tcp: tsq: relax tcp_small_queue_check() when rtx queue contains a single skb

[platform/kernel/linux-starfive.git] / net / ipv4 / tcp_output.c

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index bbd8567..f072346 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2542,6 +2542,18 @@ static bool tcp_pacing_check(struct sock *sk)
        return true;
 }
 
+static bool tcp_rtx_queue_empty_or_single_skb(const struct sock *sk)
+{
+       const struct rb_node *node = sk->tcp_rtx_queue.rb_node;
+
+       /* No skb in the rtx queue. */
+       if (!node)
+               return true;
+
+       /* Only one skb in rtx queue. */
+       return !node->rb_left && !node->rb_right;
+}
+
 /* TCP Small Queues :
  * Control number of packets in qdisc/devices to two packets / or ~1 ms.
  * (These limits are doubled for retransmits)
@@ -2579,12 +2591,12 @@ static bool tcp_small_queue_check(struct sock *sk, const struct sk_buff *skb,
                limit += extra_bytes;
        }
        if (refcount_read(&sk->sk_wmem_alloc) > limit) {
-               /* Always send skb if rtx queue is empty.
+               /* Always send skb if rtx queue is empty or has one skb.
                 * No need to wait for TX completion to call us back,
                 * after softirq/tasklet schedule.
                 * This helps when TX completions are delayed too much.
                 */
-               if (tcp_rtx_queue_empty(sk))
+               if (tcp_rtx_queue_empty_or_single_skb(sk))
                        return false;
 
                set_bit(TSQ_THROTTLED, &sk->sk_tsq_flags);