[PATCH 06/14] nvme: don't unquiesce the admin queue in nvme_kill_queues

Christoph Hellwig
2022-11-01T15:01:34Z

None of the callers of nvme_kill_queues needs it to unquiesce the
admin queues, as all of them already do it themselves:

1) nvme_reset_work explicit call nvme_start_admin_queue toward the
beginning of the function. The extra call to nvme_start_admin_queue
in nvme_reset_work this won't do anything as
NVME_CTRL_ADMIN_Q_STOPPED will already be cleared.
2) nvme_remove calls nvme_dev_disable with shutdown flag set to true at
the very beginning of the function if the PCIe device was not present,
which is the precondition for the call to nvme_kill_queues.
nvme_dev_disable already calls nvme_start_admin_queue toward the
end of the function when the shutdown flag is set to true, so the
admin queue is already enabled at this point.
3) nvme_remove_dead_ctrl schedules a workqueue to unbind the driver,
which will end up in nvme_remove, which calls nvme_dev_disable with
the shutdown flag. This case will call nvme_start_admin_queue a bit
later than before.
4) apple_nvme_remove uses the same sequence as nvme_remove_dead_ctrl
above.
5) nvme_remove_namespaces only calls nvme_kill_queues when the
controller is in the DEAD state. That can only happen in the PCIe
driver, and only from nvme_remove. See item 2) above for the
conditions there.

So it is safe to just remove the call to nvme_start_admin_queue in
nvme_kill_queues without replacement.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
---
drivers/nvme/host/core.c | 4 ----
1 file changed, 4 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 871a8ab7ec199..bb62803de5b21 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -5135,10 +5135,6 @@ void nvme_kill_queues(struct nvme_ctrl *ctrl)

down_read(&ctrl->namespaces_rwsem);

- /* Forcibly unquiesce queues to avoid blocking dispatch */
- if (ctrl->admin_q && !blk_queue_dying(ctrl->admin_q))
- nvme_start_admin_queue(ctrl);
-
list_for_each_entry(ns, &ctrl->namespaces, list)
nvme_set_queue_dying(ns);

--
2.30.2