The following error was shown when a bpf program was compiled without vmlinux.h auto-generated from BTF: # clang -I./linux/tools/lib/ -I/lib/modules/$(uname -r)/build/include/ \ -O2 -Wall -target bpf -emit-llvm -c bpf_prog.c -o bpf_prog.bc ... In file included from linux/tools/lib/bpf/bpf_helpers.h:5: linux/tools/lib/bpf/bpf_helper_defs.h:56:82: error: unknown type name '__u64' ... It seems that bpf programs are intended for being built together with the vmlinux.h (which will have all the __u64 and other typedefs). But users may mistakenly think "include <linux/types.h>" is missing because the vmlinux.h is not common for non-bpf developers. IMO, an explicit comment therefore should be added to bpf_helpers.h as this patch shows. Signed-off-by: Yoshiki Komachi <komachi.yoshiki@xxxxxxxxx> --- tools/lib/bpf/bpf_helpers.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index f69cc208778a..60aad054eea1 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -2,6 +2,12 @@ #ifndef __BPF_HELPERS__ #define __BPF_HELPERS__ +/* + * Note that bpf programs need to include either + * vmlinux.h (auto-generated from BTF) or linux/types.h + * in advance since bpf_helper_defs.h uses such types + * as __u64. + */ #include "bpf_helper_defs.h" #define __uint(name, val) int (*name)[val] -- 2.24.1
