Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <226c4072-a3ca-a5a4-1b7f-f7104b43af03@kernel.dk>
Date:   Mon, 11 Apr 2022 10:51:28 -0600
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:91.0) Gecko/20100101
 Thunderbird/91.7.0
Subject: Re: [PATCH] cdrom: do not print info list when there is no cdrom
 device
Content-Language: en-US
To:     Enze Li <lienze@kylinos.cn>, Phillip Potter <phil@philpotter.co.uk>
Cc:     linux-kernel@vger.kernel.org, linux-block@vger.kernel.org
References: <20220408084221.1681592-1-lienze@kylinos.cn>
 <25390602-cfa0-dba3-bfbc-a35ed6b44bcf@kernel.dk>
 <20220409122530.60353fcd@asus> <YlFA7USiCtqsFvVD@equinox>
 <f74b6933-5357-6b2c-3127-7a3465dadbdf@kylinos.cn>
From:   Jens Axboe <axboe@kernel.dk>
In-Reply-To: <f74b6933-5357-6b2c-3127-7a3465dadbdf@kylinos.cn>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 4/11/22 2:41 AM, Enze Li wrote:
> 
> On 4/9/22 16:16, Phillip Potter wrote:
>> On Sat, Apr 09, 2022 at 12:25:30PM +0800, Enze Li wrote:
> 
> <snip>
> 
>>> On Fri, 8 Apr 2022 06:34:04 -0600
>>> Jens Axboe <axboe@kernel.dk> wrote:
>>>> Will this potentially break applications that parse it?
>>>>
>>> I dunno, is there any way to confirm this thing?  And if this is really
>>> a possibility, does it mean that we cannot make changes?
>>>
>> Sorry, anything that can be parsed from userspace has the potential to
>> break userspace applications. For that reason, I would have to say I
>> don't think this patch is suitable. Sure there are times it's
>> appropriate to change userspace interfaces, but I'd rather err on the
>> side of caution here. Thanks for the patch though.
>>
>> Nacked-by: Phillip Potter <phil@philpotter.co.uk>
>>
>> Regards,
>> Phil
> 
> Hi Phil,
> 
> Thanks for your review.  I got what you said. ?
> 
> In addition, I noticed that in the source file[1], there is a Todo List there.  I'm quite
> interested in it.  It says:
> ================================================
>   17 To Do List:
>   18 ----------------------------------
>   19
>   20  -- Modify sysctl/proc interface. I plan on having one directory per                 
>   21  drive, with entries for outputing general drive information, and sysctl             
>   22  based tunable parameters such as whether the tray should auto-close for             
>   23  that drive. Suggestions (or patches) for this welcome!
> ================================================
> I'd like to know if the relevant patches are still welcome?
> 
> IIUC, the TODO List says that we need to implement a modification of the
> following form:
> ----------------------------------------------------------------------------------------------------------
> $ tree /proc/sys/dev/cdrom
> /proc/sys/dev/cdrom
> |--sr0--autoclose
> |       |-autoeject
> |       |-check_media
> |       |-debug
> |       |-info
> |       |-lock
> |
> |--sr1--autoclose
> |       |-autoeject
> |       |-check_media
> |       |-debug
> |       |-info
> |       |-lock
> |
> |--sr2 ...
> .
> .
> .
> ----------------------------------------------------------------------------------------------------------
> I would appreciate it if you could give me some advice.

Let's not do that, this advice is perhaps 20 years old. /proc isn't to
be used for anything like that these days.

-- 
Jens Axboe