linux-kernel - Re: [PATCH -mm] call_usermodehelper: call info->init() after set_user

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Message-ID: <20100310201837.GB3770@hmsreliant.think-freely.org>
Date:	Wed, 10 Mar 2010 15:18:37 -0500
From:	Neil Horman <nhorman@...driver.com>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH -mm] call_usermodehelper: call info->init() after
 set_user_nice()

On Wed, Mar 10, 2010 at 07:44:39PM +0100, Oleg Nesterov wrote:
> Mostly cosmetic, but imho it makes sense to call sub_info->init() right
> before kernel_execve(). This looks more natural and allows ->init() hook
> to change the priority if needed.
> 
> Signed-off-by: Oleg Nesterov <oleg@...hat.com>
> ---
> 
>  kernel/kmod.c |   12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> --- mm/kernel/kmod.c~5_MOVE_INIT_DOWN	2010-03-10 17:36:37.000000000 +0100
> +++ mm/kernel/kmod.c	2010-03-10 19:40:24.000000000 +0100
> @@ -159,6 +159,11 @@ static int ____call_usermodehelper(void 
>  
>  	/* We can run anywhere, unlike our parent keventd(). */
>  	set_cpus_allowed_ptr(current, cpu_all_mask);
> +	/*
> +	 * Our parent is keventd, which runs with elevated scheduling priority.
> +	 * Avoid propagating that into the userspace child.
> +	 */
> +	set_user_nice(current, 0);
>  
>  	if (sub_info->init) {
>  		retval = sub_info->init(sub_info);
> @@ -166,14 +171,7 @@ static int ____call_usermodehelper(void 
>  			goto fail;
>  	}
>  
> -	/*
> -	 * Our parent is keventd, which runs with elevated scheduling priority.
> -	 * Avoid propagating that into the userspace child.
> -	 */
> -	set_user_nice(current, 0);
> -
>  	retval = kernel_execve(sub_info->path, sub_info->argv, sub_info->envp);
> -
>  	/* Exec failed? */
>  fail:
>  	sub_info->retval = retval;
> 
> 
> 

Sure, why not. :)

Acked-by: Neil Horman <nhorman@...driver.com>

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