[PATCH 1/2] NVMe: Refactor doorbell

[Keith Busch]

On Fri, 11 Oct 2013, Matias Bjorling wrote:
> The doorbell code is repeated various places. Refactor it into its own function
> for clarity.
>
> Signed-off-by: Matias Bjorling <m at bjorling.me>

Looks good to me.
Reviewed-by: Keith Busch <keith.busch at intel.com>

> ---
> drivers/block/nvme-core.c | 29 +++++++++++++----------------
> 1 file changed, 13 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
> index da52092..40998d5 100644
> --- a/drivers/block/nvme-core.c
> +++ b/drivers/block/nvme-core.c
> @@ -242,6 +242,13 @@ void put_nvmeq(struct nvme_queue *nvmeq)
> 	put_cpu();
> }
>
> +static inline void nvme_ring_doorbell(struct nvme_queue *nvmeq)
> +{
> +	if (++nvmeq->sq_tail == nvmeq->q_depth)
> +		nvmeq->sq_tail = 0;
> +	writel(nvmeq->sq_tail, nvmeq->q_db);
> +}
> +
> /**
>  * nvme_submit_cmd() - Copy a command into a queue and ring the doorbell
>  * @nvmeq: The queue to use
> @@ -252,14 +259,10 @@ void put_nvmeq(struct nvme_queue *nvmeq)
> static int nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
> {
> 	unsigned long flags;
> -	u16 tail;
> +
> 	spin_lock_irqsave(&nvmeq->q_lock, flags);
> -	tail = nvmeq->sq_tail;
> -	memcpy(&nvmeq->sq_cmds[tail], cmd, sizeof(*cmd));
> -	if (++tail == nvmeq->q_depth)
> -		tail = 0;
> -	writel(tail, nvmeq->q_db);
> -	nvmeq->sq_tail = tail;
> +	memcpy(&nvmeq->sq_cmds[nvmeq->sq_tail], cmd, sizeof(*cmd));
> +	nvme_ring_doorbell(nvmeq);
> 	spin_unlock_irqrestore(&nvmeq->q_lock, flags);
>
> 	return 0;
> @@ -619,9 +622,7 @@ static int nvme_submit_discard(struct nvme_queue *nvmeq, struct nvme_ns *ns,
> 	cmnd->dsm.nr = 0;
> 	cmnd->dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);
>
> -	if (++nvmeq->sq_tail == nvmeq->q_depth)
> -		nvmeq->sq_tail = 0;
> -	writel(nvmeq->sq_tail, nvmeq->q_db);
> +	nvme_ring_doorbell(nvmeq);
>
> 	return 0;
> }
> @@ -636,9 +637,7 @@ static int nvme_submit_flush(struct nvme_queue *nvmeq, struct nvme_ns *ns,
> 	cmnd->common.command_id = cmdid;
> 	cmnd->common.nsid = cpu_to_le32(ns->ns_id);
>
> -	if (++nvmeq->sq_tail == nvmeq->q_depth)
> -		nvmeq->sq_tail = 0;
> -	writel(nvmeq->sq_tail, nvmeq->q_db);
> +	nvme_ring_doorbell(nvmeq);
>
> 	return 0;
> }
> @@ -729,9 +728,7 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
> 	cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);
>
> 	nvme_start_io_acct(bio);
> -	if (++nvmeq->sq_tail == nvmeq->q_depth)
> -		nvmeq->sq_tail = 0;
> -	writel(nvmeq->sq_tail, nvmeq->q_db);
> +	nvme_ring_doorbell(nvmeq);
>
> 	return 0;
>
> -- 
> 1.8.1.2
>
>
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