netdev - Re: [PATCH V10 12/15] ptp: Added a brand new class driver for ptp clocks.

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] [day] [month] [year] [list]

Date:	Tue, 15 Feb 2011 18:29:41 +0100
From:	Richard Cochran <richardcochran@...il.com>
To:	John Stultz <john.stultz@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linux-api@...r.kernel.org,
	netdev@...r.kernel.org, Alan Cox <alan@...rguk.ukuu.org.uk>,
	Arnd Bergmann <arnd@...db.de>,
	Christoph Lameter <cl@...ux.com>,
	David Miller <davem@...emloft.net>,
	Krzysztof Halasa <khc@...waw.pl>,
	Peter Zijlstra <peterz@...radead.org>,
	Rodolfo Giometti <giometti@...ux.it>,
	Thomas Gleixner <tglx@...utronix.de>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
	Mike Frysinger <vapier@...too.org>,
	Paul Mackerras <paulus@...ba.org>,
	Russell King <linux@....linux.org.uk>
Subject: Re: [PATCH V10 12/15] ptp: Added a brand new class driver for ptp
 clocks.

On Fri, Feb 11, 2011 at 09:15:24AM +0100, Richard Cochran wrote:
> On Tue, Feb 01, 2011 at 06:00:31PM -0800, John Stultz wrote:
> > So what is serializing access to the timestamp_event_queue here? I don't
> > see any usage of tsevq_mux by the callers. Am I missing it? It looks
> > like its called from interrupt context, so do you really need a spinlock
> > and not a mutex here?
> 
> The external timestamp FIFO is written only from interrupt context.

Oops, I lied. After reworking the phyter driver, I find that I want to
enqueue time stamps from non-interrupt contexts, too.

So, you are right. This will need a spin lock...

Thanks,

Richard
--
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