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Subject: Re: [PATCH -v3 1/7] kexec jump: clean up #ifdef and comments
From: Huang Ying <ying.huang@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Pavel Machek <pavel@ucw.cz>,
       nigel@nigel.suspend2.net, "Rafael J. Wysocki" <rjw@sisk.pl>,
       Vivek Goyal <vgoyal@redhat.com>, mingo@elte.hu,
       Linus Torvalds <torvalds@linux-foundation.org>,
       linux-kernel@vger.kernel.org,
       Kexec Mailing List <kexec@lists.infradead.org>
In-Reply-To: <20080812204900.db63deaa.akpm@linux-foundation.org>
References: <1218510861.24951.40.camel@caritas-dev.intel.com>
	 <20080812204900.db63deaa.akpm@linux-foundation.org>
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Date: Wed, 13 Aug 2008 12:44:49 +0800
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On Tue, 2008-08-12 at 20:49 -0700, Andrew Morton wrote:
> On Tue, 12 Aug 2008 11:14:21 +0800 Huang Ying <ying.huang@intel.com> wrote:
> 
> >  	xchg(&kexec_lock, 0);
> 
> kernel/kexec.c: In function 'kernel_kexec':
> kernel/kexec.c:1501: warning: value computed is not used
> 
> Is there any reason why we cannot use the more conventional
> test_and_set_bit() etc, rather than this peculiarity?
> 
> Or perhaps spin_trylock?

Hi, Andrew,

I think it is of no problem to replace xchg() with test_and_set_bit() or
spin_trylock().

Hi, Eric,

Do you have some reason to use xchg() instead of others?

Best Regards,
Huang Ying