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, 9 insertions, 6 deletions

diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 3e358cbb1247..6a480d1fd8f6 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -326,24 +326,27 @@ static void tcp_retransmit_timer(struct sock *sk)
                 goto out;
 
         if (icsk->icsk_retransmits == 0) {
+                int mib_idx;
+
                 if (icsk->icsk_ca_state == TCP_CA_Disorder ||
                     icsk->icsk_ca_state == TCP_CA_Recovery) {
                         if (tcp_is_sack(tp)) {
                                 if (icsk->icsk_ca_state == TCP_CA_Recovery)
-                                        NET_INC_STATS_BH(LINUX_MIB_TCPSACKRECOVERYFAIL);
+                                        mib_idx = LINUX_MIB_TCPSACKRECOVERYFAIL;
                                 else
-                                        NET_INC_STATS_BH(LINUX_MIB_TCPSACKFAILURES);
+                                        mib_idx = LINUX_MIB_TCPSACKFAILURES;
                         } else {
                                 if (icsk->icsk_ca_state == TCP_CA_Recovery)
-                                        NET_INC_STATS_BH(LINUX_MIB_TCPRENORECOVERYFAIL);
+                                        mib_idx = LINUX_MIB_TCPRENORECOVERYFAIL;
                                 else
-                                        NET_INC_STATS_BH(LINUX_MIB_TCPRENOFAILURES);
+                                        mib_idx = LINUX_MIB_TCPRENOFAILURES;
                         }
                 } else if (icsk->icsk_ca_state == TCP_CA_Loss) {
-                        NET_INC_STATS_BH(LINUX_MIB_TCPLOSSFAILURES);
+                        mib_idx = LINUX_MIB_TCPLOSSFAILURES;
                 } else {
-                        NET_INC_STATS_BH(LINUX_MIB_TCPTIMEOUTS);
+                        mib_idx = LINUX_MIB_TCPTIMEOUTS;
                 }
+                NET_INC_STATS_BH(mib_idx);
         }
 
         if (tcp_use_frto(sk)) {