Re: [PATCH v2 3/6] rust: device: Support testing devices for equality

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Feb 03, 2026 at 05:29:16PM +0100, Danilo Krummrich wrote:
> On Tue Feb 3, 2026 at 5:17 PM CET, Greg Kroah-Hartman wrote:
> > And I don't see what patch in this series uses this, am I missing it?
> 
> 	impl Smem {
> 	    pub(crate) fn access<'a>(&'a self, dev: &'a Device<Bound>) -> Option<&'a Mmio> {
> 	        if *dev != *self.dev {
> 	            return None;
> 	        }
> 	
> 	        // SAFETY: By our invariant, this was a subrange of what was returned by smem_aux_get, for
> 	        // self.dev, and by our above check, that auxdev is still available.
> 	        Some(unsafe { Mmio::from_raw(&self.raw) })
> 	    }
> 	}
> 
> It's used to ensure that the Smem provided by the auxiliary parent can only be
> accessed as long as the auxiliary parent device is bound.

But how can a parent device ever bevome "unbound"?  A child can always
rely on its parent being present (some odd scsi devices are the one
exception, that mess is hell at times...)

thanks,

greg k-h