Re: PATCH: Multiprobe sanitizer

[Greg KH <greg@kroah.com>]

On Thu, Aug 17, 2006 at 03:04:21PM +0200, Arjan van de Ven wrote:
> On Thu, 2006-08-17 at 14:37 +0200, Benjamin Herrenschmidt wrote:
> > On Thu, 2006-08-17 at 05:22 -0700, Greg KH wrote:
> > > On Thu, Aug 17, 2006 at 02:12:57PM +0200, Benjamin Herrenschmidt wrote:
> > > > On Thu, 2006-08-17 at 05:00 -0700, Greg KH wrote:
> > > > > On Thu, Aug 17, 2006 at 11:24:35AM +0200, Benjamin Herrenschmidt wrote:
> > > > > > Probe ordering is fragile and completely defeated with busses that are
> > > > > > already probed asynchronously (like USB or firewire), and things can
> > > > > > only get worse. Thus we need to look for generic solutions, the trick of
> > > > > > maintaining probe ordering will work around problems today but we'll
> > > > > > still hit the wall in an increasing number of cases in the future.
> > > > > 
> > > > > That's exactly why udev was created :)
> > > > > 
> > > > > It can handle bus ordering issues already today just fine, and distros
> > > > > use it this way in shipping, "enterprise ready" products.
> > > > 
> > > > Only up to a certain point and for certain drivers... but yeah. 
> > > 
> > > What drivers are not supported by this?  Seriously, have we missed any?
> > 
> > udev will not create stable names for a bunch of things... at least not
> > with the default config that comes with distros. On my shuttle with the
> > built-in USB card reader, whatever config comes up with the box will
> > cause the machine to boot or fail to boot due to sda not beeing what
> > it's expected to be, and udev is of no help because it won't create
> > stable device names. 
> 
> that's what mount by label is for though..
> 
> (which isn't a udev but a distro thing)

No, it's a udev thing too, look in /dev/disk/by-label/ and use that in
your fstab.

So yes, udev already handles this for block devices and input devices.
It is simple to add new rules for other subsystems as people find that
they need them.

thanks,

greg k-h