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From: Qais Yousef <qais.yousef@arm•com>
To: shuo.a.liu@intel•com
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
	linux-kernel@vger•kernel.org, linux-next@vger•kernel.org,
	Randy Dunlap <rdunlap@infradead•org>,
	Stephen Rothwell <sfr@canb•auug.org.au>,
	Thomas Gleixner <tglx@linutronix•de>
Subject: Re: [PATCH RESEND v2 2/2] virt: acrn: Make remove_cpu sysfs invisible with !CONFIG_HOTPLUG_CPU
Date: Tue, 23 Feb 2021 15:25:30 +0000	[thread overview]
Message-ID: <20210223152530.y2qfyozdaowmfcat@e107158-lin> (raw)
In-Reply-To: <20210221134339.57851-2-shuo.a.liu@intel.com>

On 02/21/21 21:43, shuo.a.liu@intel•com wrote:
> From: Shuo Liu <shuo.a.liu@intel•com>
> 
> Without cpu hotplug support, vCPU cannot be removed from a Service VM.
> Don't expose remove_cpu sysfs when CONFIG_HOTPLUG_CPU disabled.
> 
> Signed-off-by: Shuo Liu <shuo.a.liu@intel•com>
> Acked-by: Randy Dunlap <rdunlap@infradead•org> # build-tested
> Cc: Stephen Rothwell <sfr@canb•auug.org.au>
> Cc: Thomas Gleixner <tglx@linutronix•de>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation•org>
> Cc: Qais Yousef <qais.yousef@arm•com>
> ---
>  drivers/virt/acrn/hsm.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/virt/acrn/hsm.c b/drivers/virt/acrn/hsm.c
> index 1f6b7c54a1a4..6996ea6219e5 100644
> --- a/drivers/virt/acrn/hsm.c
> +++ b/drivers/virt/acrn/hsm.c
> @@ -404,6 +404,14 @@ static ssize_t remove_cpu_store(struct device *dev,
>  }
>  static DEVICE_ATTR_WO(remove_cpu);
>  
> +static umode_t acrn_attr_visible(struct kobject *kobj, struct attribute *a, int n)
> +{
> +       if (a == &dev_attr_remove_cpu.attr)
> +               return IS_ENABLED(CONFIG_HOTPLUG_CPU) ? a->mode : 0;
> +
> +       return a->mode;
> +}
> +

I can't find this code in Linus' master. But this looks fine from my narrow
PoV. Protecting the attribute with ifdef CONFIG_HOTPLUG_CPU is easier to read
for me, but this doesn't mean this approach is not fine.

Thanks

--
Qais Yousef

>  static struct attribute *acrn_attrs[] = {
>  	&dev_attr_remove_cpu.attr,
>  	NULL
> @@ -411,6 +419,7 @@ static struct attribute *acrn_attrs[] = {
>  
>  static struct attribute_group acrn_attr_group = {
>  	.attrs = acrn_attrs,
> +	.is_visible = acrn_attr_visible,
>  };
>  
>  static const struct attribute_group *acrn_attr_groups[] = {
> -- 
> 2.28.0
> 

next prev parent reply	other threads:[~2021-02-23 15:26 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-21 13:43 [PATCH RESEND v2 1/2] cpu/hotplug: Fix build error of using {add,remove}_cpu() with !CONFIG_SMP shuo.a.liu
2021-02-21 13:43 ` [PATCH RESEND v2 2/2] virt: acrn: Make remove_cpu sysfs invisible with !CONFIG_HOTPLUG_CPU shuo.a.liu
2021-02-23 15:25   ` Qais Yousef [this message]
2021-02-24  1:11     ` Shuo A Liu
2021-02-23 15:10 ` [PATCH RESEND v2 1/2] cpu/hotplug: Fix build error of using {add,remove}_cpu() with !CONFIG_SMP Qais Yousef

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