Merge tag 'sysctl-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

Pull sysctl updates from Luis Chamberlain:
 "To help make the move of sysctls out of kernel/sysctl.c not incur a
  size penalty sysctl has been changed to allow us to not require the
  sentinel, the final empty element on the sysctl array. Joel Granados
  has been doing all this work.

  In the v6.6 kernel we got the major infrastructure changes required to
  support this. For v6.7 we had all arch/ and drivers/ modified to
  remove the sentinel. For v6.8-rc1 we get a few more updates for fs/
  directory only.

  The kernel/ directory is left but we'll save that for v6.9-rc1 as
  those patches are still being reviewed. After that we then can expect
  also the removal of the no longer needed check for procname == NULL.

  Let us recap the purpose of this work:

   - this helps reduce the overall build time size of the kernel and run
     time memory consumed by the kernel by about ~64 bytes per array

   - the extra 64-byte penalty is no longer inncurred now when we move
     sysctls out from kernel/sysctl.c to their own files

  Thomas Weißschuh also sent a few cleanups, for v6.9-rc1 we expect to
  see further work by Thomas Weißschuh with the constificatin of the
  struct ctl_table.

  Due to Joel Granados's work, and to help bring in new blood, I have
  suggested for him to become a maintainer and he's accepted. So for
  v6.9-rc1 I look forward to seeing him sent you a pull request for
  further sysctl changes. This also removes Iurii Zaikin as a maintainer
  as he has moved on to other projects and has had no time to help at
  all"

* tag 'sysctl-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  sysctl: remove struct ctl_path
  sysctl: delete unused define SYSCTL_PERM_EMPTY_DIR
  coda: Remove the now superfluous sentinel elements from ctl_table array
  sysctl: Remove the now superfluous sentinel elements from ctl_table array
  fs: Remove the now superfluous sentinel elements from ctl_table array
  cachefiles: Remove the now superfluous sentinel element from ctl_table array
  sysclt: Clarify the results of selftest run
  sysctl: Add a selftest for handling empty dirs
  sysctl: Fix out of bounds access for empty sysctl registers
  MAINTAINERS: Add Joel Granados as co-maintainer for proc sysctl
  MAINTAINERS: remove Iurii Zaikin from proc sysctl

1 files changed, 29 insertions, 2 deletions

diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c
index 8036aa91a1cb..9321d850931f 100644
--- a/lib/test_sysctl.c
+++ b/lib/test_sysctl.c
@@ -35,6 +35,8 @@ static struct {
 	struct ctl_table_header *test_h_setup_node;
 	struct ctl_table_header *test_h_mnt;
 	struct ctl_table_header *test_h_mnterror;
+	struct ctl_table_header *empty_add;
+	struct ctl_table_header *empty;
 } sysctl_test_headers;
 
 struct test_sysctl_data {
@@ -130,7 +132,6 @@ static struct ctl_table test_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_do_large_bitmap,
 	},
-	{ }
 };
 
 static void test_sysctl_calc_match_int_ok(void)
@@ -184,7 +185,6 @@ static struct ctl_table test_table_unregister[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
 	},
-	{}
 };
 
 static int test_sysctl_run_unregister_nested(void)
@@ -220,6 +220,25 @@ static int test_sysctl_run_register_mount_point(void)
 	return 0;
 }
 
+static struct ctl_table test_table_empty[] = { };
+
+static int test_sysctl_run_register_empty(void)
+{
+	/* Tets that an empty dir can be created */
+	sysctl_test_headers.empty_add
+		= register_sysctl("debug/test_sysctl/empty_add", test_table_empty);
+	if (!sysctl_test_headers.empty_add)
+		return -ENOMEM;
+
+	/* Test that register on top of an empty dir works */
+	sysctl_test_headers.empty
+		= register_sysctl("debug/test_sysctl/empty_add/empty", test_table_empty);
+	if (!sysctl_test_headers.empty)
+		return -ENOMEM;
+
+	return 0;
+}
+
 static int __init test_sysctl_init(void)
 {
 	int err;
@@ -233,6 +252,10 @@ static int __init test_sysctl_init(void)
 		goto out;
 
 	err = test_sysctl_run_register_mount_point();
+	if (err)
+		goto out;
+
+	err = test_sysctl_run_register_empty();
 
 out:
 	return err;
@@ -248,6 +271,10 @@ static void __exit test_sysctl_exit(void)
 		unregister_sysctl_table(sysctl_test_headers.test_h_mnt);
 	if (sysctl_test_headers.test_h_mnterror)
 		unregister_sysctl_table(sysctl_test_headers.test_h_mnterror);
+	if (sysctl_test_headers.empty)
+		unregister_sysctl_table(sysctl_test_headers.empty);
+	if (sysctl_test_headers.empty_add)
+		unregister_sysctl_table(sysctl_test_headers.empty_add);
 }
 
 module_exit(test_sysctl_exit);