On 16/11/2020 16:33, Jens Axboe wrote: > On 11/15/20 5:56 AM, Pavel Begunkov wrote: >> As tasks now cancel only theirs requests, and inflight_wait is awaited >> only in io_uring_cancel_files(), which should be called with ->in_idle >> set, instead of keeping a separate inflight_wait use tctx->wait. >> >> That will add some spurious wakeups but actually is safer from point of >> not hanging the task. >> >> e.g. >> task1 | IRQ >> | *start* io_complete_rw_common(link) >> | link: req1 -> req2 -> req3(with files) >> *cancel_files() | >> io_wq_cancel(), etc. | >> | put_req(link), adds to io-wq req2 >> schedule() | >> >> So, task1 will never try to cancel req2 or req3. If req2 is >> long-standing (e.g. read(empty_pipe)), this may hang. > > This looks like it's against 5.11, but also looks like we should add > it for 5.10? Yeah, 5.10 completely slipped my mind, I'll resend -- Pavel Begunkov
