Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Christoph Hellwig]

On Thu, May 24, 2018 at 10:06:59AM -0700, Kees Cook wrote:
> On Thu, May 24, 2018 at 1:00 AM, Christoph Hellwig  wrote:
> > On Wed, May 23, 2018 at 03:14:19PM -0600, Jens Axboe wrote:
> >> 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...
> >
> > Oh well.  How about something like this respin of Kees' series?
> >
> > http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/sense-cleanup
> 
> Does the CONFIG_PCMCIA in drivers/scsi/Makefile now get exposed in
> weird config cases?

That just includes drivers/scsi/pcmcia/Makefile, which only
has three conditional modules in it, so it should be fine.

> Otherwise, yeah, looks good to me. Thanks!

Can you pick up my tweaks and ressend?

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Kees Cook]

On Thu, May 24, 2018 at 1:00 AM, Christoph Hellwig  wrote:
> On Wed, May 23, 2018 at 03:14:19PM -0600, Jens Axboe wrote:
>> 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...
>
> Oh well.  How about something like this respin of Kees' series?
>
> http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/sense-cleanup

Does the CONFIG_PCMCIA in drivers/scsi/Makefile now get exposed in
weird config cases?

Otherwise, yeah, looks good to me. Thanks!

-Kees

-- 
Kees Cook
Pixel Security

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Christoph Hellwig]

On Wed, May 23, 2018 at 03:14:19PM -0600, Jens Axboe wrote:
> 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...

Oh well.  How about something like this respin of Kees' series?

http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/sense-cleanup

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Christoph Hellwig]

On Wed, May 23, 2018 at 02:17:14PM -0700, Kees Cook wrote:
> 
> True, though I'm finding other robustness issues in the CDROM code.
> They're probably all insane corner cases, but it seems like it'd be
> nice to just fix them:
> 
> diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
> index 3522d2cae1b6..7726c8618c30 100644
> --- a/drivers/cdrom/cdrom.c
> +++ b/drivers/cdrom/cdrom.c
> @@ -,9 +2223,12 @@ static int cdrom_read_cdda_bpc(struct
> cdrom_device_info *cdi, __u8 __user *ubuf,
> 
> blk_execute_rq(q, cdi->disk, rq, 0);
> if (scsi_req(rq)->result) {
> -   struct request_sense *s = req->sense;
> +   struct scsi_sense_hdr sshdr;
> +
> ret = -EIO;
> -   cdi->last_sense = s->sense_key;
> +   scsi_normalize_sense(req->sense, req->sense_len,
> +);
> +   cdi->last_sense = sshdr.sense_key;
> }
> 
> if (blk_rq_unmap_user(bio))

The proper fix here is to rewrite this function to use the the
->generic_packet cdrom_device_ops method.  Is is the only caller
going straight to the scsi passthrough requests, which is a layering
violation.

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Randy Dunlap]

On 05/23/2018 02:22 PM, Jens Axboe wrote:
> On 5/23/18 3:20 PM, Randy Dunlap wrote:
>> 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  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.
> 
> Right, that was the initial option, the later two are the other options.
> 

Sorry, I'm late to the party.

-- 
~Randy

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Jens Axboe]

On 5/23/18 3:20 PM, Randy Dunlap wrote:
> 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  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.

Right, that was the initial option, the later two are the other options.

-- 
Jens Axboe

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Randy Dunlap]

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  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

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Kees Cook]

On Wed, May 23, 2018 at 2:06 PM, Martin K. Petersen
 wrote:
>
> Kees,
>
>> 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?
>
> The reason this sucks is that scsi_normalize_sense() is an inherent core
> feature in the SCSI layer. Dealing with sense data for ioctls is just a
> fringe use case.

True, though I'm finding other robustness issues in the CDROM code.
They're probably all insane corner cases, but it seems like it'd be
nice to just fix them:

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 3522d2cae1b6..7726c8618c30 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -,9 +2223,12 @@ static int cdrom_read_cdda_bpc(struct
cdrom_device_info *cdi, __u8 __user *ubuf,

blk_execute_rq(q, cdi->disk, rq, 0);
if (scsi_req(rq)->result) {
-   struct request_sense *s = req->sense;
+   struct scsi_sense_hdr sshdr;
+
ret = -EIO;
-   cdi->last_sense = s->sense_key;
+   scsi_normalize_sense(req->sense, req->sense_len,
+);
+   cdi->last_sense = sshdr.sense_key;
}

if (blk_rq_unmap_user(bio))

This code wasn't checking req->sense_len, for example. It'll just get
stale data at worst case, but it's still ugly, especially since we
have a solution to do it right.

> I don't want to get too hung up on what goes where. But architecturally
> it really irks me to move a core piece of SCSI state machine
> functionality out of the subsystem to accommodate ioctl handling.

It looks like there is more in block/scsi_ioctl.c than just ioctl
handling, which is why I put the function in there originally.
Honestly, it's almost so small I could make it a static inline. :P

> I'm traveling today so I probably won't get a chance to look closely
> until tomorrow morning.

No worries; thanks for looking at it!

-Kees

-- 
Kees Cook
Pixel Security

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Jens Axboe]

On 5/23/18 2:52 PM, Kees Cook wrote:
> On Wed, May 23, 2018 at 7:31 AM, Jens Axboe  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...

-- 
Jens Axboe

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Martin K. Petersen]

Kees,

> 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?

The reason this sucks is that scsi_normalize_sense() is an inherent core
feature in the SCSI layer. Dealing with sense data for ioctls is just a
fringe use case.

I don't want to get too hung up on what goes where. But architecturally
it really irks me to move a core piece of SCSI state machine
functionality out of the subsystem to accommodate ioctl handling.

I'm traveling today so I probably won't get a chance to look closely
until tomorrow morning.

-- 
Martin K. Petersen  Oracle Linux Engineering

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Kees Cook]

On Wed, May 23, 2018 at 7:31 AM, Jens Axboe  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?

-Kees

-- 
Kees Cook
Pixel Security

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Jens Axboe]

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.

-- 
Jens Axboe

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Christoph Hellwig]

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.

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Jens Axboe]

On 5/22/18 5:49 PM, Kees Cook wrote:
> On Tue, May 22, 2018 at 4:42 PM, Jens Axboe  wrote:
>> On May 22, 2018, at 5:31 PM, Kees Cook  wrote:
>>>
 On Tue, May 22, 2018 at 12:16 PM, Jens Axboe  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, but
>> 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 practical 
>> terms it doesn’t matter that much, since most folks would be using 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-$(CONFIG_BLK_SCSI_REQUEST)   += scsi_ioctl.o
> 
> Should I move to code to a new drivers/scsi/scsi_sense.c and add it to
> drivers/scsi/Makefile as:
> 
> obj-$(CONFIG_BLK_SCSI_REQUEST)+= 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.

-- 
Jens Axboe

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Kees Cook]

On Tue, May 22, 2018 at 4:42 PM, Jens Axboe  wrote:
> On May 22, 2018, at 5:31 PM, Kees Cook  wrote:
>>
>>> On Tue, May 22, 2018 at 12:16 PM, Jens Axboe  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, but
> 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 practical 
> terms it doesn’t matter that much, since most folks would be using 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)   += 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)+= 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

-- 
Kees Cook
Pixel Security

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Jens Axboe]

On May 22, 2018, at 5:31 PM, Kees Cook  wrote:
> 
>> On Tue, May 22, 2018 at 12:16 PM, Jens Axboe  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, but
 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 practical 
terms it doesn’t matter that much, since most folks would be using sr. I still 
think a split would be vastly superior. Just keep the scsi code in 
drivers/scsi/ and make it independently selectable.

Jens

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Randy Dunlap]

On 05/22/2018 04:39 PM, Kees Cook wrote:
> On Tue, May 22, 2018 at 4:34 PM, Randy Dunlap  wrote:
>> On 05/22/2018 04:31 PM, Kees Cook wrote:
>>> On Tue, May 22, 2018 at 12:16 PM, Jens Axboe  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, but
>> 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?
>>
>> No.  Do not select an entire subsystem.  Use depends on it instead.
> 
> I looked at that first, but it seems it's designed for that. For
> example, "config ATA" already has a "select SCSI".
> 
> It does look fishy, though, since "config SCSI" has a "depends" which
> would be ignored by "select". Luckily, all these uses already do a
> "depends on BLOCK" (directly or indirectly).

Linus has railed against selecting subsystems.  We shouldn't be adding
more IMHO, although it is difficult to get rid of ones that we already have.


-- 
~Randy

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Kees Cook]

On Tue, May 22, 2018 at 4:34 PM, Randy Dunlap  wrote:
> On 05/22/2018 04:31 PM, Kees Cook wrote:
>> On Tue, May 22, 2018 at 12:16 PM, Jens Axboe  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, but
> 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?
>
> No.  Do not select an entire subsystem.  Use depends on it instead.

I looked at that first, but it seems it's designed for that. For
example, "config ATA" already has a "select SCSI".

It does look fishy, though, since "config SCSI" has a "depends" which
would be ignored by "select". Luckily, all these uses already do a
"depends on BLOCK" (directly or indirectly).

-Kees

-- 
Kees Cook
Pixel Security

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Randy Dunlap]

On 05/22/2018 04:31 PM, Kees Cook wrote:
> On Tue, May 22, 2018 at 12:16 PM, Jens Axboe  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, but
 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?

No.  Do not select an entire subsystem.  Use depends on it instead.


> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> index ad9b687a236a..220ff321c102 100644
> --- a/drivers/block/Kconfig
> +++ b/drivers/block/Kconfig
> @@ -79,7 +79,7 @@ config GDROM
> tristate "SEGA Dreamcast GD-ROM drive"
> depends on SH_DREAMCAST
> select CDROM
> -   select BLK_SCSI_REQUEST # only for the generic cdrom code
> +   select SCSI
> help
>   A standard SEGA Dreamcast comes with a modified CD ROM drive called 
> a
>   "GD-ROM" by SEGA to signify it is capable of reading special disks
> @@ -345,7 +345,7 @@ config CDROM_PKTCDVD
> tristate "Packet writing on CD/DVD media (DEPRECATED)"
> depends on !UML
> select CDROM
> -   select BLK_SCSI_REQUEST
> +   select SCSI
> help
>   Note: This driver is deprecated and will be removed from the
>   kernel in the near future!
> diff --git a/drivers/block/paride/Kconfig b/drivers/block/paride/Kconfig
> index f8bd6ef3605a..7fdfcc5eaca5 100644
> --- a/drivers/block/paride/Kconfig
> +++ b/drivers/block/paride/Kconfig
> @@ -27,7 +27,7 @@ config PARIDE_PCD
> tristate "Parallel port ATAPI CD-ROMs"
> depends on PARIDE
> select CDROM
> -   select BLK_SCSI_REQUEST # only for the generic cdrom code
> +   select SCSI
> ---help---
>   This option enables the high-level driver for ATAPI CD-ROM devices
>   connected through a parallel port. If you chose to build PARIDE
> 
>>> but as long as that stuff just keeps working I'd rather worry about
>>> everyone else, and keep the scsi code where it belongs.
>>
>> Fine with me then, hopefully we can some day kill it off.
> 
> I'll send a v2. I found a few other things to fix up (including the
> cdrom.c one).


-- 
~Randy

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Kees Cook]

On Tue, May 22, 2018 at 12:16 PM, Jens Axboe  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, but
>>> 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?

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index ad9b687a236a..220ff321c102 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -79,7 +79,7 @@ config GDROM
tristate "SEGA Dreamcast GD-ROM drive"
depends on SH_DREAMCAST
select CDROM
-   select BLK_SCSI_REQUEST # only for the generic cdrom code
+   select SCSI
help
  A standard SEGA Dreamcast comes with a modified CD ROM drive called a
  "GD-ROM" by SEGA to signify it is capable of reading special disks
@@ -345,7 +345,7 @@ config CDROM_PKTCDVD
tristate "Packet writing on CD/DVD media (DEPRECATED)"
depends on !UML
select CDROM
-   select BLK_SCSI_REQUEST
+   select SCSI
help
  Note: This driver is deprecated and will be removed from the
  kernel in the near future!
diff --git a/drivers/block/paride/Kconfig b/drivers/block/paride/Kconfig
index f8bd6ef3605a..7fdfcc5eaca5 100644
--- a/drivers/block/paride/Kconfig
+++ b/drivers/block/paride/Kconfig
@@ -27,7 +27,7 @@ config PARIDE_PCD
tristate "Parallel port ATAPI CD-ROMs"
depends on PARIDE
select CDROM
-   select BLK_SCSI_REQUEST # only for the generic cdrom code
+   select SCSI
---help---
  This option enables the high-level driver for ATAPI CD-ROM devices
  connected through a parallel port. If you chose to build PARIDE

>> but as long as that stuff just keeps working I'd rather worry about
>> everyone else, and keep the scsi code where it belongs.
>
> Fine with me then, hopefully we can some day kill it off.

I'll send a v2. I found a few other things to fix up (including the
cdrom.c one).

Thanks!

-Kees

-- 
Kees Cook
Pixel Security

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Jens Axboe]

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, but
>> 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 :-)

> but as long as that stuff just keeps working I'd rather worry about
> everyone else, and keep the scsi code where it belongs.

Fine with me then, hopefully we can some day kill it off.

-- 
Jens Axboe

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Christoph Hellwig]

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, but
> 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,
but as long as that stuff just keeps working I'd rather worry about
everyone else, and keep the scsi code where it belongs.

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Jens Axboe]

On 5/22/18 12:59 PM, Kees Cook wrote:
> On Tue, May 22, 2018 at 11:50 AM, Martin K. Petersen
>  wrote:
>>
>> Christoph,
>>
>>> On Tue, May 22, 2018 at 11:15:09AM -0700, Kees Cook wrote:
 Both SCSI and ATAPI share the sense header. In preparation for using the
 struct scsi_sense_hdr more widely, move this into a separate header and
 move the helper function to scsi_ioctl.c which is linked with CONFIG_IDE
 by way of CONFIG_BLK_SCSI_REQUEST.
>>>
>>> Please keep the code where it is and just depend on SCSI on the legacy
>>> ide driver.  No need to do gymnastics just for a legacy case.
>>
>> Yup, I agree.
> 
> Oh, er, this was mainly done at Jens's request. Jens, can you advise?

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, but
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.

-- 
Jens Axboe

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Kees Cook]

On Tue, May 22, 2018 at 11:50 AM, Martin K. Petersen
 wrote:
>
> Christoph,
>
>> On Tue, May 22, 2018 at 11:15:09AM -0700, Kees Cook wrote:
>>> Both SCSI and ATAPI share the sense header. In preparation for using the
>>> struct scsi_sense_hdr more widely, move this into a separate header and
>>> move the helper function to scsi_ioctl.c which is linked with CONFIG_IDE
>>> by way of CONFIG_BLK_SCSI_REQUEST.
>>
>> Please keep the code where it is and just depend on SCSI on the legacy
>> ide driver.  No need to do gymnastics just for a legacy case.
>
> Yup, I agree.

Oh, er, this was mainly done at Jens's request. Jens, can you advise?

-Kees

-- 
Kees Cook
Pixel Security

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Martin K. Petersen]

Christoph,

> On Tue, May 22, 2018 at 11:15:09AM -0700, Kees Cook wrote:
>> Both SCSI and ATAPI share the sense header. In preparation for using the
>> struct scsi_sense_hdr more widely, move this into a separate header and
>> move the helper function to scsi_ioctl.c which is linked with CONFIG_IDE
>> by way of CONFIG_BLK_SCSI_REQUEST.
>
> Please keep the code where it is and just depend on SCSI on the legacy
> ide driver.  No need to do gymnastics just for a legacy case.

Yup, I agree.

-- 
Martin K. Petersen  Oracle Linux Engineering

Re: [PATCH 3/6] block: Create scsi_sense.h for SCSI and ATAPI

[Christoph Hellwig]

On Tue, May 22, 2018 at 11:15:09AM -0700, Kees Cook wrote:
> Both SCSI and ATAPI share the sense header. In preparation for using the
> struct scsi_sense_hdr more widely, move this into a separate header and
> move the helper function to scsi_ioctl.c which is linked with CONFIG_IDE
> by way of CONFIG_BLK_SCSI_REQUEST.

Please keep the code where it is and just depend on SCSI on the legacy
ide driver.  No need to do gymnastics just for a legacy case.