linux-kernel - RE: [PATCH] sysfs: Remove page boundary align limitation on sysfs_emit and sysfs_emit

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Message-ID: <DM6PR12MB4250302F4EB80233D5807CB6FBD49@DM6PR12MB4250.namprd12.prod.outlook.com>
Date:   Wed, 8 Sep 2021 12:52:43 +0000
From:   "Yu, Lang" <Lang.Yu@....com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC:     Joe Perches <joe@...ches.com>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] sysfs: Remove page boundary align limitation on
 sysfs_emit and sysfs_emit_at

[AMD Official Use Only]

Thanks for your reply.
Just curious if we don't put such a limitation, what are the consequences?
If we remove the limitation, sys_emit/sys_emit_at api will be more flexible.
Since the comments of  sysfs_emit/ sys_emit_at api are  
" sysfs_emit - scnprintf equivalent, aware of PAGE_SIZE buffer. ",
Why not make them more equivalent with scnprintf?

Regards,
Lang  

>-----Original Message-----
>From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
>Sent: Wednesday, September 8, 2021 8:32 PM
>To: Yu, Lang <Lang.Yu@....com>
>Cc: Joe Perches <joe@...ches.com>; Rafael J . Wysocki <rafael@...nel.org>;
>linux-kernel@...r.kernel.org
>Subject: Re: [PATCH] sysfs: Remove page boundary align limitation on sysfs_emit
>and sysfs_emit_at
>
>On Wed, Sep 08, 2021 at 08:07:23PM +0800, Lang Yu wrote:
>> The key purpose of sysfs_emit and sysfs_emit_at is to ensure that no
>> overrun is done. Make them more equivalent with scnprintf.
>
>That's not the only purpose.
>
>So why are you changing this?
>
>What in-kernel users are being tripped up by this, shouldn't we fix them instead?
>
>Remember, sysfs files are "one value per file", so why are the boundries not
>properly set here?
>
>thanks,
>
>greg k-h