Messages in this thread | | | From | Neal Cardwell <> | Date | Sat, 23 Jan 2021 19:19:13 -0500 | Subject | Re: [PATCH net] tcp: make TCP_USER_TIMEOUT accurate for zero window probes |
| |
On Fri, Jan 22, 2021 at 9:45 PM Enke Chen <enkechen2020@gmail.com> wrote: > > Hi, Jakub: > > On Fri, Jan 22, 2021 at 06:34:24PM -0800, Jakub Kicinski wrote: > > On Fri, 22 Jan 2021 18:28:23 -0800 Enke Chen wrote: > > > Hi, Jakub: > > > > > > In terms of backporting, this patch should go together with: > > > > > > 9d9b1ee0b2d1 tcp: fix TCP_USER_TIMEOUT with zero window > > > > As in it: > > > > Fixes: 9d9b1ee0b2d1 tcp: fix TCP_USER_TIMEOUT with zero window > > > > or does it further fix the same issue, so: > > > > Fixes: 9721e709fa68 ("tcp: simplify window probe aborting on USER_TIMEOUT") > > > > ? > > Let me clarify: > > 1) 9d9b1ee0b2d1 tcp: fix TCP_USER_TIMEOUT with zero window > > fixes the bug and makes it work. > > 2) The current patch makes the TCP_USER_TIMEOUT accurate for 0-window probes. > It's independent.
Patch (2) ("tcp: make TCP_USER_TIMEOUT accurate for zero window probes") is indeed conceptually independent of (1) but its implementation depends on the icsk_probes_tstamp field defined in (1), so AFAICT (2) cannot be backported further back than (1).
Patch (1) fixes a bug in 5.1: Fixes: 9721e709fa68 ("tcp: simplify window probe aborting on USER_TIMEOUT")
So probably (1) and (2) should be backported as a pair, and only back as far as 5.1. (That covers 2 LTS kernels, 5.4 and 5.10, so hopefully that is good enough.)
neal
| |