[U-Boot-Users] [PATCH] Use `ln -sf` rather than `rm -f && ln -s`

[Mike Frysinger]

On Monday 28 January 2008, Johannes Stezenbach wrote:
> On Mon, Jan 28, 2008 at 06:38:58AM -0500, Mike Frysinger wrote:
> > The -f option to `ln` should give the same behavior as the -f option to
> > the `rm` command.  It is better to do this in one shot so as to avoid
> > race conditions when building in parallel.  I build on a quad G5 and
> > without this change, it isn't uncommon for the build to fail when using
> > -j8 due to this small window where the files don't actually exist.
>
> Since there is a clear dependency of environment.o on environment.c
> there is no way for make to run the rm/ln and $(CC) commands
> in parallel, so there should be no race condition.
> For illustrative purposes: you should be able to put a sleep
> between the rm and the ln -s, and it should still build.

right, i know the issue isnt between the link and the compile, it was that the 
rm/ln was run multiple times.  but i never dug deeper into the issue to find 
the true cause of the problem.

> It seems the real problem is one level above, the commands
> were run twice in parallel, once for "depend" and once
> for the SUBDIRS "all". Please test the patch below.

thanks for poking deeper

> -$(OBJS):	$(obj)include/autoconf.mk
> +$(OBJS):	depend $(obj)include/autoconf.mk
>  		$(MAKE) -C cpu/$(CPU) $(if $(REMOTE_BUILD),$@,$(notdir $@))
>
> -$(LIBS):	$(obj)include/autoconf.mk
> +$(LIBS):	depend $(obj)include/autoconf.mk
>  		$(MAKE) -C $(dir $(subst $(obj),,$@))
>
> -$(SUBDIRS):	$(obj)include/autoconf.mk
> +$(SUBDIRS):	depend $(obj)include/autoconf.mk
>  		$(MAKE) -C $@ all

perhaps depend should get its own line ?
u-boot $(OBJS) $(LIBS) $(SUBDIRS): depend
or not, doesnt matter to me ... as long as it works :)
-mike
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