tcp: de-bloat a bit with factoring NET_INC_STATS_BH out

There are some places in TCP that select one MIB index to
bump snmp statistics like this:

	if (<something>)
		NET_INC_STATS_BH(<some_id>);
	else if (<something_else>)
		NET_INC_STATS_BH(<some_other_id>);
	...
	else
		NET_INC_STATS_BH(<default_id>);

or in a more tricky but still similar way.

On the other hand, this NET_INC_STATS_BH is a camouflaged
increment of percpu variable, which is not that small.

Factoring those cases out de-bloats 235 bytes on non-preemptible
i386 config and drives parts of the code into 80 columns.

add/remove: 0/0 grow/shrink: 0/7 up/down: 0/-235 (-235)
function                                     old     new   delta
tcp_fastretrans_alert                       1437    1424     -13
tcp_dsack_set                                137     124     -13
tcp_xmit_retransmit_queue                    690     676     -14
tcp_try_undo_recovery                        283     265     -18
tcp_sacktag_write_queue                     1550    1515     -35
tcp_update_reordering                        162     106     -56
tcp_retransmit_timer                         990     904     -86

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 8f83ab432705..edef2afe905e 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1985,14 +1985,17 @@ void tcp_xmit_retransmit_queue(struct sock *sk)
 
                         if (sacked & TCPCB_LOST) {
                                 if (!(sacked & (TCPCB_SACKED_ACKED|TCPCB_SACKED_RETRANS))) {
+                                        int mib_idx;
+
                                         if (tcp_retransmit_skb(sk, skb)) {
                                                 tp->retransmit_skb_hint = NULL;
                                                 return;
                                         }
                                         if (icsk->icsk_ca_state != TCP_CA_Loss)
-                                                NET_INC_STATS_BH(LINUX_MIB_TCPFASTRETRANS);
+                                                mib_idx = LINUX_MIB_TCPFASTRETRANS;
                                         else
-                                                NET_INC_STATS_BH(LINUX_MIB_TCPSLOWSTARTRETRANS);
+                                                mib_idx = LINUX_MIB_TCPSLOWSTARTRETRANS;
+                                        NET_INC_STATS_BH(mib_idx);
 
                                         if (skb == tcp_write_queue_head(sk))
                                                 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,