Re: [RFC PATCH 05/13] bpf tools: Save engine type in bpf_program

From: Arnaldo Carvalho de Melo
Date: Wed Apr 20 2016 - 15:23:24 EST


Em Wed, Apr 20, 2016 at 06:01:45PM +0000, Wang Nan escreveu:
> Add an 'engine' field in bpf_program to indicate whether a program is a
> ubpf program or kernel bpf program. For compatibility, the default
> engine is kernel bpf, unless explicitly set to ubpf using
> bpf_program__set_ubpf().
>
> Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
> Cc: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Li Zefan <lizefan@xxxxxxxxxx>
> ---
> tools/lib/bpf/libbpf.c | 40 ++++++++++++++++++++++++++++++++++++++++
> tools/lib/bpf/libbpf.h | 4 ++++
> 2 files changed, 44 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index dd5a107..3755846 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -80,6 +80,7 @@ static const char *libbpf_strerror_table[NR_ERRNO] = {
> [ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading",
> [ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
> [ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
> + [ERRCODE_OFFSET(NOUBPF)] = "UBPF support is not compiled",
> };
>
> int libbpf_strerror(int err, char *buf, size_t size)
> @@ -147,6 +148,11 @@ union prog_instance {
> * linux/filter.h.
> */
> struct bpf_program {
> + enum {
> + ENGINE_UNKNOWN,
> + ENGINE_KBPF,
> + ENGINE_UBPF,
> + } engine;
> /* Index in elf obj file, for relocation use. */
> int idx;
> char *section_name;
> @@ -291,6 +297,7 @@ bpf_program__init(void *data, size_t size, char *name, int idx,
> memcpy(prog->insns, data,
> prog->insns_cnt * sizeof(struct bpf_insn));
> prog->idx = idx;
> + prog->engine = ENGINE_UNKNOWN;
> prog->instances.array = NULL;
> prog->instances.nr = -1;
>
> @@ -941,6 +948,11 @@ bpf_program__load(struct bpf_program *prog,
> {
> int err = 0, fd, i;
>
> + if (prog->engine == ENGINE_UNKNOWN)
> + prog->engine = ENGINE_KBPF;
> + if (prog->engine != ENGINE_KBPF)

else if (prog->engine != ENGINE_KBPF)

Nitpicking a bit :-)

> + return -EINVAL;
> +
> if (prog->instances.nr < 0 || !prog->instances.array) {
> if (prog->preprocessor) {
> pr_warning("Internal error: can't load program '%s'\n",
> @@ -1318,6 +1330,34 @@ int bpf_program__nth_fd(struct bpf_program *prog, int n)
> return fd;
> }
>
> +#ifdef HAVE_UBPF_SUPPORT
> +int bpf_program__set_ubpf(struct bpf_program *prog)
> +{
> + if (prog->engine != ENGINE_UNKNOWN) {
> + pr_warning("Can't set program %s to ubpf\n",
> + prog->section_name);
> + return -EINVAL;
> + }
> + prog->engine = ENGINE_UBPF;
> + return 0;
> +}
> +
> +bool bpf_program__is_ubpf(struct bpf_program *prog)
> +{
> + return prog->engine == ENGINE_UBPF;
> +}
> +#else
> +int bpf_program__set_ubpf(struct bpf_program *prog __maybe_unused)
> +{
> + return -LIBBPF_ERRNO__NOUBPF;
> +}
> +
> +bool bpf_program__is_ubpf(struct bpf_program *prog __maybe_unused)
> +{
> + return false;
> +}
> +#endif
> +
> int bpf_map__get_fd(struct bpf_map *map)
> {
> if (!map)
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index a51594c..f6965ce 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -26,6 +26,7 @@ enum libbpf_errno {
> LIBBPF_ERRNO__VERIFY, /* Kernel verifier blocks program loading */
> LIBBPF_ERRNO__PROG2BIG, /* Program too big */
> LIBBPF_ERRNO__KVER, /* Incorrect kernel version */
> + LIBBPF_ERRNO__NOUBPF, /* UBPF support is not compiled */
> __LIBBPF_ERRNO__END,
> };
>
> @@ -86,6 +87,9 @@ int bpf_program__get_private(struct bpf_program *prog,
>
> const char *bpf_program__title(struct bpf_program *prog, bool needs_copy);
>
> +int bpf_program__set_ubpf(struct bpf_program *prog);
> +bool bpf_program__is_ubpf(struct bpf_program *prog);
> +
> int bpf_program__fd(struct bpf_program *prog);
>
> struct bpf_insn;
> --
> 1.8.3.4