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Subject[PATCH linux-next] mpls: don't build sysctl related code when sysctl is disabled
Date
Some sysctl related code and data structures are never referenced
when CONFIG_SYSCTL is not set.
While this is usually harmless, it produces a build failure since sysctl
shared variables exist, due to missing sysctl_vals symbol:

ld: net/mpls/af_mpls.o: in function `mpls_platform_labels':
af_mpls.c:(.text+0x162a): undefined reference to `sysctl_vals'
ld: net/mpls/af_mpls.o:(.rodata+0x830): undefined reference to `sysctl_vals'
ld: net/mpls/af_mpls.o:(.rodata+0x838): undefined reference to `sysctl_vals'
ld: net/mpls/af_mpls.o:(.rodata+0x870): undefined reference to `sysctl_vals'

Fix this by moving all sysctl related code under #ifdef CONFIG_SYSCTL

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Matteo Croce <mcroce@redhat.com>
---
net/mpls/af_mpls.c | 389 ++++++++++++++++++++++++---------------------
1 file changed, 204 insertions(+), 185 deletions(-)

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index c312741df2ce..5aacbf129ec5 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -37,9 +37,6 @@

#define MPLS_NEIGH_TABLE_UNSPEC (NEIGH_LINK_TABLE + 1)

-static int label_limit = (1 << 20) - 1;
-static int ttl_max = 255;
-
#if IS_ENABLED(CONFIG_NET_IP_TUNNEL)
static size_t ipgre_mpls_encap_hlen(struct ip_tunnel_encap *e)
{
@@ -1179,31 +1176,6 @@ static int mpls_netconf_msgsize_devconf(int type)
return size;
}

-static void mpls_netconf_notify_devconf(struct net *net, int event,
- int type, struct mpls_dev *mdev)
-{
- struct sk_buff *skb;
- int err = -ENOBUFS;
-
- skb = nlmsg_new(mpls_netconf_msgsize_devconf(type), GFP_KERNEL);
- if (!skb)
- goto errout;
-
- err = mpls_netconf_fill_devconf(skb, mdev, 0, 0, event, 0, type);
- if (err < 0) {
- /* -EMSGSIZE implies BUG in mpls_netconf_msgsize_devconf() */
- WARN_ON(err == -EMSGSIZE);
- kfree_skb(skb);
- goto errout;
- }
-
- rtnl_notify(skb, net, 0, RTNLGRP_MPLS_NETCONF, NULL, GFP_KERNEL);
- return;
-errout:
- if (err < 0)
- rtnl_set_sk_err(net, RTNLGRP_MPLS_NETCONF, err);
-}
-
static const struct nla_policy devconf_mpls_policy[NETCONFA_MAX + 1] = {
[NETCONFA_IFINDEX] = { .len = sizeof(int) },
};
@@ -1362,6 +1334,36 @@ static int mpls_netconf_dump_devconf(struct sk_buff *skb,
#define MPLS_PERDEV_SYSCTL_OFFSET(field) \
(&((struct mpls_dev *)0)->field)

+#ifdef CONFIG_SYSCTL
+
+static int label_limit = (1 << 20) - 1;
+static int ttl_max = 255;
+
+static void mpls_netconf_notify_devconf(struct net *net, int event,
+ int type, struct mpls_dev *mdev)
+{
+ struct sk_buff *skb;
+ int err = -ENOBUFS;
+
+ skb = nlmsg_new(mpls_netconf_msgsize_devconf(type), GFP_KERNEL);
+ if (!skb)
+ goto errout;
+
+ err = mpls_netconf_fill_devconf(skb, mdev, 0, 0, event, 0, type);
+ if (err < 0) {
+ /* -EMSGSIZE implies BUG in mpls_netconf_msgsize_devconf() */
+ WARN_ON(err == -EMSGSIZE);
+ kfree_skb(skb);
+ goto errout;
+ }
+
+ rtnl_notify(skb, net, 0, RTNLGRP_MPLS_NETCONF, NULL, GFP_KERNEL);
+ return;
+errout:
+ if (err < 0)
+ rtnl_set_sk_err(net, RTNLGRP_MPLS_NETCONF, err);
+}
+
static int mpls_conf_proc(struct ctl_table *ctl, int write,
void __user *buffer,
size_t *lenp, loff_t *ppos)
@@ -1445,6 +1447,173 @@ static void mpls_dev_sysctl_unregister(struct net_device *dev,
mpls_netconf_notify_devconf(net, RTM_DELNETCONF, 0, mdev);
}

+static int resize_platform_label_table(struct net *net, size_t limit)
+{
+ size_t size = sizeof(struct mpls_route *) * limit;
+ size_t old_limit;
+ size_t cp_size;
+ struct mpls_route __rcu **labels = NULL, **old;
+ struct mpls_route *rt0 = NULL, *rt2 = NULL;
+ unsigned index;
+
+ if (size) {
+ labels = kvzalloc(size, GFP_KERNEL);
+ if (!labels)
+ goto nolabels;
+ }
+
+ /* In case the predefined labels need to be populated */
+ if (limit > MPLS_LABEL_IPV4NULL) {
+ struct net_device *lo = net->loopback_dev;
+ rt0 = mpls_rt_alloc(1, lo->addr_len, 0);
+ if (IS_ERR(rt0))
+ goto nort0;
+ RCU_INIT_POINTER(rt0->rt_nh->nh_dev, lo);
+ rt0->rt_protocol = RTPROT_KERNEL;
+ rt0->rt_payload_type = MPT_IPV4;
+ rt0->rt_ttl_propagate = MPLS_TTL_PROP_DEFAULT;
+ rt0->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
+ rt0->rt_nh->nh_via_alen = lo->addr_len;
+ memcpy(__mpls_nh_via(rt0, rt0->rt_nh), lo->dev_addr,
+ lo->addr_len);
+ }
+ if (limit > MPLS_LABEL_IPV6NULL) {
+ struct net_device *lo = net->loopback_dev;
+ rt2 = mpls_rt_alloc(1, lo->addr_len, 0);
+ if (IS_ERR(rt2))
+ goto nort2;
+ RCU_INIT_POINTER(rt2->rt_nh->nh_dev, lo);
+ rt2->rt_protocol = RTPROT_KERNEL;
+ rt2->rt_payload_type = MPT_IPV6;
+ rt2->rt_ttl_propagate = MPLS_TTL_PROP_DEFAULT;
+ rt2->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
+ rt2->rt_nh->nh_via_alen = lo->addr_len;
+ memcpy(__mpls_nh_via(rt2, rt2->rt_nh), lo->dev_addr,
+ lo->addr_len);
+ }
+
+ rtnl_lock();
+ /* Remember the original table */
+ old = rtnl_dereference(net->mpls.platform_label);
+ old_limit = net->mpls.platform_labels;
+
+ /* Free any labels beyond the new table */
+ for (index = limit; index < old_limit; index++)
+ mpls_route_update(net, index, NULL, NULL);
+
+ /* Copy over the old labels */
+ cp_size = size;
+ if (old_limit < limit)
+ cp_size = old_limit * sizeof(struct mpls_route *);
+
+ memcpy(labels, old, cp_size);
+
+ /* If needed set the predefined labels */
+ if ((old_limit <= MPLS_LABEL_IPV6NULL) &&
+ (limit > MPLS_LABEL_IPV6NULL)) {
+ RCU_INIT_POINTER(labels[MPLS_LABEL_IPV6NULL], rt2);
+ rt2 = NULL;
+ }
+
+ if ((old_limit <= MPLS_LABEL_IPV4NULL) &&
+ (limit > MPLS_LABEL_IPV4NULL)) {
+ RCU_INIT_POINTER(labels[MPLS_LABEL_IPV4NULL], rt0);
+ rt0 = NULL;
+ }
+
+ /* Update the global pointers */
+ net->mpls.platform_labels = limit;
+ rcu_assign_pointer(net->mpls.platform_label, labels);
+
+ rtnl_unlock();
+
+ mpls_rt_free(rt2);
+ mpls_rt_free(rt0);
+
+ if (old) {
+ synchronize_rcu();
+ kvfree(old);
+ }
+ return 0;
+
+nort2:
+ mpls_rt_free(rt0);
+nort0:
+ kvfree(labels);
+nolabels:
+ return -ENOMEM;
+}
+
+static int mpls_platform_labels(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ struct net *net = table->data;
+ int platform_labels = net->mpls.platform_labels;
+ int ret;
+ struct ctl_table tmp = {
+ .procname = table->procname,
+ .data = &platform_labels,
+ .maxlen = sizeof(int),
+ .mode = table->mode,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = &label_limit,
+ };
+
+ ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+
+ if (write && ret == 0)
+ ret = resize_platform_label_table(net, platform_labels);
+
+ return ret;
+}
+
+#define MPLS_NS_SYSCTL_OFFSET(field) \
+ (&((struct net *)0)->field)
+
+static const struct ctl_table mpls_table[] = {
+ {
+ .procname = "platform_labels",
+ .data = NULL,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = mpls_platform_labels,
+ },
+ {
+ .procname = "ip_ttl_propagate",
+ .data = MPLS_NS_SYSCTL_OFFSET(mpls.ip_ttl_propagate),
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
+ {
+ .procname = "default_ttl",
+ .data = MPLS_NS_SYSCTL_OFFSET(mpls.default_ttl),
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = SYSCTL_ONE,
+ .extra2 = &ttl_max,
+ },
+ { }
+};
+
+#else
+
+static int mpls_dev_sysctl_register(struct net_device *dev,
+ struct mpls_dev *mdev)
+{
+ return 0;
+}
+
+static void mpls_dev_sysctl_unregister(struct net_device *dev,
+ struct mpls_dev *mdev)
+{
+}
+
+#endif
+
static struct mpls_dev *mpls_add_dev(struct net_device *dev)
{
struct mpls_dev *mdev;
@@ -2497,168 +2666,12 @@ static int mpls_getroute(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
return err;
}

-static int resize_platform_label_table(struct net *net, size_t limit)
-{
- size_t size = sizeof(struct mpls_route *) * limit;
- size_t old_limit;
- size_t cp_size;
- struct mpls_route __rcu **labels = NULL, **old;
- struct mpls_route *rt0 = NULL, *rt2 = NULL;
- unsigned index;
-
- if (size) {
- labels = kvzalloc(size, GFP_KERNEL);
- if (!labels)
- goto nolabels;
- }
-
- /* In case the predefined labels need to be populated */
- if (limit > MPLS_LABEL_IPV4NULL) {
- struct net_device *lo = net->loopback_dev;
- rt0 = mpls_rt_alloc(1, lo->addr_len, 0);
- if (IS_ERR(rt0))
- goto nort0;
- RCU_INIT_POINTER(rt0->rt_nh->nh_dev, lo);
- rt0->rt_protocol = RTPROT_KERNEL;
- rt0->rt_payload_type = MPT_IPV4;
- rt0->rt_ttl_propagate = MPLS_TTL_PROP_DEFAULT;
- rt0->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
- rt0->rt_nh->nh_via_alen = lo->addr_len;
- memcpy(__mpls_nh_via(rt0, rt0->rt_nh), lo->dev_addr,
- lo->addr_len);
- }
- if (limit > MPLS_LABEL_IPV6NULL) {
- struct net_device *lo = net->loopback_dev;
- rt2 = mpls_rt_alloc(1, lo->addr_len, 0);
- if (IS_ERR(rt2))
- goto nort2;
- RCU_INIT_POINTER(rt2->rt_nh->nh_dev, lo);
- rt2->rt_protocol = RTPROT_KERNEL;
- rt2->rt_payload_type = MPT_IPV6;
- rt2->rt_ttl_propagate = MPLS_TTL_PROP_DEFAULT;
- rt2->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
- rt2->rt_nh->nh_via_alen = lo->addr_len;
- memcpy(__mpls_nh_via(rt2, rt2->rt_nh), lo->dev_addr,
- lo->addr_len);
- }
-
- rtnl_lock();
- /* Remember the original table */
- old = rtnl_dereference(net->mpls.platform_label);
- old_limit = net->mpls.platform_labels;
-
- /* Free any labels beyond the new table */
- for (index = limit; index < old_limit; index++)
- mpls_route_update(net, index, NULL, NULL);
-
- /* Copy over the old labels */
- cp_size = size;
- if (old_limit < limit)
- cp_size = old_limit * sizeof(struct mpls_route *);
-
- memcpy(labels, old, cp_size);
-
- /* If needed set the predefined labels */
- if ((old_limit <= MPLS_LABEL_IPV6NULL) &&
- (limit > MPLS_LABEL_IPV6NULL)) {
- RCU_INIT_POINTER(labels[MPLS_LABEL_IPV6NULL], rt2);
- rt2 = NULL;
- }
-
- if ((old_limit <= MPLS_LABEL_IPV4NULL) &&
- (limit > MPLS_LABEL_IPV4NULL)) {
- RCU_INIT_POINTER(labels[MPLS_LABEL_IPV4NULL], rt0);
- rt0 = NULL;
- }
-
- /* Update the global pointers */
- net->mpls.platform_labels = limit;
- rcu_assign_pointer(net->mpls.platform_label, labels);
-
- rtnl_unlock();
-
- mpls_rt_free(rt2);
- mpls_rt_free(rt0);
-
- if (old) {
- synchronize_rcu();
- kvfree(old);
- }
- return 0;
-
-nort2:
- mpls_rt_free(rt0);
-nort0:
- kvfree(labels);
-nolabels:
- return -ENOMEM;
-}
-
-static int mpls_platform_labels(struct ctl_table *table, int write,
- void __user *buffer, size_t *lenp, loff_t *ppos)
-{
- struct net *net = table->data;
- int platform_labels = net->mpls.platform_labels;
- int ret;
- struct ctl_table tmp = {
- .procname = table->procname,
- .data = &platform_labels,
- .maxlen = sizeof(int),
- .mode = table->mode,
- .extra1 = SYSCTL_ZERO,
- .extra2 = &label_limit,
- };
-
- ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
-
- if (write && ret == 0)
- ret = resize_platform_label_table(net, platform_labels);
-
- return ret;
-}
-
-#define MPLS_NS_SYSCTL_OFFSET(field) \
- (&((struct net *)0)->field)
-
-static const struct ctl_table mpls_table[] = {
- {
- .procname = "platform_labels",
- .data = NULL,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = mpls_platform_labels,
- },
- {
- .procname = "ip_ttl_propagate",
- .data = MPLS_NS_SYSCTL_OFFSET(mpls.ip_ttl_propagate),
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = SYSCTL_ZERO,
- .extra2 = SYSCTL_ONE,
- },
- {
- .procname = "default_ttl",
- .data = MPLS_NS_SYSCTL_OFFSET(mpls.default_ttl),
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = SYSCTL_ONE,
- .extra2 = &ttl_max,
- },
- { }
-};
-
static int mpls_net_init(struct net *net)
{
+#ifdef CONFIG_SYSCTL
struct ctl_table *table;
int i;

- net->mpls.platform_labels = 0;
- net->mpls.platform_label = NULL;
- net->mpls.ip_ttl_propagate = 1;
- net->mpls.default_ttl = 255;
-
table = kmemdup(mpls_table, sizeof(mpls_table), GFP_KERNEL);
if (table == NULL)
return -ENOMEM;
@@ -2674,6 +2687,12 @@ static int mpls_net_init(struct net *net)
kfree(table);
return -ENOMEM;
}
+#endif
+
+ net->mpls.platform_labels = 0;
+ net->mpls.platform_label = NULL;
+ net->mpls.ip_ttl_propagate = 1;
+ net->mpls.default_ttl = 255;

return 0;
}
--
2.21.0
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