Subject: Re: [PATCH bpf-next 2/4] tools/resolve_btfids: Check objects before removing

From: Jiri Olsa <[email-masked]>
Date: Fri, 5 Feb 2021 11:40:24 +0100

On Thu, Feb 04, 2021 at 04:42:41PM -0800, Andrii Nakryiko wrote:
> On Thu, Feb 4, 2021 at 1:20 PM Jiri Olsa <[email-masked]> wrote:
> >
> > We want this clean to be called from tree's root clean
> > and that one is silent if there's nothing to clean.
> >
> > Adding check for all object to clean and display CLEAN
> > messages only if there are objects to remove.
> >
> > Signed-off-by: Jiri Olsa <[email-masked]>
> > ---
> >  tools/bpf/resolve_btfids/Makefile | 17 ++++++++++++-----
> >  1 file changed, 12 insertions(+), 5 deletions(-)
> >
> > diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
> > index b780b3a9fb07..3007cfabf5e6 100644
> > --- a/tools/bpf/resolve_btfids/Makefile
> > +++ b/tools/bpf/resolve_btfids/Makefile
> > @@ -64,13 +64,20 @@ $(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
> >         $(call msg,LINK,$@)
> >         $(Q)$(CC) $(BINARY_IN) $(LDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
> >
> > +clean_objects := $(wildcard $(OUTPUT)/*.o                \
> > +                            $(OUTPUT)/.*.o.cmd           \
> > +                            $(OUTPUT)/.*.o.d             \
> > +                            $(OUTPUT)/libbpf             \
> > +                            $(OUTPUT)/libsubcmd          \
> > +                            $(OUTPUT)/resolve_btfids)
> > +
> > +clean:
> > +
> > +ifneq ($(clean_objects),)
> >  clean: fixdep-clean
> 
> this looks a bit weird, declaring clean twice. Wouldn't moving ifneq
> inside the clean work just fine?

it has the fixdep-clean dependency we don't want to run
if clean_objects is not defined.. I could move the empty
clean to the the else path

jirka

---
diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
index 1d46a247ec95..be09ec4f03ff 100644
--- a/tools/bpf/resolve_btfids/Makefile
+++ b/tools/bpf/resolve_btfids/Makefile
@@ -64,13 +64,20 @@ $(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
 	$(call msg,LINK,$@)
 	$(Q)$(CC) $(BINARY_IN) $(LDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
 
+clean_objects := $(wildcard $(OUTPUT)/*.o                \
+                            $(OUTPUT)/.*.o.cmd           \
+                            $(OUTPUT)/.*.o.d             \
+                            $(OUTPUT)/libbpf             \
+                            $(OUTPUT)/libsubcmd          \
+                            $(OUTPUT)/resolve_btfids)
+
+ifneq ($(clean_objects),)
 clean: fixdep-clean
 	$(call msg,CLEAN,$(BINARY))
-	$(Q)$(RM) -f $(BINARY); \
-	$(RM) -rf $(if $(OUTPUT),$(OUTPUT),.)/feature; \
-	$(RM) -rf $(OUTPUT)/libbpf; \
-	$(RM) -rf $(OUTPUT)/libsubcmd; \
-	find $(if $(OUTPUT),$(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
+	$(Q)$(RM) -rf $(clean_objects)
+else
+clean:
+endif
 
 tags:
 	$(call msg,GEN,,tags)