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From: John Levon <levon@movementarian.org>
To: Kernel List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Notifier for significant events on i386
Date: Wed, 11 Dec 2002 20:27:27 +0000	[thread overview]
Message-ID: <20021211202727.GF20735@compsoc.man.ac.uk> (raw)
In-Reply-To: <20021211171337.A17600@in.ibm.com>

On Wed, Dec 11, 2002 at 05:13:37PM +0530, Vamsi Krishna S . wrote:

> Unless I am missing something, notifiers have always been racy. 
> No amount of locking you do in individual modules to prevent
> races will help as the notifier chain is walked inside 
> notifier_call_chain() in kernel/sys.c. One would need to
> add some form of locking there (*) so that users of notifier
> chains need not worry about races/locking at all.

There are notifiers being used that sleep inside the called notifiers.

You could easily make a __notifier_call_chain that is lockless and
another one that readlocks the notifier_lock ...

regards
john
-- 
"Anyone who says you can have a lot of widely dispersed people hack away on
 a complicated piece of code and avoid total anarchy has never managed a 
 software project."
	- Andy Tanenbaum

  parent reply	other threads:[~2002-12-11 20:19 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-12-09 22:02 [PATCH] Notifier for significant events on i386 Stephen Hemminger
2002-12-11 11:21 ` Vamsi Krishna S .
2002-12-11 11:16   ` William Lee Irwin III
2002-12-11 11:43     ` Vamsi Krishna S .
2002-12-11 16:56       ` [lkcd-devel] " Stephen Hemminger
2002-12-11 20:27       ` John Levon [this message]
2002-12-11 21:15         ` Alan Cox
2002-12-12  0:19           ` Stephen Hemminger
2002-12-12  7:34             ` Vamsi Krishna S .
2002-12-12 17:53               ` Stephen Hemminger
2002-12-12 17:58                 ` John Levon
2002-12-13 12:32                   ` Vamsi Krishna S .
2002-12-12  8:13           ` Vamsi Krishna S .
2002-12-11 13:57   ` Corey Minyard

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