netdev - [PATCH bpf-next v3 6/6] libbpf: Add getter for program size

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Message-ID: <157325766119.27401.7134121980544613977.stgit@toke.dk>
Date:   Sat, 09 Nov 2019 01:01:01 +0100
From:   Toke Høiland-Jørgensen <toke@...hat.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Andrii Nakryiko <andrii.nakryiko@...il.com>,
        David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
        bpf@...r.kernel.org
Subject: [PATCH bpf-next v3 6/6] libbpf: Add getter for program size

From: Toke Høiland-Jørgensen <toke@...hat.com>

This adds a new getter for the BPF program size (in bytes). This is useful
for a caller that is trying to predict how much memory will be locked by
loading a BPF object into the kernel.

Acked-by: Andrii Nakryiko <andriin@...com>
Acked-by: David S. Miller <davem@...emloft.net>
Acked-by: Song Liu <songliubraving@...com>
Signed-off-by: Toke Høiland-Jørgensen <toke@...hat.com>
---
 tools/lib/bpf/libbpf.c   |    5 +++++
 tools/lib/bpf/libbpf.h   |    3 +++
 tools/lib/bpf/libbpf.map |    1 +
 3 files changed, 9 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 094f5c64611a..70fec4a565af 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4782,6 +4782,11 @@ int bpf_program__fd(const struct bpf_program *prog)
 	return bpf_program__nth_fd(prog, 0);
 }
 
+size_t bpf_program__size(const struct bpf_program *prog)
+{
+	return prog->insns_cnt * sizeof(struct bpf_insn);
+}
+
 int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
 			  bpf_program_prep_t prep)
 {
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index f0947cc949d2..5aa27caad6c2 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -214,6 +214,9 @@ LIBBPF_API void bpf_program__set_ifindex(struct bpf_program *prog,
 LIBBPF_API const char *bpf_program__title(const struct bpf_program *prog,
 					  bool needs_copy);
 
+/* returns program size in bytes */
+LIBBPF_API size_t bpf_program__size(const struct bpf_program *prog);
+
 LIBBPF_API int bpf_program__load(struct bpf_program *prog, char *license,
 				 __u32 kern_version);
 LIBBPF_API int bpf_program__fd(const struct bpf_program *prog);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index d1a782a3a58d..9f39ee06b2d4 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -203,4 +203,5 @@ LIBBPF_0.0.6 {
 		bpf_program__get_type;
 		bpf_program__is_tracing;
 		bpf_program__set_tracing;
+		bpf_program__size;
 } LIBBPF_0.0.5;