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Commit 846cc05f authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

nvme: simplify resets 



Don't delete the controller from dev_list before queuing a reset, instead
just check for it being reset in the polling kthread.  This allows to remove
the dev_list_lock in various places, and in addition we can simply rely on
checking the queue_work return value to see if we could reset a controller.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 297465c8

drivers/nvme/host/pci.c

+13 −26
Original line number Diff line number Diff line
@@ -77,7 +77,6 @@ struct nvme_dev; 
struct nvme_queue;

struct nvme_iod;



static int __nvme_reset(struct nvme_dev *dev);

static int nvme_reset(struct nvme_dev *dev);

static void nvme_process_cq(struct nvme_queue *nvmeq);

static void nvme_unmap_data(struct nvme_dev *dev, struct nvme_iod *iod);
@@ -1093,13 +1092,11 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved) 
	 * the admin queue.

	 */

	if (!nvmeq->qid || cmd_rq->aborted) {

		spin_lock_irq(&dev_list_lock);

		if (!__nvme_reset(dev)) {

		if (queue_work(nvme_workq, &dev->reset_work)) {

			dev_warn(dev->dev,

				 "I/O %d QID %d timeout, reset controller\n",

				 req->tag, nvmeq->qid);

		}

		spin_unlock_irq(&dev_list_lock);

		return BLK_EH_RESET_TIMER;

	}
@@ -1496,9 +1493,15 @@ static int nvme_kthread(void *data) 
			int i;

			u32 csts = readl(dev->bar + NVME_REG_CSTS);



			/*

			 * Skip controllers currently under reset.

			 */

			if (work_pending(&dev->reset_work) || work_busy(&dev->reset_work))

				continue;



			if ((dev->subsystem && (csts & NVME_CSTS_NSSRO)) ||

							csts & NVME_CSTS_CFS) {

				if (!__nvme_reset(dev)) {

				if (queue_work(nvme_workq, &dev->reset_work)) {

					dev_warn(dev->dev,

						"Failed status: %x, reset controller\n",

						readl(dev->bar + NVME_REG_CSTS));
@@ -2228,35 +2231,19 @@ static void nvme_reset_work(struct work_struct *ws) 
	schedule_work(&dev->probe_work);

}



static int __nvme_reset(struct nvme_dev *dev)

{

	if (work_pending(&dev->reset_work))

		return -EBUSY;

	list_del_init(&dev->node);

	queue_work(nvme_workq, &dev->reset_work);

	return 0;

}



static int nvme_reset(struct nvme_dev *dev)

{

	int ret;



	if (!dev->ctrl.admin_q || blk_queue_dying(dev->ctrl.admin_q))

		return -ENODEV;



	spin_lock(&dev_list_lock);

	ret = __nvme_reset(dev);

	spin_unlock(&dev_list_lock);

	if (!queue_work(nvme_workq, &dev->reset_work))

		return -EBUSY;



	if (!ret) {

	flush_work(&dev->reset_work);

	flush_work(&dev->probe_work);

	return 0;

}



	return ret;

}



static int nvme_pci_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val)

{

	*val = readl(to_nvme_dev(ctrl)->bar + off);