On Sat, Oct 2, 2021 at 3:12 PM Quentin Monnet <quentin@xxxxxxxxxxxxx> wrote: > > On Sat, 2 Oct 2021 at 21:27, Quentin Monnet <quentin@xxxxxxxxxxxxx> wrote: > > > > On Sat, 2 Oct 2021 at 00:20, Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> wrote: > > > > > > On Fri, Oct 1, 2021 at 4:09 AM Quentin Monnet <quentin@xxxxxxxxxxxxx> wrote: > > > > > > > > API headers from libbpf should not be accessed directly from the > > > > library's source directory. Instead, they should be exported with "make > > > > install_headers". Let's make sure that bpf/preload/iterators/Makefile > > > > installs the headers properly when building. > > > > > > > > > > -$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT) > > > > +$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) \ > > > > + | $(LIBBPF_OUTPUT) $(LIBBPF_INCLUDE) > > > > > > Would it make sense for libbpf's Makefile to create include and output > > > directories on its own? We wouldn't need to have these order-only > > > dependencies everywhere, right? > > > > Good point, I'll have a look at it. > > Quentin > > So libbpf already creates the include (and parent $(DESTDIR)) > directory, so I can get rid of the related dependencies. But I don't > see an easy solution for the output directory for the object files. > The issue is that libbpf's Makefile includes > tools/scripts/Makefile.include, which checks $(OUTPUT) and errors out Did you check what benefits the use of tools/scripts/Makefile.include brings? Last time I had to deal with some non-trivial Makefile problem, this extra dance with tools/scripts/Makefile.include and some related complexities didn't seem very justified. So unless there are some very big benefits to having tool's Makefile.include included, I'd rather simplify libbpf's in-kernel Makefile and make it more straightforward. We have a completely independent separate Makefile for libbpf in Github, and I think it's more straightforward. Doesn't have to be done in this change, of course, but I was curious to hear your thoughts given you seem to have spent tons of time on this already. > if the directory does not exist. This prevents us from creating the > directory as part of the regular targets. We could create it > unconditionally before running any target, but it's ugly; and I don't > see any simple workaround. > > So I'll remove the deps on $(LIBBPF_INCLUDE) and keep the ones on > $(LIBBPF_OUTPUT).
