On Thu, Nov 15, 2018 at 04:52:55PM +0800, Ming Lei wrote: > BTRFS is the only user of this helper, so move this helper into > BTRFS, and implement it via bio_for_each_segment_all(), since > bio->bi_vcnt may not equal to number of pages after multipage bvec > is enabled. btrfs only uses the value to check if it is larger than 1. No amount of multipage bio merging should ever make bi_vcnt go from 0 to 1 or vice versa.