* [PATCH v2] tcp: fix tp->undo_retrans accounting in tcp_sacktag_one()
@ 2021-08-29 14:52 zhenggy
2021-09-10 13:49 ` Neal Cardwell
0 siblings, 1 reply; 2+ messages in thread
From: zhenggy @ 2021-08-29 14:52 UTC (permalink / raw)
To: ncardwell, netdev
Cc: edumazet, davem, yoshfuji, dsahern, kuba, ycheng, zhenggy
Commit a71d77e6be1e ("tcp: fix segment accounting when DSACK range covers
multiple segments") fix some DSACK accounting for multiple segments.
In tcp_sacktag_one(), we should also use the actual DSACK rang(pcount)
for tp->undo_retrans accounting.
Fixes: 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time")
Before that commit, the assumption underlying the tp->undo_retrans--
seems correct, AFAICT.
Signed-off-by: zhenggy <zhenggy@chinatelecom.cn>
---
net/ipv4/tcp_input.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3f7bd7a..141e85e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1346,7 +1346,7 @@ static u8 tcp_sacktag_one(struct sock *sk,
if (dup_sack && (sacked & TCPCB_RETRANS)) {
if (tp->undo_marker && tp->undo_retrans > 0 &&
after(end_seq, tp->undo_marker))
- tp->undo_retrans--;
+ tp->undo_retrans = max_t(int, 0, tp->undo_retrans - pcount);
if ((sacked & TCPCB_SACKED_ACKED) &&
before(start_seq, state->reord))
state->reord = start_seq;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] tcp: fix tp->undo_retrans accounting in tcp_sacktag_one()
2021-08-29 14:52 [PATCH v2] tcp: fix tp->undo_retrans accounting in tcp_sacktag_one() zhenggy
@ 2021-09-10 13:49 ` Neal Cardwell
0 siblings, 0 replies; 2+ messages in thread
From: Neal Cardwell @ 2021-09-10 13:49 UTC (permalink / raw)
To: zhenggy; +Cc: netdev, edumazet, davem, yoshfuji, dsahern, kuba, ycheng
On Thu, Sep 9, 2021 at 10:40 PM zhenggy <zhenggy@chinatelecom.cn> wrote:
>
> Commit a71d77e6be1e ("tcp: fix segment accounting when DSACK range covers
> multiple segments") fix some DSACK accounting for multiple segments.
> In tcp_sacktag_one(), we should also use the actual DSACK rang(pcount)
nit: typo; I'd suggest: "range (pcount)"
> for tp->undo_retrans accounting.
>
> Fixes: 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time")
>
> Before that commit, the assumption underlying the tp->undo_retrans--
> seems correct, AFAICT.
>
> Signed-off-by: zhenggy <zhenggy@chinatelecom.cn>
Please take a look at the standard formatting in the "git log"
history. The Fixes: tag should be in the footers section, typically
the first footer, preceding fields like Reported-by: and Cc: and
Signed-off-by:.
Please consider something like:
----
Since 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time")
this logic can no longer assume that a retransmitted packet is a single segment.
Fixes: 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time")
Signed-off-by: zhenggy <zhenggy@chinatelecom.cn>
---
thanks,
neal
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