Well, if this simple patch to the current pioctl can be made without all
that overhead, then someone else can fix this, unfortunately.  I thought
this would be relatively simple, and it's a fix I don't really need
personally.  Sorry to be selfish...

The real question is: do I need a new pioctl for this?  I'm just modifying
the existing code and changing it's behavior.

On Tue, Oct 19, 2010 at 2:08 PM, Jeffrey Altman <
[email protected]> wrote:

> On 10/19/2010 2:02 PM, Phillip Moore wrote:
> >
> > That means I will need a new kernel module installed in order to test
> > this, doesn't it?
> >
> > Is there anything I need to worry about if I change
> >  DECL_PIOCTL(PPrecache) to behave more
> > like DECL_PIOCTL(PSetCachingThreshold)?
> >
> > The change seems pretty obvious, but this is the first time (OK, in
> > about 13 years) that I've touched any of the code in the kernel module.
>
> Be very careful about modifying pioctls.  They are effectively RPCs and
> you can't be sure that the clients (userland fs) and servers (kernel
> modules) will be updates at the same time.  You are in most cases going
> to need to request the allocation of new pioctl numbers from the
> registrar and implement the revised pioctl independently from the
> existing implementation which might or might not be removed.
>
> Jeffrey Altman
>
>

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