linux-kernel - Re: [PATCH] arch/x86/kernel/microcode_core.c: add missing platform_device

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Date:	Wed, 24 Aug 2011 17:44:08 +0200 (CEST)
From:	Julia Lawall <julia@...u.dk>
To:	Borislav Petkov <bp@...64.org>
Cc:	Tigran Aivazian <tigran@...azian.fsnet.co.uk>,
	kernel-janitors@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arch/x86/kernel/microcode_core.c: add missing
 platform_device_unregister

On Wed, 24 Aug 2011, Borislav Petkov wrote:

> On Wed, Aug 24, 2011 at 05:10:52PM +0200, Julia Lawall wrote:
> > From: Julia Lawall <julia@...u.dk>
> > 
> > Call platform_device_unregister as in the previous error-handling code.
> > 
> > Signed-off-by: Julia Lawall <julia@...u.dk>
> > 
> > ---
> > This is not tested, but I couldn't see how else platform_device_unregister
> > could be called.
> > 
> >  arch/x86/kernel/microcode_core.c |    4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c
> > index f924280..1872a3a 100644
> > --- a/arch/x86/kernel/microcode_core.c
> > +++ b/arch/x86/kernel/microcode_core.c
> > @@ -532,8 +532,10 @@ static int __init microcode_init(void)
> >  	}
> >  
> >  	error = microcode_dev_init();
> > -	if (error)
> > +	if (error) {
> > +		platform_device_unregister(microcode_pdev);
> >  		return error;
> > +	}
> >  
> >  	register_syscore_ops(&mc_syscore_ops);
> >  	register_hotcpu_notifier(&mc_cpu_notifier);
> 
> I guess the most sensible thing to do here is to convert this to the
> classic goto with labels kernel style:
> 
> 	...
> 	error = sysdev_driver_register(..);
> 	mutex_unlock(&microcode_mutex);
> 	put_online_cpus();
> 	if (error)
> 		goto err_sysdev;
> 
> 	error = microcode_dev_init();
> 	if (error)
> 		goto err_dev;
> 
> 	...
> 
> err_dev:
>         get_online_cpus();
>         mutex_lock(&microcode_mutex);
> 
>         sysdev_driver_unregister(&cpu_sysdev_class, &mc_sysdev_driver);
> 
>         mutex_unlock(&microcode_mutex);
>         put_online_cpus();
> 
> 
> err_sysdev:
> 	platform_device_unregister(microcode_pdev);
> 
> out:
> 	return err;
> 
> or something to that effect.

That seems like a fairly big change.  Is it desirable to move the calls to 
sysdev_driver_register and microcode_dev_init up over the get_online_cpus 
... put_online_cpus sequence?

julia
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