[PATCH] net/802/Makefile

[PATCH] net/802/Makefile

[Olaf Hering]

Hi,

the build stops when cl2llc.c has no write permissions.

diff -urN linuxppc_2_4/net/802/Makefile.broken linuxppc_2_4/net/802/Makefile
--- linuxppc_2_4/net/802/Makefile.broken        Mon Nov 26 13:28:56 2001
+++ linuxppc_2_4/net/802/Makefile       Mon Nov 26 13:51:10 2001
@@ -57,4 +57,5 @@
 include $(TOPDIR)/Rules.make
 
 cl2llc.c: cl2llc.pre
+       chmod u+w cl2llc.c
        sed -f ./pseudo/opcd2num.sed cl2llc.pre >cl2llc.c



Gruss Olaf

-- 
 $ man clone

BUGS
       Main feature not yet implemented...

Re: [PATCH] net/802/Makefile

[Olaf Hering]

On Mon, Nov 26, Olaf Hering wrote:

> Hi,
> 
> the build stops when cl2llc.c has no write permissions.

Here is a better version, suggested by Rik:

diff -urN linuxppc_2_4/net/802/Makefile.broken
linuxppc_2_4/net/802/Makefile
--- linuxppc_2_4/net/802/Makefile.broken        Mon Nov 26 13:28:56 2001
+++ linuxppc_2_4/net/802/Makefile       Mon Nov 26 14:22:55 2001
@@ -57,4 +57,6 @@
 include $(TOPDIR)/Rules.make
 
 cl2llc.c: cl2llc.pre
+       touch cl2llc.c
+       chmod u+w cl2llc.c
        sed -f ./pseudo/opcd2num.sed cl2llc.pre >cl2llc.c



Gruss Olaf

-- 
 $ man clone

BUGS
       Main feature not yet implemented...

Re: [PATCH] net/802/Makefile

[Christoph Hellwig]

In article <20011126142425.B27554@suse.de> you wrote:
> On Mon, Nov 26, Olaf Hering wrote:
>> 
>> the build stops when cl2llc.c has no write permissions.
>
> Here is a better version, suggested by Rik:

What about just removing cl2llc.c from the tarball?

	Christoph

-- 
Of course it doesn't work. We've performed a software upgrade.

Re: [PATCH] net/802/Makefile

[Keith Owens]

On Mon, 26 Nov 2001 14:32:26 +0100, 
Christoph Hellwig <hch@ns.caldera.de> wrote:
>In article <20011126142425.B27554@suse.de> you wrote:
>> On Mon, Nov 26, Olaf Hering wrote:
>>> 
>>> the build stops when cl2llc.c has no write permissions.
>>
>> Here is a better version, suggested by Rik:
>
>What about just removing cl2llc.c from the tarball?

I was going to do that but AC said that all of net/802 was being
rewritten and removing cl2llc.c now would just be noise.  The file will
be removed in kbuild 2.5.

Re: [PATCH] net/802/Makefile

[Andreas Schwab]

Olaf Hering <olh@suse.de> writes:

|> On Mon, Nov 26, Olaf Hering wrote:
|> 
|> > Hi,
|> > 
|> > the build stops when cl2llc.c has no write permissions.
|> 
|> Here is a better version, suggested by Rik:
|> 
|> diff -urN linuxppc_2_4/net/802/Makefile.broken
|> linuxppc_2_4/net/802/Makefile
|> --- linuxppc_2_4/net/802/Makefile.broken        Mon Nov 26 13:28:56 2001
|> +++ linuxppc_2_4/net/802/Makefile       Mon Nov 26 14:22:55 2001
|> @@ -57,4 +57,6 @@
|>  include $(TOPDIR)/Rules.make
|>  
|>  cl2llc.c: cl2llc.pre
|> +       touch cl2llc.c
|> +       chmod u+w cl2llc.c
|>         sed -f ./pseudo/opcd2num.sed cl2llc.pre >cl2llc.c

How about this:

@@ -57,4 +57,5 @@
 include $(TOPDIR)/Rules.make
 
 cl2llc.c: cl2llc.pre
+	rm -f cl2llc.c
 	sed -f ./pseudo/opcd2num.sed cl2llc.pre >cl2llc.c
 
 
Andreas.

-- 
Andreas Schwab                                  "And now for something
Andreas.Schwab@suse.de				completely different."
SuSE Labs, SuSE GmbH, Schanzäckerstr. 10, D-90443 Nürnberg
Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5

Re: [PATCH] net/802/Makefile

[Alan Cox]

> I was going to do that but AC said that all of net/802 was being
> rewritten and removing cl2llc.c now would just be noise.  The file will
> be removed in kbuild 2.5.

The 802.2LLC layer will be replaced when netbeui goes in

Re: [PATCH] net/802/Makefile

[Marcelo Tosatti]

Olaf, 


Let the correction come to me through the 802 maintainer, please. 

On Mon, 26 Nov 2001, Olaf Hering wrote:

> Hi,
> 
> the build stops when cl2llc.c has no write permissions.
> 
> diff -urN linuxppc_2_4/net/802/Makefile.broken linuxppc_2_4/net/802/Makefile
> --- linuxppc_2_4/net/802/Makefile.broken        Mon Nov 26 13:28:56 2001
> +++ linuxppc_2_4/net/802/Makefile       Mon Nov 26 13:51:10 2001
> @@ -57,4 +57,5 @@
>  include $(TOPDIR)/Rules.make
>  
>  cl2llc.c: cl2llc.pre
> +       chmod u+w cl2llc.c
>         sed -f ./pseudo/opcd2num.sed cl2llc.pre >cl2llc.c
> 
> 
> 
> Gruss Olaf
> 
> -- 
>  $ man clone
> 
> BUGS
>        Main feature not yet implemented...
> 

Re: [PATCH] net/802/Makefile

[David S. Miller]

   From: Marcelo Tosatti <marcelo@conectiva.com.br>
   Date: Mon, 26 Nov 2001 15:14:33 -0200 (BRST)
   
   Let the correction come to me through the 802 maintainer, please. 

Technically there is no such person currently.  At best it comes under
"networking" and that I guess would be me.

The person who originally wrote this 802 stuff is not active anymore
and he is only mentioned in the credits.

Re: [PATCH] net/802/Makefile

[Olaf Hering]

On Mon, Nov 26, David S. Miller wrote:

>    From: Marcelo Tosatti <marcelo@conectiva.com.br>
>    Date: Mon, 26 Nov 2001 15:14:33 -0200 (BRST)
>    
>    Let the correction come to me through the 802 maintainer, please. 
> 
> Technically there is no such person currently.  At best it comes under
> "networking" and that I guess would be me.
> 
> The person who originally wrote this 802 stuff is not active anymore
> and he is only mentioned in the credits.

Can you submit that version? ;)

diff -u linuxppc_2_4/net/802/Makefile.broken linuxppc_2_4/net/802/Makefile
--- linuxppc_2_4/net/802/Makefile.broken        Mon Nov 26 13:28:56 2001
+++ linuxppc_2_4/net/802/Makefile       Mon Nov 26 20:34:22 2001
@@ -57,4 +57,5 @@
 include $(TOPDIR)/Rules.make
 
 cl2llc.c: cl2llc.pre
+       rm -f cl2llc.c
        sed -f ./pseudo/opcd2num.sed cl2llc.pre >cl2llc.c



Gruss Olaf

-- 
 $ man clone

BUGS
       Main feature not yet implemented...

Re: [PATCH] net/802/Makefile

[David S. Miller]

   From: Olaf Hering <olh@suse.de>
   Date: Mon, 26 Nov 2001 20:35:27 +0100

   Can you submit that version? ;)
   
No, because it is writable by the user in every kernel source tree I
have ever seen, the change makes no sense.

In the official tarballs it is writable, and even in every CVS tree
(2.2.x, 2.4.x vger) I have looked at it is writable.

And as Alan has stated, this code is pretty irrelevant soon.

Re: [PATCH] net/802/Makefile

[Tom Rini]

On Mon, Nov 26, 2001 at 11:40:45AM -0800, David S. Miller wrote:
>    From: Olaf Hering <olh@suse.de>
>    Date: Mon, 26 Nov 2001 20:35:27 +0100
> 
>    Can you submit that version? ;)
>    
> No, because it is writable by the user in every kernel source tree I
> have ever seen, the change makes no sense.

You haven't tried a BitKeeper tree then.  You have to explicitly get
write permission.

> In the official tarballs it is writable, and even in every CVS tree
> (2.2.x, 2.4.x vger) I have looked at it is writable.
> 
> And as Alan has stated, this code is pretty irrelevant soon.

If this rewrite goes into 2.4, yes.  And using 2.2 as an example it
could after a while...

-- 
Tom Rini (TR1265)
http://gate.crashing.org/~trini/

Re: [PATCH] net/802/Makefile

[David S. Miller]

   From: Tom Rini <trini@kernel.crashing.org>
   Date: Mon, 26 Nov 2001 22:10:12 -0700

   On Mon, Nov 26, 2001 at 11:40:45AM -0800, David S. Miller wrote:
   > No, because it is writable by the user in every kernel source tree I
   > have ever seen, the change makes no sense.
   
   You haven't tried a BitKeeper tree then.  You have to explicitly get
   write permission.
   
That doesn't make any sense to me.

Firstly, the *.c file should be newer than the template it is
generated from, so the rule which tries to write the file should
never run if your file timestamps are setup correctly.  So get the
timestamps correct in your bitkeeper trees :)

Secondly, there is no reason the version control system should prevent
a file from being writable to the user who owns the file, especially
in a case like this.

In fact, this is one of the things that makes my balls hurt when I
download source tarballs from some places.  I have to chmod +w the
files to edit them just to make hack test local changes that I don't
care if anyone ever sees ever again.  At that point I'm fighting
whatever source control system those sources came from.

Re: [PATCH] net/802/Makefile

[Keith Owens]

On Mon, 26 Nov 2001 21:26:58 -0800 (PST), 
"David S. Miller" <davem@redhat.com> wrote:
>   From: Tom Rini <trini@kernel.crashing.org>
>   You haven't tried a BitKeeper tree then.  You have to explicitly get
>   write permission.
>   
>That doesn't make any sense to me.
>
>Firstly, the *.c file should be newer than the template it is
>generated from, so the rule which tries to write the file should
>never run if your file timestamps are setup correctly.  So get the
>timestamps correct in your bitkeeper trees :)

The source repository (whether BK or any other system) is not the
problem.  You can get the timestamps right in the source but the moment
you generate and ship a diff then you lose control of timestamps.  See
the long screed below about the problems with shipping generated files,
from kbuild-2.5.txt.

SHIPPING GENERATED FILES

  In general it is bad practice to include generated files in the kernel
  source tree.  The only exceptions are when the generating code is not in
  the kernel or when the generating code is in the kernel but it requires
  additional tools which not all users have installed.  An example of a
  generated file without the code to regenerate it is firmware for a network
  driver.  An example of a generation process that requires extra tools is
  drivers/char/defkeymap.c which requires the loadkeys program.

  There is no justification for shipping any other generated file as part of
  the kernel.  This is especially true if the user is always expected to
  regenerate the file, even more so if the generated data depends upon the
  user's .config.  Under these circumstances it is dangerous to ship a
  generated file because it can be used when it does not reflect the user's
  kernel.

  When a generated file has no kernel support to regenerate it, the file can
  be shipped as is.  The question of whether including generated files in the
  kernel without the underlying code is a violation of the kernel license is
  outside the scope of this document.

  For generated files where the code is included but not all users can run
  it, you must be careful about when the generated file is rebuilt.  make
  looks at the time stamp of the generating and generated files to decide if
  the output needs to be regenerated.  This works for the person making the
  changes because they control when the files are updated.

  Time stamps do not work when the change is issued to the rest of the world
  as a diff.  After patch has run you cannot guarantee which of the updated
  files has the more recent time.  The patch program does not preserve time
  stamps (it must not) so the time stamps on the changed files depend on the
  order of the entries in the patch set.  There is no defined order for
  entries in a patch set, it depends on the program that generated the
  difference listing.  GNU diff generates patches in alphabetical order but
  only when it is given an entire directory.  When diff is invoked from a
  source repository tool it is typically called once for each file and the
  file order is controlled by the repository tool.  Even if your repository
  generates the patch in the correct order, that order can change when the
  patch is merged into the kernel.

  Since you cannot rely on time stamps to decide if a generated and shipped
  file needs to be regenerated, you must use another mechanism for this case.
  There are two basic possibilities, manual or automatic (otherwise known as
  lazy or correct).

  In the manual case you ignore changes to the generated or generating files
  until the user performs some manual operation, such as selecting
  CONFIG_REGENERATE_foo.  This is easy to implement but it is also the lazy
  approach, making the end user do extra work to save the maintainer doing
  anything.  This goes against the whole idea of *automatically* deciding
  what needs to be rebuilt and relies on human intervention.

  In the automatic case the maintainer has to do more work but the make rules
  can automatically determine if the end user has changed any of the related
  files and regenerate automatically.  This is the correct method.  In the
  absence of reliable time stamps you need another method to check if the
  generating and generated files are in sync or not.  The obvious method is a
  checksum of files.


The 2.5 implementation for correctly handling generated files has been
skipped, read Documentation/kbuild/kbuild-2.5.txt for the gory details.

Re: [PATCH] net/802/Makefile

[David S. Miller]

   From: Keith Owens <kaos@ocs.com.au>
   Date: Tue, 27 Nov 2001 17:12:04 +1100
   
   The source repository (whether BK or any other system) is not the
   problem.  You can get the timestamps right in the source but the moment
   you generate and ship a diff then you lose control of timestamps.  See
   the long screed below about the problems with shipping generated files,
   from kbuild-2.5.txt.

Even after reading this I don't understand why defkeymap.c gets
special treatment just because it requires external tools to generate.

If the timestamps get messed up, it's going to try to regerenerate the
file with loadkeys whether you have it or not.

At best, I'd be happy to take a patch which commented out the rule
which tries to generate net/802/cl2llc.c but not one which will chmod
it.  Because the latter only makes sense if we are now deciding to do
this for _every_ such case in the tree.

Re: [PATCH] net/802/Makefile

[Keith Owens]

On Mon, 26 Nov 2001 22:18:55 -0800 (PST), 
"David S. Miller" <davem@redhat.com> wrote:
>   From: Keith Owens <kaos@ocs.com.au>
>   Date: Tue, 27 Nov 2001 17:12:04 +1100
>   
>   The source repository (whether BK or any other system) is not the
>   problem.  You can get the timestamps right in the source but the moment
>   you generate and ship a diff then you lose control of timestamps.  See
>   the long screed below about the problems with shipping generated files,
>   from kbuild-2.5.txt.
>
>Even after reading this I don't understand why defkeymap.c gets
>special treatment just because it requires external tools to generate.
>
>If the timestamps get messed up, it's going to try to regerenerate the
>file with loadkeys whether you have it or not.

When the maintainer did the build on their system, the timestamps were
right.  The moment the change is converted to a patch and sent for
inclusion in the kernel, timestamp order cannot be guaranteed, the
final result on kernel.org may have the base file being older or newer
than the generated output.  kbuild 2.4 is completely broken for
generated files, tthe only reason it "works" is because most of these
files do not change.

kbuild 2.5 fixes this problem.  It knows that you can never rely on
timestamps when you ship both a base file and a file that has been
generated from it.  Instead it uses checksums to detect any changes,
that is part of the gory details that were omitted from the previous
mail.

>At best, I'd be happy to take a patch which commented out the rule
>which tries to generate net/802/cl2llc.c but not one which will chmod
>it.  Because the latter only makes sense if we are now deciding to do
>this for _every_ such case in the tree.

I have fixed _every_ such case in 2.5.  It is unfixable in 2.4, the
order of timestamps on generated and shipped files is not reliable.