diff options
Diffstat (limited to 'net/ipv4')
-rw-r--r-- | net/ipv4/tcp_output.c | 51 |
1 files changed, 25 insertions, 26 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 9a9510a..9058e0a 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1017,13 +1017,29 @@ static void tcp_cwnd_validate(struct sock *sk) } } -static unsigned int tcp_window_allows(struct tcp_sock *tp, struct sk_buff *skb, unsigned int mss_now, unsigned int cwnd) +/* Returns the portion of skb which can be sent right away without + * introducing MSS oddities to segment boundaries. In rare cases where + * mss_now != mss_cache, we will request caller to create a small skb + * per input skb which could be mostly avoided here (if desired). + */ +static unsigned int tcp_mss_split_point(struct sock *sk, struct sk_buff *skb, + unsigned int mss_now, + unsigned int cwnd) { - u32 window, cwnd_len; + struct tcp_sock *tp = tcp_sk(sk); + u32 needed, window, cwnd_len; window = (tp->snd_una + tp->snd_wnd - TCP_SKB_CB(skb)->seq); cwnd_len = mss_now * cwnd; - return min(window, cwnd_len); + + if (likely(cwnd_len <= window && skb != tcp_write_queue_tail(sk))) + return cwnd_len; + + if (skb == tcp_write_queue_tail(sk) && cwnd_len <= skb->len) + return cwnd_len; + + needed = min(skb->len, window); + return needed - needed % mss_now; } /* Can at least one segment of SKB be sent right now, according to the @@ -1458,17 +1474,9 @@ static int tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle) } limit = mss_now; - if (tso_segs > 1) { - limit = tcp_window_allows(tp, skb, - mss_now, cwnd_quota); - - if (skb->len < limit) { - unsigned int trim = skb->len % mss_now; - - if (trim) - limit = skb->len - trim; - } - } + if (tso_segs > 1) + limit = tcp_mss_split_point(sk, skb, mss_now, + cwnd_quota); if (skb->len > limit && unlikely(tso_fragment(sk, skb, limit, mss_now))) @@ -1515,7 +1523,6 @@ void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, */ void tcp_push_one(struct sock *sk, unsigned int mss_now) { - struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb = tcp_send_head(sk); unsigned int tso_segs, cwnd_quota; @@ -1530,17 +1537,9 @@ void tcp_push_one(struct sock *sk, unsigned int mss_now) BUG_ON(!tso_segs); limit = mss_now; - if (tso_segs > 1) { - limit = tcp_window_allows(tp, skb, - mss_now, cwnd_quota); - - if (skb->len < limit) { - unsigned int trim = skb->len % mss_now; - - if (trim) - limit = skb->len - trim; - } - } + if (tso_segs > 1) + limit = tcp_mss_split_point(sk, skb, mss_now, + cwnd_quota); if (skb->len > limit && unlikely(tso_fragment(sk, skb, limit, mss_now))) |