net ipv4: Convert devinet to use register_net_sysctl

Using an ascii path to register_net_sysctl as opposed to the slightly
awkward ctl_path allows for much simpler code.

We no longer need to malloc dev_name to keep it alive the length of our
sysctl register instead we can use a small temporary buffer on the
stack.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 34 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 8a01bfb7c873..88c9e3f68c78 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1585,7 +1585,6 @@ static int ipv4_doint_and_flush(ctl_table *ctl, int write,
 static struct devinet_sysctl_table {
         struct ctl_table_header *sysctl_header;
         struct ctl_table devinet_vars[__IPV4_DEVCONF_MAX];
-        char *dev_name;
 } devinet_sysctl = {
         .devinet_vars = {
                 DEVINET_SYSCTL_COMPLEX_ENTRY(FORWARDING, "forwarding",
@@ -1627,16 +1626,7 @@ static int __devinet_sysctl_register(struct net *net, char *dev_name,
 {
         int i;
         struct devinet_sysctl_table *t;
-
-#define DEVINET_CTL_PATH_DEV    3
-
-        struct ctl_path devinet_ctl_path[] = {
-                { .procname = "net",  },
-                { .procname = "ipv4", },
-                { .procname = "conf", },
-                { /* to be set */ },
-                { },
-        };
+        char path[sizeof("net/ipv4/conf/") + IFNAMSIZ];
 
         t = kmemdup(&devinet_sysctl, sizeof(*t), GFP_KERNEL);
         if (!t)
@@ -1648,27 +1638,15 @@ static int __devinet_sysctl_register(struct net *net, char *dev_name,
                 t->devinet_vars[i].extra2 = net;
         }
 
-        /*
-         * Make a copy of dev_name, because '.procname' is regarded as const
-         * by sysctl and we wouldn't want anyone to change it under our feet
-         * (see SIOCSIFNAME).
-         */
-        t->dev_name = kstrdup(dev_name, GFP_KERNEL);
-        if (!t->dev_name)
-                goto free;
-
-        devinet_ctl_path[DEVINET_CTL_PATH_DEV].procname = t->dev_name;
+        snprintf(path, sizeof(path), "net/ipv4/conf/%s", dev_name);
 
-        t->sysctl_header = register_net_sysctl_table(net, devinet_ctl_path,
-                        t->devinet_vars);
+        t->sysctl_header = register_net_sysctl(net, path, t->devinet_vars);
         if (!t->sysctl_header)
-                goto free_procname;
+                goto free;
 
         p->sysctl = t;
         return 0;
 
-free_procname:
-        kfree(t->dev_name);
 free:
         kfree(t);
 out:
@@ -1684,7 +1662,6 @@ static void __devinet_sysctl_unregister(struct ipv4_devconf *cnf)
 
         cnf->sysctl = NULL;
         unregister_net_sysctl_table(t->sysctl_header);
-        kfree(t->dev_name);
         kfree(t);
 }
 
@@ -1714,12 +1691,6 @@ static struct ctl_table ctl_forward_entry[] = {
         },
         { },
 };
-
-static __net_initdata struct ctl_path net_ipv4_path[] = {
-        { .procname = "net", },
-        { .procname = "ipv4", },
-        { },
-};
 #endif
 
 static __net_init int devinet_init_net(struct net *net)
@@ -1765,7 +1736,7 @@ static __net_init int devinet_init_net(struct net *net)
                 goto err_reg_dflt;
 
         err = -ENOMEM;
-        forw_hdr = register_net_sysctl_table(net, net_ipv4_path, tbl);
+        forw_hdr = register_net_sysctl(net, "net/ipv4", tbl);
         if (forw_hdr == NULL)
                 goto err_reg_ctl;
         net->ipv4.forw_hdr = forw_hdr;