linux-kernel - Re: [PATCH 1/6 RFC] arch/blackfin/kernel/process.c: Remove the BKL from sys

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Message-ID: <20091012224532.GB4711@nowhere>
Date:	Tue, 13 Oct 2009 00:45:33 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	John Kacur <jkacur@...hat.com>
Cc:	linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
	Vincent Sanders <vince@...tec.co.uk>,
	Ingo Molnar <mingo@...e.hu>,
	Christoph Hellwig <hch@...radead.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jonathan Corbet <corbet@....net>,
	Mike Frysinger <vapier@...too.org>,
	David Howells <dhowells@...hat.com>,
	Yoshinori Sato <ysato@...rs.sourceforge.jp>,
	Roman Zippel <zippel@...ux-m68k.org>,
	Greg Ungerer <gerg@...inux.org>,
	Koichi Yasutake <yasutake.koichi@...panasonic.com>
Subject: Re: [PATCH 1/6 RFC] arch/blackfin/kernel/process.c: Remove the BKL
	from sys_execve

On Tue, Oct 13, 2009 at 12:33:21AM +0200, John Kacur wrote:
> From b9b41b5a546ed0202c099f0d973da4df9aea314a Mon Sep 17 00:00:00 2001
> From: John Kacur <jkacur@...hat.com>
> Date: Mon, 12 Oct 2009 22:44:40 +0200
> Subject: [PATCH] arch/blackfin/kernel/process.c: Remove the BKL from sys_execve
> 
> This looks like a cut-and-paste job.
> For example, compare this function to sys_execve in
> arch/x86/kernel/process_64.c
> 
> and it is almost line by line the same, except the one in x86 nolonger has the
> big kernel lock. All of the functions called between the lock are generic
> and not specific to blackfin - thus, I believe it is safe to remove the
> bkl here.
> 
> Signed-off-by: John Kacur <jkacur@...hat.com>
> ---
>  arch/blackfin/kernel/process.c |    6 +-----
>  1 files changed, 1 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/blackfin/kernel/process.c b/arch/blackfin/kernel/process.c
> index 430ae39..7d9c975 100644
> --- a/arch/blackfin/kernel/process.c
> +++ b/arch/blackfin/kernel/process.c
> @@ -215,22 +215,18 @@ copy_thread(unsigned long clone_flags,
>  /*
>   * sys_execve() executes a new program.
>   */
> -
>  asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
>  {
>  	int error;
>  	char *filename;
>  	struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
>  
> -	lock_kernel();
>  	filename = getname(name);
>  	error = PTR_ERR(filename);
>  	if (IS_ERR(filename))
> -		goto out;
> +		return error;
>  	error = do_execve(filename, argv, envp, regs);
>  	putname(filename);
> - out:
> -	unlock_kernel();
>  	return error;
>  }
>  
> -- 
> 1.6.0.6
> 
> 


Yeah, there seem to be nothing to protect there.

Reviewed-by: Frederic Weisbecker <fweisbec@...il.com>

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