BUG_ON(!skb || !tcp_skb_pcount(skb));
if (clone_it) {
- const struct sk_buff *fclone = skb + 1;
-
skb_mstamp_get(&skb->skb_mstamp);
- if (unlikely(skb->fclone == SKB_FCLONE_ORIG &&
- fclone->fclone == SKB_FCLONE_CLONE))
- NET_INC_STATS(sock_net(sk),
- LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES);
-
if (unlikely(skb_cloned(skb)))
skb = pskb_copy(skb, gfp_mask);
else
return mss_now;
}
-/* Congestion window validation. (RFC2861) */
-static void tcp_cwnd_validate(struct sock *sk)
+/* RFC2861, slow part. Adjust cwnd, after it was not full during one rto.
+ * As additional protections, we do not touch cwnd in retransmission phases,
+ * and if application hit its sndbuf limit recently.
+ */
+static void tcp_cwnd_application_limited(struct sock *sk)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ if (inet_csk(sk)->icsk_ca_state == TCP_CA_Open &&
+ sk->sk_socket && !test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
+ /* Limited by application or receiver window. */
+ u32 init_win = tcp_init_cwnd(tp, __sk_dst_get(sk));
+ u32 win_used = max(tp->snd_cwnd_used, init_win);
+ if (win_used < tp->snd_cwnd) {
+ tp->snd_ssthresh = tcp_current_ssthresh(sk);
+ tp->snd_cwnd = (tp->snd_cwnd + win_used) >> 1;
+ }
+ tp->snd_cwnd_used = 0;
+ }
+ tp->snd_cwnd_stamp = tcp_time_stamp;
+}
+
+static void tcp_cwnd_validate(struct sock *sk, u32 unsent_segs)
{
struct tcp_sock *tp = tcp_sk(sk);
- if (tp->packets_out >= tp->snd_cwnd) {
+ tp->lsnd_pending = tp->packets_out + unsent_segs;
+
+ if (tcp_is_cwnd_limited(sk)) {
/* Network is feed fully. */
tp->snd_cwnd_used = 0;
tp->snd_cwnd_stamp = tcp_time_stamp;
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
- unsigned int tso_segs, sent_pkts;
+ unsigned int tso_segs, sent_pkts, unsent_segs = 0;
int cwnd_quota;
int result;
break;
} else {
if (!push_one && tcp_tso_should_defer(sk, skb))
- break;
+ goto compute_unsent_segs;
}
/* TCP Small Queues :
* there is no smp_mb__after_set_bit() yet
*/
smp_mb__after_clear_bit();
- if (atomic_read(&sk->sk_wmem_alloc) > limit)
+ if (atomic_read(&sk->sk_wmem_alloc) > limit) {
+ u32 unsent_bytes;
+
+compute_unsent_segs:
+ unsent_bytes = tp->write_seq - tp->snd_nxt;
+ unsent_segs = DIV_ROUND_UP(unsent_bytes, mss_now);
break;
+ }
}
limit = mss_now;
/* Send one loss probe per tail loss episode. */
if (push_one != 2)
tcp_schedule_loss_probe(sk);
- tcp_cwnd_validate(sk);
+ tcp_cwnd_validate(sk, unsent_segs);
return false;
}
return (push_one == 2) || (!tp->packets_out && tcp_send_head(sk));
return true;
}
+/* Thanks to skb fast clones, we can detect if a prior transmit of
+ * a packet is still in a qdisc or driver queue.
+ * In this case, there is very little point doing a retransmit !
+ * Note: This is called from BH context only.
+ */
+static bool skb_still_in_host_queue(const struct sock *sk,
+ const struct sk_buff *skb)
+{
+ const struct sk_buff *fclone = skb + 1;
+
+ if (unlikely(skb->fclone == SKB_FCLONE_ORIG &&
+ fclone->fclone == SKB_FCLONE_CLONE)) {
+ NET_INC_STATS_BH(sock_net(sk),
+ LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES);
+ return true;
+ }
+ return false;
+}
+
/* When probe timeout (PTO) fires, send a new segment if one exists, else
* retransmit the last segment.
*/
if (WARN_ON(!skb))
goto rearm_timer;
+ if (skb_still_in_host_queue(sk, skb))
+ goto rearm_timer;
+
pcount = tcp_skb_pcount(skb);
if (WARN_ON(!pcount))
goto rearm_timer;
min(sk->sk_wmem_queued + (sk->sk_wmem_queued >> 2), sk->sk_sndbuf))
return -EAGAIN;
+ if (skb_still_in_host_queue(sk, skb))
+ return -EBUSY;
+
if (before(TCP_SKB_CB(skb)->seq, tp->snd_una)) {
if (before(TCP_SKB_CB(skb)->end_seq, tp->snd_una))
BUG();
err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC);
}
- if (likely(!err))
+ if (likely(!err)) {
TCP_SKB_CB(skb)->sacked |= TCPCB_EVER_RETRANS;
+ /* Update global TCP statistics. */
+ TCP_INC_STATS(sock_net(sk), TCP_MIB_RETRANSSEGS);
+ if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
+ NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNRETRANS);
+ tp->total_retrans++;
+ }
return err;
}
int err = __tcp_retransmit_skb(sk, skb);
if (err == 0) {
- /* Update global TCP statistics. */
- TCP_INC_STATS(sock_net(sk), TCP_MIB_RETRANSSEGS);
- if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)
- NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNRETRANS);
- tp->total_retrans++;
-
#if FASTRETRANS_DEBUG > 0
if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_RETRANS) {
net_dbg_ratelimited("retrans_out leaked\n");
* see tcp_input.c tcp_sacktag_write_queue().
*/
TCP_SKB_CB(skb)->ack_seq = tp->snd_nxt;
- } else {
+ } else if (err != -EBUSY) {
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPRETRANSFAIL);
}
return err;