[PATCH v6 08/18] nvme: Implement cross-controller reset recovery

[Daniel Wagner]

> +static int nvme_issue_wait_ccr(struct nvme_ctrl *sctrl, struct nvme_ctrl *ictrl,
> +			       unsigned long deadline)
> +{
> +	struct nvme_ccr_entry ccr = { };
> +	union nvme_result res = { 0 };
> +	struct nvme_command c = { };
> +	unsigned long flags, now, tmo = 0;
> +	bool completed = false;
> +	int ret = 0;
> +	u32 result;
> +
> +	init_completion(&ccr.complete);
> +	ccr.ictrl = ictrl;
> +
> +	spin_lock_irqsave(&sctrl->lock, flags);
> +	list_add_tail(&ccr.list, &sctrl->ccr_list);
> +	spin_unlock_irqrestore(&sctrl->lock, flags);
> +
> +	c.ccr.opcode = nvme_admin_cross_ctrl_reset;
> +	c.ccr.ciu = ictrl->ciu;
> +	c.ccr.icid = cpu_to_le16(ictrl->cntlid);
> +	c.ccr.cirn = cpu_to_le64(ictrl->cirn);
> +	ret = __nvme_submit_sync_cmd(sctrl->admin_q, &c, &res,
> +				     NULL, 0, NVME_QID_ANY, 0);
> +	if (ret) {
> +		ret = -EIO;
> +		goto out;
> +	}
> +
> +	result = le32_to_cpu(res.u32);
> +	if (result & 0x01) /* Immediate Reset Successful */
> +		goto out;
> +
> +	now = jiffies;
> +	if (time_before(now, deadline))
> +		tmo = min_t(unsigned long,
> +			    secs_to_jiffies(ictrl->kato), deadline - now);
> +
> +	if (!wait_for_completion_timeout(&ccr.complete, tmo)) {
> +		ret = -ETIMEDOUT;
> +		goto out;
> +	}
> +
> +	completed = true;
> +
> +out:
> +	spin_lock_irqsave(&sctrl->lock, flags);
> +	list_del(&ccr.list);
> +	spin_unlock_irqrestore(&sctrl->lock, flags);
> +	if (completed) {
> +		if (ccr.ccrs == NVME_CCR_STATUS_SUCCESS)
> +			return 0;
> +		return -EREMOTEIO;
> +	}
> +	return ret;


This part could be made a bit simpler and there is no need for the local
completed variable:

[...]
        if (!wait_for_completion_timeout(&ccr.complete, tmo))
                ret = -ETIMEDOUT;

out:
        spin_lock_irqsave(&sctrl->lock, flags);
        list_del(&ccr.list);
        spin_unlock_irqrestore(&sctrl->lock, flags);

        if (ret || !completion_done(&ccr.complete))
                return ret;
        if (ccr.ccrs == NVME_CCR_STATUS_SUCCESS)
                return 0;
        return -EREMOTEIO;
}