On Tue, Aug 18, 2020 at 12:02:36AM -0700, Song Liu wrote: > These functions can be used to enable iostat for partitions on devices > like md, bcache. Please follow a model like bio_start_io_acct - that is pass a bio for all the input parameters except for the gendisk. Given that we don't have anywhere for the part to store that will need another output paramater. The end_io function should drop the hd_struct reference as well for a well rounded API.