From cf8b9671f59ce789d852c7cf5646478ef6d4a4d4 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 11 Mar 2013 17:41:28 -0700 Subject: [PATCH] decnet: Fix disappearing sysctl entries When decnet is built as a module a simple: echo 0.0 >/proc/sys/net/decnet/node_address results in most of the sysctl entries under /proc/sys/net/decnet and /proc/sys/net/decnet/conf disappearing. For more details see http://www.spinics.net/lists/netdev/msg226123.html. This change applies the same workaround used in net/core/sysctl_net_core.c and net/ipv6/sysctl_net_ipv6.c of creating a skeleton of decnet sysctl entries before doing anything else. The problem first appeared in kernel 2.6.27. The later rewrite of sysctl in kernel 3.4 restored the previous behavior and eliminated the need for this workaround. This patch was heavily inspired by a similar but more complex patch by Larry Baker. Reported-by: Larry Baker Signed-off-by: "Eric W. Biederman" Acked-by: David Miller Signed-off-by: Greg Kroah-Hartman --- net/decnet/af_decnet.c | 4 ++++ net/decnet/sysctl_net_decnet.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c index ea3b6ee21fc9..d71f0d2b8dd4 100644 --- a/net/decnet/af_decnet.c +++ b/net/decnet/af_decnet.c @@ -2355,6 +2355,8 @@ static const struct proto_ops dn_proto_ops = { .sendpage = sock_no_sendpage, }; +void dn_register_sysctl_skeleton(void); +void dn_unregister_sysctl_skeleton(void); void dn_register_sysctl(void); void dn_unregister_sysctl(void); @@ -2375,6 +2377,7 @@ static int __init decnet_init(void) if (rc != 0) goto out; + dn_register_sysctl_skeleton(); dn_neigh_init(); dn_dev_init(); dn_route_init(); @@ -2414,6 +2417,7 @@ static void __exit decnet_exit(void) dn_fib_cleanup(); proc_net_remove(&init_net, "decnet"); + dn_unregister_sysctl_skeleton(); proto_unregister(&dn_proto); diff --git a/net/decnet/sysctl_net_decnet.c b/net/decnet/sysctl_net_decnet.c index 28f8b5e5f73b..d1cc2fd72838 100644 --- a/net/decnet/sysctl_net_decnet.c +++ b/net/decnet/sysctl_net_decnet.c @@ -55,6 +55,7 @@ static int max_decnet_no_fc_max_cwnd[] = { NSP_MAX_WINDOW }; static char node_name[7] = "???"; static struct ctl_table_header *dn_table_header = NULL; +static struct ctl_table_header *dn_skeleton_table_header = NULL; /* * ctype.h :-) @@ -356,6 +357,27 @@ static struct ctl_path dn_path[] = { { } }; +static struct ctl_table empty[1]; + +static struct ctl_table dn_skeleton[] = { + { + .procname = "conf", + .mode = 0555, + .child = empty, + }, + { } +}; + +void dn_register_sysctl_skeleton(void) +{ + dn_skeleton_table_header = register_sysctl_paths(dn_path, dn_skeleton); +} + +void dn_unregister_sysctl_skeleton(void) +{ + unregister_sysctl_table(dn_skeleton_table_header); +} + void dn_register_sysctl(void) { dn_table_header = register_sysctl_paths(dn_path, dn_table); @@ -367,6 +389,12 @@ void dn_unregister_sysctl(void) } #else /* CONFIG_SYSCTL */ +void dn_register_sysctl_skeleton(void) +{ +} +void dn_unregister_sysctl_skeleton(void) +{ +} void dn_unregister_sysctl(void) { } -- 2.39.5