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    SubjectRe: another IDE cleanup: kill duplicated code
    On Tue, Feb 12, 2002 at 01:45:10PM +0100, Martin Dalecki wrote:

    >>> The first does control an array of values, which doesn't make sense in
    >>> first place. I.e. changing it doesn't
    >>> change ANY behaviour of the kernel.

    >> Actually HFS uses it ...

    > Please note that the use in HFS is inappriopriate. It's supposed to
    > optimize the read throughput there, which is something that shouldn't
    > be done at the fs setup layer at all. The usage of read_ahead there
    > can be just removed and everything should be fine (modulo the fact
    > that in current state the HFS filesystem code is just non-working
    > obsolete code garbage anyway ;-).

    Yes; I just commented on that it does change some behavior of the
    kernel.

    >>> The second of them is trying to control a file-system level constant
    >>> inside the actual block device driver. This is a blatant violation of
    >>> the layering principle in software design, and should go as soon as
    >>> possible.

    >> Yes. But still block device drivers allocate the array ...

    > Well if we do:
    >
    > find ./ -name "*.c" -exec grep max_readahead /dev/null {} \;
    >
    > One can already easly see that apart from ide, md, and acorn drivers
    > this has been already abstracted away one level up at the block device
    > handling as well. My suspiction is that there is now already *double*
    > initialization of the sub-slices of this array there. Anyway ide
    > should be adapted here to the same way as it's done now for scsi.
    >
    > Will you look after this or should me? (I can't until afternoon,
    > becouse I'm at my "true live" job now and have other things to do...)

    Am I understanding you correctly that we can just remove the
    max_readahead references in IDE (and possibly also md and acorn)?

    --
    Vojtech Pavlik
    SuSE Labs
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