On Mon, Apr 20, 2020 at 5:06 PM Yoshiki Komachi <komachi.yoshiki@xxxxxxxxx> wrote: > > 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> > --- LGTM. Acked-by: Andrii Nakryiko <andriin@xxxxxx> > 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 >
