netdev - Re: [TCP]: min_t/max_t confusion in tcp_select_initial

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.00.0912232321090.10866@melkinpaasi.cs.helsinki.fi>
Date:	Wed, 23 Dec 2009 23:23:11 +0200 (EET)
From:	"Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>
To:	David Miller <davem@...emloft.net>
cc:	roel.kluin@...il.com, Netdev <netdev@...r.kernel.org>
Subject: Re: [TCP]: min_t/max_t confusion in tcp_select_initial_window()?

On Wed, 23 Dec 2009, David Miller wrote:

> From: "Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>
> Date: Wed, 23 Dec 2009 21:45:57 +0200 (EET)
> 
> > On Tue, 22 Dec 2009, David Miller wrote:
> > 
> >> From: Roel Kluin <roel.kluin@...il.com>
> >> Date: Wed, 23 Dec 2009 03:00:24 +0100
> >> 
> >> > I could be confused, but in net/ipv4/tcp_output.c:217:
> >> > 
> >> >                 space = max_t(u32, sysctl_tcp_rmem[2], sysctl_rmem_max);
> >> >                 space = min_t(u32, space, *window_clamp);
> >> > ------------------------^^^^^
>  ...
> > 
> > I don't understand how window_clamp line could be changed to max_t.
> > ...I guess min in both would seem the most reasonable one?
> 
> Nope, the first one must be max.  Since I'm pretty sure we let the
> dynamic RX buffer resizing exceed sysctl_rmem_max if necessary.
> 
> And that's what is controlled by sysctl_tcp_rmem[2]

Yeah, I'm wrong, and besides misread your "It looks correct" to mean the 
proposed change rather than the current code.

-- 
 i.