fork: mv threads-max into kernel/fork.c

make sysctl_max_threads static as it no longer needs to be exported into
sysctl.c.

This is part of a greater effort to move ctl tables into their
respective subsystems which will reduce the merge conflicts in
kernel/sysctl.c.

Reviewed-by: Luis Chamberlain <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

Author: Joelgranados

include/linux/sysctl.h

@@ -284,7 +284,4 @@ static inline bool sysctl_is_alias(char *param)
 }
 #endif /* CONFIG_SYSCTL */
 
-int sysctl_max_threads(const struct ctl_table *table, int write, void *buffer,
-		size_t *lenp, loff_t *ppos);
-
 #endif /* _LINUX_SYSCTL_H */

kernel/fork.c

@@ -3216,7 +3216,7 @@ int unshare_files(void)
 	return 0;
 }
 
-int sysctl_max_threads(const struct ctl_table *table, int write,
+static int sysctl_max_threads(const struct ctl_table *table, int write,
 		       void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table t;
@@ -3238,3 +3238,21 @@ int sysctl_max_threads(const struct ctl_table *table, int write,
 
 	return 0;
 }
+
+static const struct ctl_table fork_sysctl_table[] = {
+	{
+		.procname	= "threads-max",
+		.data		= NULL,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= sysctl_max_threads,
+	},
+};
+
+static int __init init_fork_sysctl(void)
+{
+	register_sysctl_init("kernel", fork_sysctl_table);
+	return 0;
+}
+
+subsys_initcall(init_fork_sysctl);

kernel/sysctl.c

@@ -1630,13 +1630,6 @@ static const struct ctl_table kern_table[] = {
 		.proc_handler	= proc_do_cad_pid,
 	},
 #endif
-	{
-		.procname	= "threads-max",
-		.data		= NULL,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= sysctl_max_threads,
-	},
 	{
 		.procname	= "overflowuid",
 		.data		= &overflowuid,