On Wed, Jun 13, 2018 at 03:56:32PM +0200, Christoph Hellwig wrote: > On Wed, Jun 13, 2018 at 07:06:41PM +0800, Ming Lei wrote: > > > before bio_alloc_pages) that can be switched to something that just creates a > > > single bvec. > > > > Yes, multipage bvec shouldn't break any driver or fs. > > It probably isn't broken, at least I didn't see assumptions of the same > number of segments. However the current poking into the bio internals as > a bad idea for a couple of reasons. First because it requires touching > bcache for any of these changes, second because it won't get merging of > pages into a single bio segment for bіos built by bch_bio_map or > bch_bio_alloc_pages, and third bcache is the last user of > bio_for_each_chunk_all in your branch, which I'd like to kill off to > keep the number of iterators down. Agreed about bio_for_each_chunk_all(), but I just looked at the patch that introduces them and it looks to me like there's no need, they should just be bio_for_each_segment_all(). Converting bch_bio_map() and bch_bio_alloc_pages() to bio_add_page() is fine by me, but your patch series doesn't do any of those actual cleanups: your description of the patch series does not actually match what it does.
