linux-kernel - Re: [PATCH V2 15/19] selftests/resctrl: Change return type of umount

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Message-ID: <2e9ea256-cbf4-8222-c639-74479400fd77@intel.com>
Date:   Thu, 21 May 2020 11:15:15 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     "Prakhya, Sai Praneeth" <sai.praneeth.prakhya@...el.com>,
        "shuah@...nel.org" <shuah@...nel.org>,
        "skhan@...uxfoundation.org" <skhan@...uxfoundation.org>,
        "linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>
Cc:     "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>, "Luck, Tony" <tony.luck@...el.com>,
        "babu.moger@....com" <babu.moger@....com>,
        "james.morse@....com" <james.morse@....com>,
        "Shankar, Ravi V" <ravi.v.shankar@...el.com>,
        "Yu, Fenghua" <fenghua.yu@...el.com>,
        "x86@...nel.org" <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        "dan.carpenter@...cle.com" <dan.carpenter@...cle.com>,
        "dcb314@...mail.com" <dcb314@...mail.com>
Subject: Re: [PATCH V2 15/19] selftests/resctrl: Change return type of
 umount_resctrlfs() to void

Hi Sai,

On 5/21/2020 10:19 AM, Prakhya, Sai Praneeth wrote:
> Hi Reinette,
> 
>> -----Original Message-----
>> From: Reinette Chatre <reinette.chatre@...el.com>
>> Sent: Wednesday, May 20, 2020 4:52 PM
>> To: Prakhya, Sai Praneeth <sai.praneeth.prakhya@...el.com>;
>> shuah@...nel.org; skhan@...uxfoundation.org; linux-kselftest@...r.kernel.org
>> Cc: tglx@...utronix.de; mingo@...hat.com; bp@...en8.de; Luck, Tony
>> <tony.luck@...el.com>; babu.moger@....com; james.morse@....com;
>> Shankar, Ravi V <ravi.v.shankar@...el.com>; Yu, Fenghua
>> <fenghua.yu@...el.com>; x86@...nel.org; linux-kernel@...r.kernel;
>> dan.carpenter@...cle.com; dcb314@...mail.com
>> Subject: Re: [PATCH V2 15/19] selftests/resctrl: Change return type of
>> umount_resctrlfs() to void
>>
>> Hi Sai,
>>
>> On 5/18/2020 3:08 PM, Sai Praneeth Prakhya wrote:
>>> umount_resctrlfs() is used only during tear down path and there is
>>> nothing much to do if unmount of resctrl file system fails, so, all
>>> the callers of this function are not checking for the return value.
>>> Hence, change the return type of this function from int to void.
>>
>> Should the callers be ignoring the return value? From what I can tell the
>> filesystem is unmounted between test runs so I wonder if it may help if the
>> return code is used and the test exits with an appropriate error to user space for
>> possible investigation instead of attempting to run a new test on top of the
>> resctrl filesystem that could potentially be having issues at the time.
> 
> Makes sense to me to check for the return value of umount() and take appropriate
> action rather than ignoring it. But, since this might happen very rarely (I haven't
> noticed umount() failing till now), I am thinking to queue this up for cleanup series.
> What do you think?

That sounds good.

> 
> This bug fixes series will then have patches 16 and 17 because they are fixing a bug
> that could be easily noticed. Please let me know if you think otherwise.

I don't, dropping this change that makes it easy to ignore an error in
this round so that any errors could be dealt with better in a later
patch sounds good to me.

Thank you

Reinette