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

[Alan Stern]

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

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