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From:   Kees Cook <keescook@chromium.org>
Date:   Tue, 22 May 2018 16:49:58 -0700
Message-ID: <CAGXu5jJsGWDsZNDJvUUqncSaAcvond_B_J7=BbvVW0X3r6Sxww@mail.gmail.com>
Subject: Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI
To:     Jens Axboe <axboe@kernel.dk>
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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On Tue, May 22, 2018 at 4:42 PM, Jens Axboe <axboe@kernel.dk> wrote:
> On May 22, 2018, at 5:31 PM, Kees Cook <keescook@chromium.org> wrote:
>>
>>> On Tue, May 22, 2018 at 12:16 PM, Jens Axboe <axboe@kernel.dk> wrote:
>>>> On 5/22/18 1:13 PM, Christoph Hellwig wrote:
>>>>> On Tue, May 22, 2018 at 01:09:41PM -0600, Jens Axboe wrote:
>>>>> I think Martin and Christoph are objecting to moving the code to
>>>>> block/scsi_ioctl.h. I don't care too much about where the code is, bu=
t
>>>>> think it would be nice to have the definitions in a separate header. =
But
>>>>> if they prefer just pulling in all of SCSI for it, well then I guess
>>>>> it's pointless to move the header bits. Seems very heavy handed to me=
,
>>>>> though.
>>>>
>>>> It might be heavy handed for the 3 remaining users of drivers/ide,
>>>
>>> Brutal :-)
>>
>> Heh. I noticed a similar sense buffer use in drivers/cdrom/cdrom.c
>> too. Is this okay under the same considerations?
>
> This is going from somewhat crazy to pretty nuts, imho. I guess in practi=
cal terms it doesn=E2=80=99t matter that much, since most folks would be us=
ing sr. I still think a split would be vastly superior. Just keep the scsi =
code in drivers/scsi/ and make it independently selectable.

I had originally tied it to BLK_SCSI_REQUEST. Logically speaking,
sense buffers are part of the request, and the CONFIG work is already
done. This is roughly what I tried to do before, since scsi_ioctl.c is
the only code pulled in for CONFIG_BLK_SCSI_REQUEST:

$ git grep BLK_SCSI_REQUEST | grep Makefile
block/Makefile:obj-$(CONFIG_BLK_SCSI_REQUEST)   +=3D scsi_ioctl.o

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)    +=3D 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

-Kees

--=20
Kees Cook
Pixel Security