[RFC PATCH v2 1/5] jump_label: split out declaration parts into its own headers

Michal Hocko
2020-10-09T12:30:04Z

From: Michal Hocko <mhocko@suse.com>

Follow up patch would like to add a static key into kernel.h and that
requires a declaration of the key in the same file. Including
jump_label.h into kernel.h is not possible due to headers dependencies.

Separate parts needed for declaration into its own header which doesn't
depend on any other header file. kernel.h can include jump_abel_type.h.

Signed-off-by: Michal Hocko <mhocko@suse.com>
---
include/linux/jump_label.h | 44 +----------------------------
include/linux/jump_label_type.h | 49 +++++++++++++++++++++++++++++++++
2 files changed, 50 insertions(+), 43 deletions(-)
create mode 100644 include/linux/jump_label_type.h

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 32809624d422..bd0d846d0bde 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -75,6 +75,7 @@

#include <linux/types.h>
#include <linux/compiler.h>
+#include <linux/jump_label_type.h>

extern bool static_key_initialized;

@@ -82,35 +83,6 @@ extern bool static_key_initialized;
"%s(): static key '%pS' used before call to jump_label_init()", \
__func__, (key))

-#ifdef CONFIG_JUMP_LABEL
-
-struct static_key {
- atomic_t enabled;
-/*
- * Note:
- * To make anonymous unions work with old compilers, the static
- * initialization of them requires brackets. This creates a dependency
- * on the order of the struct with the initializers. If any fields
- * are added, STATIC_KEY_INIT_TRUE and STATIC_KEY_INIT_FALSE may need
- * to be modified.
- *
- * bit 0 => 1 if key is initially true
- * 0 if initially false
- * bit 1 => 1 if points to struct static_key_mod
- * 0 if points to struct jump_entry
- */
- union {
- unsigned long type;
- struct jump_entry *entries;
- struct static_key_mod *next;
- };
-};
-
-#else
-struct static_key {
- atomic_t enabled;
-};
-#endif /* CONFIG_JUMP_LABEL */
#endif /* __ASSEMBLY__ */

#ifdef CONFIG_JUMP_LABEL
@@ -343,14 +315,6 @@ static inline void static_key_disable(struct static_key *key)
* All the below code is macros in order to play type games.
*/

-struct static_key_true {
- struct static_key key;
-};
-
-struct static_key_false {
- struct static_key key;
-};
-
#define STATIC_KEY_TRUE_INIT (struct static_key_true) { .key = STATIC_KEY_INIT_TRUE, }
#define STATIC_KEY_FALSE_INIT (struct static_key_false){ .key = STATIC_KEY_INIT_FALSE, }

@@ -360,18 +324,12 @@ struct static_key_false {
#define DEFINE_STATIC_KEY_TRUE_RO(name) \
struct static_key_true name __ro_after_init = STATIC_KEY_TRUE_INIT

-#define DECLARE_STATIC_KEY_TRUE(name) \
- extern struct static_key_true name
-
#define DEFINE_STATIC_KEY_FALSE(name) \
struct static_key_false name = STATIC_KEY_FALSE_INIT

#define DEFINE_STATIC_KEY_FALSE_RO(name) \
struct static_key_false name __ro_after_init = STATIC_KEY_FALSE_INIT

-#define DECLARE_STATIC_KEY_FALSE(name) \
- extern struct static_key_false name
-
#define DEFINE_STATIC_KEY_ARRAY_TRUE(name, count) \
struct static_key_true name[count] = { \
[0 ... (count) - 1] = STATIC_KEY_TRUE_INIT, \
diff --git a/include/linux/jump_label_type.h b/include/linux/jump_label_type.h
new file mode 100644
index 000000000000..37cb02c12f35
--- /dev/null
+++ b/include/linux/jump_label_type.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_JUMP_LABEL_TYPE_H
+#define _LINUX_JUMP_LABEL_TYPE_H
+
+#ifdef CONFIG_JUMP_LABEL
+
+struct static_key {
+ atomic_t enabled;
+/*
+ * Note:
+ * To make anonymous unions work with old compilers, the static
+ * initialization of them requires brackets. This creates a dependency
+ * on the order of the struct with the initializers. If any fields
+ * are added, STATIC_KEY_INIT_TRUE and STATIC_KEY_INIT_FALSE may need
+ * to be modified.
+ *
+ * bit 0 => 1 if key is initially true
+ * 0 if initially false
+ * bit 1 => 1 if points to struct static_key_mod
+ * 0 if points to struct jump_entry
+ */
+ union {
+ unsigned long type;
+ struct jump_entry *entries;
+ struct static_key_mod *next;
+ };
+};
+
+#else
+struct static_key {
+ atomic_t enabled;
+};
+#endif /* CONFIG_JUMP_LABEL */
+
+struct static_key_true {
+ struct static_key key;
+};
+
+struct static_key_false {
+ struct static_key key;
+};
+
+#define DECLARE_STATIC_KEY_TRUE(name) \
+ extern struct static_key_true name
+
+#define DECLARE_STATIC_KEY_FALSE(name) \
+ extern struct static_key_false name
+
+#endif /* _LINUX_JUMP_LABEL_TYPE_H */
--
2.28.0