linux-kernel - Re: [PATCH 2/6] [-mm] epoll: don't use current in irq context

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Message-ID: <alpine.DEB.1.10.0902271406170.3810@makko.or.mcafeemobile.com>
Date:	Fri, 27 Feb 2009 14:08:29 -0800 (PST)
From:	Davide Libenzi <davidel@...ilserver.org>
To:	Tony Battersby <tonyb@...ernetics.com>
cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Jonathan Corbet <corbet@....net>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/6] [-mm] epoll: don't use current in irq context

On Tue, 24 Feb 2009, Tony Battersby wrote:

> ep_call_nested() (formerly ep_poll_safewake()) uses "current" to detect
> callback recursion, but it may be called from irq context where the
> use of current is generally frowned upon.  It would be better to use
> get_cpu() and put_cpu() to detect the callback recursion.

Oh, I forgot about this one ...
We're not actually dereferencing anything in current, by using it as a 
cookie. But yes, getting the CPU is better, even at preemption expenses.
Thank you for your report Tony.


Acked-by: Davide Libenzi <davidel@...ilserver.org>


- Davide


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