Re: Re: [PATCH] kobject: kobject_add_internal cleanup

From: Greg KH
Date: Thu Jul 29 2021 - 10:08:58 EST


A: http://en.wikipedia.org/wiki/Top_post
Q: Were do I find info about this thing called top-posting?
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

A: No.
Q: Should I include quotations after my reply?

http://daringfireball.net/2007/07/on_top

On Thu, Jul 29, 2021 at 09:42:34PM +0800, qiaoyanbo_310 wrote:
> Hi Greg k-h,
>
>
> First at all, there is my mistake about From line different with Sign off line. They all should be "Qiao Yanbo".

Great, please fix that up.

> Secondly, the problem this patch wants to solve is: In this function, the parent variable is first called "kobject_get (kobj->parent) " assignment. When the parent is not null, the just obtained parent is assigned back to "kobj - > parent", which is meaningless. Actually, "kobj->kset->kobj" will be assigned to "kobj->parent" only when the parent is NULL. So this patch solves the problem of meaningless assignment.

Why is this a problem? What bug is this solving? Is the code somehow
now faster or smaller that can be measured?

> Finally , I tested this patch and didn't see any additional problems in my environment.
>
>
> Here is the original code snippet. I hope you can understand my idea.
> =======================================================
> parent = kobject_get(kobj->parent);
>
>
> /* join kset if set, use it as parent if we do not already have one */
> if (kobj->kset) {
> if (!parent)
> parent = kobject_get(&kobj->kset->kobj);
> kobj_kset_join(kobj);
> kobj->parent = parent;

I do not see a bug with this code, what is wrong with it?

thanks,

greg k-h