[PATCH V2 3/3] nvme: introduce pr_work to handle resv event

[Sagi Grimberg]

> When a reservation event is reported, the corresponding log page is
> already on the target side, and the host side needs to send a get
> log command to clear these log pages.

AENs are already sent to userspace, I don't see why the kernel
should read the log page unless it has something meaningful to
do with it.

> 
> Signed-off-by: Guixin Liu <kanie at linux.alibaba.com>
> ---
>   drivers/nvme/host/core.c | 47 +++++++++++++++++++++++++++++++++++++++-
>   drivers/nvme/host/nvme.h |  1 +
>   2 files changed, 47 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 60f14019f981..a906aea2f4a8 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -4220,6 +4220,47 @@ static void nvme_handle_aer_persistent_error(struct nvme_ctrl *ctrl)
>   	nvme_reset_ctrl(ctrl);
>   }
>   
> +static void nvme_queue_pr(struct nvme_ctrl *ctrl)
> +{
> +	if (nvme_ctrl_state(ctrl) == NVME_CTRL_LIVE)
> +		queue_work(nvme_wq, &ctrl->pr_work);
> +}
> +
> +static void nvme_pr_work(struct work_struct *work)
> +{
> +	struct nvme_ctrl *ctrl = container_of(work, struct nvme_ctrl, pr_work);
> +	struct nvme_pr_log log = { 0 };
> +	int error;
> +
> +	if (nvme_ctrl_state(ctrl) != NVME_CTRL_LIVE)
> +		return;
> +
> +	error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_RESERVATION, 0,
> +			NVME_CSI_NVM, &log, sizeof(log), 0);
> +	if (error) {
> +		dev_warn(ctrl->device,
> +			 "reading reservation log failed: %d\n", error);
> +		return;
> +	}
> +
> +	if (log.nr_avl_pages)
> +		nvme_queue_pr(ctrl);
> +}
> +
> +static void nvme_handle_aen_css(struct nvme_ctrl *ctrl, u32 result)
> +{
> +	u32 aer_css_type = nvme_aer_subtype(result);
> +
> +	switch (aer_css_type) {
> +	case NVME_AEN_RESV_LOG_PAGE_AVALIABLE:
> +		nvme_queue_pr(ctrl);
> +		break;
> +	default:
> +		ctrl->aen_result = result;
> +		dev_warn(ctrl->device, "async event result %08x\n", result);
> +	}
> +}
> +
>   void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
>   		volatile union nvme_result *res)
>   {
> @@ -4236,6 +4277,9 @@ void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
>   	case NVME_AER_NOTICE:
>   		requeue = nvme_handle_aen_notice(ctrl, result);
>   		break;
> +	case NVME_AER_CSS:
> +		nvme_handle_aen_css(ctrl, result);
> +		break;
>   	case NVME_AER_ERROR:
>   		/*
>   		 * For a persistent internal error, don't run async_event_work
> @@ -4247,7 +4291,6 @@ void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
>   		}
>   		fallthrough;
>   	case NVME_AER_SMART:
> -	case NVME_AER_CSS:
>   	case NVME_AER_VS:
>   		ctrl->aen_result = result;
>   		break;
> @@ -4389,6 +4432,7 @@ void nvme_stop_ctrl(struct nvme_ctrl *ctrl)
>   	nvme_stop_keep_alive(ctrl);
>   	nvme_stop_failfast_work(ctrl);
>   	flush_work(&ctrl->async_event_work);
> +	flush_work(&ctrl->pr_work);
>   	cancel_work_sync(&ctrl->fw_act_work);
>   	if (ctrl->ops->stop_ctrl)
>   		ctrl->ops->stop_ctrl(ctrl);
> @@ -4494,6 +4538,7 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
>   	ctrl->quirks = quirks;
>   	ctrl->numa_node = NUMA_NO_NODE;
>   	INIT_WORK(&ctrl->scan_work, nvme_scan_work);
> +	INIT_WORK(&ctrl->pr_work, nvme_pr_work);
>   	INIT_WORK(&ctrl->async_event_work, nvme_async_event_work);
>   	INIT_WORK(&ctrl->fw_act_work, nvme_fw_act_work);
>   	INIT_WORK(&ctrl->delete_work, nvme_delete_ctrl_work);
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index e7411dac00f7..6ea4552c4de3 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -334,6 +334,7 @@ struct nvme_ctrl {
>   	struct nvme_effects_log *effects;
>   	struct xarray cels;
>   	struct work_struct scan_work;
> +	struct work_struct pr_work;
>   	struct work_struct async_event_work;
>   	struct delayed_work ka_work;
>   	struct delayed_work failfast_work;