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Date: Tue, 19 May 2015 16:02:13 +0200
From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org, "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>, linux-kernel@vger.kernel.org,
        Dexuan Cui <decui@microsoft.com>, Ingo Molnar <mingo@kernel.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 1/2] cpu-hotplug: export
 cpu_hotplug_enable/cpu_hotplug_disable
Message-ID: <20150519140213.GB10445@potion.brq.redhat.com>
References: <1432037742-25923-1-git-send-email-vkuznets@redhat.com>
 <1432037742-25923-2-git-send-email-vkuznets@redhat.com>
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2015-05-19 14:15+0200, Vitaly Kuznetsov:
> Loaded Hyper-V module will use these functions to disable CPU hotplug
> under certain circumstances.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
>  kernel/cpu.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index 94bbe46..dc005e7 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -193,6 +193,7 @@ void cpu_hotplug_disable(void)
>  	cpu_hotplug_disabled = 1;

(I think it would be safer to make this into a counter, at least, so
  cpu_hotplug_disable() |
                        | cpu_hotplug_disable()
  cpu_hotplug_enable()  |
 wouldn't end up with enabled hotplug, when this switch is intended for
 hotplug-and-die situations.)

>  	cpu_maps_update_done();
>  }
> +EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
>  
>  void cpu_hotplug_enable(void)
>  {
> @@ -200,7 +201,7 @@ void cpu_hotplug_enable(void)
>  	cpu_hotplug_disabled = 0;
>  	cpu_maps_update_done();
>  }
> -
> +EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
>  #endif	/* CONFIG_HOTPLUG_CPU */
>  
>  /* Need to know about CPUs going up/down? */
> -- 
> 1.9.3
>