[PATCH -next 2/2] kbuild: fix for updated LZ4 tool with the new streaming format

Andrew Morton
2013-07-15T22:03:42Z

On Fri, 12 Jul 2013 09:56:02 +0200 Ingo Molnar <mingo@kernel.org> wrote:

>
> * Kyungsik Lee <kyungsik.lee@lge.com> wrote:
> > quiet_cmd_lz4 = LZ4 $@
> > cmd_lz4 = (cat $(filter-out FORCE,$^) | \
> > - lz4demo -c1 stdin stdout && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
> > + lz4c -l -c1 stdin stdout && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
> > (rm -f $@ ; false)
>
> None of the major distros I tried has the lz4 or lz4c binary available,
> and this breaks randconfig builds:
>
> /bin/sh: lz4c: command not found
>
> If:
>
> CONFIG_HAVE_KERNEL_LZ4=y
> CONFIG_KERNEL_LZ4=y
> CONFIG_RD_LZ4=y
> CONFIG_LZ4_DECOMPRESS=y
> CONFIG_DECOMPRESS_LZ4=y
>
> If a utility is not widely available yet and if the utility is not in the
> kernel proper, could you please at least make sure that randconfig does
> not stumble over non-buildable kernels?

I don't know how to do this. Any suggestions?

It has to be done at `make config' time. We'd need to probe for the
presence of lz4c and then.... what?

Is there any precedent for this?

I don't think we can just ignore the absence of lz4c - the user has
selected a config which his system cannot build. The problem lies
within randconfig itself.