[PATCH for-7.1 0/8] nbd: actually make s->state thread-safe

[Paolo Bonzini]

The main point of this series is patch 6, which removes the dubious and
probably wrong use of atomics in block/nbd.c.  This in turn is enabled
mostly by the cleanups in patches 3-5.  Together, they introduce a
QemuMutex that synchronizes the NBD client coroutines, the reconnect_delay
timer and nbd_cancel_in_flight() as well.

The fixes happen to remove an incorrect use of qemu_co_queue_restart_all
and qemu_co_enter_next on the s->free_sema CoQueue, which was not guarded
by s->send_mutex.

The rest is bugfixes, simplifying the code a bit, and extra documentation.

Paolo Bonzini (8):
  nbd: actually implement reply_possible safeguard
  nbd: mark more coroutine_fns
  nbd: remove peppering of nbd_client_connected
  nbd: keep send_mutex/free_sema handling outside
    nbd_co_do_establish_connection
  nbd: use a QemuMutex to synchronize reconnection with coroutines
  nbd: move s->state under requests_lock
  nbd: take receive_mutex when reading requests[].receiving
  nbd: document what is protected by the CoMutexes

 block/coroutines.h |   4 +-
 block/nbd.c        | 303 +++++++++++++++++++++++----------------------
 2 files changed, 157 insertions(+), 150 deletions(-)

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2.35.1