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

Chaitanya Kulkarni
2022-11-02T01:24:24Z

On 11/1/22 08:00, Christoph Hellwig wrote:
> 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 ----

Thanks a lot for detailed explanation..
Looks good.

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

-ck