Hi Bart, I generally like this. Two thoughs: - I suspect most places that currently pass a enum req_op might really want a blk_opf_t for future extensibility, exceptions are very low-level helpers like req_op() and bio_op() where the enum is very nice to force switch statements to handle all ops or have a default statements - a lot of the flags printinting is a mess, and introduce the code smell of __force casts. It migh make sense to introduce a new %psomething format specifier first to print a blk_opf_t using printk/vsprintf/etc and switch everyone to that first instead of hand crafted printing.
