On Sun, Dec 2, 2018 at 12:48 AM Christoph Hellwig <hch@xxxxxx> wrote: > > On Fri, Nov 30, 2018 at 01:36:09PM -0700, Jens Axboe wrote: > > On 11/30/18 1:26 PM, Keith Busch wrote: > > > A driver may wish to iterate every tagged request, not just ones that > > > satisfy blk_mq_request_started(). The intended use is so a driver may > > > terminate entered requests on quiesced queues. > > > > How about we just move the started check into the handler passed in for > > those that care about it? Much saner to make the interface iterate > > everything, and leave whatever state check to the callback. > > So we used to do that, and I changed it back in May to test for > MQ_RQ_IN_FLIGHT, and then Ming changed it to check > blk_mq_request_started. So this is clearly a minefield of sorts.. The change to blk_mq_request_started() is for just fixing SCSI's boot hang issue. > > Note that at least mtip32xx, nbd, skd and the various nvme transports > want to use the function to terminate all requests in the error > path, and it would be great to have one single understood, documented > and debugged helper for that in the core, so this is a vote for moving > more of the logic in your second helper into the core code. skd > will need actually use ->complete to release resources for that, though > and mtip plays some odd abort bits. If it weren't for the interesting > abort behavior in nvme-fc that means we could even unexport the > low-level interface. Agree, and especially SCSI's use should be understood given SCSI is so widely deployed in product system. thanks, Ming Lei
