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Subject: Re: read_proc issue
To: val@nmt.edu (Val Henson)
Date: Wed, 27 Feb 2002 21:42:04 +0000 (GMT)
Cc: rddunlap@osdl.org (Randy.Dunlap), laurent@augias.org (Laurent),
        linux-kernel@vger.kernel.org
In-Reply-To: <20020227140432.L20918@boardwalk> from "Val Henson" at Feb 27, 2002 02:04:32 PM
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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
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> I've encountered this problem before, too.  What is the "One True Way"
> to do this cleanly?  In other words, if you want to do a calculation
> once every time someone runs "cat /proc/foo", what is the cleanest way
> to do that?  The solution we came up with was to check the file offset
> and only do the calculation if offset == 0, which seems pretty
> hackish.

Another approach is to do the calculation open and remember it in per
fd private data. You can recover that and free it on release. It could
even be a buffer holding the actual "content"
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