Re: Passing references to kobjects between userland and kernel

[Daniele Orlandi <daniele@orlandi.com>]

On Saturday 17 June 2006 01:58, Greg KH wrote:
>
> Use the kobject_uevent() call from kernelspace to let userspace know
> whatever you want it to.  That is what it is there for :)

kobject_uevent() is fine if I want to asynchronously notify the user space of 
an event.

What I need is a synchronous bidirectional interface, e.g. I tell the kernel 
"connect node X with node Y" and I get back the resulting pipeline 
identifier.

> Or use configfs :)

Configfs is very interesting, it's surely well suited for several tasks I'm 
doing and I will add support for it into my subsystem.

What it's missing is the ability to create non-persistent configurations, 
bound to a process and disappearing along with the process that created them.

For example, my process creates pipelines between nodes using a ioctl() 
interface. If the process dies unexpectedly the file descriptor is 
automatically closed and I can release all the pipelines. I don't see a way I 
could accomplish the same with configfs or sysfs. 

OTOH, for what concerns persistent pipelines, configfs is quite good. It would 
be even better if I could create links from configfs objects to sysfs 
objects.

Bye,

-- 
  Daniele "Vihai" Orlandi