sgi-xp: simplify sysctl registration

Although this driver is a good use case for having a directory
that is not other directories and then subdirectories with more
entries, the usage of register_sysctl_table() can recurse and
increases complexity so to avoid that just split out the
registration to each directory with its own entries.

register_sysctl_table() is a deprecated compatibility wrapper.
register_sysctl() can do the directory creation for you so just use
that.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lore.kernel.org/r/20230302204612.782387-6-mcgrof@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/sgi-xp/xpc_main.c

@@ -93,7 +93,7 @@ int xpc_disengage_timelimit = XPC_DISENGAGE_DEFAULT_TIMELIMIT;
 static int xpc_disengage_min_timelimit;	/* = 0 */
 static int xpc_disengage_max_timelimit = 120;
 
-static struct ctl_table xpc_sys_xpc_hb_dir[] = {
+static struct ctl_table xpc_sys_xpc_hb[] = {
 	{
 	 .procname = "hb_interval",
 	 .data = &xpc_hb_interval,
@@ -112,11 +112,7 @@ static struct ctl_table xpc_sys_xpc_hb_dir[] = {
 	 .extra2 = &xpc_hb_check_max_interval},
 	{}
 };
-static struct ctl_table xpc_sys_xpc_dir[] = {
-	{
-	 .procname = "hb",
-	 .mode = 0555,
-	 .child = xpc_sys_xpc_hb_dir},
+static struct ctl_table xpc_sys_xpc[] = {
 	{
 	 .procname = "disengage_timelimit",
 	 .data = &xpc_disengage_timelimit,
@@ -127,14 +123,9 @@ static struct ctl_table xpc_sys_xpc_dir[] = {
 	 .extra2 = &xpc_disengage_max_timelimit},
 	{}
 };
-static struct ctl_table xpc_sys_dir[] = {
-	{
-	 .procname = "xpc",
-	 .mode = 0555,
-	 .child = xpc_sys_xpc_dir},
-	{}
-};
+
 static struct ctl_table_header *xpc_sysctl;
+static struct ctl_table_header *xpc_sysctl_hb;
 
 /* non-zero if any remote partition disengage was timed out */
 int xpc_disengage_timedout;
@@ -1041,6 +1032,8 @@ xpc_do_exit(enum xp_retval reason)
 
 	if (xpc_sysctl)
 		unregister_sysctl_table(xpc_sysctl);
+	if (xpc_sysctl_hb)
+		unregister_sysctl_table(xpc_sysctl_hb);
 
 	xpc_teardown_partitions();
 
@@ -1243,7 +1236,8 @@ xpc_init(void)
 		goto out_1;
 	}
 
-	xpc_sysctl = register_sysctl_table(xpc_sys_dir);
+	xpc_sysctl = register_sysctl("xpc", xpc_sys_xpc);
+	xpc_sysctl_hb = register_sysctl("xpc/hb", xpc_sys_xpc_hb);
 
 	/*
 	 * Fill the partition reserved page with the information needed by
@@ -1308,6 +1302,8 @@ xpc_init(void)
 	(void)unregister_die_notifier(&xpc_die_notifier);
 	(void)unregister_reboot_notifier(&xpc_reboot_notifier);
 out_2:
+	if (xpc_sysctl_hb)
+		unregister_sysctl_table(xpc_sysctl_hb);
 	if (xpc_sysctl)
 		unregister_sysctl_table(xpc_sysctl);