[PATCH bpf-next v3 01/10] bpf: btf: Add btf_type_by_name_kind

[KP Singh <kpsingh@chromium.org>]

From: KP Singh <kpsingh@google.com>

- The LSM code does the combination of btf_find_by_name_kind and
  btf_type_by_id a couple of times to figure out the BTF type for
  security_hook_heads and security_list_options.
- Add an extern for btf_vmlinux in btf.h

Signed-off-by: KP Singh <kpsingh@google.com>
Reviewed-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Florent Revest <revest@google.com>
Reviewed-by: Thomas Garnier <thgarnie@google.com>
---
 include/linux/btf.h |  3 +++
 kernel/bpf/btf.c    | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/btf.h b/include/linux/btf.h
index 5c1ea99b480f..d4e859f90a39 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);	\
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 32963b6d5a9c..ea53c16802cb 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -441,6 +441,18 @@ 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)
+{
+	s32 type_id;
+
+	type_id = btf_find_by_name_kind(btf, name, kind);
+	if (type_id < 0)
+		return ERR_PTR(type_id);
+
+	return btf_type_by_id(btf, type_id);
+}
+
 /* Types that act only as a source, not sink or intermediate
  * type when resolving.
  */
-- 
2.20.1