bpf: Use BTF_ID to resolve bpf_ctx_convert struct

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>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200711215329.41165-7-jolsa@kernel.org

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 71140b7..a710e3e 100644 (file)
--- 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);