Re: seq_file and exporting dynamically allocated data

From: William Lee Irwin III
Date: Mon Nov 17 2003 - 04:12:32 EST


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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/