linux-kernel - Re: [PATCH v4 3/3] cred: change keyctl_session_to_parent() to use task_work

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Message-ID: <20120417163606.GC14527@redhat.com>
Date:	Tue, 17 Apr 2012 18:36:06 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	David Howells <dhowells@...hat.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Alexander Gordeev <agordeev@...hat.com>,
	Chris Zankel <chris@...kel.net>,
	David Smith <dsmith@...hat.com>,
	"Frank Ch. Eigler" <fche@...hat.com>,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Larry Woodman <lwoodman@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Tejun Heo <tj@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/3] cred: change keyctl_session_to_parent() to use
	task_work_add()

On 04/17, David Howells wrote:
>
> Oleg Nesterov <oleg@...hat.com> wrote:
>
> > -	int ret;
> > +	struct cred *cred;
> > +	int err;
>
> There's no need to change ret to be err.  It produces slightly less churn if
> you don't.

OK, I'll change it back.

>
> > +	err = -ENOMEM;
> > +	newwork = kmalloc(sizeof(struct task_work), GFP_KERNEL);
> > +	if (!newwork)
> > +		goto error_keyring;
>
> This passes unnecessarily through kfree(newwork).

but harmless, newwork == NULL in this case,

> Please add a new goto label
> and go to that.

OK, probably this is more clear, will do.

> > -/*
> > - * Replace a process's session keyring on behalf of one of its children when
> > - * the target  process is about to resume userspace execution.
> > - */
>
> Please don't delete the banner comment saying what the function does.

OOPS, sorry, this was unintentional.

> > -void key_replace_session_keyring(void)
> > +void key_change_session_keyring(struct task_work *twork)
>
> There's no particular need to change the name of the function.

There is.

Until we cleanup arch/* do_notify_resume() still does

	if (current->replacement_session_keyring)
		key_replace_session_keyring();

Oleg.

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