Re: [PATCH 6/8] mtip32xx: quiesce request queues to make sure no submissions are inflight
From: Ming Lei <hidden>
Date: 2017-07-04 22:32:52
Also in:
linux-nvme
On Tue, Jul 04, 2017 at 10:55:10AM +0300, Sagi Grimberg wrote:
quoted hunk ↗ jump to hunk
Unlike blk_mq_stop_hw_queues, blk_mq_quiesce_queue respects the submission path rcu grace. quiesce the queue before iterating on live tags, or performing device io quiescing. Signed-off-by: Sagi Grimberg <sagi@grimberg.me> --- drivers/block/mtip32xx/mtip32xx.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c index 61b046f256ca..69a62aeace2a 100644 --- a/drivers/block/mtip32xx/mtip32xx.c +++ b/drivers/block/mtip32xx/mtip32xx.c@@ -950,7 +950,7 @@ static int mtip_quiesce_io(struct mtip_port *port, unsigned long timeout) unsigned long to; bool active = true; - blk_mq_stop_hw_queues(port->dd->queue); + blk_mq_quiesce_queue(port->dd->queue); to = jiffies + msecs_to_jiffies(timeout); do {@@ -970,10 +970,10 @@ static int mtip_quiesce_io(struct mtip_port *port, unsigned long timeout) break; } while (time_before(jiffies, to)); - blk_mq_start_stopped_hw_queues(port->dd->queue, true); + blk_mq_unquiesce_queue(port->dd->queue); return active ? -EBUSY : 0; err_fault: - blk_mq_start_stopped_hw_queues(port->dd->queue, true); + blk_mq_unquiesce_queue(port->dd->queue); return -EFAULT; }
The above change looks correct.
quoted hunk ↗ jump to hunk
@@ -3995,7 +3995,7 @@ static int mtip_block_remove(struct driver_data *dd) dd->disk->disk_name); blk_freeze_queue_start(dd->queue); - blk_mq_stop_hw_queues(dd->queue); + blk_mq_quiesce_queue(dd->queue); blk_mq_tagset_busy_iter(&dd->tags, mtip_no_dev_cleanup, dd);
We still need to unquiesce queue for avoiding hanging blk_freeze_queue() in blk_cleanup_queue() since any new request queued during quiescing can't be dispatched to driver/device. There are other blk_mq_tagset_busy_iter() in mtip_service_thread(), which looks need quiesce too. This case is even worse, because both mtip_abort_cmd() and mtip_queue_cmd() do not check if the req is started. -- Ming