[PATCH bpf-next v4 03/11] btf: Add BTF_ID_LIST_SINGLE macro

[Lorenz Bauer <lmb@xxxxxxxxxxxxxx>]

Add a convenience macro that allows defining a BTF ID list with
a single item. This lets us cut down on repetitive macros.

Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
Suggested-by: Andrii Nakryiko <andriin@xxxxxx>
Acked-by: Martin KaFai Lau <kafai@xxxxxx>
---
 include/linux/btf_ids.h       | 8 ++++++++
 tools/include/linux/btf_ids.h | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 210b086188a3..57890b357f85 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -76,6 +76,13 @@ extern u32 name[];
 #define BTF_ID_LIST_GLOBAL(name)			\
 __BTF_ID_LIST(name, globl)
 
+/* The BTF_ID_LIST_SINGLE macro defines a BTF_ID_LIST with
+ * a single entry.
+ */
+#define BTF_ID_LIST_SINGLE(name, prefix, typename)	\
+	BTF_ID_LIST(name) \
+	BTF_ID(prefix, typename)
+
 /*
  * The BTF_ID_UNUSED macro defines 4 zero bytes.
  * It's used when we want to define 'unused' entry
@@ -140,6 +147,7 @@ extern struct btf_id_set name;
 #define BTF_ID(prefix, name)
 #define BTF_ID_UNUSED
 #define BTF_ID_LIST_GLOBAL(name) u32 name[1];
+#define BTF_ID_LIST_SINGLE(name, prefix, typename) static u32 name[1];
 #define BTF_SET_START(name) static struct btf_id_set name = { 0 };
 #define BTF_SET_START_GLOBAL(name) static struct btf_id_set name = { 0 };
 #define BTF_SET_END(name)
diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h
index 210b086188a3..57890b357f85 100644
--- a/tools/include/linux/btf_ids.h
+++ b/tools/include/linux/btf_ids.h
@@ -76,6 +76,13 @@ extern u32 name[];
 #define BTF_ID_LIST_GLOBAL(name)			\
 __BTF_ID_LIST(name, globl)
 
+/* The BTF_ID_LIST_SINGLE macro defines a BTF_ID_LIST with
+ * a single entry.
+ */
+#define BTF_ID_LIST_SINGLE(name, prefix, typename)	\
+	BTF_ID_LIST(name) \
+	BTF_ID(prefix, typename)
+
 /*
  * The BTF_ID_UNUSED macro defines 4 zero bytes.
  * It's used when we want to define 'unused' entry
@@ -140,6 +147,7 @@ extern struct btf_id_set name;
 #define BTF_ID(prefix, name)
 #define BTF_ID_UNUSED
 #define BTF_ID_LIST_GLOBAL(name) u32 name[1];
+#define BTF_ID_LIST_SINGLE(name, prefix, typename) static u32 name[1];
 #define BTF_SET_START(name) static struct btf_id_set name = { 0 };
 #define BTF_SET_START_GLOBAL(name) static struct btf_id_set name = { 0 };
 #define BTF_SET_END(name)
-- 
2.25.1