On 3/17/19 8:29 PM, Ming Lei wrote:
In NVMe's error handler, follows the typical steps for tearing down hardware: 1) stop blk_mq hw queues 2) stop the real hw queues 3) cancel in-flight requests via blk_mq_tagset_busy_iter(tags, cancel_request, ...) cancel_request(): mark the request as abort blk_mq_complete_request(req); 4) destroy real hw queues However, there may be race between #3 and #4, because blk_mq_complete_request() actually completes the request asynchronously. This patch introduces blk_mq_complete_request_sync() for fixing the above race.
Other block drivers wait until outstanding requests have completed by calling blk_cleanup_queue() before hardware queues are destroyed. Why can't the NVMe driver follow that approach?
Thanks, Bart.
