- Add a dm-crypt optional "high_priority" flag that enables the crypt workqueues to use WQ_HIGHPRI. - Export dm-crypt workqueues via sysfs (by enabling WQ_SYSFS) to allow for improved visibility and controls over IO and crypt workqueues. - Fix dm-crypt to no longer constrain max_segment_size to PAGE_SIZE. This limit isn't needed given that the block core provides late bio splitting if bio exceeds underlying limits (e.g. max_segment_size). - Fix dm-crypt crypt_queue's use of WQ_UNBOUND to not use WQ_CPU_INTENSIVE because it is meaningless with WQ_UNBOUND. - Fix various issues with dm-delay target (ranging from a resource teardown fix, a fix for hung task when using kthread mode, and other improvements that followed from code inspection).