Re: [PATCH bpf-next v5 00/11] tools: Use consistent libbpf include paths everywhere

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Mon, Jan 20, 2020 at 5:08 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>
> We are currently being somewhat inconsistent with the libbpf include paths,
> which makes it difficult to move files from the kernel into an external
> libbpf-using project without adjusting include paths.
>
> Having the bpf/ subdir of $INCLUDEDIR in the include path has never been a
> requirement for building against libbpf before, and indeed the libbpf pkg-config
> file doesn't include it. So let's make all libbpf includes across the kernel
> tree use the bpf/ prefix in their includes. Since bpftool skeleton generation
> emits code with a libbpf include, this also ensures that those can be used in
> existing external projects using the regular pkg-config include path.
>
> This turns out to be a somewhat invasive change in the number of files touched;
> however, the actual changes to files are fairly trivial (most of them are simply
> made with 'sed'). The series is split to make the change for one tool subdir at
> a time, while trying not to break the build along the way. It is structured like
> this:
>
> - Patch 1-3: Trivial fixes to Makefiles for issues I discovered while changing
>   the include paths.
>
> - Patch 4-8: Change the include directives to use the bpf/ prefix, and updates
>   Makefiles to make sure tools/lib/ is part of the include path, but without
>   removing tools/lib/bpf
>
> - Patch 9-11: Remove tools/lib/bpf from include paths to make sure we don't
>   inadvertently re-introduce includes without the bpf/ prefix.
>
> Changelog:
>
> v5:
>   - Combine the libbpf build rules in selftests Makefile (using Andrii's
>     suggestion for a make rule).
>   - Re-use self-tests libbpf build for runqslower (new patch 10)
>   - Formatting fixes
>
> v4:
>   - Move runqslower error on missing BTF into make rule
>   - Make sure we don't always force a rebuild selftests
>   - Rebase on latest bpf-next (dropping patch 11)
>
> v3:
>   - Don't add the kernel build dir to the runqslower Makefile, pass it in from
>     selftests instead.
>   - Use libbpf's 'make install_headers' in selftests instead of trying to
>     generate bpf_helper_defs.h in-place (to also work on read-only filesystems).
>   - Use a scratch builddir for both libbpf and bpftool when building in selftests.
>   - Revert bpf_helpers.h to quoted include instead of angled include with a bpf/
>     prefix.
>   - Fix a few style nits from Andrii
>
> v2:
>   - Do a full cleanup of libbpf includes instead of just changing the
>     bpf_helper_defs.h include.
>
> ---
>

Looks good, it's a clear improvement on what we had before, thanks!

It doesn't re-build bpftool when bpftool sources changes, but I think
it was like that even before, so no need to block on that. Would be
nice to have a follow up fixing that, though. $(wildcard
$(BPFTOOL_DIR)/*.[ch] $(BPFTOOL_DIR)/Makefile) should do it, same as
for libbpf.

So, for the series:

Acked-by: Andrii Nakryiko <andriin@fb.com>
Tested-by: Andrii Nakryiko <andriin@fb.com>

> Toke Høiland-Jørgensen (11):
>       samples/bpf: Don't try to remove user's homedir on clean
>       tools/bpf/runqslower: Fix override option for VMLINUX_BTF
>       selftests: Pass VMLINUX_BTF to runqslower Makefile
>       tools/runqslower: Use consistent include paths for libbpf
>       selftests: Use consistent include paths for libbpf
>       bpftool: Use consistent include paths for libbpf
>       perf: Use consistent include paths for libbpf
>       samples/bpf: Use consistent include paths for libbpf
>       tools/runqslower: Remove tools/lib/bpf from include path
>       runsqslower: Support user-specified libbpf include and object paths
>       selftests: Refactor build to remove tools/lib/bpf from include path
>
>

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