| Message ID | 1499154912-10420-9-git-send-email-sagi@grimberg.me (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jul 04, 2017 at 10:55:12AM +0300, Sagi Grimberg wrote: > Before calling blk_cleanup_queue one must make sure > that no request is being queued. In order to guarantee that > we need to use blk_mq_quiesce as it respects the submission > path rcu grace. > > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > Cc: Roger Pau Monné <roger.pau@citrix.com> > Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> > Cc: Juergen Gross <jgross@suse.com> > Signed-off-by: Sagi Grimberg <sagi@grimberg.me> > --- > drivers/block/xen-blkfront.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c > index c852ed3c01d5..5272ca8fb0dc 100644 > --- a/drivers/block/xen-blkfront.c > +++ b/drivers/block/xen-blkfront.c > @@ -1187,7 +1187,7 @@ static void xlvbd_release_gendisk(struct blkfront_info *info) > return; > > /* No more blkif_request(). */ > - blk_mq_stop_hw_queues(info->rq); > + blk_mq_quiesce_queue(info->rq); > > for (i = 0; i < info->nr_rings; i++) { > struct blkfront_ring_info *rinfo = &info->rinfo[i]; > @@ -1217,7 +1217,7 @@ static void xlvbd_release_gendisk(struct blkfront_info *info) > static inline void kick_pending_request_queues_locked(struct blkfront_ring_info *rinfo) > { > if (!RING_FULL(&rinfo->ring)) > - blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true); > + blk_mq_unquiesce_queue(rinfo->dev_info->rq); > } Looks the above change isn't needed since this blk_mq_start_stopped_hw_queues() should have been the counterpart of blk_mq_stop_hw_queue() in blkif_queue_rq().
> Looks the above change isn't needed since this blk_mq_start_stopped_hw_queues() > should have been the counterpart of blk_mq_stop_hw_queue() in > blkif_queue_rq(). Removed the patch altogether in v2 as I'm not convinced it is needed.
On Wed, Jul 05, 2017 at 09:29:26AM +0300, Sagi Grimberg wrote: > > >> Looks the above change isn't needed since this blk_mq_start_stopped_hw_queues() >> should have been the counterpart of blk_mq_stop_hw_queue() in >> blkif_queue_rq(). > > Removed the patch altogether in v2 as I'm not convinced it is needed. I've only started reading the series, but to me it seems like the two places where xen-blkfront currently calls blk_mq_stop_hw_queues should probably converted, as they are the same category as the other calls converted in your series.
>>> Looks the above change isn't needed since this blk_mq_start_stopped_hw_queues() >>> should have been the counterpart of blk_mq_stop_hw_queue() in >>> blkif_queue_rq(). >> >> Removed the patch altogether in v2 as I'm not convinced it is needed. > > I've only started reading the series, but to me it seems like the > two places where xen-blkfront currently calls blk_mq_stop_hw_queues > should probably converted, as they are the same category as the other > calls converted in your series. I'm not familiar enough with the code, I can restore a correct version of it if it makes sense to you guys...
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index c852ed3c01d5..5272ca8fb0dc 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1187,7 +1187,7 @@ static void xlvbd_release_gendisk(struct blkfront_info *info) return; /* No more blkif_request(). */ - blk_mq_stop_hw_queues(info->rq); + blk_mq_quiesce_queue(info->rq); for (i = 0; i < info->nr_rings; i++) { struct blkfront_ring_info *rinfo = &info->rinfo[i]; @@ -1217,7 +1217,7 @@ static void xlvbd_release_gendisk(struct blkfront_info *info) static inline void kick_pending_request_queues_locked(struct blkfront_ring_info *rinfo) { if (!RING_FULL(&rinfo->ring)) - blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true); + blk_mq_unquiesce_queue(rinfo->dev_info->rq); } static void kick_pending_request_queues(struct blkfront_ring_info *rinfo) @@ -1346,7 +1346,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; /* No more blkif_request(). */ if (info->rq) - blk_mq_stop_hw_queues(info->rq); + blk_mq_quiesce_queue(info->rq); for (i = 0; i < info->nr_rings; i++) blkif_free_ring(&info->rinfo[i]); @@ -2032,7 +2032,7 @@ static int blkif_recover(struct blkfront_info *info) BUG_ON(req->nr_phys_segments > segs); blk_mq_requeue_request(req, false); } - blk_mq_start_stopped_hw_queues(info->rq, true); + blk_mq_unquiesce_queue(info->rq); blk_mq_kick_requeue_list(info->rq); while ((bio = bio_list_pop(&info->bio_list)) != NULL) {
Before calling blk_cleanup_queue one must make sure that no request is being queued. In order to guarantee that we need to use blk_mq_quiesce as it respects the submission path rcu grace. Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Roger Pau Monné <roger.pau@citrix.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> --- drivers/block/xen-blkfront.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)