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Date:   Thu, 3 Sep 2020 16:03:50 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Jesper Dangaard Brouer <brouer@redhat.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>,
        bpf@vger.kernel.org
Subject: Re: [PATCH] tools build feature: cleanup feature files on make clean
Message-ID: <20200903190350.GI3495158@kernel.org>
References: <159851841661.1072907.13770213104521805592.stgit@firesoul>
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Em Thu, Aug 27, 2020 at 10:53:36AM +0200, Jesper Dangaard Brouer escreveu:
> The system for "Auto-detecting system features" located under
> tools/build/ are (currently) used by perf, libbpf and bpftool. It can
> contain stalled feature detection files, which are not cleaned up by
> libbpf and bpftool on make clean (side-note: perf tool is correct).
> 
> Fix this by making the users invoke the make clean target.
> 
> Some details about the changes. The libbpf Makefile already had a
> clean-config target (which seems to be copy-pasted from perf), but this
> target was not "connected" (a make dependency) to clean target. Choose
> not to rename target as someone might be using it. Did change the output
> from "CLEAN config" to "CLEAN feature-detect", to make it more clear
> what happens.

Since this mostly touches BPF, should it go via the BPF tree?

- Arnaldo
 
> This is related to the complaint and troubleshooting in link:
> Link: https://lore.kernel.org/lkml/20200818122007.2d1cfe2d@carbon/
> 
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> ---
>  tools/build/Makefile |    2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
> index 8462690a039b..02c99bc95c69 100644
> --- a/tools/bpf/bpftool/Makefile
> +++ b/tools/bpf/bpftool/Makefile
> @@ -176,7 +176,11 @@ $(OUTPUT)bpftool: $(OBJS) $(LIBBPF)
>  $(OUTPUT)%.o: %.c
>  	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $<
>  
> -clean: $(LIBBPF)-clean
> +feature-detect-clean:
> +	$(call QUIET_CLEAN, feature-detect)
> +	$(Q)$(MAKE) -C $(srctree)/tools/build/feature/ clean >/dev/null
> +
> +clean: $(LIBBPF)-clean feature-detect-clean
>  	$(call QUIET_CLEAN, bpftool)
>  	$(Q)$(RM) -- $(OUTPUT)bpftool $(OUTPUT)*.o $(OUTPUT)*.d
>  	$(Q)$(RM) -- $(BPFTOOL_BOOTSTRAP) $(OUTPUT)*.skel.h $(OUTPUT)vmlinux.h
> diff --git a/tools/build/Makefile b/tools/build/Makefile
> index 727050c40f09..722f1700d96a 100644
> --- a/tools/build/Makefile
> +++ b/tools/build/Makefile
> @@ -38,6 +38,8 @@ clean:
>  	$(call QUIET_CLEAN, fixdep)
>  	$(Q)find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
>  	$(Q)rm -f $(OUTPUT)fixdep
> +	$(call QUIET_CLEAN, feature-detect)
> +	$(Q)$(MAKE) -C feature/ clean >/dev/null
>  
>  $(OUTPUT)fixdep-in.o: FORCE
>  	$(Q)$(MAKE) $(build)=fixdep
> diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
> index bf8ed134cb8a..bbb89551468a 100644
> --- a/tools/lib/bpf/Makefile
> +++ b/tools/lib/bpf/Makefile
> @@ -269,10 +269,10 @@ install: install_lib install_pkgconfig install_headers
>  ### Cleaning rules
>  
>  config-clean:
> -	$(call QUIET_CLEAN, config)
> +	$(call QUIET_CLEAN, feature-detect)
>  	$(Q)$(MAKE) -C $(srctree)/tools/build/feature/ clean >/dev/null
>  
> -clean:
> +clean: config-clean
>  	$(call QUIET_CLEAN, libbpf) $(RM) -rf $(CMD_TARGETS)		     \
>  		*~ .*.d .*.cmd LIBBPF-CFLAGS $(BPF_HELPER_DEFS)		     \
>  		$(SHARED_OBJDIR) $(STATIC_OBJDIR)			     \
> 
> 

-- 

- Arnaldo