Move the umh sysctl registration to its own file, the array is
already there. We do this to remove the clutter out of kernel/sysctl.c
to avoid merge conflicts.

This also lets the sysctls not be built at all now when CONFIG_SYSCTL
is not enabled.

This has a small penalty of 23 bytes but soon we'll be removing
all the empty entries on sysctl arrays so just do this cleanup
now:

./scripts/bloat-o-meter vmlinux.base vmlinux.1
add/remove: 2/0 grow/shrink: 0/1 up/down: 49/-26 (23)
Function                                     old     new   delta
init_umh_sysctls                               -      33     +33
__pfx_init_umh_sysctls                         -      16     +16
sysctl_init_bases                            111      85     -26
Total: Before=21256914, After=21256937, chg +0.00%

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 include/linux/umh.h |  2 --
 kernel/sysctl.c     |  1 -
 kernel/umh.c        | 11 ++++++++++-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/include/linux/umh.h b/include/linux/umh.h
index 5d1f6129b847..daa6a7048c11 100644
--- a/include/linux/umh.h
+++ b/include/linux/umh.h
@@ -42,8 +42,6 @@ call_usermodehelper_setup(const char *path, char **argv, char **envp,
 extern int
 call_usermodehelper_exec(struct subprocess_info *info, int wait);
 
-extern struct ctl_table usermodehelper_table[];
-
 enum umh_disable_depth {
 	UMH_ENABLED = 0,
 	UMH_FREEZING,
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 241b817c0240..caf4a91522a1 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2322,7 +2322,6 @@ static struct ctl_table vm_table[] = {
 int __init sysctl_init_bases(void)
 {
 	register_sysctl_init("kernel", kern_table);
-	register_sysctl_init("kernel/usermodehelper", usermodehelper_table);
 #ifdef CONFIG_KEYS
 	register_sysctl_init("kernel/keys", key_sysctls);
 #endif
diff --git a/kernel/umh.c b/kernel/umh.c
index 60aa9e764a38..41088c5c39fd 100644
--- a/kernel/umh.c
+++ b/kernel/umh.c
@@ -544,7 +544,8 @@ static int proc_cap_handler(struct ctl_table *table, int write,
 	return 0;
 }
 
-struct ctl_table usermodehelper_table[] = {
+#if defined(CONFIG_SYSCTL)
+static struct ctl_table usermodehelper_table[] = {
 	{
 		.procname	= "bset",
 		.data		= &usermodehelper_bset,
@@ -561,3 +562,11 @@ struct ctl_table usermodehelper_table[] = {
 	},
 	{ }
 };
+
+static int __init init_umh_sysctls(void)
+{
+	register_sysctl_init("kernel/usermodehelper", usermodehelper_table);
+	return 0;
+}
+early_initcall(init_umh_sysctls);
+#endif /* CONFIG_SYSCTL */
-- 
2.39.2

On Wed May 31, 2023 at 2:29 AM EEST, Luis Chamberlain wrote:
> Move the umh sysctl registration to its own file, the array is
> already there. We do this to remove the clutter out of kernel/sysctl.c
> to avoid merge conflicts.
>
> This also lets the sysctls not be built at all now when CONFIG_SYSCTL
> is not enabled.
>
> This has a small penalty of 23 bytes but soon we'll be removing
> all the empty entries on sysctl arrays so just do this cleanup
> now:
>
> ./scripts/bloat-o-meter vmlinux.base vmlinux.1
> add/remove: 2/0 grow/shrink: 0/1 up/down: 49/-26 (23)
> Function                                     old     new   delta
> init_umh_sysctls                               -      33     +33
> __pfx_init_umh_sysctls                         -      16     +16
> sysctl_init_bases                            111      85     -26
> Total: Before=21256914, After=21256937, chg +0.00%
>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
>  include/linux/umh.h |  2 --
>  kernel/sysctl.c     |  1 -
>  kernel/umh.c        | 11 ++++++++++-
>  3 files changed, 10 insertions(+), 4 deletions(-)

Acked-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko