Merge branch 'for-5.13/io_uring' into io_uring-fops.v3

Merge branch 'for-5.13/io_uring' into io_uring-fops.v3

* for-5.13/io_uring:
  io_uring: cache async and regular file state for fixed files
  io_uring: don't check for io_uring_fops for fixed files
  io_uring: simplify io_sqd_update_thread_idle()
  io_uring: switch to atomic_t for io_kiocb reference count
  io_uring: wrap io_kiocb reference count manipulation in helpers
  io_uring: simplify io_resubmit_prep()
  io_uring: merge defer_prep() and prep_async()
  io_uring: rethink def->needs_async_data
  io_uring: untie alloc_async_data and needs_async_data
  io_uring: refactor out send/recv async setup
  io_uring: use better types for cflags
  io_uring: refactor provide/remove buffer locking
  io_uring: add a helper failing not issued requests
  io_uring: further deduplicate file slot selection
  io_uring: reuse io_req_task_queue_fail()
  io_uring: avoid taking ctx refs for task-cancel