On Thu, Jun 28, 2018 at 11:21 PM, Bart Van Assche <bart.vanassche@xxxxxxx> wrote: > On 06/27/18 17:30, Ming Lei wrote: >> >> One core idea of immutable bvec is to use bio->bi_iter and the original >> bvec table to iterate over anywhere in the bio. That is why .bi_io_vec >> needs to copy, but not see any reason why .bi_vcnt needs to do. >> >> Do you have use cases on .bi_vcnt for cloned bio? > > > So far this is only a theoretical concern. There are many functions in the > block layer that use .bi_vcnt, and it is a lot of work to figure out all the > callers of all these functions. No, any functions using .bi_vcnt on a cloned-bio may be a bug, and we should take a close look. Thanks, Ming Lei
