[INET]: Generalise tcp_tw_bucket, aka TIME_WAIT sockets

This paves the way to generalise the rest of the sock ID lookup
routines and saves some bytes in TCPv4 TIME_WAIT sockets on distro
kernels (where IPv6 is always built as a module):

[root@qemu ~]# grep tw_sock /proc/slabinfo
tw_sock_TCPv6  0  0  128  31  1
tw_sock_TCP    0  0   96  41  1
[root@qemu ~]#

Now if a protocol wants to use the TIME_WAIT generic infrastructure it
only has to set the sk_prot->twsk_obj_size field with the size of its
inet_timewait_sock derived sock and proto_register will create
sk_prot->twsk_slab, for now its only for INET sockets, but we can
introduce timewait_sock later if some non INET transport protocolo
wants to use this stuff.

Next changesets will take advantage of this new infrastructure to
generalise even more TCP code.

[acme@toy net-2.6.14]$ grep built-in /tmp/before.size /tmp/after.size
/tmp/before.size: 188646   11764    5068  205478   322a6 net/ipv4/built-in.o
/tmp/after.size:  188144   11764    5068  204976   320b0 net/ipv4/built-in.o
[acme@toy net-2.6.14]$

Tested with both IPv4 & IPv6 (::1 (localhost) & ::ffff:172.20.0.1
(qemu host)).

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 10 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 2f4b1a374bb7..f1a708bf7a97 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -271,8 +271,6 @@ int sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
 
 DEFINE_SNMP_STAT(struct tcp_mib, tcp_statistics);
 
-kmem_cache_t *tcp_timewait_cachep;
-
 atomic_t tcp_orphan_count = ATOMIC_INIT(0);
 
 int sysctl_tcp_mem[3];
@@ -2264,13 +2262,6 @@ void __init tcp_init(void)
         if (!tcp_hashinfo.bind_bucket_cachep)
                 panic("tcp_init: Cannot alloc tcp_bind_bucket cache.");
 
-        tcp_timewait_cachep = kmem_cache_create("tcp_tw_bucket",
-                                                sizeof(struct tcp_tw_bucket),
-                                                0, SLAB_HWCACHE_ALIGN,
-                                                NULL, NULL);
-        if (!tcp_timewait_cachep)
-                panic("tcp_init: Cannot alloc tcp_tw_bucket cache.");
-
         /* Size and allocate the main established and bind bucket
          * hash tables.
          *
@@ -2363,4 +2354,3 @@ EXPORT_SYMBOL(tcp_sendpage);
 EXPORT_SYMBOL(tcp_setsockopt);
 EXPORT_SYMBOL(tcp_shutdown);
 EXPORT_SYMBOL(tcp_statistics);
-EXPORT_SYMBOL(tcp_timewait_cachep);