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Subject: Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI
To:     Jens Axboe <axboe@kernel.dk>, Kees Cook <keescook@chromium.org>
Cc:     Christoph Hellwig <hch@infradead.org>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        James Bottomley <James.Bottomley@hansenpartnership.com>,
        Tejun Heo <tj@kernel.org>, Borislav Petkov <bp@alien8.de>,
        "David S. Miller" <davem@davemloft.net>,
        "Manoj N. Kumar" <manoj@linux.vnet.ibm.com>,
        "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>,
        Uma Krishnan <ukrishn@linux.vnet.ibm.com>,
        linux-block <linux-block@vger.kernel.org>,
        linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>
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From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <e9eb326b-aa80-07a3-4579-6828f22cdad2@infradead.org>
Date:   Wed, 23 May 2018 14:20:44 -0700
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On 05/23/2018 02:14 PM, Jens Axboe wrote:
> On 5/23/18 2:52 PM, Kees Cook wrote:
>> On Wed, May 23, 2018 at 7:31 AM, Jens Axboe <axboe@kernel.dk> wrote:
>>> On 5/23/18 8:25 AM, Christoph Hellwig wrote:
>>>> On Wed, May 23, 2018 at 08:13:56AM -0600, Jens Axboe wrote:
>>>>>> Should I move to code to a new drivers/scsi/scsi_sense.c and add it to
>>>>>> drivers/scsi/Makefile as:
>>>>>>
>>>>>> obj-$(CONFIG_BLK_SCSI_REQUEST)    += scsi_sense.o
>>>>>>
>>>>>> Every place I want to use the code is already covered by
>>>>>> CONFIG_BLK_SCSI_REQUEST, so it seems like I just need to know where to
>>>>>> put the .c file. :P
>>>>>
>>>>> I think this is so much saner than a SCSI select or dependency, so I'll
>>>>> have to disagree with Martin and Christoph. Just put it in drivers/scsi,
>>>>> if it's the location they care about.
>>>>
>>>> I actually plan to remove CONFIG_BLK_SCSI_REQUEST in a merge window
>>>> or two.  The only users are scsi and the ide layer, (virtio_blk
>>>> support has already been accidentally disabled for a while), and getting
>>>> rid of it allows to to shrink and simply the scsi data structures.
>>>>
>>>> But if you want this for now lets keep scsi_sense.c in drivers/scsi
>>>> but depend on CONFIG_BLK_SCSI_REQUEST, that is easy enough to fix up.
>>>
>>> It could be a stand-alone dependency, doesn't have to be BLK_SCSI_REQUEST.
>>> BLA_SCSI_SENSE or something would do. I don't care too much about that,
>>> mostly getting rid of the entire stack dependency.
>>
>> Aaand, I can't do this and leave it in drivers/scsi because of drivers/Makefile:
>>
>> obj-$(CONFIG_SCSI)              += scsi/
>>
>> So: this needs to live in block/ just like CONFIG_BLK_SCSI_REQUEST's
>> scsi_ioctl.c. I will split it into CONFIG_BLK_SCSI_SENSE, but I'll
>> still need to move the code from drivers/scsi/ to block/. Is this
>> okay?
> 
> Ugh, so that would necessitate a change there too. As I said before,
> I don't really care where it lives. I know the SCSI folks seem bothered
> by moving it, but in reality, it's not like this stuff will likely ever
> really change. Of the two choices (select entire SCSI stack, or just move
> this little bit), I know what I would consider the saner option...
> 

or option 3:

obj-y                           += scsi/

so that make descends into drivers/scsi/ and then builds whatever is needed,
depending on individual kconfig options.

-- 
~Randy