Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
IronPort-SDR: YSK4tgk1LlxGNK/cPWePiSadLqj7YB+5ingjal3DtmUpHnmcIkQcCVxaIS1vs93oQR5qBkKtYm
 2z8pmfxkUh3Q==
IronPort-SDR: uyEPPLgSCDKNELgIyYb6qvYzhUNE1Jz8SxVKSdd+x1yvjeQLF/YhYhlIvTPl2PwDFFOFfU3q7M
 IuCIWf6ZDSsw==
Date:   Thu, 3 Jun 2021 12:53:19 +0300
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Tian Tao <tiantao6@hisilicon.com>
Cc:     gregkh@linuxfoundation.org, rafael@kernel.org,
        akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
        jonathan.cameron@huawei.com, song.bao.hua@hisilicon.com
Subject: Re: [PATCH v3 3/3] drivers/base/node.c: use bin_attribute to avoid
 buff overflow
Message-ID: <YLimj+KPaQ2P/cnl@smile.fi.intel.com>
References: <1622712162-7028-1-git-send-email-tiantao6@hisilicon.com>
 <1622712162-7028-4-git-send-email-tiantao6@hisilicon.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1622712162-7028-4-git-send-email-tiantao6@hisilicon.com>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
Precedence: bulk

On Thu, Jun 03, 2021 at 05:22:42PM +0800, Tian Tao wrote:
> Reading sys/devices/system/cpu/cpuX/nodeX/ returns cpumap and cpulist.
> However, the size of this file is limited to PAGE_SIZE because of the
> limitation for sysfs attribute. so we use bin_attribute instead of
> attribute to avoid NR_CPUS too big to cause buff overflow.

...

>  }
>  
> -static DEVICE_ATTR_RO(cpumap);
>  
> -static inline ssize_t cpulist_show(struct device *dev,
> -				   struct device_attribute *attr,
> -				   char *buf)
> +static BIN_ATTR_RO(cpumap, 0);

So, you will have 2 blank lines in a row after this. Why one is not enough?
Same question for other similar cases, if any.

-- 
With Best Regards,
Andy Shevchenko