[Qemu-block] [PATCH v2 00/13] block: Move I/O throttling to BlockBackend

[Kevin Wolf]

This is another feature that was "logically" part of the BlockBackend, but
implemented as a BlockDriverState feature. It was always kept on top using
swap_feature_fields().

This series moves it to be actually implemented in the BlockBackend, removing
another obstacle for removing bs->blk and allowing multiple BBs per BDS.

Applies to block-next.

v2:
- Rebased on top of Paolo's 'bdrv_flush_io_queue removal, shared LinuxAioState'
  Most notable this includes a complete rewrite of patch 9 (was 10): 'block:
  Drain throttling queue with BdrvChild'. Instead of a single drain_queue()
  callback we now have a drained_begin/end() pair.

- Patch 2 (was 3): 'block: Introduce BlockBackendPublic'
  Add int dummy to yet empty struct BlockBackendPublic [Eric]

- Patch 11: 'block: Remove bdrv_move_feature_fields()'
  After the rebase, the function ended up empty, we can remove it now

- Patch 12: 'Revert "block: Forbid I/O throttling on nodes with
             multiple parents for 2.6"'
  This was committed to master after v1 had been posted, so this one is new as
  well. The reason for forbidding this was that patch 6 ('block: Move actual
  I/O throttling to BlockBackend') would change the behaviour of the non-BB
  parents. Now that the final behaviour is implemented, we can allow the setup.

Kevin Wolf (13):
  block: Make sure throttled BDSes always have a BB
  block: Introduce BlockBackendPublic
  block: throttle-groups: Use BlockBackend pointers internally
  block: Convert throttle_group_get_name() to BlockBackend
  block: Move throttling fields from BDS to BB
  block: Move actual I/O throttling to BlockBackend
  block: Move I/O throttling configuration functions to BlockBackend
  block: Introduce BdrvChild.opaque
  block: Drain throttling queue with BdrvChild callback
  block: Decouple throttling from BlockDriverState
  block: Remove bdrv_move_feature_fields()
  Revert "block: Forbid I/O throttling on nodes with multiple parents
    for 2.6"
  block: Don't check throttled reqs in bdrv_requests_pending()

 block.c                         |  58 +---------
 block/block-backend.c           | 135 ++++++++++++++++++-----
 block/io.c                      |  83 ++++----------
 block/qapi.c                    |   6 +-
 block/throttle-groups.c         | 234 +++++++++++++++++++++-------------------
 blockdev.c                      |  50 +++------
 include/block/block.h           |   4 -
 include/block/block_int.h       |  27 +----
 include/block/throttle-groups.h |  14 +--
 include/sysemu/block-backend.h  |  27 +++++
 tests/test-throttle.c           |  62 ++++++-----
 11 files changed, 343 insertions(+), 357 deletions(-)

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1.8.3.1