On Tue, 2018-05-22 at 08:06 -0600, Keith Busch wrote: > On Mon, May 21, 2018 at 11:29:21PM +0000, Bart Van Assche wrote: > > Can you explain why the NVMe driver needs reference counting of requests but > > no other block driver needs this? Additionally, why is it that for all block > > drivers except NVMe the current block layer API is sufficient > > (blk_get_request()/blk_execute_rq()/blk_mq_start_request()/ > > blk_mq_complete_request()/blk_mq_end_request())? > > I'm pretty sure NVMe isn't the only driver where a call to > blk_mq_complete_request silently fails to transition the request to > COMPLETE, forcing unnecessary error handling. This patch isn't so > much about NVMe as it is about removing that silent exception from the > block API.
Hello Keith, Please have a look at v13 of the timeout handling rework patch that I posted. That patch should not introduce any new race conditions and should also handle the scenario fine in which blk_mq_complete_request() is called while the NVMe timeout handling function is in progress. Thanks, Bart.
