netdev - [PATCH v5 bpf-next 6/9] bpf: Use BTF_ID to resolve bpf_ctx

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Date:   Fri,  3 Jul 2020 11:51:08 +0200
From:   Jiri Olsa <jolsa@...nel.org>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        Martin KaFai Lau <kafai@...com>,
        David Miller <davem@...hat.com>,
        John Fastabend <john.fastabend@...il.com>,
        Wenbo Zhang <ethercflow@...il.com>,
        KP Singh <kpsingh@...omium.org>,
        Andrii Nakryiko <andriin@...com>,
        Brendan Gregg <bgregg@...flix.com>,
        Florent Revest <revest@...omium.org>,
        Al Viro <viro@...iv.linux.org.uk>
Subject: [PATCH v5 bpf-next 6/9] 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@...nel.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