[PATCH v3 0/5] block-copy: protect block-copy internal structures

[Emanuele Giuseppe Esposito]

This serie of patches aims to reduce the usage of the
AioContexlock in block-copy, by introducing smaller granularity
locks thus on making the block layer thread safe. 

This serie depends on my previous serie that brings thread safety
to the smaller API used by block-copy, like ratelimit, progressmeter
abd co-shared-resource.

What's missing for block-copy to be fully thread-safe is fixing
the CoSleep API to allow cross-thread sleep and wakeup.
Paolo is working on it.

Patch 1 introduces the .method field in BlockCopyState, to be used
instead of .use_copy_range, .copy_size and .zeros.
Patch 2-3 provide comments and refactoring in preparation to
the lock added in patch 4 on BlockCopyTask, BlockCopyCallState and
BlockCopyState. Patch 5 uses load_acquire/store_release to make sure
BlockCopyCallState OUT fields are updated before finished is set to
true. 

Based-on: <20210518094058.25952-1-eesposit@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
v3:
* Use a single lock instead of two [Paolo, Vladimir]
* Extend lock to protect also BdrvDirtyBitmap API [Vladimir]
* Drop patch 6 (set .method as atomic) since with current refactoring
  it can be simply included in the near critical sections protected by
  the lock

Emanuele Giuseppe Esposito (4):
  block-copy: improve comments of BlockCopyTask and BlockCopyState types
    and functions
  block-copy: move progress_set_remaining in block_copy_task_end
  block-copy: add a CoMutex
  block-copy: atomic .cancelled and .finished fields in
    BlockCopyCallState

Paolo Bonzini (1):
  block-copy: streamline choice of copy_range vs. read/write

 block/block-copy.c | 319 +++++++++++++++++++++++++--------------------
 1 file changed, 181 insertions(+), 138 deletions(-)

-- 
2.30.2