[PATCH 1/2] nvme: sanitize KATO setting

[Sagi Grimberg]

On 3/11/21 2:55 AM, Christoph Hellwig wrote:
>> +/*
>> + * Recommended frequency for KATO commands
>> + *
>> + * NVMe 1.4 section 7.12.1 states:
>> + * The host should send Keep Alive commands at half of the
>> + * Keep Alive Timeout accounting for transport roundtrip times [..].
>> + */
>> +#define NVME_KATO_DELAY(k)	(((k) > 1)?(k) >> 1:(k))
> 
> This should have been an inline if added at all, and use proper
> formatting, as well as avoiding the shift obsfucation.
> 
> I think the best is to just move this into the only caller, where
> we also know that ctrl->kato can't be 0 due to the check in
> nvme_start_keep_alive:
> 
> /*
>   * Recommended frequency for KATO commands per  NVMe 1.4 section 7.12.1:
>   *
>   *     The host should send Keep Alive commands at half of the
>   *     Keep Alive Timeout accounting for transport roundtrip times [..].
> */
> static inline void nvme_queue_keep_alive_work(struct nvme_ctrl *ctrl)
> {
> 	queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ / 2);
> }
> 
> Also please keep this helper inside of core.c.

Agreed.