Re: I don't understand what goes where, very confused about POM-ng

[Martijn Lievaart <netfilter-devel@rtij.nl>]

Jozsef Kadlecsik wrote:

>Hi Martijn,
>  
>

Hi, thanks for taking the time to answer my questions.

>On Wed, 5 May 2004, Martijn Lievaart wrote:
>
>  
>
>>Using CVS of today 5/5/2004.
>>
>>I'm trying to port the psd match to 2.6. The C code is ready (not much
>>of a change needed). However POM will not apply the headerfile from the
>>linux/ tree, I need to copy it to the linux-2.6 tree. I would expect
>>that everything in the linux tree would also be applied, eventually
>>overridden by something in the linux-2.6 tree. Why else have seperate
>>linux-2.4 trees?
>>    
>>
>
>No, every tree is for their own version(s) and they must contain
>everything which is needed for a patch to be complete installed. The
>reason for this is that there can be missing/added files in different
>kernel trees. For example how could a program figure out in the case
>
>	linux/include/linux/netfilter_foo.h
>	linux/include/linux/netfilter_bar.h
>
>	linux-2.6/include/linux/netfilter_foo.h
>
>that linux/include/linux/netfilter_bar.h is required for linux-2.6 or not?
>
>  
>

Well, there are also linux-2.4 trees. So at first sight it would seem 
that linux-<version>/ is specific to that version and plain linux/ is 
for any version. But it seemes the linux/ is a synonym for linux-2.4 right?

>>By now I gather that POM-ng tries to find a best match, and does this
>>independently for the ladds and the files (and the patches as well?). I
>>find this very confusing, but I think this is by design?
>>    
>>
>
>Yes, this is by design. Or call it a feature :-).
>  
>

Confusing, but I see the value, yes.


>  
>
>>Anyhow, I looked at a couple of other patches and many have their header
>>file only in the linux-tree. Many are also base, so probably already
>>applied to any 2.6 kernel, but the why have a linux-2.6 tree in that
>>case? One patch where this really breaks is the XOR patch, it does not
>>apply to 2.6 because POM-ng does not copy the header.
>>    
>>
>
>Then those patches are broken in pom-ng and have to be fixed.
>  
>

Clear. Someone, please copy 
XOR/linux/include/linux/netfilter_ipv4/ipt_XOR.h to 
XOR/linux-2.6/include/linux/netfilter_ipv4/ipt_XOR.h in CVS.

>>As an alternative, would it be possible to just create a linux-2.6.patch
>>file that applies after the 2.4 patch has applied? This would be a good
>>solution because many patches need only minor modifications to newly
>>added files (especially only ipt_xxx.c) to make them run under 2.6.
>>    
>>
>
>No, that won't go either. What should we do when linux-2.7 comes out and
>from some reason there are 2.4, 2.6 versions supported? Should the
>linux-2.7.patch depend on linux-2.4.patch and linux-2.6.patch then?
>  
>

Not what I ment, but never mind. If I can find time I'll express it in 
code and submit it.

>I believe the current behaviour is the most simple and straightforward:
>every three contains everything which is required. No cross-dependency.
>No magic between trees. Simpler pom scripts. Also, we support broken out
>patches. How could that fitted into other designs easily?
>
>  
>

It makes maintenance of the patches more difficult, you have exactly the 
same files multiple times, because only one or a few from a set are 
different. And those that are different are often only different in a 
few lines. Having a way to say "for 2.6, copy this file from linux-2.4, 
then patch with this patchfile" (or vice versa for those that are on 
2.6) seems a nice feature. But I can live without it.

Thanks,
Martijn Lievaart