linux-kernel - Re: [PATCH] nsproxy: remove judge of timens_on

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Date:   Tue, 17 Nov 2020 23:35:40 +0800
From:   Hui Su <sh_def@....com>
To:     Andrey Vagin <avagin@...nvz.org>,
        Christian Brauner <christian.brauner@...ntu.com>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] nsproxy: remove judge of timens_on_fork()'s return val

On Tue, Nov 17, 2020 at 12:30:26AM -0800, Andrey Vagin wrote:
> On Sun, Nov 15, 2020 at 10:36 AM Hui Su <sh_def@....com> wrote:
> >
> > timens_on_fork() always return 0, and maybe not
> > need to judge the return value in copy_namespaces().
> 
> Thank you for cleaning this up. I think we can go even further and
> change timens_on_fork to return nothing:
> 
> -int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk)
> +void timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk)
>  {
>         struct ns_common *nsc = &nsproxy->time_ns_for_children->ns;
>         struct time_namespace *ns = to_time_ns(nsc);
> 
>         /* create_new_namespaces() already incremented the ref counter */
>         if (nsproxy->time_ns == nsproxy->time_ns_for_children)
> -               return 0;
> +               return;
> 
>         get_time_ns(ns);
>         put_time_ns(nsproxy->time_ns);
>         nsproxy->time_ns = ns;
> 
>         timens_commit(tsk, ns);
> -
> -       return 0;
>  }
> 
> 
> >
> > Signed-off-by: Hui Su <sh_def@....com>
> > ---
> >  kernel/nsproxy.c | 7 +------
> >  1 file changed, 1 insertion(+), 6 deletions(-)
> >
> > diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> > index 12dd41b39a7f..e2e6c5dc433f 100644
> > --- a/kernel/nsproxy.c
> > +++ b/kernel/nsproxy.c
> > @@ -153,7 +153,6 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
> >         struct nsproxy *old_ns = tsk->nsproxy;
> >         struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns);
> >         struct nsproxy *new_ns;
> > -       int ret;
> >
> >         if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
> >                               CLONE_NEWPID | CLONE_NEWNET |
> > @@ -180,11 +179,7 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
> >         if (IS_ERR(new_ns))
> >                 return  PTR_ERR(new_ns);
> >
> > -       ret = timens_on_fork(new_ns, tsk);
> > -       if (ret) {
> > -               free_nsproxy(new_ns);
> > -               return ret;
> > -       }
> > +       timens_on_fork(new_ns, tsk);
> >
> >         tsk->nsproxy = new_ns;
> >         return 0;
> > --
> > 2.29.0
> >
> >

Yeah, thank for your reply, Andrey.

I will resend PATCH V2 with makeing timens_on_fork() return nothing.

Thanks.