netdev - Re: Regression in net-2.6.24?

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]

Date:	Fri, 12 Oct 2007 01:39:23 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	mchan@...adcom.com
Cc:	shemminger@...ux-foundation.org, takano@...-inc.co.jp,
	netdev@...r.kernel.org, ilpo.jarvinen@...sinki.fi
Subject: Re: Regression in net-2.6.24?

From: "Michael Chan" <mchan@...adcom.com>
Date: Fri, 12 Oct 2007 01:54:13 -0700

> On Thu, 2007-10-11 at 19:40 -0700, David Miller wrote:
> > Hmmm, the old code didn't do that and seemingly has the same
> > problem.  Also, if you look at the before-patch code and think
> > about what it does if we ->poll() multiple times for a single
> > interrupt the side-effects are essentially the same.
> > 
> 
> No, the old code before tonight's patch did this:
> 
> if (tp->tg3_flags & TG3_FLAG_TAGGED_STATUS) {
> 	tp->last_tag = sblk->status_tag;
> 	rmb();
> }
> 
> before checking for more work.  The rmb() is there to make sure that the
> status tag is read and stored before we check for more work.

No I understand, thanks!

> [TG3]: Refine napi poll loop.
> 
> Need to read and store sblk->status_tag before checking for more work.
> The status tag is later written back to the hardware when enabling
> interrupts to acknowledge how much work has been processed.  If the
> order is reversed, we can end up acknowledging work we haven't
> processed.
> 
> When we detect tx error, it is more correct to return the rx
> work_done so far instead of 0.
> 
> Signed-off-by: Michael Chan <mchan@...adcom.com>

I'll apply this, thanks a lot!
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html