From: Jerome Marchand <jmarchan@redhat.com>
Date: Sat, 7 May 2022 18:16:35 +0200
Subject: samples: bpf: Don't fail for a missing VMLINUX_BTF when VMLINUX_H is
 provided
Patch-mainline: v5.19-rc1
Git-commit: ec24704492d8791a52a75a39e3ad762b6e017bc6
References: jsc#PED-1377

samples/bpf build currently always fails if it can't generate
vmlinux.h from vmlinux, even when vmlinux.h is directly provided by
VMLINUX_H variable, which makes VMLINUX_H pointless.
Only fails when neither method works.

Fixes: 384b6b3bbf0d ("samples: bpf: Add vmlinux.h generation support")
Reported-by: CKI Project <cki-project@redhat.com>
Reported-by: Veronika Kabatova <vkabatov@redhat.com>
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220507161635.2219052-1-jmarchan@redhat.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 samples/bpf/Makefile |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -369,16 +369,15 @@ VMLINUX_BTF ?= $(abspath $(firstword $(w
 
 $(obj)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL)
 ifeq ($(VMLINUX_H),)
+ifeq ($(VMLINUX_BTF),)
+	$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)",\
+		build the kernel or set VMLINUX_BTF or VMLINUX_H variable)
+endif
 	$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
 else
 	$(Q)cp "$(VMLINUX_H)" $@
 endif
 
-ifeq ($(VMLINUX_BTF),)
-	$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)",\
-		build the kernel or set VMLINUX_BTF variable)
-endif
-
 clean-files += vmlinux.h
 
 # Get Clang's default includes on this system, as opposed to those seen by