linux-kernel - Re: [PATCH] "volatile considered harmful", take 2

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Message-Id: <E1HmQhG-00057A-00@calista.eckenfels.net>
Date:	Fri, 11 May 2007 10:41:54 +0200
From:	Bernd Eckenfels <ecki@...a.inka.de>
To:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] "volatile considered harmful", take 2

In article <6143.1178828419@....net> you wrote:
> +Consider a typical block of kernel code:
> +
> +    spin_lock(&the_lock);
> +    do_something_on(&shared_data);
> +    do_something_else_with(&shared_data);
> +    spin_unlock(&the_lock);
> +
> +If all the code follows the locking rules, the value of shared_data cannot
> +change unexpectedly while the_lock is held.

Well maybe it is trivial, but I would add e.g. "all places where the
shared_data is accessed must be protected by this spinlock"

> +  - The jiffies variable is special in that it can have a different value

what about other atomic readable counters (like interface counters)?

Gruss
Bernd
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