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Commit 5861f8e5 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

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: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7cd0a638

net/ipv4/tcp_input.c

+2 −5
Original line number Diff line number Diff line
@@ -4248,7 +4248,6 @@ static void tcp_sack_remove(struct tcp_sock *tp) 
		this_sack++;

		sp++;

	}

	if (num_sacks != tp->rx_opt.num_sacks)

	tp->rx_opt.num_sacks = num_sacks;

}
@@ -4325,7 +4324,6 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) 


	TCP_ECN_accept_cwr(tp, skb);



	if (tp->rx_opt.dsack)

	tp->rx_opt.dsack = 0;



	/*  Queue data for delivery to the user.
@@ -4445,7 +4443,6 @@ drop: 
		/* 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;

net/ipv4/tcp_output.c

+1 −2
Original line number Diff line number Diff line
@@ -441,7 +441,6 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp, 
			*ptr++ = htonl(sp[this_sack].end_seq);

		}



		if (tp->rx_opt.dsack)

		tp->rx_opt.dsack = 0;

	}

}