Hello, On Mon, Apr 02, 2018 at 10:09:18PM +0000, Bart Van Assche wrote: > Please elaborate what your long-term goal is for the blk-mq timeout handler. Hmm... I don't really have any plans beyond what's been posted. > The legacy block layer suspends request state changes while a timeout is > being processed by holding the request queue lock while requests are being > processed, while processing a timeout and while calling q->rq_timed_out_fn(rq). > Do you think it is possible to make the blk-mq core suspend request processing > while processing a timeout without introducing locking in > blk_mq_complete_request()? If you do not plan to add locking in > blk_mq_complete_request(), do you think it is possible to fix all the races we > discussed in previous e-mails? I don't know of multiple race conditions. What am I missing? AFAIK, there's one non-critical race condition which has always been there. We have a larger race window for that case but don't yet know whether that's problematic or not. If that actually is problematic, we can figure out a way to solve that but such effort / added complexity doesn't seem justified yet. No? Thanks. -- tejun
