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Date: Tue, 25 Sep 2007 21:00:36 +0200
From: Sam Ravnborg <sam@ravnborg.org>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
       Christoph Hellwig <hch@infradead.org>,
       Randy Dunlap <randy.dunlap@oracle.com>
Subject: Re: [patch 3/5] Add samples subdir
Message-ID: <20070925190036.GA14579@uranus.ravnborg.org>
References: <20070925121145.262664884@polymtl.ca> <20070925121251.954162366@polymtl.ca>
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Hi Mathieu & Randy.

On Tue, Sep 25, 2007 at 08:11:48AM -0400, Mathieu Desnoyers wrote:
> From: Randy Dunlap <randy.dunlap@oracle.com>
> 
> Begin infrastructure for kernel code samples in the samples/ directory.
> Add its Kconfig and Kbuild files.
> Source its Kconfig file in all arch/ Kconfigs.

Sorry for not commenting on this before...
The samples directory contains sample code so it is wrong to actually
include it as part of the kernel IMHO.
We only want to keep the samples buildable and to do so
we can make a much simpler hack in the top-level Makefile.
Consider following patch:

@@ -760,6 +760,9 @@ vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) $(kallsyms.o) vmlinux.o
 ifdef CONFIG_HEADERS_CHECK
        $(Q)$(MAKE) -f $(srctree)/Makefile headers_check
 endif
+ifdef CONFIG_SAMPLES
+       $(Q)$(MAKE) $(build)=samples
+endif
        $(call vmlinux-modpost)
        $(call if_changed_rule,vmlinux__)
        $(Q)rm -f .old_version


With this we build the samples when CONFIG_SAMPLES are selected and
when the kernel is about to be linked.


As for the Kconfig file I am in favour of it but think a much more
natural place is to source it in lib/Kconfig.debug.
Then it will appear in "Kernel hacking" and the smaples
are used for kernel hacking and not for regular people
building their own kernel.

Sourcing samples/Kconfig from lib/Kconfig.debug will then
take effect for all archs so the result is a much simpler
Kconfig patch too.

	Sam