Re: [PATCH v2] tcp: fix tp->undo_retrans accounting in tcp_sacktag_one()

On Thu, Sep 9, 2021 at 10:40 PM zhenggy [off-list ref] 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 <redacted>

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 <redacted>
---

thanks,
neal