[PATCH v2 for-7.1 0/9] nbd: actually make s->state thread-safe

[Paolo Bonzini]

The main point of this series is patch 7, 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.

v1->v2:
- cleaner patch 1
- fix grammar in patch 4
- split out patch 6

Paolo Bonzini (9):
  nbd: safeguard against waking up invalid coroutine
  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 yanking, reconnection and
    coroutines
  nbd: code motion and function renaming
  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        | 298 +++++++++++++++++++++++----------------------
 2 files changed, 154 insertions(+), 148 deletions(-)

-- 
2.35.1