From mboxrd@z Thu Jan  1 00:00:00 1970
From: hch@lst.de (Christoph Hellwig)
Date: Mon, 11 Mar 2019 19:28:25 +0100
Subject: [PATCH 4/8] nvme/pci: Remove last_cq_seen
In-Reply-To: <20190308174313.5134-4-keith.busch@intel.com>
References: <20190308174313.5134-1-keith.busch@intel.com>
 <20190308174313.5134-4-keith.busch@intel.com>
Message-ID: <20190311182825.GD11448@lst.de>

> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 45db4a39795e..62f29ab93f5a 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -193,7 +193,6 @@ struct nvme_queue {
>  	u16 sq_tail;
>  	u16 last_sq_tail;
>  	u16 cq_head;
> -	u16 last_cq_head;
>  	u16 qid;
>  	u8 cq_phase;
>  	unsigned long flags;
> @@ -1044,10 +1043,7 @@ static irqreturn_t nvme_irq(int irq, void *data)
>  	 * the irq handler, even if that was on another CPU.
>  	 */
>  	rmb();
> -	if (nvmeq->cq_head != nvmeq->last_cq_head)
> -		ret = IRQ_HANDLED;
>  	nvme_process_cq(nvmeq, &start, &end);
> -	nvmeq->last_cq_head = nvmeq->cq_head;
>  	wmb();
>  
>  	if (start != end) {

This looks good, but we can also kill the ret variable now, and
simplify the tail a bit to:

	if (start == end)
		return IRQ_NONE;
	nvme_complete_cqes(nvmeq, start, end);
	return IRQ_HANDLED;