On Tue, Jun 12, 2018 at 02:16:30AM -0400, Kent Overstreet wrote: > On Mon, Jun 11, 2018 at 09:48:01PM +0200, Christoph Hellwig wrote: > > This abstracts out a way to reuse a bio without destroying the > > data pointers. > > What is the point of this? What "data pointers" does it not destroy? It keeps bi_vcnt and bi_size intact in addition to bi_max_vecs/bi_io_vec already kept by the existing bio_reset. The befit is that you don't need to rebuild bi_vcnt, bio_io_vec and bi_size when reusing the bio.