On Thu, May 07, 2020 at 05:43:40PM +0200, Stefan Haberland wrote: > Not checked till now. I just was thinking about the basicapproach. > > I could either check the block_device_operations like you suggested > or I could verify that the gendisk pointer is already in our devmap > and therefor belongs to the DASD driver. The ops pointer check is simpler and cheaper, so I'd suggest that.