[PATCH v2 00/12] Fix deadlock with bdrv_open of self-served NBD

[Eric Blake <eblake@redhat.com>]

v1 was here:
https://lore.kernel.org/qemu-devel/20251103202849.3687643-10-eblake@redhat.com/T/#t

In v2:
 - split or otherwise add a few patches
 - reorder latent bug fixes earlier in series
 - improved commit messages
 - improved consistency in trace naming, and make traces unconditional
 - rearrange contents of QIONetListener rather than adding field to
   QIOChannelSocket
 - add new opt-in API rather than retro-fitting existing
   qio_net_listener_set_client_func
 - use existing QIO aio functions rather than lower-level aio.h functions
 - further enhance iotest
See individual patches for more details on changes since v1.  The series
is different enough that I did not preserve any Reviewed-by tags from v1.

A deadlock fix counts as a bug fix, so even though this missed soft
freeze, I'm hoping we can get it in -rc1 or at the latest -rc2.  But
it's also not a new regression, but a long-standing issue; so if it
slides into 11.0 out of concerns of being too risky this close to
release, I understand.

Key:
[----] : patches are identical
[####] : number of functional differences between upstream/downstream patch
[down] : patch is downstream-only
The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively

001/12:[down] 'iotests: Drop execute permissions on vvfat.out'
002/12:[0027] [FC] 'qio: Add trace points to net_listener'
003/12:[down] 'qio: Unwatch before notify in QIONetListener'
004/12:[0026] [FC] 'qio: Remember context of qio_net_listener_set_client_func_full'
005/12:[0003] [FC] 'qio: Minor optimization when callback function is unchanged'
006/12:[0039] [FC] 'qio: Factor out helpers qio_net_listener_[un]watch'
007/12:[0002] [FC] 'qio: Hoist ref of listener outside loop'
	008/12:[down] 'qio: Provide accessor around QIONetListener->sioc'
009/12:[down] 'qio: Prepare NetListener to use AioContext'
010/12:[down] 'qio: Add QIONetListener API for using AioContext'
011/12:[down] 'nbd: Avoid deadlock in client connecting to same-process server'
012/12:[0035] [FC] 'iotests: Add coverage of recent NBD qio deadlock fix'

Eric Blake (12):
  iotests: Drop execute permissions on vvfat.out
  qio: Add trace points to net_listener
  qio: Unwatch before notify in QIONetListener
  qio: Remember context of qio_net_listener_set_client_func_full
  qio: Minor optimization when callback function is unchanged
  qio: Factor out helpers qio_net_listener_[un]watch
  qio: Hoist ref of listener outside loop
  qio: Provide accessor around QIONetListener->sioc
  qio: Prepare NetListener to use AioContext
  qio: Add QIONetListener API for using AioContext
  nbd: Avoid deadlock in client connecting to same-process server
  iotests: Add coverage of recent NBD qio deadlock fix

 include/io/net-listener.h                     |  47 +++-
 blockdev-nbd.c                                |   4 +-
 chardev/char-socket.c                         |   3 +-
 io/net-listener.c                             | 233 ++++++++++++------
 migration/socket.c                            |   5 +-
 ui/vnc.c                                      |  36 ++-
 io/trace-events                               |   5 +
 tests/qemu-iotests/tests/nbd-in-qcow2-chain   |  94 +++++++
 .../qemu-iotests/tests/nbd-in-qcow2-chain.out |  75 ++++++
 tests/qemu-iotests/tests/vvfat.out            |   0
 10 files changed, 411 insertions(+), 91 deletions(-)
 create mode 100755 tests/qemu-iotests/tests/nbd-in-qcow2-chain
 create mode 100644 tests/qemu-iotests/tests/nbd-in-qcow2-chain.out
 mode change 100755 => 100644 tests/qemu-iotests/tests/vvfat.out

-- 
2.51.1