| Message ID | 1630238373-12912-1-git-send-email-zhenggy@chinatelecom.cn (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: fix tp->undo_retrans accounting in tcp_sacktag_one() | expand |
On Thu, Sep 9, 2021 at 6:34 AM 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) > for tp->undo_retrans accounting. > > 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; > -- Thanks for the fix! I think it would be useful to have a Fixes: footer to help maintainers know how far back to backport the fix. I think an appropriate fixes footer might be the following: 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. thanks, neal
On Thu, Sep 9, 2021 at 9:38 AM Neal Cardwell <ncardwell@google.com> wrote: > > On Thu, Sep 9, 2021 at 6:34 AM 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) > > for tp->undo_retrans accounting. > > > > Signed-off-by: zhenggy <zhenggy@chinatelecom.cn> Another nit: in the commit title, rather than "net": net: fix tp->undo_retrans accounting in tcp_sacktag_one() ...I would suggest the more specific "tcp", which is more typical for commits fixing tcp*.c files: tcp: fix tp->undo_retrans accounting in tcp_sacktag_one() thanks, neal
Hi，Neal： Thanks very much for your checking, I will send a v2 patch to make it. 在 2021/9/9 21:38, Neal Cardwell 写道: > On Thu, Sep 9, 2021 at 6:34 AM 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) >> for tp->undo_retrans accounting. >> >> 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; >> -- > > Thanks for the fix! > > I think it would be useful to have a Fixes: footer to help maintainers > know how far back to backport the fix. > > I think an appropriate fixes footer might be the following: > > 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. > > thanks, > neal >
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;
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. Signed-off-by: zhenggy <zhenggy@chinatelecom.cn> --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)