sysctl: treewide: constify ctl_table_header::ctl_table_arg

To be able to constify instances of struct ctl_tables it is necessary to
remove ways through which non-const versions are exposed from the
sysctl core.
One of these is the ctl_table_arg member of struct ctl_table_header.

Constify this reference as a prerequisite for the full constification of
struct ctl_table instances.
No functional change.

Signed-off-by: Thomas Weißschuh <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: t-8ch

drivers/net/vrf.c

@@ -1971,7 +1971,7 @@ static int vrf_netns_init_sysctl(struct net *net, struct netns_vrf *nn_vrf)
 static void vrf_netns_exit_sysctl(struct net *net)
 {
 	struct netns_vrf *nn_vrf = net_generic(net, vrf_net_id);
-	struct ctl_table *table;
+	const struct ctl_table *table;
 
 	table = nn_vrf->ctl_hdr->ctl_table_arg;
 	unregister_net_sysctl_table(nn_vrf->ctl_hdr);

include/linux/sysctl.h

@@ -182,7 +182,7 @@ struct ctl_table_header {
 		struct rcu_head rcu;
 	};
 	struct completion *unregistering;
-	struct ctl_table *ctl_table_arg;
+	const struct ctl_table *ctl_table_arg;
 	struct ctl_table_root *root;
 	struct ctl_table_set *set;
 	struct ctl_dir *parent;

ipc/ipc_sysctl.c

@@ -306,7 +306,7 @@ bool setup_ipc_sysctls(struct ipc_namespace *ns)
 
 void retire_ipc_sysctls(struct ipc_namespace *ns)
 {
-	struct ctl_table *tbl;
+	const struct ctl_table *tbl;
 
 	tbl = ns->ipc_sysctls->ctl_table_arg;
 	unregister_sysctl_table(ns->ipc_sysctls);

ipc/mq_sysctl.c

@@ -160,7 +160,7 @@ bool setup_mq_sysctls(struct ipc_namespace *ns)
 
 void retire_mq_sysctls(struct ipc_namespace *ns)
 {
-	struct ctl_table *tbl;
+	const struct ctl_table *tbl;
 
 	tbl = ns->mq_sysctls->ctl_table_arg;
 	unregister_sysctl_table(ns->mq_sysctls);

kernel/ucount.c

@@ -119,7 +119,7 @@ bool setup_userns_sysctls(struct user_namespace *ns)
 void retire_userns_sysctls(struct user_namespace *ns)
 {
 #ifdef CONFIG_SYSCTL
-	struct ctl_table *tbl;
+	const struct ctl_table *tbl;
 
 	tbl = ns->sysctls->ctl_table_arg;
 	unregister_sysctl_table(ns->sysctls);

net/ax25/sysctl_net_ax25.c

@@ -171,7 +171,7 @@ int ax25_register_dev_sysctl(ax25_dev *ax25_dev)
 void ax25_unregister_dev_sysctl(ax25_dev *ax25_dev)
 {
 	struct ctl_table_header *header = ax25_dev->sysheader;
-	struct ctl_table *table;
+	const struct ctl_table *table;
 
 	if (header) {
 		ax25_dev->sysheader = NULL;

net/bridge/br_netfilter_hooks.c

@@ -1275,7 +1275,7 @@ static int br_netfilter_sysctl_init_net(struct net *net)
 static void br_netfilter_sysctl_exit_net(struct net *net,
 					 struct brnf_net *brnet)
 {
-	struct ctl_table *table = brnet->ctl_hdr->ctl_table_arg;
+	const struct ctl_table *table = brnet->ctl_hdr->ctl_table_arg;
 
 	unregister_net_sysctl_table(brnet->ctl_hdr);
 	if (!net_eq(net, &init_net))

net/core/sysctl_net_core.c

@@ -743,7 +743,7 @@ static __net_init int sysctl_core_net_init(struct net *net)
 
 static __net_exit void sysctl_core_net_exit(struct net *net)
 {
-	struct ctl_table *tbl;
+	const struct ctl_table *tbl;
 
 	tbl = net->core.sysctl_hdr->ctl_table_arg;
 	unregister_net_sysctl_table(net->core.sysctl_hdr);

net/ieee802154/6lowpan/reassembly.c

@@ -399,7 +399,7 @@ static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
 
 static void __net_exit lowpan_frags_ns_sysctl_unregister(struct net *net)
 {
-	struct ctl_table *table;
+	const struct ctl_table *table;
 	struct netns_ieee802154_lowpan *ieee802154_lowpan =
 		net_ieee802154_lowpan(net);
 

net/ipv4/devinet.c

@@ -2749,7 +2749,7 @@ static __net_init int devinet_init_net(struct net *net)
 static __net_exit void devinet_exit_net(struct net *net)
 {
 #ifdef CONFIG_SYSCTL
-	struct ctl_table *tbl;
+	const struct ctl_table *tbl;
 
 	tbl = net->ipv4.forw_hdr->ctl_table_arg;
 	unregister_net_sysctl_table(net->ipv4.forw_hdr);