Re: [PATCH 5/6] ibmvscsi: Remove unsupported host config MAD and sysfs interface

From	Tyrel Datwyler <turtle.in.the.kernel@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 5/6] ibmvscsi: Remove unsupported host config MAD and sysfs interface
Date	2016-02-04 18:50 +0100
Message-ID	<qYwcy-5aH-23@gated-at.bofh.it> (permalink)
References	<qYf24-oH-53@gated-at.bofh.it> <qYf24-oH-51@gated-at.bofh.it> <qYn9f-5Wd-1@gated-at.bofh.it>
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On 02/04/2016 12:03 AM, Johannes Thumshirn wrote:
> On Wed, Feb 03, 2016 at 05:28:33PM -0600, Tyrel Datwyler wrote:
>> A VIOSRP_HOST_CONFIG_TYPE management datagram (MAD) has existed in
>> the code for some time. From what information I've gathered from
>> Brian King this was likely implemented on the host side in a SLES 9
>> based VIOS, which is no longer supported anywhere. Further, it is
>> not defined in PAPR or supported by any AIX based VIOS.
>>
>> Treating as bit rot and removing the sysfs interface and associated
>> host config code accordingly.
> 
> Doesn't removing a sysfs interface potentially break userspace code?
> 

In the general case yes, but I feel in this case no. First, Reading from
this config attribute of a vscsi host adapter always returns nothing.
Second, any userspace code using this attribute better be checking for
the existence of config. Just a quick look for
/sys/class/scsi_host/host*/config under other host adapters on my system
I find that attribute doesn't exist for any of them.

If there is truly enough concern that somebody may actually be accessing
this useless attribute from userspace then we can still strip out the
unsupported code, but leave the attribute and return nothing directly
from the show function.

-Tyrel

Thread

[PATCH 5/6] ibmvscsi: Remove unsupported host config MAD and sysfs interface Tyrel Datwyler <tyreld@linux.vnet.ibm.com> - 2016-02-04 00:30 +0100
  Re: [PATCH 5/6] ibmvscsi: Remove unsupported host config MAD and  sysfs interface Johannes Thumshirn <jthumshirn@suse.de> - 2016-02-04 09:10 +0100
    Re: [PATCH 5/6] ibmvscsi: Remove unsupported host config MAD and  sysfs interface Tyrel Datwyler <turtle.in.the.kernel@gmail.com> - 2016-02-04 18:50 +0100
      Re: [PATCH 5/6] ibmvscsi: Remove unsupported host config MAD and  sysfs interface Johannes Thumshirn <jthumshirn@suse.de> - 2016-02-05 09:40 +0100

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