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-rw-r--r--include/net/tcp.h11
-rw-r--r--net/ipv4/tcp_output.c5
2 files changed, 13 insertions, 3 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 86b9a8766648..e460ea7f767b 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1766,9 +1766,18 @@ static inline bool tcp_skb_is_last(const struct sock *sk,
return skb_queue_is_last(&sk->sk_write_queue, skb);
}
+/**
+ * tcp_write_queue_empty - test if any payload (or FIN) is available in write queue
+ * @sk: socket
+ *
+ * Since the write queue can have a temporary empty skb in it,
+ * we must not use "return skb_queue_empty(&sk->sk_write_queue)"
+ */
static inline bool tcp_write_queue_empty(const struct sock *sk)
{
- return skb_queue_empty(&sk->sk_write_queue);
+ const struct tcp_sock *tp = tcp_sk(sk);
+
+ return tp->write_seq == tp->snd_nxt;
}
static inline bool tcp_rtx_queue_empty(const struct sock *sk)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 57f434a8e41f..36902d08473e 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3129,7 +3129,7 @@ void sk_forced_mem_schedule(struct sock *sk, int size)
*/
void tcp_send_fin(struct sock *sk)
{
- struct sk_buff *skb, *tskb = tcp_write_queue_tail(sk);
+ struct sk_buff *skb, *tskb, *tail = tcp_write_queue_tail(sk);
struct tcp_sock *tp = tcp_sk(sk);
/* Optimization, tack on the FIN if we have one skb in write queue and
@@ -3137,6 +3137,7 @@ void tcp_send_fin(struct sock *sk)
* Note: in the latter case, FIN packet will be sent after a timeout,
* as TCP stack thinks it has already been transmitted.
*/
+ tskb = tail;
if (!tskb && tcp_under_memory_pressure(sk))
tskb = skb_rb_last(&sk->tcp_rtx_queue);
@@ -3144,7 +3145,7 @@ void tcp_send_fin(struct sock *sk)
TCP_SKB_CB(tskb)->tcp_flags |= TCPHDR_FIN;
TCP_SKB_CB(tskb)->end_seq++;
tp->write_seq++;
- if (tcp_write_queue_empty(sk)) {
+ if (!tail) {
/* This means tskb was already sent.
* Pretend we included the FIN on previous transmit.
* We need to set tp->snd_nxt to the value it would have