Messages in this thread | | | Date | Fri, 3 Aug 2018 01:06:01 +0800 | From | Ming Lei <> | Subject | Re: [PATCH] blk-mq: fix blk_mq_tagset_busy_iter |
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On Thu, Aug 02, 2018 at 09:54:06AM -0700, James Bottomley wrote: > On Fri, 2018-08-03 at 00:43 +0800, Ming Lei wrote: > > Commit d250bf4e776ff09d5("blk-mq: only iterate over inflight requests > > in blk_mq_tagset_busy_iter") uses 'blk_mq_rq_state(rq) == > > MQ_RQ_IN_FLIGHT' > > to replace 'blk_mq_request_started(req)', this way is wrong, and > > causes > > lots of test system hang during booting. > > > > Fix the issue by using blk_mq_request_started(req) inside > > bt_tags_iter(). > > > > Fixes: d250bf4e776ff09d5 ("blk-mq: only iterate over inflight > > requests in blk_mq_tagset_busy_iter") > > Cc: Josef Bacik <josef@toxicpanda.com> > > Cc: Christoph Hellwig <hch@lst.de> > > Cc: Guenter Roeck <linux@roeck-us.net> > > Cc: Mark Brown <broonie@kernel.org> > > Cc: Matt Hart <matthew.hart@linaro.org> > > Cc: Johannes Thumshirn <jthumshirn@suse.de> > > Cc: John Garry <john.garry@huawei.com> > > Cc: Hannes Reinecke <hare@suse.com>, > > Cc: "Martin K. Petersen" <martin.petersen@oracle.com>, > > Cc: James Bottomley <James.Bottomley@hansenpartnership.com> > > Cc: linux-scsi@vger.kernel.org > > Cc: linux-kernel@vger.kernel.org > > Signed-off-by: Ming Lei <ming.lei@redhat.com> > > --- > > block/blk-mq-tag.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c > > index 09b2ee6694fb..3de0836163c2 100644 > > --- a/block/blk-mq-tag.c > > +++ b/block/blk-mq-tag.c > > @@ -271,7 +271,7 @@ static bool bt_tags_iter(struct sbitmap *bitmap, > > unsigned int bitnr, void *data) > > * test and set the bit before assining ->rqs[]. > > */ > > rq = tags->rqs[bitnr]; > > - if (rq && blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT) > > + if (rq && blk_mq_request_started(rq)) > > So now we have dueling versions of this patch: > > https://marc.info/?l=linux-scsi&m=153322802207688 > > Can we at least make sure we've root caused the problem and confirmed > we've got it fixed before we start the formal patch process? When we
EH uses scsi_host_busy to check if the error handler needs to be waken up. And blk_mq_tagset_busy_iter() is used for implementing scsi_host_busy(), so causes EH not waken up, then this timed-out request can't be handled.
> do start the formal patch process, please give appropriate credit to > the reporter(s) since this has been a royal pain for them to help us > track down.
Sure.
Jens, could you add reported-by if you are fine with this version? Or please just let me know if new version is needed, then I can add it.
Thanks, Ming
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