linux-kernel - [PATCH bpf-next v2 01/10] bpf: btf: Make some of the API visible outside BTF

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Message-Id: <20200115171333.28811-2-kpsingh@chromium.org>
Date:   Wed, 15 Jan 2020 18:13:24 +0100
From:   KP Singh <kpsingh@...omium.org>
To:     linux-kernel@...r.kernel.org, bpf@...r.kernel.org,
        linux-security-module@...r.kernel.org
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        James Morris <jmorris@...ei.org>,
        Kees Cook <keescook@...omium.org>,
        Thomas Garnier <thgarnie@...omium.org>,
        Michael Halcrow <mhalcrow@...gle.com>,
        Paul Turner <pjt@...gle.com>,
        Brendan Gregg <brendan.d.gregg@...il.com>,
        Jann Horn <jannh@...gle.com>,
        Matthew Garrett <mjg59@...gle.com>,
        Christian Brauner <christian@...uner.io>,
        Mickaël Salaün <mic@...ikod.net>,
        Florent Revest <revest@...omium.org>,
        Brendan Jackman <jackmanb@...omium.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Stanislav Fomichev <sdf@...gle.com>,
        Quentin Monnet <quentin.monnet@...ronome.com>,
        Andrey Ignatov <rdna@...com>, Joe Stringer <joe@...d.net.nz>
Subject: [PATCH bpf-next v2 01/10] bpf: btf: Make some of the API visible outside BTF

From: KP Singh <kpsingh@...gle.com>

- Add an extern for btf_vmlinux in btf.h
- Add btf_type_by_name_kind, the LSM code does the combination of
  btf_find_by_name_kind and btf_type_by_id quite often.

Signed-off-by: KP Singh <kpsingh@...gle.com>
---
 include/linux/btf.h |  8 ++++++++
 kernel/bpf/btf.c    | 17 +++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/include/linux/btf.h b/include/linux/btf.h
index 881e9b76ef49..dc650d294bc4 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -15,6 +15,7 @@ struct btf_type;
 union bpf_attr;
 
 extern const struct file_operations btf_fops;
+extern struct btf *btf_vmlinux;
 
 void btf_put(struct btf *btf);
 int btf_new_fd(const union bpf_attr *attr);
@@ -66,6 +67,8 @@ const struct btf_type *
 btf_resolve_size(const struct btf *btf, const struct btf_type *type,
 		 u32 *type_size, const struct btf_type **elem_type,
 		 u32 *total_nelems);
+const struct btf_type *btf_type_by_name_kind(
+	struct btf *btf, const char *name, u8 kind);
 
 #define for_each_member(i, struct_type, member)			\
 	for (i = 0, member = btf_type_member(struct_type);	\
@@ -142,6 +145,11 @@ static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
 {
 	return NULL;
 }
+static inline const struct btf_type *btf_type_by_name_kind(
+	struct btf *btf, const char *name, u8 kind)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
 static inline const char *btf_name_by_offset(const struct btf *btf,
 					     u32 offset)
 {
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 832b5d7fd892..b8968cec8718 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -436,6 +436,23 @@ const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
 	return NULL;
 }
 
+const struct btf_type *btf_type_by_name_kind(
+	struct btf *btf, const char *name, u8 kind)
+{
+	const struct btf_type *t;
+	s32 type_id;
+
+	type_id = btf_find_by_name_kind(btf, name, kind);
+	if (type_id < 0)
+		return ERR_PTR(-EINVAL);
+
+	t = btf_type_by_id(btf, type_id);
+	if (!t)
+		return ERR_PTR(-EINVAL);
+
+	return t;
+}
+
 /* Types that act only as a source, not sink or intermediate
  * type when resolving.
  */
-- 
2.20.1