tcp: remove pointless .dsack/.num_sacks code
In the pure assignment case, the earlier zeroing is
still in effect.
David S. Miller raised concerns if the ifs are there to avoid
dirtying cachelines. I came to these conclusions:
> We'll be dirty it anyway (now that I check), the first "real" statement
> in tcp_rcv_established is:
>
> tp->rx_opt.saw_tstamp = 0;
>
> ...that'll land on the same dword. :-/
>
> I suppose the blocks are there just because they had more complexity
> inside when they had to calculate the eff_sacks too (maybe it would
> have been better to just remove them in that drop-patch so you would
> have had less head-ache :-)).
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 5ecd7aa..cd39d1d 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4248,8 +4248,7 @@
this_sack++;
sp++;
}
- if (num_sacks != tp->rx_opt.num_sacks)
- tp->rx_opt.num_sacks = num_sacks;
+ tp->rx_opt.num_sacks = num_sacks;
}
/* This one checks to see if we can put data from the
@@ -4325,8 +4324,7 @@
TCP_ECN_accept_cwr(tp, skb);
- if (tp->rx_opt.dsack)
- tp->rx_opt.dsack = 0;
+ tp->rx_opt.dsack = 0;
/* Queue data for delivery to the user.
* Packets in sequence go to the receive queue.
@@ -4445,7 +4443,6 @@
/* Initial out of order segment, build 1 SACK. */
if (tcp_is_sack(tp)) {
tp->rx_opt.num_sacks = 1;
- tp->rx_opt.dsack = 0;
tp->selective_acks[0].start_seq = TCP_SKB_CB(skb)->seq;
tp->selective_acks[0].end_seq =
TCP_SKB_CB(skb)->end_seq;