[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/include/net/sock.h b/include/net/sock.h
index 391d00b..c902c57 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -88,6 +88,7 @@
} while(0)
struct sock;
+struct proto;
/**
* struct sock_common - minimal network layer representation of sockets
@@ -98,10 +99,11 @@
* @skc_node: main hash linkage for various protocol lookup tables
* @skc_bind_node: bind hash linkage for various protocol lookup tables
* @skc_refcnt: reference count
+ * @skc_prot: protocol handlers inside a network family
*
* This is the minimal network layer representation of sockets, the header
- * for struct sock and struct tcp_tw_bucket.
- */
+ * for struct sock and struct inet_timewait_sock.
+ */
struct sock_common {
unsigned short skc_family;
volatile unsigned char skc_state;
@@ -110,11 +112,12 @@
struct hlist_node skc_node;
struct hlist_node skc_bind_node;
atomic_t skc_refcnt;
+ struct proto *skc_prot;
};
/**
* struct sock - network layer representation of sockets
- * @__sk_common: shared layout with tcp_tw_bucket
+ * @__sk_common: shared layout with inet_timewait_sock
* @sk_shutdown: mask of %SEND_SHUTDOWN and/or %RCV_SHUTDOWN
* @sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
* @sk_lock: synchronizer
@@ -140,7 +143,6 @@
* @sk_backlog: always used with the per-socket spinlock held
* @sk_callback_lock: used with the callbacks in the end of this struct
* @sk_error_queue: rarely used
- * @sk_prot: protocol handlers inside a network family
* @sk_prot_creator: sk_prot of original sock creator (see ipv6_setsockopt, IPV6_ADDRFORM for instance)
* @sk_err: last error
* @sk_err_soft: errors that don't cause failure but are the cause of a persistent failure not just 'timed out'
@@ -173,7 +175,7 @@
*/
struct sock {
/*
- * Now struct tcp_tw_bucket also uses sock_common, so please just
+ * Now struct inet_timewait_sock also uses sock_common, so please just
* don't add nothing before this first member (__sk_common) --acme
*/
struct sock_common __sk_common;
@@ -184,6 +186,7 @@
#define sk_node __sk_common.skc_node
#define sk_bind_node __sk_common.skc_bind_node
#define sk_refcnt __sk_common.skc_refcnt
+#define sk_prot __sk_common.skc_prot
unsigned char sk_shutdown : 2,
sk_no_check : 2,
sk_userlocks : 4;
@@ -218,7 +221,6 @@
struct sk_buff *tail;
} sk_backlog;
struct sk_buff_head sk_error_queue;
- struct proto *sk_prot;
struct proto *sk_prot_creator;
rwlock_t sk_callback_lock;
int sk_err,
@@ -557,6 +559,9 @@
kmem_cache_t *slab;
unsigned int obj_size;
+ kmem_cache_t *twsk_slab;
+ unsigned int twsk_obj_size;
+
struct request_sock_ops *rsk_prot;
struct module *owner;