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Re: How to do a mmap ?

Erik Mouw wrote:
> 
> On Wed, Feb 05, 2003 at 11:51:24PM +0100, Jerome de Vivie wrote:
> > Erik Mouw wrote:
> > > Using files from kernel mode is policy, while the kernel should only
> > > implement mechanisms. Rethink your design so the file usage is done
> > > where it belongs: userland. This has the nice advantage that you can
> > > get the same information from weird locations like a remote SQL
> > > database by just rewriting the userland backend. There's no way to do
> > > this from kernel.
> >
> > The module implement a stackable filesystem (which should work over
> > NFS). I use a file because i need to store persistant data and i also
> > need to hide this file from userland. As I need to access some data very
> > frequently, i prefer using direct memory operation than read/write. All
> > thoses operations are protected by a mandatory.
> 
> Persistent data really should be handled by a usermode helper, cause
> the decision *where* to store it is policy. See for example how alsactl
> handles the state of all ALSA soundcards in the system. See also how a
> couple of USB devices get their firmware uploaded through a generic
> device node.

Are you really sure that every "policy" thing should stay outside
kernelspace ? You don't even know want i want to do. How can you judge
my design ? I need to update my "persistant" upon filesystem events.
Will you help me to trap those from userspace ?

j.

-- 
Jérôme de Vivie
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