Re: [PATCH for-next 3/3] IB/hfi1: Use the ibdev in hfi1_devdata as the parent of cdev

[Jason Gunthorpe <jgg@ziepe.ca>]

On Fri, Mar 20, 2020 at 05:30:40PM +0000, Wan, Kaike wrote:

> > > If this is not desirable, we could keep the current approach to create
> > > the struct device dynamically through device_create(). In that case,
> > > all we need to do is to clean up the code. Which one do you prefer?
> > 
> > The issue here was parentage. There should not be a virtual device involved.
> > 
> > The hfi1 user_class device should be parented to the ib_device, look at how
> > things like umad work to do this properly.
> So all we need to do is:
> -- Change user_device from struct device * to struct device in hfi1_devdata;
> -- Set up dd->user_device properly including setting its parent to ib_device;
> -- call cdev_device_all().

Yes, but keep in mind that putting multiple krefs inside the same
structure is very tricky - be sure to do it right.

Jason