tcp: kill eff_sacks "cache", the sole user can calculate itself

Also fixes insignificant bug that would cause sending of stale
SACK block (would occur in some corner cases).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 6 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 61445b57610c..1555bb73b638 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -441,10 +441,8 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
                         *ptr++ = htonl(sp[this_sack].end_seq);
                 }
 
-                if (tp->rx_opt.dsack) {
+                if (tp->rx_opt.dsack)
                         tp->rx_opt.dsack = 0;
-                        tp->rx_opt.eff_sacks = tp->rx_opt.num_sacks;
-                }
         }
 }
 
@@ -550,6 +548,7 @@ static unsigned tcp_established_options(struct sock *sk, struct sk_buff *skb,
         struct tcp_skb_cb *tcb = skb ? TCP_SKB_CB(skb) : NULL;
         struct tcp_sock *tp = tcp_sk(sk);
         unsigned size = 0;
+        unsigned int eff_sacks;
 
 #ifdef CONFIG_TCP_MD5SIG
         *md5 = tp->af_specific->md5_lookup(sk, sk);
@@ -568,10 +567,11 @@ static unsigned tcp_established_options(struct sock *sk, struct sk_buff *skb,
                 size += TCPOLEN_TSTAMP_ALIGNED;
         }
 
-        if (unlikely(tp->rx_opt.eff_sacks)) {
+        eff_sacks = tp->rx_opt.num_sacks + tp->rx_opt.dsack;
+        if (unlikely(eff_sacks)) {
                 const unsigned remaining = MAX_TCP_OPTION_SPACE - size;
                 opts->num_sack_blocks =
-                        min_t(unsigned, tp->rx_opt.eff_sacks,
+                        min_t(unsigned, eff_sacks,
                               (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
                               TCPOLEN_SACK_PERBLOCK);
                 size += TCPOLEN_SACK_BASE_ALIGNED +
@@ -1418,7 +1418,7 @@ static int tcp_mtu_probe(struct sock *sk)
             icsk->icsk_mtup.probe_size ||
             inet_csk(sk)->icsk_ca_state != TCP_CA_Open ||
             tp->snd_cwnd < 11 ||
-            tp->rx_opt.eff_sacks)
+            tp->rx_opt.num_sacks || tp->rx_opt.dsack)
                 return -1;
 
         /* Very simple search strategy: just double the MSS. */