Merge branch 'libbpf: rename btf__get_from_id() and btf__load() APIs, support split BTF'

Quentin Monnet says:

====================

As part of the effort to move towards a v1.0 for libbpf [0], this set
improves some confusing function names related to BTF loading from and to
the kernel:

- btf__load() becomes btf__load_into_kernel().
- btf__get_from_id becomes btf__load_from_kernel_by_id().
- A new version btf__load_from_kernel_by_id_split() extends the former to
  add support for split BTF.

The last patch is a trivial change to bpftool to add support for dumping
split BTF objects by referencing them by their id (and not only by their
BTF path).

[0] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#btfh-apis

v3:
- Use libbpf_err_ptr() in btf__load_from_kernel_by_id(), ERR_PTR() in
  bpftool's get_map_kv_btf().
- Move the definition of btf__load_from_kernel_by_id() closer to the
  btf__parse() group in btf.h (move the legacy function with it).
- Fix a bug on the return value in libbpf_find_prog_btf_id(), as a new
  patch.
- Move the btf__free() fixes to their own patch.
- Add "Fixes:" tags to relevant patches.

v2:
- Remove deprecation marking of legacy functions (patch 4/6 from v1).
- Make btf__load_from_kernel_by_id{,_split}() return the btf struct, adjust
  surrounding code and call btf__free() when missing.
- Add new functions to v0.5.0 API (and not v0.6.0).
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

1 files changed, 6 insertions, 5 deletions

diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index cdecda1ddd36..996d025b8ed8 100644
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -223,10 +223,10 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 			free(info_linear);
 			return -1;
 		}
-		if (btf__get_from_id(info->btf_id, &btf)) {
+		btf = btf__load_from_kernel_by_id(info->btf_id);
+		if (libbpf_get_error(btf)) {
 			pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
 			err = -1;
-			btf = NULL;
 			goto out;
 		}
 		perf_env__fetch_btf(env, info->btf_id, btf);
@@ -296,7 +296,7 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 
 out:
 	free(info_linear);
-	free(btf);
+	btf__free(btf);
 	return err ? -1 : 0;
 }
 
@@ -478,7 +478,8 @@ static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 	if (btf_id == 0)
 		goto out;
 
-	if (btf__get_from_id(btf_id, &btf)) {
+	btf = btf__load_from_kernel_by_id(btf_id);
+	if (libbpf_get_error(btf)) {
 		pr_debug("%s: failed to get BTF of id %u, aborting\n",
 			 __func__, btf_id);
 		goto out;
@@ -486,7 +487,7 @@ static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 	perf_env__fetch_btf(env, btf_id, btf);
 
 out:
-	free(btf);
+	btf__free(btf);
 	close(fd);
 }