[PATCH v5 bpf-next 6/9] bpf: Use BTF_ID to resolve bpf_ctx_convert struct

Jiri Olsa
2020-07-03T09:51:55Z

This way the ID is resolved during compile time,
and we can remove the runtime name search.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/bpf/btf.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 71140b73ae3c..a710e3ee1f18 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -18,6 +18,7 @@
#include <linux/sort.h>
#include <linux/bpf_verifier.h>
#include <linux/btf.h>
+#include <linux/btf_ids.h>
#include <linux/skmsg.h>
#include <linux/perf_event.h>
#include <net/sock.h>
@@ -3621,12 +3622,15 @@ static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
return kern_ctx_type->type;
}

+BTF_ID_LIST(bpf_ctx_convert_btf_id)
+BTF_ID(struct, bpf_ctx_convert)
+
struct btf *btf_parse_vmlinux(void)
{
struct btf_verifier_env *env = NULL;
struct bpf_verifier_log *log;
struct btf *btf = NULL;
- int err, btf_id;
+ int err;

env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
if (!env)
@@ -3659,14 +3663,8 @@ struct btf *btf_parse_vmlinux(void)
if (err)
goto errout;

- /* find struct bpf_ctx_convert for type checking later */
- btf_id = btf_find_by_name_kind(btf, "bpf_ctx_convert", BTF_KIND_STRUCT);
- if (btf_id < 0) {
- err = btf_id;
- goto errout;
- }
/* btf_parse_vmlinux() runs under bpf_verifier_lock */
- bpf_ctx_convert.t = btf_type_by_id(btf, btf_id);
+ bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);

/* find bpf map structs for map_ptr access checking */
err = btf_vmlinux_map_ids_init(btf, log);
--
2.25.4