[PATCH 2/2] nvme-pci: don't wait freeze during resetting

[Chao Leng]

On 2022/8/21 16:47, Ming Lei wrote:
> First it isn't necessary to call nvme_wait_freeze in nvme_reset_work().
> If tagset isn't allocated, there can't be any inflight IOs; otherwise
> blk_mq_update_nr_hw_queues can freeze & wait queues.
> 
> Second, since commit bdd6316094e0 ("block: Allow unfreezing of a queue
> while requests are in progress"), it is fine to unfreeze queue without
> draining inflight IOs.
> 
> Signed-off-by: Ming Lei <ming.lei at redhat.com>
> ---
>   drivers/nvme/host/pci.c | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 3a1c37f32f30..91b2903fcc24 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -2910,7 +2910,6 @@ static void nvme_reset_work(struct work_struct *work)
>   		nvme_free_tagset(dev);
>   	} else {
>   		nvme_start_queues(&dev->ctrl);
> -		nvme_wait_freeze(&dev->ctrl);
It is not safe.
nvme_dev_add may call blk_mq_update_nr_hw_queues, blk_mq_update_nr_hw_queues
require the state is frozen.
>   		if (!dev->ctrl.tagset)
>   			nvme_pci_alloc_tag_set(dev);
>   		else
>