[PATCH v4 1/4] sysctl: Add register_sysctl_init() interface

[Xiaoming Ni]

In order to eliminate the duplicate code for registering the sysctl
interface during the initialization of each feature, add the
register_sysctl_init() interface

Signed-off-by: Xiaoming Ni <nixiaoming@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 include/linux/sysctl.h |  2 ++
 kernel/sysctl.c        | 19 +++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 50bb7f3..857ba93 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -197,6 +197,8 @@ struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
 void unregister_sysctl_table(struct ctl_table_header * table);
 
 extern int sysctl_init(void);
+extern void register_sysctl_init(const char *path, struct ctl_table *table,
+				 const char *table_name);
 void do_sysctl_args(void);
 
 extern int pwrsw_enabled;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index cc1fcba..8afd713 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -3358,6 +3358,25 @@ int __init sysctl_init(void)
 	kmemleak_not_leak(hdr);
 	return 0;
 }
+
+/*
+ * The sysctl interface is used to modify the interface value,
+ * but the feature interface has default values. Even if register_sysctl fails,
+ * the feature body function can also run. At the same time, malloc small
+ * fragment of memory during the system initialization phase, almost does
+ * not fail. Therefore, the function return is designed as void
+ */
+void __init register_sysctl_init(const char *path, struct ctl_table *table,
+				 const char *table_name)
+{
+	struct ctl_table_header *hdr = register_sysctl(path, table);
+
+	if (unlikely(!hdr)) {
+		pr_err("failed when register_sysctl %s to %s\n", table_name, path);
+		return;
+	}
+	kmemleak_not_leak(hdr);
+}
 #endif /* CONFIG_SYSCTL */
 /*
  * No sense putting this after each symbol definition, twice,
-- 
1.8.5.6