[PATCH 4.11 068/115] nvme: use blk_mq_start_hw_queues() in nvme_kill_queues()

Greg Kroah-Hartman
2017-06-05T16:31:53Z

From: Ming Lei <ming.lei@redhat.com>

commit 806f026f9b901eaf1a6baeb48b5da18d6a4f818e upstream.

Inside nvme_kill_queues(), we have to start hw queues for
draining requests in sw queues, .dispatch list and requeue list,
so use blk_mq_start_hw_queues() instead of blk_mq_start_stopped_hw_queues()
which only run queues if queues are stopped, but the queues may have
been started already, for example nvme_start_queues() is called in reset work
function.

blk_mq_start_hw_queues() run hw queues in current context, instead
of running asynchronously like before. Given nvme_kill_queues() is
run from either remove context or reset worker context, both are fine
to run hw queue directly. And the mutex of namespaces_mutex isn't a
problem too becasue nvme_start_freeze() runs hw queue in this way
already.

Reported-by: Zhang Yi <yizhan@redhat.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/nvme/host/core.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2345,7 +2345,13 @@ void nvme_kill_queues(struct nvme_ctrl *
revalidate_disk(ns->disk);
blk_set_queue_dying(ns->queue);
blk_mq_abort_requeue_list(ns->queue);
- blk_mq_start_stopped_hw_queues(ns->queue, true);
+
+ /*
+ * Forcibly start all queues to avoid having stuck requests.
+ * Note that we must ensure the queues are not stopped
+ * when the final removal happens.
+ */
+ blk_mq_start_hw_queues(ns->queue);
}
mutex_unlock(&ctrl->namespaces_mutex);
}