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tcp: call tcp_set_skb_tso_segs() from tcp_write_xmit() 

tcp_write_xmit() calls tcp_init_tso_segs()
to set gso_size and gso_segs on the packet.

tcp_init_tso_segs() requires the stack to maintain
an up to date tcp_skb_pcount(), and this makes sense
for packets in rtx queue. Not so much for packets
still in the write queue.

In the following patch, we don't want to deal with
tcp_skb_pcount() when moving payload from 2nd
skb to 1st skb in the write queue.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240418214600.1291486-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2024-04-18 21:45:59 +00:00 committed by Jakub Kicinski
parent 22555032c5
commit d5b38a71d3
1 changed files with 14 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
net/ipv4/tcp_output.c
View File

@ -1502,18 +1502,22 @@ static void tcp_queue_skb(struct sock *sk, struct sk_buff *skb)
}
/* Initialize TSO segments for a packet. */
static void tcp_set_skb_tso_segs(struct sk_buff *skb, unsigned int mss_now)
static int tcp_set_skb_tso_segs(struct sk_buff *skb, unsigned int mss_now)
{
int tso_segs;
if (skb->len <= mss_now) {
/* Avoid the costly divide in the normal
* non-TSO case.
*/
tcp_skb_pcount_set(skb, 1);
TCP_SKB_CB(skb)->tcp_gso_size = 0;
} else {
tcp_skb_pcount_set(skb, DIV_ROUND_UP(skb->len, mss_now));
TCP_SKB_CB(skb)->tcp_gso_size = mss_now;
tcp_skb_pcount_set(skb, 1);
return 1;
}
TCP_SKB_CB(skb)->tcp_gso_size = mss_now;
tso_segs = DIV_ROUND_UP(skb->len, mss_now);
tcp_skb_pcount_set(skb, tso_segs);
return tso_segs;
}
/* Pcount in the middle of the write queue got changed, we need to do various
@ -2097,10 +2101,9 @@ static int tcp_init_tso_segs(struct sk_buff *skb, unsigned int mss_now)
{
int tso_segs = tcp_skb_pcount(skb);
if (!tso_segs || (tso_segs > 1 && tcp_skb_mss(skb) != mss_now)) {
tcp_set_skb_tso_segs(skb, mss_now);
tso_segs = tcp_skb_pcount(skb);
}
if (!tso_segs || (tso_segs > 1 && tcp_skb_mss(skb) != mss_now))
return tcp_set_skb_tso_segs(skb, mss_now);
return tso_segs;
}
@ -2733,9 +2736,6 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
if (tcp_pacing_check(sk))
break;
tso_segs = tcp_init_tso_segs(skb, mss_now);
BUG_ON(!tso_segs);
cwnd_quota = tcp_cwnd_test(tp);
if (!cwnd_quota) {
if (push_one == 2)
@ -2745,6 +2745,8 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
break;
}
tso_segs = tcp_set_skb_tso_segs(skb, mss_now);
if (unlikely(!tcp_snd_wnd_test(tp, skb, mss_now))) {
is_rwnd_limited = true;
break;