Re: Future devfs plans (sorry for previous incomplete message)

From: Trent Lloyd
Date: Tue Jul 27 2004 - 19:13:20 EST


I see your point, but I wonder how it differs from the current devfs
implementation (i don't know how it works in these cases)

> Trent Lloyd <lathiat@xxxxxx> writes:
>
> > Wouldn't a possible solution to do this to develop an extension to tmpfs to
> > catch files accessed that don't exist etc and use that in conjuction
> > with udev?
>
> There is a problem with that scheme. Imagine that a program attempts
> to access a non-existing device. The special fs would call modprobe
> or similar which would load the correct module. Loading this module
> would cause hotplug events upon which udev would create the device
> node. However, all this is asynchronous. The special fs could wait
> for a while for the device to appear, but this doesn't quite look like
> a nice solution. The exit status of modprobe can't be used, since
> even if the module loads perfectly it might not cause the requested
> device to be created. Even if it does, there will be some delay from
> the module being loaded to udev creating the device node, so how long
> should the kernel wait for the device to appear? I haven't thought
> about it further, but I smell races here.
>
> --
> M?ns Rullg?rd
> mru@xxxxxx
>
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--
Trent Lloyd <lathiat@xxxxxx>
Bur.st Networking Inc.
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