Re: [PATCH 044/196] kset: add kset_create_and_add function

Dave Young
2008-01-25T09:10:07Z

On Jan 25, 2008 3:09 PM, Greg Kroah-Hartman <gregkh@suse.de> wrote:
> Now ksets can be dynamically created on the fly, no static definitions
> are required. Thanks to Miklos for hints on how to make this work
> better for the callers.
>
> And thanks to Kay for finding some stupid bugs in my original version
> and pointing out that we need to handle the fact that kobject's can have
> a kset as a parent and to handle that properly in kobject_add().
>
> Cc: Kay Sievers <kay.sievers@vrfy.org>
> Cc: Miklos Szeredi <miklos@szeredi.hu>
> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> ---
> include/linux/kobject.h | 4 ++-
> lib/kobject.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 94 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/kobject.h b/include/linux/kobject.h
> index 0b97b3a..f91aeb7 100644
> --- a/include/linux/kobject.h
> +++ b/include/linux/kobject.h
> @@ -150,11 +150,13 @@ struct kset {
> struct kset_uevent_ops *uevent_ops;
> };
>
> -
> extern void kset_init(struct kset * k);
> extern int __must_check kset_add(struct kset * k);
> extern int __must_check kset_register(struct kset * k);
> extern void kset_unregister(struct kset * k);
> +extern struct kset * __must_check kset_create_and_add(const char *name,
> + struct kset_uevent_ops *u,
> + struct kobject *parent_kobj);
>
> static inline struct kset * to_kset(struct kobject * kobj)
> {
> diff --git a/lib/kobject.c b/lib/kobject.c
> index 8f24940..4fb27ba 100644
> --- a/lib/kobject.c
> +++ b/lib/kobject.c
> @@ -186,8 +186,15 @@ int kobject_add(struct kobject * kobj)
> if (kobj->kset) {
> spin_lock(&kobj->kset->list_lock);
>
> - if (!parent)
> + if (!parent) {
> parent = kobject_get(&kobj->kset->kobj);
> + /*
> + * If the kset is our parent, get a second
> + * reference, we drop both the kset and the
> + * parent ref on cleanup
> + */
> + kobject_get(parent);
> + }
>
> list_add_tail(&kobj->entry,&kobj->kset->list);
> spin_unlock(&kobj->kset->list_lock);
> @@ -787,6 +794,89 @@ int subsys_create_file(struct kset *s, struct subsys_attribute *a)
> return error;
> }
>
> +static void kset_release(struct kobject *kobj)
> +{
> + struct kset *kset = container_of(kobj, struct kset, kobj);
> + pr_debug("kset %s: now freed\n", kobject_name(kobj));
> + kfree(kset);
> +}
> +
> +static struct kobj_type kset_type = {
> + .release = kset_release,
> +};
> +
> +/**
> + * kset_create - create a struct kset dynamically
> + *
> + * @name: the name for the kset
> + * @uevent_ops: a struct kset_uevent_ops for the kset
> + * @parent_kobj: the parent kobject of this kset, if any.
> + *
> + * This function creates a kset structure dynamically. This structure can
> + * then be registered with the system and show up in sysfs with a call to
> + * kset_register(). When you are finished with this structure, if
> + * kset_register() has been called, call kset_unregister() and the
> + * structure will be dynamically freed when it is no longer being used.
> + *
> + * If the kset was not able to be created, NULL will be returned.
> + */
> +static struct kset *kset_create(const char *name,
> + struct kset_uevent_ops *uevent_ops,
> + struct kobject *parent_kobj)
> +{
> + struct kset *kset;
> +
> + kset = kzalloc(sizeof(*kset), GFP_KERNEL);
> + if (!kset)
> + return NULL;
> + kobject_set_name(&kset->kobj, name);
> + kset->uevent_ops = uevent_ops;
> + kset->kobj.parent = parent_kobj;
> +
> + /*
> + * The kobject of this kset will have a type of kset_type and belong to
> + * no kset itself. That way we can properly free it when it is
> + * finished being used.
> + */
> + kset->kobj.ktype = &kset_type;
> + kset->kobj.kset = NULL;
> +
> + return kset;
> +}
> +
> +/**
> + * kset_create_and_add - create a struct kset dynamically and add it to sysfs
> + *
> + * @name: the name for the kset
> + * @uevent_ops: a struct kset_uevent_ops for the kset
> + * @parent_kobj: the parent kobject of this kset, if any.
> + *
> + * This function creates a kset structure dynamically and registers it
> + * with sysfs. When you are finished with this structure, call
> + * kset_unregister() and the structure will be dynamically freed when it
> + * is no longer being used.
> + *
> + * If the kset was not able to be created, NULL will be returned.
> + */
> +struct kset *kset_create_and_add(const char *name,
> + struct kset_uevent_ops *uevent_ops,
> + struct kobject *parent_kobj)
> +{
> + struct kset *kset;
> + int error;
> +
> + kset = kset_create(name, uevent_ops, parent_kobj);
> + if (!kset)
> + return NULL;
> + error = kset_register(kset);
> + if (error) {
> + kfree(kset);

How about : kobject_put(&kset->kobj);

> + return NULL;
> + }
> + return kset;
> +}
> +EXPORT_SYMBOL_GPL(kset_create_and_add);
> +
> EXPORT_SYMBOL(kobject_init);
> EXPORT_SYMBOL(kobject_register);
> EXPORT_SYMBOL(kobject_unregister);
> --
> 1.5.3.8
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>