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From: Johannes Thumshirn <jthumshirn@suse.de>
To: Tyrel Datwyler <turtle.in.the.kernel@gmail.com>
Cc: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
	martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
	JBottomley@odin.com, linux-kernel@vger.kernel.org, hare@suse.de,
	brking@linux.vnet.ibm.com, nfont@linux.vnet.ibm.com,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 5/6] ibmvscsi: Remove unsupported host config MAD and sysfs interface
Date: Fri, 5 Feb 2016 09:34:13 +0100	[thread overview]
Message-ID: <20160205083413.GF27969@c203.arch.suse.de> (raw)
In-Reply-To: <56B38EE7.6060102@gmail.com>

On Thu, Feb 04, 2016 at 09:48:23AM -0800, Tyrel Datwyler wrote:
> 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.

Which is what I kinda prefer. Slowly deprecate and phase out, but don't break
userspace. You never know who is writing some obscure piece of code relaying on
some sysfs attribute.

Thanks,
	Johannes

-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850

  reply	other threads:[~2016-02-05  8:34 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-03 23:28 [PATCH 0/6] ibmvscsi: code cleanup Tyrel Datwyler
2016-02-03 23:28 ` [PATCH 1/6] ibmvscsi: Correct values for several viosrp_crq_format enums Tyrel Datwyler
2016-02-04  8:38   ` Johannes Thumshirn
2016-02-04  8:38     ` Johannes Thumshirn
2016-02-03 23:28 ` [PATCH 2/6] ibmvscsi: Add and use enums for valid CRQ header values Tyrel Datwyler
2016-02-04  8:39   ` Johannes Thumshirn
2016-02-04 19:55   ` Manoj Kumar
2016-02-04 21:25     ` Tyrel Datwyler
2016-02-09 17:41       ` Manoj Kumar
2016-02-09 18:27         ` Tyrel Datwyler
2016-02-03 23:28 ` [PATCH 3/6] ibmvscsi: Replace magic values in set_adpater_info() with defines Tyrel Datwyler
2016-02-04  8:44   ` Johannes Thumshirn
2016-02-04  8:44     ` Johannes Thumshirn
2016-02-03 23:28 ` [PATCH 4/6] ibmvscsi: Use of_root to access OF device tree root node Tyrel Datwyler
2016-02-04  8:45   ` Johannes Thumshirn
2016-02-04  8:45     ` Johannes Thumshirn
2016-02-03 23:28 ` [PATCH 5/6] ibmvscsi: Remove unsupported host config MAD and sysfs interface Tyrel Datwyler
2016-02-04  8:03   ` Johannes Thumshirn
2016-02-04 17:48     ` Tyrel Datwyler
2016-02-05  8:34       ` Johannes Thumshirn [this message]
2016-02-03 23:28 ` [PATCH 6/6] ibmvscsi: Add endian conversions to sysfs attribute show functions Tyrel Datwyler
2016-02-04  8:45   ` Johannes Thumshirn

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