diff options
| author | Arnaldo Carvalho de Melo <acme@mandriva.com> | 2006-11-27 17:56:43 -0200 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2006-12-02 21:30:46 -0800 |
| commit | 850db6b8c53ff12eadee9ef2aa69360c06bce057 (patch) | |
| tree | ae4932e2802d9c114a9b210adb3011660ae42ec4 | |
| parent | 4c0a6cb0db19de411c4bf7fcdc79d4c7c4ccafb1 (diff) | |
[INET_CONNECTION_SOCK]: Pack struct inet_connection_sock_af_ops
We have a hole in:
[acme@newtoy net-2.6.20]$ pahole net/ipv6/tcp_ipv6.o inet_connection_sock_af_ops
/* /pub/scm/linux/kernel/git/acme/net-2.6.20/include/net/inet_connection_sock.h:38 */
struct inet_connection_sock_af_ops {
int (*queue_xmit)(); /* 0 4 */
void (*send_check)(); /* 4 4 */
int (*rebuild_header)(); /* 8 4 */
int (*conn_request)(); /* 12 4 */
struct sock * (*syn_recv_sock)(); /* 16 4 */
int (*remember_stamp)(); /* 20 4 */
__u16 net_header_len; /* 24 2 */
/* XXX 2 bytes hole, try to pack */
int (*setsockopt)(); /* 28 4 */
int (*getsockopt)(); /* 32 4 */
int (*compat_setsockopt)(); /* 36 4 */
int (*compat_getsockopt)(); /* 40 4 */
void (*addr2sockaddr)(); /* 44 4 */
int sockaddr_len; /* 48 4 */
}; /* size: 52, sum members: 50, holes: 1, sum holes: 2 */
But we don't need sockaddr_len to be an int:
[acme@newtoy net-2.6.20]$ find net -name "*.[ch]" | xargs grep '\.sockaddr_len.\+=' | sort -u
net/dccp/ipv4.c: .sockaddr_len = sizeof(struct sockaddr_in),
net/dccp/ipv6.c: .sockaddr_len = sizeof(struct sockaddr_in6),
net/ipv4/tcp_ipv4.c: .sockaddr_len = sizeof(struct sockaddr_in),
net/ipv6/tcp_ipv6.c: .sockaddr_len = sizeof(struct sockaddr_in6),
net/sctp/ipv6.c: .sockaddr_len = sizeof(struct sockaddr_in6),
net/sctp/protocol.c: .sockaddr_len = sizeof(struct sockaddr_in),
[acme@newtoy net-2.6.20]$ pahole --sizes net/ipv6/tcp_ipv6.o | grep sockaddr_in
struct sockaddr_in: 16 0
struct sockaddr_in6: 28 0
[acme@newtoy net-2.6.20]$
So I turned sockaddr_len a 'u16', and now:
[acme@newtoy net-2.6.20]$ pahole net/ipv6/tcp_ipv6.o inet_connection_sock_af_ops
/* /pub/scm/linux/kernel/git/acme/net-2.6.20/include/net/inet_connection_sock.h:38 */
struct inet_connection_sock_af_ops {
int (*queue_xmit)(); /* 0 4 */
void (*send_check)(); /* 4 4 */
int (*rebuild_header)(); /* 8 4 */
int (*conn_request)(); /* 12 4 */
struct sock * (*syn_recv_sock)(); /* 16 4 */
int (*remember_stamp)(); /* 20 4 */
u16 net_header_len; /* 24 2 */
u16 sockaddr_len; /* 26 2 */
int (*setsockopt)(); /* 28 4 */
int (*getsockopt)(); /* 32 4 */
int (*compat_setsockopt)(); /* 36 4 */
int (*compat_getsockopt)(); /* 40 4 */
void (*addr2sockaddr)(); /* 44 4 */
}; /* size: 48 */
So we've saved 4 bytes:
[acme@newtoy net-2.6.20]$ codiff -sV /tmp/tcp_ipv6.o.before net/ipv6/tcp_ipv6.o
/pub/scm/linux/kernel/git/acme/net-2.6.20/net/ipv6/tcp_ipv6.c:
struct inet_connection_sock_af_ops | -4
net_header_len;
from: __u16 /* 24(0) 2(0) */
to: u16 /* 24(0) 2(0) */
sockaddr_len;
from: int /* 48(0) 4(0) */
to: u16 /* 26(0) 2(0) */
1 struct changed
[acme@newtoy net-2.6.20]$
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
| -rw-r--r-- | include/net/inet_connection_sock.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index fd3f1d8cdc4..cccea051e92 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -46,7 +46,8 @@ struct inet_connection_sock_af_ops { struct request_sock *req, struct dst_entry *dst); int (*remember_stamp)(struct sock *sk); - __u16 net_header_len; + u16 net_header_len; + u16 sockaddr_len; int (*setsockopt)(struct sock *sk, int level, int optname, char __user *optval, int optlen); int (*getsockopt)(struct sock *sk, int level, int optname, @@ -58,7 +59,6 @@ struct inet_connection_sock_af_ops { int level, int optname, char __user *optval, int __user *optlen); void (*addr2sockaddr)(struct sock *sk, struct sockaddr *); - int sockaddr_len; }; /** inet_connection_sock - INET connection oriented sock |