linux-kernel - Re: [PATCH 20/25] x86/mcheck: Be prepared for a rollback back to the ONLINE state

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Message-ID: <20161107103219.sm4otwhwptzckvzh@pd.tnic>
Date:   Mon, 7 Nov 2016 11:32:19 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:     linux-kernel@...r.kernel.org, rt@...utronix.de,
        Tony Luck <tony.luck@...el.com>, linux-edac@...r.kernel.org,
        x86@...nel.org, Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 20/25] x86/mcheck: Be prepared for a rollback back to the
 ONLINE state

On Thu, Nov 03, 2016 at 03:50:16PM +0100, Sebastian Andrzej Siewior wrote:
> If we try a CPU down and fail in the middle then we roll back to the
> online state. This  means we would perform CPU_ONLINE()
> without invoking CPU_DEAD() for the cleanup of what was allocated in

Are CPU_ONLINE() and CPU_DEAD() functions? Those are the states, right?

> CPU_ONLINE.
> Be prepared for this and don't allocate the struct if we have it
> already.
> 
> Cc: Tony Luck <tony.luck@...el.com>
> Cc: Borislav Petkov <bp@...en8.de>
> Cc: linux-edac@...r.kernel.org
> Cc: x86@...nel.org
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> ---
>  arch/x86/kernel/cpu/mcheck/mce.c     | 4 ++++
>  arch/x86/kernel/cpu/mcheck/mce_amd.c | 3 +++
>  2 files changed, 7 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index a7fdf453d895..e9ffd6d9e32d 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -2409,6 +2409,10 @@ static int mce_device_create(unsigned int cpu)
>  	if (!mce_available(&boot_cpu_data))
>  		return -EIO;
>  
> +	dev = per_cpu(mce_device, cpu);
> +	if (dev)
> +		return 0;
> +
>  	dev = kzalloc(sizeof *dev, GFP_KERNEL);
>  	if (!dev)
>  		return -ENOMEM;
> diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
> index 55cd018bc1ae..3e529fd747f8 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
> @@ -1097,6 +1097,9 @@ static int threshold_create_device(unsigned int cpu)
>  	struct threshold_bank **bp;
>  	int err = 0;
>  
> +	bp = per_cpu(threshold_banks, cpu);
> +	if (bp)
> +		return 0;

<--- newline here.

>  	bp = kzalloc(sizeof(struct threshold_bank *) * mca_cfg.banks,
>  		     GFP_KERNEL);
>  	if (!bp)
> -- 
> 2.10.2
> 
> 

-- 
Regards/Gruss,
    Boris.

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