[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>
diff --git a/net/core/sock.c b/net/core/sock.c
index a1a23be..aba31fe 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1378,7 +1378,8 @@
int proto_register(struct proto *prot, int alloc_slab)
{
- char *request_sock_slab_name;
+ char *request_sock_slab_name = NULL;
+ char *timewait_sock_slab_name;
int rc = -ENOBUFS;
if (alloc_slab) {
@@ -1409,6 +1410,23 @@
goto out_free_request_sock_slab_name;
}
}
+
+ if (prot->twsk_obj_size) {
+ static const char mask[] = "tw_sock_%s";
+
+ timewait_sock_slab_name = kmalloc(strlen(prot->name) + sizeof(mask) - 1, GFP_KERNEL);
+
+ if (timewait_sock_slab_name == NULL)
+ goto out_free_request_sock_slab;
+
+ sprintf(timewait_sock_slab_name, mask, prot->name);
+ prot->twsk_slab = kmem_cache_create(timewait_sock_slab_name,
+ prot->twsk_obj_size,
+ 0, SLAB_HWCACHE_ALIGN,
+ NULL, NULL);
+ if (prot->twsk_slab == NULL)
+ goto out_free_timewait_sock_slab_name;
+ }
}
write_lock(&proto_list_lock);
@@ -1417,6 +1435,13 @@
rc = 0;
out:
return rc;
+out_free_timewait_sock_slab_name:
+ kfree(timewait_sock_slab_name);
+out_free_request_sock_slab:
+ if (prot->rsk_prot && prot->rsk_prot->slab) {
+ kmem_cache_destroy(prot->rsk_prot->slab);
+ prot->rsk_prot->slab = NULL;
+ }
out_free_request_sock_slab_name:
kfree(request_sock_slab_name);
out_free_sock_slab:
@@ -1444,6 +1469,14 @@
prot->rsk_prot->slab = NULL;
}
+ if (prot->twsk_slab != NULL) {
+ const char *name = kmem_cache_name(prot->twsk_slab);
+
+ kmem_cache_destroy(prot->twsk_slab);
+ kfree(name);
+ prot->twsk_slab = NULL;
+ }
+
list_del(&prot->node);
write_unlock(&proto_list_lock);
}