Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- Fix crashes and hangs related to iothreads, bdrv_drain and block jobs:
    - Fix some AIO context locking in jobs
    - Fix blk->in_flight during blk_wait_while_drained()
- vpc: Don't round up already aligned BAT sizes

# gpg: Signature made Tue 07 Apr 2020 15:25:24 BST
# gpg:                using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  vpc: Don't round up already aligned BAT sizes
  block: Fix blk->in_flight during blk_wait_while_drained()
  block: Increase BB.in_flight for coroutine and sync interfaces
  block-backend: Reorder flush/pdiscard function definitions
  backup: don't acquire aio_context in backup_clean
  replication: assert we own context before job_cancel_sync
  job: take each job's lock individually in job_txn_apply

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>