The branch main has been updated by rscheff:
URL:
https://cgit.FreeBSD.org/src/commit/?id=48396dc77922c68377ecac0ead2f8b0b5453c451
commit 48396dc77922c68377ecac0ead2f8b0b5453c451
Author: Richard Scheffenegger <rsch...@freebsd.org>
AuthorDate: 2021-02-25 16:59:45 +0000
Commit: Richard Scheffenegger <rsch...@freebsd.org>
CommitDate: 2021-02-25 17:32:04 +0000
Address two incorrect calculations and enhance readability of PRR code
- address second instance of cwnd potentially becoming zero
- fix sublte bug due to implicit int to uint typecase in max()
- fix bug due to typo in hand-coded CEILING() function by using howmany()
macro
- use int instead of long, and add a missing long typecast
- replace if conditionals with easier to read imax/imin (as in pseudocode)
Reviewed By: #transport, kbowling
MFC after: 3 days
Sponsored by: NetApp, Inc.
Differential Revision: https://reviews.freebsd.org/D28813
---
sys/netinet/tcp_input.c | 60 ++++++++++++++++++++-----------------------------
1 file changed, 24 insertions(+), 36 deletions(-)
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 59a5a2d6bf34..ca4a4c833dc2 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -2570,8 +2570,8 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct
socket *so,
if (V_tcp_do_prr &&
IN_FASTRECOVERY(tp->t_flags) &&
(tp->t_flags & TF_SACK_PERMIT)) {
- long snd_cnt = 0, limit = 0;
- long del_data = 0, pipe = 0;
+ int snd_cnt = 0, limit = 0;
+ int del_data = 0, pipe = 0;
/*
* In a duplicate ACK del_data
is only the
* diff_in_sack. If no SACK is
used del_data
@@ -2588,39 +2588,29 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th,
struct socket *so,
if (pipe > tp->snd_ssthresh) {
if
(tp->sackhint.recover_fs == 0)
tp->sackhint.recover_fs =
- max(1,
tp->snd_nxt - tp->snd_una);
- snd_cnt =
(tp->sackhint.prr_delivered *
- tp->snd_ssthresh /
-
tp->sackhint.recover_fs) +
- 1 -
tp->sackhint.sack_bytes_rexmit;
+ imax(1,
tp->snd_nxt - tp->snd_una);
+ snd_cnt =
howmany((long)tp->sackhint.prr_delivered *
+ tp->snd_ssthresh,
tp->sackhint.recover_fs) -
+
tp->sackhint.sack_bytes_rexmit;
} else {
if
(V_tcp_do_prr_conservative)
limit =
tp->sackhint.prr_delivered -
tp->sackhint.sack_bytes_rexmit;
else
- if
((tp->sackhint.prr_delivered -
-
tp->sackhint.sack_bytes_rexmit) >
- del_data)
- limit =
tp->sackhint.prr_delivered -
-
tp->sackhint.sack_bytes_rexmit +
-
maxseg;
- else
- limit =
del_data + maxseg;
- if ((tp->snd_ssthresh -
pipe) < limit)
- snd_cnt =
tp->snd_ssthresh - pipe;
- else
- snd_cnt = limit;
+ limit =
imax(tp->sackhint.prr_delivered -
+
tp->sackhint.sack_bytes_rexmit,
+
del_data) + maxseg;
+ snd_cnt =
imin(tp->snd_ssthresh - pipe, limit);
}
- snd_cnt = max((snd_cnt /
maxseg), 0);
+ snd_cnt = imax(snd_cnt, 0) /
maxseg;
/*
* Send snd_cnt new data into
the network in
* response to this ACK. If
there is a going
* to be a SACK retransmission,
adjust snd_cwnd
* accordingly.
*/
- tp->snd_cwnd = tp->snd_nxt -
tp->snd_recover +
-
tp->sackhint.sack_bytes_rexmit +
- (snd_cnt * maxseg);
+ tp->snd_cwnd = imax(maxseg,
tp->snd_nxt - tp->snd_recover +
+
tp->sackhint.sack_bytes_rexmit + (snd_cnt * maxseg));
} else if ((tp->t_flags &
TF_SACK_PERMIT) &&
IN_FASTRECOVERY(tp->t_flags)) {
int awnd;
@@ -3948,7 +3938,7 @@ tcp_mssopt(struct in_conninfo *inc)
void
tcp_prr_partialack(struct tcpcb *tp, struct tcphdr *th)
{
- long snd_cnt = 0, limit = 0, del_data = 0, pipe = 0;
+ int snd_cnt = 0, limit = 0, del_data = 0, pipe = 0;
int maxseg = tcp_maxseg(tp);
INP_WLOCK_ASSERT(tp->t_inpcb);
@@ -3974,29 +3964,27 @@ tcp_prr_partialack(struct tcpcb *tp, struct tcphdr *th)
if (pipe > tp->snd_ssthresh) {
if (tp->sackhint.recover_fs == 0)
tp->sackhint.recover_fs =
- max(1, tp->snd_nxt - tp->snd_una);
- snd_cnt = (tp->sackhint.prr_delivered * tp->snd_ssthresh /
- tp->sackhint.recover_fs) - tp->sackhint.sack_bytes_rexmit;
+ imax(1, tp->snd_nxt - tp->snd_una);
+ snd_cnt = howmany((long)tp->sackhint.prr_delivered *
+ tp->snd_ssthresh, tp->sackhint.recover_fs) -
+ tp->sackhint.sack_bytes_rexmit;
} else {
if (V_tcp_do_prr_conservative)
limit = tp->sackhint.prr_delivered -
tp->sackhint.sack_bytes_rexmit;
else
- if ((tp->sackhint.prr_delivered -
- tp->sackhint.sack_bytes_rexmit) > del_data)
- limit = tp->sackhint.prr_delivered -
- tp->sackhint.sack_bytes_rexmit + maxseg;
- else
- limit = del_data + maxseg;
- snd_cnt = min((tp->snd_ssthresh - pipe), limit);
+ limit = imax(tp->sackhint.prr_delivered -
+ tp->sackhint.sack_bytes_rexmit,
+ del_data) + maxseg;
+ snd_cnt = imin((tp->snd_ssthresh - pipe), limit);
}
- snd_cnt = max((snd_cnt / maxseg), 0);
+ snd_cnt = imax(snd_cnt, 0) / maxseg;
/*
* Send snd_cnt new data into the network in response to this ack.
* If there is going to be a SACK retransmission, adjust snd_cwnd
* accordingly.
*/
- tp->snd_cwnd = max(maxseg, (int64_t)tp->snd_nxt - tp->snd_recover +
+ tp->snd_cwnd = imax(maxseg, tp->snd_nxt - tp->snd_recover +
tp->sackhint.sack_bytes_rexmit + (snd_cnt * maxseg));
tp->t_flags |= TF_ACKNOW;
(void) tcp_output(tp);
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