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Commit a0fa9647 authored by Jens Axboe's avatar Jens Axboe
Browse files

NVMe: add blk polling support 



Add nvme_poll(), which will check a specific completion queue for
command completions. Wire that up to the new block layer poll
mechanism.

Signed-off-by: default avatarJens Axboe <axboe@fb.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarKeith Busch <keith.busch@intel.com>
parent 05229bee

drivers/nvme/host/pci.c

+28 −4
Original line number Diff line number Diff line
@@ -90,7 +90,7 @@ static struct class *nvme_class; 


static int __nvme_reset(struct nvme_dev *dev);

static int nvme_reset(struct nvme_dev *dev);

static int nvme_process_cq(struct nvme_queue *nvmeq);

static void nvme_process_cq(struct nvme_queue *nvmeq);

static void nvme_dead_ctrl(struct nvme_dev *dev);



struct async_cmd_info {
@@ -935,7 +935,7 @@ static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx, 
	return BLK_MQ_RQ_QUEUE_BUSY;

}



static int nvme_process_cq(struct nvme_queue *nvmeq)

static void __nvme_process_cq(struct nvme_queue *nvmeq, unsigned int *tag)

{

	u16 head, phase;
@@ -953,6 +953,8 @@ static int nvme_process_cq(struct nvme_queue *nvmeq) 
			head = 0;

			phase = !phase;

		}

		if (tag && *tag == cqe.command_id)

			*tag = -1;

		ctx = nvme_finish_cmd(nvmeq, cqe.command_id, &fn);

		fn(nvmeq, ctx, &cqe);

	}
@@ -964,14 +966,18 @@ static int nvme_process_cq(struct nvme_queue *nvmeq) 
	 * a big problem.

	 */

	if (head == nvmeq->cq_head && phase == nvmeq->cq_phase)

		return 0;

		return;



	writel(head, nvmeq->q_db + nvmeq->dev->db_stride);

	nvmeq->cq_head = head;

	nvmeq->cq_phase = phase;



	nvmeq->cqe_seen = 1;

	return 1;

}



static void nvme_process_cq(struct nvme_queue *nvmeq)

{

	__nvme_process_cq(nvmeq, NULL);

}



static irqreturn_t nvme_irq(int irq, void *data)
@@ -995,6 +1001,23 @@ static irqreturn_t nvme_irq_check(int irq, void *data) 
	return IRQ_WAKE_THREAD;

}



static int nvme_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag)

{

	struct nvme_queue *nvmeq = hctx->driver_data;



	if ((le16_to_cpu(nvmeq->cqes[nvmeq->cq_head].status) & 1) ==

	    nvmeq->cq_phase) {

		spin_lock_irq(&nvmeq->q_lock);

		__nvme_process_cq(nvmeq, &tag);

		spin_unlock_irq(&nvmeq->q_lock);



		if (tag == -1)

			return 1;

	}



	return 0;

}



/*

 * Returns 0 on success.  If the result is negative, it's a Linux error code;

 * if the result is positive, it's an NVM Express status code
@@ -1654,6 +1677,7 @@ static struct blk_mq_ops nvme_mq_ops = { 
	.init_hctx	= nvme_init_hctx,

	.init_request	= nvme_init_request,

	.timeout	= nvme_timeout,

	.poll		= nvme_poll,

};



static void nvme_dev_remove_admin(struct nvme_dev *dev)