On Mon, Mar 18, 2019 at 10:37:08AM -0700, James Smart wrote: > > > 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. Yeah, I saw the FC code, it is supposed to address the asynchronous completion of blk_mq_complete_request() in error handler. Also I think it is always the correct thing to abort requests synchronously in error handler, isn't it? thanks, Ming
