Subject: [PATCH v2 7/8] cdrom: simplify subdirectory registration with register_sysctl()

From: Luis Chamberlain <[email-masked]>
Date: Tue, 23 Nov 2021 12:24:21 -0800

There is no need to user boiler plate code to specify a set of base
directories we're going to stuff sysctls under. Simplify this by using
register_sysctl() and specifying the directory path directly.

// pycocci sysctl-subdir-register-sysctl-simplify.cocci PATH

@c1@
expression E1;
identifier subdir, sysctls;
@@

static struct ctl_table subdir[] = {
	{
		.procname = E1,
		.maxlen = 0,
		.mode = 0555,
		.child = sysctls,
	},
	{ }
};

@c2@
identifier c1.subdir;

expression E2;
identifier base;
@@

static struct ctl_table base[] = {
	{
		.procname = E2,
		.maxlen = 0,
		.mode = 0555,
		.child = subdir,
	},
	{ }
};

@c3@
identifier c2.base;
identifier header;
@@

header = register_sysctl_table(base);

@r1 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.subdir, c1.sysctls;
@@

-static struct ctl_table subdir[] = {
-	{
-		.procname = E1,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = sysctls,
-	},
-	{ }
-};

@r2 depends on c1 && c2 && c3@
identifier c1.subdir;

expression c2.E2;
identifier c2.base;
@@
-static struct ctl_table base[] = {
-	{
-		.procname = E2,
-		.maxlen = 0,
-		.mode = 0555,
-		.child = subdir,
-	},
-	{ }
-};

@initialize:python@
@@

def make_my_fresh_expression(s1, s2):
  return '"' + s1.strip('"') + "/" + s2.strip('"') + '"'

@r3 depends on c1 && c2 && c3@
expression c1.E1;
identifier c1.sysctls;
expression c2.E2;
identifier c2.base;
identifier c3.header;
fresh identifier E3 = script:python(E2, E1) { make_my_fresh_expression(E2, E1) };
@@

header =
-register_sysctl_table(base);
+register_sysctl(E3, sysctls);

Generated-by: Coccinelle SmPL
Signed-off-by: Luis Chamberlain <[email-masked]>
---
 drivers/cdrom/cdrom.c | 23 +----------------------
 1 file changed, 1 insertion(+), 22 deletions(-)

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 9877e413fce3..1b57d4666e43 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -3691,27 +3691,6 @@ static struct ctl_table cdrom_table[] = {
 	},
 	{ }
 };
-
-static struct ctl_table cdrom_cdrom_table[] = {
-	{
-		.procname	= "cdrom",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= cdrom_table,
-	},
-	{ }
-};
-
-/* Make sure that /proc/sys/dev is there */
-static struct ctl_table cdrom_root_table[] = {
-	{
-		.procname	= "dev",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= cdrom_cdrom_table,
-	},
-	{ }
-};
 static struct ctl_table_header *cdrom_sysctl_header;
 
 static void cdrom_sysctl_register(void)
@@ -3721,7 +3700,7 @@ static void cdrom_sysctl_register(void)
 	if (!atomic_add_unless(&initialized, 1, 1))
 		return;
 
-	cdrom_sysctl_header = register_sysctl_table(cdrom_root_table);
+	cdrom_sysctl_header = register_sysctl("dev/cdrom", cdrom_table);
 
 	/* set the defaults */
 	cdrom_sysctl_settings.autoclose = autoclose;
-- 
2.33.0