On Mon, Apr 11, 2022 at 01:33:58PM -0400, Mike Snitzer wrote: > When bio_{alloc,init}_clone are passed a bdev, bio_init() will call > bio_associate_blkg() so the __bio_clone() work to initialize blkcg > isn't needed. No, unfortunately it isn't as simple as that. There are bios that do not use the default cgroup and thus blkg, e.g. those that come from cgroup writeback.