fs: move namei sysctls to its own file

The kernel/sysctl.c is a kitchen sink where everyone leaves
their dirty dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to
places where they actually belong. The proc sysctl maintainers
do not want to know what sysctl knobs you wish to add for your own
piece of code, we just care about the core logic.

So move namei's own sysctl knobs to its own file.

Other than the move we also avoid initializing two static
variables to 0 as this is not needed:

  * sysctl_protected_symlinks
  * sysctl_protected_hardlinks

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

3 files changed, 54 insertions, 44 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 1f9d2187c7655..7ddcf3d005649 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1020,10 +1020,60 @@ static inline void put_link(struct nameidata *nd)
 		path_put(&last->link);
 }
 
-int sysctl_protected_symlinks __read_mostly = 0;
-int sysctl_protected_hardlinks __read_mostly = 0;
-int sysctl_protected_fifos __read_mostly;
-int sysctl_protected_regular __read_mostly;
+static int sysctl_protected_symlinks __read_mostly;
+static int sysctl_protected_hardlinks __read_mostly;
+static int sysctl_protected_fifos __read_mostly;
+static int sysctl_protected_regular __read_mostly;
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table namei_sysctls[] = {
+	{
+		.procname	= "protected_symlinks",
+		.data		= &sysctl_protected_symlinks,
+		.maxlen		= sizeof(int),
+		.mode		= 0600,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "protected_hardlinks",
+		.data		= &sysctl_protected_hardlinks,
+		.maxlen		= sizeof(int),
+		.mode		= 0600,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "protected_fifos",
+		.data		= &sysctl_protected_fifos,
+		.maxlen		= sizeof(int),
+		.mode		= 0600,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_TWO,
+	},
+	{
+		.procname	= "protected_regular",
+		.data		= &sysctl_protected_regular,
+		.maxlen		= sizeof(int),
+		.mode		= 0600,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_TWO,
+	},
+	{ }
+};
+
+static int __init init_fs_namei_sysctls(void)
+{
+	register_sysctl_init("fs", namei_sysctls, "namei");
+	return 0;
+}
+early_initcall(init_fs_namei_sysctls);
+
+#endif /* CONFIG_SYSCTL */
 
 /**
  * may_follow_link - Check symlink following for unsafe situations
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 74ad6e85a2aba..fd86cf51e3038 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -81,10 +81,6 @@ extern void __init files_maxfiles_init(void);
 extern unsigned long get_max_files(void);
 extern unsigned int sysctl_nr_open;
 extern struct inodes_stat_t inodes_stat;
-extern int sysctl_protected_symlinks;
-extern int sysctl_protected_hardlinks;
-extern int sysctl_protected_fifos;
-extern int sysctl_protected_regular;
 
 typedef __kernel_rwf_t rwf_t;
 
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index a50a2f799810e..b67c4d38489e2 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2897,42 +2897,6 @@ static struct ctl_table vm_table[] = {
 
 static struct ctl_table fs_table[] = {
 	{
-		.procname	= "protected_symlinks",
-		.data		= &sysctl_protected_symlinks,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-	{
-		.procname	= "protected_hardlinks",
-		.data		= &sysctl_protected_hardlinks,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-	{
-		.procname	= "protected_fifos",
-		.data		= &sysctl_protected_fifos,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_TWO,
-	},
-	{
-		.procname	= "protected_regular",
-		.data		= &sysctl_protected_regular,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_TWO,
-	},
-	{
 		.procname	= "suid_dumpable",
 		.data		= &suid_dumpable,
 		.maxlen		= sizeof(int),