[PATCH v4 7/8] sysctl: Refactor base paths registrations

[Joel Granados]

This is part of the general push to deprecate register_sysctl_paths and
register_sysctl_table. The old way of doing this through
register_sysctl_base and DECLARE_SYSCTL_BASE macro is replaced with a
call to register_sysctl_init. The 5 base paths affected are: "kernel",
"vm", "debug", "dev" and "fs".

We remove the register_sysctl_base function and the DECLARE_SYSCTL_BASE
macro since they are no longer needed.

In order to quickly acertain that the paths did not actually change I
executed `find /proc/sys/ | sha1sum` and made sure that the sha was the
same before and after the commit.

We end up saving 563 bytes with this change:

./scripts/bloat-o-meter vmlinux.0.base vmlinux.1.refactor-base-paths
add/remove: 0/5 grow/shrink: 2/0 up/down: 77/-640 (-563)
Function                                     old     new   delta
sysctl_init_bases                             55     111     +56
init_fs_sysctls                               12      33     +21
vm_base_table                                128       -    -128
kernel_base_table                            128       -    -128
fs_base_table                                128       -    -128
dev_base_table                               128       -    -128
debug_base_table                             128       -    -128
Total: Before=21258215, After=21257652, chg -0.00%

Signed-off-by: Joel Granados <j.granados@xxxxxxxxxxx>
[mcgrof: modified to use register_sysctl_init() over register_sysctl()
 and add bloat-o-meter stats]
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Tested-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
---
 fs/sysctls.c           |  5 ++---
 include/linux/sysctl.h | 23 -----------------------
 kernel/sysctl.c        | 30 +++++++++---------------------
 3 files changed, 11 insertions(+), 47 deletions(-)

diff --git a/fs/sysctls.c b/fs/sysctls.c
index c701273c9432..76a0aee8c229 100644
--- a/fs/sysctls.c
+++ b/fs/sysctls.c
@@ -29,11 +29,10 @@ static struct ctl_table fs_shared_sysctls[] = {
 	{ }
 };
 
-DECLARE_SYSCTL_BASE(fs, fs_shared_sysctls);
-
 static int __init init_fs_sysctls(void)
 {
-	return register_sysctl_base(fs);
+	register_sysctl_init("fs", fs_shared_sysctls);
+	return 0;
 }
 
 early_initcall(init_fs_sysctls);
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 218e56a26fb0..653b66c762b1 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -197,20 +197,6 @@ struct ctl_path {
 
 #ifdef CONFIG_SYSCTL
 
-#define DECLARE_SYSCTL_BASE(_name, _table)				\
-static struct ctl_table _name##_base_table[] = {			\
-	{								\
-		.procname	= #_name,				\
-		.mode		= 0555,					\
-		.child		= _table,				\
-	},								\
-	{ },								\
-}
-
-extern int __register_sysctl_base(struct ctl_table *base_table);
-
-#define register_sysctl_base(_name) __register_sysctl_base(_name##_base_table)
-
 void proc_sys_poll_notify(struct ctl_table_poll *poll);
 
 extern void setup_sysctl_set(struct ctl_table_set *p,
@@ -247,15 +233,6 @@ extern struct ctl_table sysctl_mount_point[];
 
 #else /* CONFIG_SYSCTL */
 
-#define DECLARE_SYSCTL_BASE(_name, _table)
-
-static inline int __register_sysctl_base(struct ctl_table *base_table)
-{
-	return 0;
-}
-
-#define register_sysctl_base(table) __register_sysctl_base(table)
-
 static inline void register_sysctl_init(const char *path, struct ctl_table *table)
 {
 }
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index bfe53e835524..73fa9cf7ee11 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1782,11 +1782,6 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= sysctl_max_threads,
 	},
-	{
-		.procname	= "usermodehelper",
-		.mode		= 0555,
-		.child		= usermodehelper_table,
-	},
 	{
 		.procname	= "overflowuid",
 		.data		= &overflowuid,
@@ -1962,13 +1957,6 @@ static struct ctl_table kern_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 #endif
-#ifdef CONFIG_KEYS
-	{
-		.procname	= "keys",
-		.mode		= 0555,
-		.child		= key_sysctls,
-	},
-#endif
 #ifdef CONFIG_PERF_EVENTS
 	/*
 	 * User-space scripts rely on the existence of this file
@@ -2348,17 +2336,17 @@ static struct ctl_table dev_table[] = {
 	{ }
 };
 
-DECLARE_SYSCTL_BASE(kernel, kern_table);
-DECLARE_SYSCTL_BASE(vm, vm_table);
-DECLARE_SYSCTL_BASE(debug, debug_table);
-DECLARE_SYSCTL_BASE(dev, dev_table);
-
 int __init sysctl_init_bases(void)
 {
-	register_sysctl_base(kernel);
-	register_sysctl_base(vm);
-	register_sysctl_base(debug);
-	register_sysctl_base(dev);
+	register_sysctl_init("kernel", kern_table);
+	register_sysctl_init("kernel/usermodehelper", usermodehelper_table);
+#ifdef CONFIG_KEYS
+	register_sysctl_init("kernel/keys", key_sysctls);
+#endif
+
+	register_sysctl_init("vm", vm_table);
+	register_sysctl_init("debug", debug_table);
+	register_sysctl_init("dev", dev_table);
 
 	return 0;
 }
-- 
2.30.2