tcp: shrink tcp6_timewait_sock by one cache line

While working on tcp listener refactoring, I found that it
would really make things easier if sock_common could include
the IPv6 addresses needed in the lookups, instead of doing
very complex games to get their values (depending on sock
being SYN_RECV, ESTABLISHED, TIME_WAIT)

For this to happen, I need to be sure that tcp6_timewait_sock
and tcp_timewait_sock consume same number of cache lines.

This is possible if we only use 32bits for tw_ttd, as we remove
one 32bit hole in inet_timewait_sock

inet_tw_time_stamp() is defined and used, even if its current
implementation looks like tcp_time_stamp : We might need finer
resolution for tcp_time_stamp in the future.

Before patch : sizeof(struct tcp6_timewait_sock) = 0xc8

After patch : sizeof(struct tcp6_timewait_sock) = 0xc0

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 5f648751fce..22000279efc 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -222,7 +222,7 @@ static int inet_twsk_diag_fill(struct inet_timewait_sock *tw,
 			       u32 portid, u32 seq, u16 nlmsg_flags,
 			       const struct nlmsghdr *unlh)
 {
-	long tmo;
+	s32 tmo;
 	struct inet_diag_msg *r;
 	struct nlmsghdr *nlh;
 
@@ -234,7 +234,7 @@ static int inet_twsk_diag_fill(struct inet_timewait_sock *tw,
 	r = nlmsg_data(nlh);
 	BUG_ON(tw->tw_state != TCP_TIME_WAIT);
 
-	tmo = tw->tw_ttd - jiffies;
+	tmo = tw->tw_ttd - inet_tw_time_stamp();
 	if (tmo < 0)
 		tmo = 0;
 
@@ -248,7 +248,7 @@ static int inet_twsk_diag_fill(struct inet_timewait_sock *tw,
 	r->id.idiag_dst[0]    = tw->tw_daddr;
 	r->idiag_state	      = tw->tw_substate;
 	r->idiag_timer	      = 3;
-	r->idiag_expires      = DIV_ROUND_UP(tmo * 1000, HZ);
+	r->idiag_expires      = jiffies_to_msecs(tmo);
 	r->idiag_rqueue	      = 0;
 	r->idiag_wqueue	      = 0;
 	r->idiag_uid	      = 0;