linux-kernel - Re: [PATCH 01/11] kset: fix documentation for kset

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Message-ID: <eb0f1459-7980-4a7b-58f9-652eeccc357e@amd.com>
Date:   Fri, 21 Oct 2022 01:34:17 -0400
From:   Luben Tuikov <luben.tuikov@....com>
To:     Yang Yingliang <yangyingliang@...wei.com>,
        linux-kernel@...r.kernel.org, qemu-devel@...gnu.org,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-erofs@...ts.ozlabs.org, ocfs2-devel@....oracle.com,
        linux-mtd@...ts.infradead.org, amd-gfx@...ts.freedesktop.org
Cc:     gregkh@...uxfoundation.org, rafael@...nel.org, somlo@....edu,
        mst@...hat.com, jaegeuk@...nel.org, chao@...nel.org,
        hsiangkao@...ux.alibaba.com, huangjianan@...o.com, mark@...heh.com,
        jlbec@...lplan.org, joseph.qi@...ux.alibaba.com,
        akpm@...ux-foundation.org, alexander.deucher@....com,
        richard@....at, liushixin2@...wei.com
Subject: Re: [PATCH 01/11] kset: fix documentation for kset_register()

On 2022-10-20 22:20, Yang Yingliang wrote:
> kset_register() is currently used in some places without calling
> kset_put() in error path, because the callers think it should be
> kset internal thing to do, but the driver core can not know what
> caller doing with that memory at times. The memory could be freed
> both in kset_put() and error path of caller, if it is called in
> kset_register().
> 
> So make the function documentation more explicit about calling
> kset_put() in the error path of caller.
> 
> Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
> ---
>  lib/kobject.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/lib/kobject.c b/lib/kobject.c
> index a0b2dbfcfa23..6da04353d974 100644
> --- a/lib/kobject.c
> +++ b/lib/kobject.c
> @@ -834,6 +834,9 @@ EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
>  /**
>   * kset_register() - Initialize and add a kset.
>   * @k: kset.
> + *
> + * If this function returns an error, kset_put() must be called to
> + * properly clean up the memory associated with the object.
>   */

And I'd continue the sentence, with " ... with the object,
for instance the memory for the kset.kobj.name when kobj_set_name(&kset.kobj, format, ...)
was called before calling kset_register()."

This makes it clear what we want to make sure is freed, in case of an early error
from kset_register().

Regards,
Luben

>  int kset_register(struct kset *k)
>  {