Re: [PATCH] Symlinks for building external modules

[Sam Ravnborg <sam@ravnborg.org>]

On Fri, Jun 04, 2004 at 08:15:02PM +0300, Jari Ruusu wrote:
> 
> How long have you recommended building external modules like this:
> 
>  make -C /lib/modules/`uname -r`/build modules SUBDIRS=`pwd`
>   or
>  make -C /lib/modules/`uname -r`/build modules M=`pwd`
> 
> Now they all have to be changed to:
> 
>  make -C /lib/modules/`uname -r`/source modules SUBDIRS=`pwd`
>   or
>  make -C /lib/modules/`uname -r`/source modules M=`pwd`

That would not work either.
You need to tell kbuild both where to find the source and the output files.
So you have to specify both -C ... and O=...
KERNEL=/lib/modules/`uname -r`
make -C $KERNEL/source O=$KERNEL/build M=`pwd`

There is no way to do the proposed chang and be backward compatible
when the kernel is build using seperate output directories.

Think of the following situation
/usr/src/linux-2.6.6-xx/  <= kernel src

/lib/modules/linux-2.6.6-xx-smp/build/ <= output files (or a symlink to them)
/lib/modules/linux-2.6.6-xx-smp/source/ <= symlink to kernel src

/lib/modules/linux-2.6.6-xx-up/build/ <= output files (or symlink)
/lib/modules/linux-2.6.6-xx-up/source/ <= symlink to kernel src

/lib/modules/linux-2.6.6-xx-4g/build/ <= output files (or symlink)
/lib/modules/linux-2.6.6-xx-4g/source/ <= symlink to kernel src

Notice they all share the _same_ kernel src.
We just have three different .config files.

If there is a way to be backward compatible with
this feature please demonstrate it.

Plese note that the patch Andreas made did not break existing setups
if a seperate output directory was not used. The only effect
would be an additional symlink to the same dir. (build and source would
be links to the same dir).


Andreas - please expalin why you want build to be a symlink, and not
the directory used when actually building the kernel.
 
	Sam