Re: [patch] 2.4.0-prerelease drm and modversions

[Michael Elizabeth Chastain]

Keith Owens writes:
kaos> drivers/char/drm/Makefile is breaking the Makefile rules.  It builds
kaos> drmlib.a and expects to link that library into both the kernel and into
kaos> modules.

Ah, shit.

kaos> The kernel makefile system assumes that everything is either kernel or
kaos> module, not both.  The components in drmlib.a get compiled for kernel
kaos> only, when used in a module they are missing the symbol versions.

I agree with Keith.

The kernel version is going to get compiled, and then the module version is
going to get compiled with different compilation flags: -DMODULE.  The two
versions are always going to fight.

kaos> +$(patsubst %.o,%.c,$(lib-objs-mod)): 
kaos> +	@ln -sf $(subst -mod,,$@) $@
kaos> +

This looks good to me.  It's missing a dependency though.  If foo-mod.c
exists, and someone edits or patches foo.c, then foo-mod.c needs to be
re-created.

Keith, what do you think of this:

  source-objs-mod := $(patsubst %-mod.o,%-mod.c,$(lib-objs-mod))
  $(source-objs-mod): $(patsubst %-mod.c,%.c,$(source-objs-mod))
    ln -sf $(patsubst %-mod.c,%.c,$@) $@

It suffers from the thundering herd problem (each *-mod.c depend on
all *.c files) but I think it's correct.

Michael