unregister(struct sys_device
*
* Loop over each class of system devices, and the devices in each
* of those classes. For each device, we call the shutdown method for
- * each driver registered for the device - the globals, the auxillaries,
+ * each driver registered for the device - the auxillaries,
* and the class driver.
*
* Note: The list is iterated in reverse order, so that we shut down
@@ -320,13 +309,7 @@ void sysdev_shutdown(void)
struct sysdev_driver * drv;
pr_debug(" %s\n", kobject_name(&sysdev->kobj));

- /* Call global drivers first. */
- list_for_each_entry(drv, &sysdev_drivers, entry) {
- if (drv->shutdown)
- drv->shutdown(sysdev);
- }
-
- /* Call auxillary drivers next. */
+ /* Call auxillary drivers first */
list_for_each_entry(drv, &cls->drivers, entry) {
if (drv->shutdown)
drv->shutdown(sysdev);
@@ -354,12 +337,6 @@ static void __sysdev_resume(struct sys_d
if (drv->resume)
drv->resume(dev);
}
-
- /* Call global drivers. */
- list_for_each_entry(drv, &sysdev_drivers, entry) {
- if (drv->resume)
- drv->resume(dev);
- }
}

/**
@@ -393,16 +370,7 @@ int sysdev_suspend(pm_message_t state)
list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
pr_debug(" %s\n", kobject_name(&sysdev->kobj));

- /* Call global drivers first. */
- list_for_each_entry(drv, &sysdev_drivers, entry) {
- if (drv->suspend) {
- ret = drv->suspend(sysdev, state);
- if (ret)
- goto gbl_driver;
- }
- }
-
- /* Call auxillary drivers next. */
+ /* Call auxillary drivers first */
list_for_each_entry(drv, &cls->drivers, entry) {
if (drv->suspend) {
ret = drv->suspend(sysdev, state);
@@ -436,18 +404,7 @@ aux_driver:
if (err_drv->resume)
err_drv->resume(sysdev);
}
- drv = NULL;

-gbl_driver:
- if (drv)
- printk(KERN_ERR "sysdev driver suspend failed for %s\n",
- kobject_name(&sysdev->kobj));
- list_for_each_entry(err_drv, &sysdev_drivers, entry) {
- if (err_drv == drv)
- break;
- if (err_drv->resume)
- err_drv->resume(sysdev);
- }
/* resume other sysdevs in current class */
list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
if (err_dev == sysdev)
-
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