On Thu, Feb 09, 2017 at 01:18:49PM +0900, Damien Le Moal wrote: > + > +/* > + * Target BIO completion. > + */ > +static inline void dmz_bio_end(struct bio *bio, int err) > +{ > + struct dm_zone_bioctx *bioctx = > + dm_per_bio_data(bio, sizeof(struct dm_zone_bioctx)); > + > + if (atomic_dec_and_test(&bioctx->ref)) { It seems like this could be simplified a bit by using bio_chain to chain the clones to the original bio.