Re: [PATCH 1/5] initdev:kernel: Asynchronously-discovered device synchronization, v5

Alan Stern
2009-05-04T15:08:15Z

On Mon, 4 May 2009, Arjan van de Ven wrote:

> > > for normal device probing we already have infrastructure though...
> > > wait_for_device_probe, driver_probe_done and friends...
> > > (the scsi scanning thread is being converted to the async
> > > infrastructure btw)
> > >
> > > do we need to invent more ?
> >
> > I suppose the usb-storage scanning thread could also be converted to
> > the async infrastructure, although I haven't heard of anybody working
> > on it.
> >
> > But the USB hub driver's thread (khubd) cannot be converted. It is
> > central to the discovery of USB-based block devices. How would you
> > handle that?
>
> take a ref in the driver_probe_done() sense, and release it when you
> know you're done probing....
>
> at that point all existing infrastructure will just work.

Isn't there still something missing? The wait_for_device_probe()
routine would wait until all attached devices had been probed. But why
should prepare_namespace() have to wait that long? Wouldn't it be
better to wait only until the root device has been registered?

Alan Stern