This is a preparation to support voluntary thread termination by
calling spdk_thread_exit().
By the last patch, the asynchronous release of I/O channel will
complete even after spdk_thread_exit() because pending messages will
be reaped.
Then this patch stops new allocation of I/O channel after
spdk_thread_exit().
Hence we will be able to release all I/O channels for exiting
thread within finite time.
Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Change-Id: I48a45bcba7c4b2c62d8c9d398ac35a584b533627
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/821
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>