From: Yonghong Song <yhs@fb.com>
Date: Thu, 23 Jul 2020 11:41:17 -0700
Subject: tools/libbpf: Add support for bpf map element iterator
Patch-mainline: v5.9-rc1
Git-commit: cd31039a7347610863aa8b77a9162048999723d0
References: bsc#1177028
Add map_fd to bpf_iter_attach_opts and flags to
bpf_link_create_opts. Later on, bpftool or selftest
will be able to create a bpf map element iterator
by passing map_fd to the kernel during link
creation time.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723184117.590673-1-yhs@fb.com
Acked-by: Gary Lin <glin@suse.com>
---
tools/lib/bpf/bpf.c | 1 +
tools/lib/bpf/bpf.h | 3 ++-
tools/lib/bpf/libbpf.c | 10 +++++++++-
tools/lib/bpf/libbpf.h | 3 ++-
4 files changed, 14 insertions(+), 3 deletions(-)
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -598,6 +598,7 @@ int bpf_link_create(int prog_fd, int tar
attr.link_create.prog_fd = prog_fd;
attr.link_create.target_fd = target_fd;
attr.link_create.attach_type = attach_type;
+ attr.link_create.flags = OPTS_GET(opts, flags, 0);
return sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr));
}
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -170,8 +170,9 @@ LIBBPF_API int bpf_prog_detach2(int prog
struct bpf_link_create_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
+ __u32 flags;
};
-#define bpf_link_create_opts__last_field sz
+#define bpf_link_create_opts__last_field flags
LIBBPF_API int bpf_link_create(int prog_fd, int target_fd,
enum bpf_attach_type attach_type,
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -8285,13 +8285,20 @@ struct bpf_link *
bpf_program__attach_iter(struct bpf_program *prog,
const struct bpf_iter_attach_opts *opts)
{
+ DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int prog_fd, link_fd;
+ __u32 target_fd = 0;
if (!OPTS_VALID(opts, bpf_iter_attach_opts))
return ERR_PTR(-EINVAL);
+ if (OPTS_HAS(opts, map_fd)) {
+ target_fd = opts->map_fd;
+ link_create_opts.flags = BPF_ITER_LINK_MAP_FD;
+ }
+
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warning("program '%s': can't attach before loaded\n",
@@ -8304,7 +8311,8 @@ bpf_program__attach_iter(struct bpf_prog
return ERR_PTR(-ENOMEM);
link->detach = &bpf_link__detach_fd;
- link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_ITER, NULL);
+ link_fd = bpf_link_create(prog_fd, target_fd, BPF_TRACE_ITER,
+ &link_create_opts);
if (link_fd < 0) {
link_fd = -errno;
free(link);
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -264,8 +264,9 @@ LIBBPF_API struct bpf_link *bpf_map__att
struct bpf_iter_attach_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
+ __u32 map_fd;
};
-#define bpf_iter_attach_opts__last_field sz
+#define bpf_iter_attach_opts__last_field map_fd
LIBBPF_API struct bpf_link *
bpf_program__attach_iter(struct bpf_program *prog,