Date: Mon, 17 Nov 2003 01:03:39 -0800
From: William Lee Irwin III <wli@holomorphy.com>
To: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>,
       viro@parcelfarce.linux.theplanet.co.uk, linux-kernel@vger.kernel.org
Subject: Re: seq_file and exporting dynamically allocated data
Message-ID: <20031117090339.GC22764@holomorphy.com>
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	Tigran Aivazian <tigran@aivazian.fsnet.co.uk>,
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On Mon, Nov 17, 2003 at 12:48:04AM -0800, William Lee Irwin III wrote:
> There's a retry loop where the buffer size is doubled each iteration
> that looks to me like automagic sizing in the code for seq_read(). I
> can't say I've actually tried to rely on getting more than a page
> at a time through seq_read(), though.

Woops. This looks like it only makes sure there's enough to get the
first ->show() into the buffer; I see that it later gives up when
m->count == m->size once the first ->show() has enough bufferspace to
complete later on. So if all ->show() operations to do are less than
PAGE_SIZE, it'll never hand back more than a page at a time, and may
hand back short reads prior to EOF, which doesn't bode well for my
short read == EOF idea (maybe not a great assumption in general).


-- wli
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