Cleanups:
- Simplify raid1_write_request() error handling.
(Abd-Alrhman Masalkhi)"
* 'md-7.2' of https://git.kernel.org/pub/scm/linux/kernel/git/mdraid/linux:
md/raid5: avoid R5_Overlap races while breaking stripe batches
md/raid5: use stripe state snapshot in break_stripe_batch_list()
md/raid5: let stripe batch bm_seq comparison wrap-safe
md/raid1: protect head_position for read balance
md/raid1: free r1_bio when REQ_NOWAIT is set and read would block on retry
md/raid1: honor REQ_NOWAIT when waiting for behind writes
md/raid5: always convert llbitmap bits for discard
md/raid5: validate discard support at request time
md/raid5: account discard IO
md/raid1: simplify raid1_write_request() error handling
md/raid10: fix writes_pending and barrier reference leaks on discard failures
md/raid10: fix writes_pending leak on write request failures
md/raid1: fix writes_pending and barrier reference leaks on write failures