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>

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 8a01bfb7c87379772655db29a111bcfbcd3c1f39..88c9e3f68c78b78261fe148871ba8074b758df76 100644 (file)
--- 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;