Re: [PATCH 1/5] radix tree test suite: fix mapshift build target

[Matthew Wilcox <willy@infradead.org>]

On Thu, May 03, 2018 at 01:24:26PM -0600, Ross Zwisler wrote:
> The following commit
> 
>   commit c6ce3e2fe3da ("radix tree test suite: Add config option for map
>   shift")
> 
> Introduced a phony makefile target called 'mapshift' that ends up
> generating the file generated/map-shift.h.  This phony target was then
> added as a dependency of the top level 'targets' build target, which is
> what is run when you go to tools/testing/radix-tree and just type 'make'.
> 
> Unfortunately, this phony target doesn't actually work as a dependency, so
> you end up getting:
> 
> $ make
> make: *** No rule to make target 'generated/map-shift.h', needed by 'main.o'.  Stop.
> make: *** Waiting for unfinished jobs....
> 
> Fix this by making the file generated/map-shift.h our real makefile target,
> and add this a dependency of the top level build target.

This commit breaks typing 'make SHIFT=6'.  It doesn't rebuild the
test suite any more.  If I revert this patch, it works.  Also, I can't
reproduce the problem you're reporting here.  So ... how do I reproduce
it?  Otherwise, I'm just going to revert this patch since it regresses
a feature I find useful.

> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> ---
>  tools/testing/radix-tree/Makefile | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/testing/radix-tree/Makefile b/tools/testing/radix-tree/Makefile
> index fa7ee369b3c9..db66f8a0d4be 100644
> --- a/tools/testing/radix-tree/Makefile
> +++ b/tools/testing/radix-tree/Makefile
> @@ -17,7 +17,7 @@ ifeq ($(BUILD), 32)
>  	LDFLAGS += -m32
>  endif
>  
> -targets: mapshift $(TARGETS)
> +targets: generated/map-shift.h $(TARGETS)
>  
>  main:	$(OFILES)
>  
> @@ -42,9 +42,7 @@ radix-tree.c: ../../../lib/radix-tree.c
>  idr.c: ../../../lib/idr.c
>  	sed -e 's/^static //' -e 's/__always_inline //' -e 's/inline //' < $< > $@
>  
> -.PHONY: mapshift
> -
> -mapshift:
> +generated/map-shift.h:
>  	@if ! grep -qws $(SHIFT) generated/map-shift.h; then		\
>  		echo "#define RADIX_TREE_MAP_SHIFT $(SHIFT)" >		\
>  				generated/map-shift.h;			\
> -- 
> 2.14.3
>