From: Finn Thain <hidden> Date: 2020-06-14 00:03:59
On Sat, 13 Jun 2020, Chris Boot wrote:
I no longer have the time to maintain this subsystem nor the hardware to
test patches with.
Then why not patch MAINTAINERS, and orphan it, as per usual practice?
$ git log --oneline MAINTAINERS | grep -i orphan
It also doesn't appear to have any active users so I doubt anyone will
miss it.
It's not unusual that any Linux driver written more than 5 years ago
"doesn't appear to have any active users".
If a driver has been orphaned and broken in the past, and no-one stepped
up to fix it within a reasonable period, removal would make sense. But
that's not the case here.
I haven't used this driver for a long time, but I still own PowerMacs with
firewire, and I know I'm not the only one.
It also doesn't appear to have any active users so I doubt anyone will
miss it.
It's not unusual that any Linux driver written more than 5 years ago
"doesn't appear to have any active users".
If a driver has been orphaned and broken in the past, and no-one stepped
up to fix it within a reasonable period, removal would make sense. But
that's not the case here.
I haven't used this driver for a long time, but I still own PowerMacs with
firewire, and I know I'm not the only one.
I expect that if someone finds this useful it can stick around (but
that's not my call). I just don't have the time or inclination or
hardware to be able to maintain it anymore, so someone else would have
to pick it up.
Cheers,
Chris
--
Chris Boot
bootc@boo.tc
From: Finn Thain <hidden> Date: 2020-06-14 23:29:02
On Sun, 14 Jun 2020, Chris Boot wrote:
I expect that if someone finds this useful it can stick around (but
that's not my call).
Who's call is that? If the patch had said "From: Martin K. Petersen" and
"This driver is being removed because it has the following defects..."
that would be some indication of a good-faith willingness to accept users
as developers in the spirit of the GPL, which is what you seem to be
alluding to (?).
I just don't have the time or inclination or hardware to be able to
maintain it anymore, so someone else would have to pick it up.
From: Chris Boot <hidden> Date: 2020-06-15 15:01:14
On 15/06/2020 00:28, Finn Thain wrote:
On Sun, 14 Jun 2020, Chris Boot wrote:
quoted
I expect that if someone finds this useful it can stick around (but
that's not my call).
Who's call is that? If the patch had said "From: Martin K. Petersen" and
"This driver is being removed because it has the following defects..."
that would be some indication of a good-faith willingness to accept users
as developers in the spirit of the GPL, which is what you seem to be
alluding to (?).
If you're asking me, I'd say it was martin's call:
SCSI TARGET SUBSYSTEM
M: "Martin K. Petersen" [off-list ref]
[...]
F: drivers/target/
F: include/target/
quoted
I just don't have the time or inclination or hardware to be able to
maintain it anymore, so someone else would have to pick it up.
Which is why most drivers get orphaned, right?
Sure, but that's not what Martin asked me to do, hence this patch.
--
Chris Boot
bootc@boo.tc
From: Finn Thain <hidden> Date: 2020-06-16 09:42:29
On Mon, 15 Jun 2020, Chris Boot wrote:
On 15/06/2020 00:28, Finn Thain wrote:
quoted
On Sun, 14 Jun 2020, Chris Boot wrote:
quoted
I expect that if someone finds this useful it can stick around (but
that's not my call).
Who's call is that? If the patch had said "From: Martin K. Petersen"
and "This driver is being removed because it has the following
defects..." that would be some indication of a good-faith willingness
to accept users as developers in the spirit of the GPL, which is what
you seem to be alluding to (?).
If you're asking me, I'd say it was martin's call:
quoted
SCSI TARGET SUBSYSTEM
M: "Martin K. Petersen" [off-list ref]
[...]
quoted
F: drivers/target/
F: include/target/
The question I asked you was intended to make you think. I wasn't asking
you to search MAINTAINERS for "drivers/target" (I had already done so).
Chris, you can find my name in that file too. That's because I see my role
as custodian of that particular code. That code lives in the kernel.org
tree because others put it there and because users find it useful -- not
merely because it happens to please the official glorious MAINTAINER of
said code.
If you would ask, "who's call is it to delete drivers/nubus? or
drivers/scsi/NCR5380.c?" my answer is, I have no idea.
quoted
quoted
I just don't have the time or inclination or hardware to be able to
maintain it anymore, so someone else would have to pick it up.
Which is why most drivers get orphaned, right?
Sure, but that's not what Martin asked me to do, hence this patch.
Martin said, "I'd appreciate a patch to remove it"
And Bart said, "do you want to keep this driver in the kernel tree?"
AFAICT both comments are quite ambiguous. I don't see an actionable
request, just an expression of interest from people doing their jobs.
Note well: there is no pay check associated with having a MAINTAINERS file
entry.
From: Bart Van Assche <bvanassche@acm.org> Date: 2020-06-16 14:09:02
On 2020-06-16 02:42, Finn Thain wrote:
Martin said, "I'd appreciate a patch to remove it"
And Bart said, "do you want to keep this driver in the kernel tree?"
AFAICT both comments are quite ambiguous. I don't see an actionable
request, just an expression of interest from people doing their jobs.
Note well: there is no pay check associated with having a MAINTAINERS file
entry.
Hi Finn,
As far as I know the sbp driver only has had one user ever and that user
is no longer user the sbp driver. So why to keep it in the kernel tree?
Restoring a kernel driver can be easy - the first step is a "git revert".
Thanks,
Bart.
From: Johannes Thumshirn <hidden> Date: 2020-06-16 14:14:02
On 16/06/2020 16:09, Bart Van Assche wrote:
On 2020-06-16 02:42, Finn Thain wrote:
quoted
Martin said, "I'd appreciate a patch to remove it"
And Bart said, "do you want to keep this driver in the kernel tree?"
AFAICT both comments are quite ambiguous. I don't see an actionable
request, just an expression of interest from people doing their jobs.
Note well: there is no pay check associated with having a MAINTAINERS file
entry.
Hi Finn,
As far as I know the sbp driver only has had one user ever and that user
is no longer user the sbp driver. So why to keep it in the kernel tree?
Restoring a kernel driver can be easy - the first step is a "git revert".
Why not move the driver to drivers/staging for 2 or 3 kernel releases and if
noone steps up, delete it?
Just my 2 Cents,
Johannes
From: James Bottomley <James.Bottomley@HansenPartnership.com> Date: 2020-06-16 15:34:34
On Tue, 2020-06-16 at 14:13 +0000, Johannes Thumshirn wrote:
On 16/06/2020 16:09, Bart Van Assche wrote:
quoted
On 2020-06-16 02:42, Finn Thain wrote:
quoted
Martin said, "I'd appreciate a patch to remove it"
And Bart said, "do you want to keep this driver in the kernel
tree?"
AFAICT both comments are quite ambiguous. I don't see an
actionable request, just an expression of interest from people
doing their jobs.
Note well: there is no pay check associated with having a
MAINTAINERS file
entry.
Hi Finn,
As far as I know the sbp driver only has had one user ever and that
user is no longer user the sbp driver. So why to keep it in the
kernel tree? Restoring a kernel driver can be easy - the first step
is a "git revert".
Why not move the driver to drivers/staging for 2 or 3 kernel releases
and if noone steps up, delete it?
Because that's pretty much the worst of all worlds: If the driver is
simply going orphaned it can stay where it is to avoid confusion. If
it's being removed, it's better to remove it from where it is because
that makes the patch to restore it easy to find.
Chris, the thing is this: if this driver has just one user on a stable
distro who complains about its removal six months to two years from
now, Linus will descend on us from a great height (which won't matter
to you, since you'll be long gone). This makes everyone very wary of
outright removal. If you're really, really sure it has no users, it
can be deleted, but if there's the slightest chance it has just one, it
should get orphaned.
James
From: Chris Boot <hidden> Date: 2020-06-16 18:00:09
On 16/06/2020 16:34, James Bottomley wrote:
On Tue, 2020-06-16 at 14:13 +0000, Johannes Thumshirn wrote:
quoted
On 16/06/2020 16:09, Bart Van Assche wrote:
quoted
On 2020-06-16 02:42, Finn Thain wrote:
quoted
Martin said, "I'd appreciate a patch to remove it"
And Bart said, "do you want to keep this driver in the kernel
tree?"
AFAICT both comments are quite ambiguous. I don't see an
actionable request, just an expression of interest from people
doing their jobs.
Note well: there is no pay check associated with having a
MAINTAINERS file
entry.
Hi Finn,
As far as I know the sbp driver only has had one user ever and that
user is no longer user the sbp driver. So why to keep it in the
kernel tree? Restoring a kernel driver can be easy - the first step
is a "git revert".
Why not move the driver to drivers/staging for 2 or 3 kernel releases
and if noone steps up, delete it?
Because that's pretty much the worst of all worlds: If the driver is
simply going orphaned it can stay where it is to avoid confusion. If
it's being removed, it's better to remove it from where it is because
that makes the patch to restore it easy to find.
Chris, the thing is this: if this driver has just one user on a stable
distro who complains about its removal six months to two years from
now, Linus will descend on us from a great height (which won't matter
to you, since you'll be long gone). This makes everyone very wary of
outright removal. If you're really, really sure it has no users, it
can be deleted, but if there's the slightest chance it has just one, it
should get orphaned.
My patch to delete the driver was based on Martin's original request:
https://lore.kernel.org/lkml/yq1img99d4k.fsf@ca-mkp.ca.oracle.com/
I don't especially want it to be gone, nor can I be sure there are no
users of what is as far as I can tell a working piece of code. I can
tell you that I never hear about it (other than the odd patch), whereas
I do get emails out of the blue for some of my other (much smaller)
stuff which clearly has users. I'd be just as happy for this to be
orphaned or for nothing to happen to it.
Honestly, I am totally ambivalent as to what happens to this code.
Martin, however, clearly cares enough to have asked me to supply a patch
to remove it.
Cheers,
Chris
--
Chris Boot
bootc@boo.tc
From: Finn Thain <hidden> Date: 2020-06-17 02:07:54
On Tue, 16 Jun 2020, Bart Van Assche wrote:
As far as I know the sbp driver only has had one user ever and that user
is no longer user the sbp driver.
So, you estimate the userbase at zero. Can you give a confidence level?
Actual measurement is hard because when end users encounter breakage, they
look for quick workarounds before they undertake post mortem, log
collection, bug reporting, mailing list discussions, analysis etc.
So why to keep it in the kernel tree?
Answer: for the same reason it was added to the tree.
Here's a different question: "Why remove it from the kernel tree?"
If maintaining this code is a burden, is it not the kind of tax that all
developers/users pay to all developers/users? Does this driver impose an
unreasonably high burden for some reason?
The growth of a maintenance burden in general has lead to the invention of
design patterns and tooling to minize it. So a good argument for removal
would describe the nature of the problem, because some driver deficiencies
can be fixed automatically, and some tooling deficiencies can compound an
otherwise insignificant or common driver deficiency.
There are spin-off benefits from legacy code besides process improvements.
Building and testing this sort of code has regularly revealed erroneous
corner cases in commits elsewhere like API changes and refactoring.
Also, legacy code is used by new developers get experience in code
modernization. And it provides more training material for neural networks
that need to be taught to recognize patches that raise quality.
Ten or twenty years ago, I doubt that anyone predicted these (and other)
spin-off benefits. If we can't predict the benefit, how will we project
the cost, and use that to justify deletion?
Please see also,
http://www.mac.linux-m68k.org/docs/obsolete.php
From: Bart Van Assche <bvanassche@acm.org> Date: 2021-01-04 17:44:43
On 6/16/20 7:07 PM, Finn Thain wrote:
On Tue, 16 Jun 2020, Bart Van Assche wrote:
quoted
As far as I know the sbp driver only has had one user ever and that user
is no longer user the sbp driver.
So, you estimate the userbase at zero. Can you give a confidence level?
Actual measurement is hard because when end users encounter breakage, they
look for quick workarounds before they undertake post mortem, log
collection, bug reporting, mailing list discussions, analysis etc.
(replying to an e-mail from six months ago)
Hi Finn,
I am confident that my estimate is an accurate estimate since I have not
seen any sbp support requests, sbp bug reports nor any sbp bug fixes since
the sbp target driver has been accepted upstream.
Here's a different question: "Why remove it from the kernel tree?"
If maintaining this code is a burden, is it not the kind of tax that all
developers/users pay to all developers/users? Does this driver impose an
unreasonably high burden for some reason?
Yes. If anyone wants to change the interface between SCSI target core and
SCSI target drivers, all target drivers, including the sbp and FCoE target
driver have to be retested. In other words, keeping unused target drivers
inside the kernel tree involves a significant maintenance burden for anyone
who wants to modify the interface between the SCSI target core and SCSI
target drivers.
Additionally, there is a good alternative available for the sbp driver.
Every system I know of that is equipped with a Firewire port also has an
Ethernet port. So users who want to provide SCSI target functionality on
such systems can use any SCSI transport protocol that is compatible with
Ethernet (iSCSI, iSER over soft-RoCE, SRP over soft-RoCE, ...).
Thanks,
Bart.
From: Finn Thain <hidden> Date: 2021-01-04 22:51:03
On Mon, 4 Jan 2021, Bart Van Assche wrote:
On 6/16/20 7:07 PM, Finn Thain wrote:
quoted
On Tue, 16 Jun 2020, Bart Van Assche wrote:
quoted
As far as I know the sbp driver only has had one user ever and that
user is no longer user the sbp driver.
So, you estimate the userbase at zero. Can you give a confidence
level? Actual measurement is hard because when end users encounter
breakage, they look for quick workarounds before they undertake post
mortem, log collection, bug reporting, mailing list discussions,
analysis etc.
(replying to an e-mail from six months ago)
Hi Finn,
I am confident that my estimate is an accurate estimate since I have not
seen any sbp support requests, sbp bug reports nor any sbp bug fixes
since the sbp target driver has been accepted upstream.
That suggests to me that the code that you're hoping to remove 1) has no
bugs, or 2) has no reported bugs, or 3) has no users at present.
I am confident that your evidence does not support your conclusion (i.e.
the code will never be used again).
Sometimes, users only appear after the unreported bugs get fixed. I've
seen it happen.
quoted
Here's a different question: "Why remove it from the kernel tree?"
If maintaining this code is a burden, is it not the kind of tax that
all developers/users pay to all developers/users? Does this driver
impose an unreasonably high burden for some reason?
Yes. If anyone wants to change the interface between SCSI target core
and SCSI target drivers, all target drivers, including the sbp and FCoE
target driver have to be retested.
I'm unaware of such an obligation. API changes happen often. When they do,
we see good test coverage of commercially viable hardware, some
best-effort testing of common hardware, and some perfunctory build
testing.
But that is missing the point, which was about a particular driver, not
about development process. You have not shown how the target API is
special, to support your claim that this driver imposes an unreasonable
burden.
In the interests of making forward progress in this discussion, shall we
discuss the kind of SCSI Target API changes that you anticipate?
In other words, keeping unused target drivers inside the kernel tree
involves a significant maintenance burden for anyone who wants to modify
the interface between the SCSI target core and SCSI target drivers.
Keeping _any_ driver in the kernel involves a maintenance burden. There
are two good ways to address that.
Firstly, by improving the development process. For example, an API change
is mostly mechanical work that lends itself to automated refactoring.
Secondly, by involving all interested parties, so that the burden is
shared.
Of course, there are other ways. E.g. "don't ship code when doing so won't
turn a profit". That, by the way, was the policy that gave us 10 billion
Android devices (or more) that don't function with a mainline kernel.
Additionally, there is a good alternative available for the sbp driver.
Every system I know of that is equipped with a Firewire port also has an
Ethernet port. So users who want to provide SCSI target functionality on
such systems can use any SCSI transport protocol that is compatible with
Ethernet (iSCSI, iSER over soft-RoCE, SRP over soft-RoCE, ...).
Ethernet is not always an alternative. That was already discussed in this
thread. But let's assume for a moment that you can migrate any and all
users of this driver over to an ethernet driver.
Why would the maintainers of that ethernet driver and its API accept that
plan, if adding users would extend their maintenance and testing
obligations? Do you think those maintainers should pay the "kind of tax
that all developers/users pay to all developers/users?"
From: Bart Van Assche <bvanassche@acm.org> Date: 2021-01-05 01:48:51
On 1/4/21 2:50 PM, Finn Thain wrote:
On Mon, 4 Jan 2021, Bart Van Assche wrote:
quoted
Additionally, there is a good alternative available for the sbp driver.
Every system I know of that is equipped with a Firewire port also has an
Ethernet port. So users who want to provide SCSI target functionality on
such systems can use any SCSI transport protocol that is compatible with
Ethernet (iSCSI, iSER over soft-RoCE, SRP over soft-RoCE, ...).
Ethernet is not always an alternative. That was already discussed in this
thread. But let's assume for a moment that you can migrate any and all
users of this driver over to an ethernet driver.
Why would the maintainers of that Ethernet driver and its API accept that
plan, if adding users would extend their maintenance and testing
obligations? Do you think those maintainers should pay the "kind of tax
that all developers/users pay to all developers/users?"
Hi Finn,
I cannot speak in the name of the iSCSI over TCP/IP or iSER driver
maintainers. But since I maintain the SRP initiator and target kernel
drivers myself, I can state that I would be happy to help SBP target users
(if that driver has any users today) to switch from SCSI over Firewire to
SCSI over SRP over RoCE or even NVMEoF over TCP.
Thanks,
Bart.