On 3/17/2019 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.
This won't help FC at all. Inherently, the "completion" has to be asynchronous as line traffic may be required.
e.g. FC doesn't use nvme_complete_request() in the iterator routine. -- james
