On Thu, Jun 13, 2019 at 11:43:05AM +0200, Christoph Hellwig wrote: > This code is a trivial wrapper around device model helpers, which > should have been integrated into the driver device model usage from > the start. Assuming it actually had users, which it never had since > the code was added more than 1 1/2 years ago. > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > --- > include/linux/hmm.h | 20 ------------ > mm/hmm.c | 80 --------------------------------------------- > 2 files changed, 100 deletions(-) I haven't looked in detail at this device memory stuff.. But I did check a bit through the mailing list archives for some clue what this was supposed to be for (wow, this is from 2016!) The commit that added this says: This introduce a dummy HMM device class so device driver can use it to create hmm_device for the sole purpose of registering device memory. Which I just can't understand at all. If we need a 'struct device' for some 'device memory' purpose then it probably ought to be the 'struct pci_device' holding the BAR, not a fake device. I also can't comprehend why a supposed fake device would need a chardev, with a stanadrd 'hmm_deviceX' name, without also defining a core kernel ABI for that char dev.. If this comes back it needs a proper explanation and review, with a user. Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Jason
