text: /*
   * NVMe over Fabrics loopback device.
   * Copyright (c) 2015-2016 HGST, a Western Digital Company.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   */
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  #include <linux/scatterlist.h>
  #include <linux/delay.h>
  #include <linux/blk-mq.h>
  #include <linux/nvme.h>
  #include <linux/module.h>
  #include <linux/parser.h>
  #include <linux/t10-pi.h>
  #include "nvmet.h"
  #include "../host/nvme.h"
  #include "../host/fabrics.h"
  
  #define NVME_LOOP_AQ_DEPTH		256
  
  #define NVME_LOOP_MAX_SEGMENTS		256
  
  /*
   * We handle AEN commands ourselves and don't even let the
   * block layer know about them.
   */
  #define NVME_LOOP_NR_AEN_COMMANDS	1
  #define NVME_LOOP_AQ_BLKMQ_DEPTH	\
  	(NVME_LOOP_AQ_DEPTH - NVME_LOOP_NR_AEN_COMMANDS)
  
  struct nvme_loop_iod {
  	struct nvme_request	nvme_req;
  	struct nvme_command	cmd;
  	struct nvme_completion	rsp;
  	struct nvmet_req	req;
  	struct nvme_loop_queue	*queue;
  	struct work_struct	work;
  	struct sg_table		sg_table;
  	struct scatterlist	first_sgl[];
  };
  
  struct nvme_loop_ctrl {
  	spinlock_t		lock;
  	struct nvme_loop_queue	*queues;
  	u32			queue_count;
  
  	struct blk_mq_tag_set	admin_tag_set;
  
  	struct list_head	list;
  	u64			cap;
  	struct blk_mq_tag_set	tag_set;
  	struct nvme_loop_iod	async_event_iod;
  	struct nvme_ctrl	ctrl;
  
  	struct nvmet_ctrl	*target_ctrl;
  	struct work_struct	delete_work;
  	struct work_struct	reset_work;
  };
  
  static inline struct nvme_loop_ctrl *to_loop_ctrl(struct nvme_ctrl *ctrl)
  {
  	return container_of(ctrl, struct nvme_loop_ctrl, ctrl);
  }
  
  struct nvme_loop_queue {
  	struct nvmet_cq		nvme_cq;
  	struct nvmet_sq		nvme_sq;
  	struct nvme_loop_ctrl	*ctrl;
  };
  
  static struct nvmet_port *nvmet_loop_port;
  
  static LIST_HEAD(nvme_loop_ctrl_list);
  static DEFINE_MUTEX(nvme_loop_ctrl_mutex);
  
  static void nvme_loop_queue_response(struct nvmet_req *nvme_req);
  static void nvme_loop_delete_ctrl(struct nvmet_ctrl *ctrl);
  
  static struct nvmet_fabrics_ops nvme_loop_ops;
  
  static inline int nvme_loop_queue_idx(struct nvme_loop_queue *queue)
  {
  	return queue - queue->ctrl->queues;
  }
  
  static void nvme_loop_complete_rq(struct request *req)
  {
  	struct nvme_loop_iod *iod = blk_mq_rq_to_pdu(req);
  	int error = 0;
  
  	nvme_cleanup_cmd(req);
  	sg_free_table_chained(&iod->sg_table, true);
  
  	if (unlikely(req->errors)) {
  		if (nvme_req_needs_retry(req, req->errors)) {
  			nvme_requeue_req(req);
  			return;
  		}
  
  		if (blk_rq_is_passthrough(req))
  			error = req->errors;
  		else
  			error = nvme_error_status(req->errors);
  	}
  
  	blk_mq_end_request(req, error);
  }
  
  static void nvme_loop_queue_response(struct nvmet_req *req)
  {
  	struct nvme_loop_iod *iod =
  		container_of(req, struct nvme_loop_iod, req);
  	struct nvme_completion *cqe = &iod->rsp;
  
  	/*
  	 * AEN requests are special as they don't time out and can
  	 * survive any kind of queue freeze and often don't respond to
  	 * aborts.  We don't even bother to allocate a struct request
  	 * for them but rather special case them here.
  	 */
  	if (unlikely(nvme_loop_queue_idx(iod->queue) == 0 &&
  			cqe->command_id >= NVME_LOOP_AQ_BLKMQ_DEPTH)) {
  		nvme_complete_async_event(&iod->queue->ctrl->ctrl, cqe->status,
  				&cqe->result);
  	} else {
  		struct request *rq = blk_mq_rq_from_pdu(iod);
  
  		iod->nvme_req.result = cqe->result;
  		blk_mq_complete_request(rq, le16_to_cpu(cqe->status) >> 1);
  	}
  }
  
  static void nvme_loop_execute_work(struct work_struct *work)
  {
  	struct nvme_loop_iod *iod =
  		container_of(work, struct nvme_loop_iod, work);
  
  	iod->req.execute(&iod->req);
  }
  
  static enum blk_eh_timer_return
  nvme_loop_timeout(struct request *rq, bool reserved)
  {
  	struct nvme_loop_iod *iod = blk_mq_rq_to_pdu(rq);
  
  	/* queue error recovery */
  	schedule_work(&iod->queue->ctrl->reset_work);
  
  	/* fail with DNR on admin cmd timeout */
  	rq->errors = NVME_SC_ABORT_REQ | NVME_SC_DNR;
  
  	return BLK_EH_HANDLED;
  }
  
  static int nvme_loop_queue_rq(struct blk_mq_hw_ctx *hctx,
  		const struct blk_mq_queue_data *bd)
  {
  	struct nvme_ns *ns = hctx->queue->queuedata;
  	struct nvme_loop_queue *queue = hctx->driver_data;
  	struct request *req = bd->rq;
  	struct nvme_loop_iod *iod = blk_mq_rq_to_pdu(req);
  	int ret;
  
  	ret = nvme_setup_cmd(ns, req, &iod->cmd);
  	if (ret != BLK_MQ_RQ_QUEUE_OK)
  		return ret;
  
  	iod->cmd.common.flags |= NVME_CMD_SGL_METABUF;
  	iod->req.port = nvmet_loop_port;
  	if (!nvmet_req_init(&iod->req, &queue->nvme_cq,
  			&queue->nvme_sq, &nvme_loop_ops)) {
  		nvme_cleanup_cmd(req);
  		blk_mq_start_request(req);
  		nvme_loop_queue_response(&iod->req);
  		return BLK_MQ_RQ_QUEUE_OK;
  	}
  
  	if (blk_rq_bytes(req)) {
  		iod->sg_table.sgl = iod->first_sgl;
  		ret = sg_alloc_table_chained(&iod->sg_table,
  				blk_rq_nr_phys_segments(req),
  				iod->sg_table.sgl);
  		if (ret)
  			return BLK_MQ_RQ_QUEUE_BUSY;
  
  		iod->req.sg = iod->sg_table.sgl;
  		iod->req.sg_cnt = blk_rq_map_sg(req->q, req, iod->sg_table.sgl);
  	}
  
  	blk_mq_start_request(req);
  
  	schedule_work(&iod->work);
  	return BLK_MQ_RQ_QUEUE_OK;
  }
  
  static void nvme_loop_submit_async_event(struct nvme_ctrl *arg, int aer_idx)
  {
  	struct nvme_loop_ctrl *ctrl = to_loop_ctrl(arg);
  	struct nvme_loop_queue *queue = &ctrl->queues[0];
  	struct nvme_loop_iod *iod = &ctrl->async_event_iod;
  
  	memset(&iod->cmd, 0, sizeof(iod->cmd));
  	iod->cmd.common.opcode = nvme_admin_async_event;
  	iod->cmd.common.command_id = NVME_LOOP_AQ_BLKMQ_DEPTH;
  	iod->cmd.common.flags |= NVME_CMD_SGL_METABUF;
  
  	if (!nvmet_req_init(&iod->req, &queue->nvme_cq, &queue->nvme_sq,
  			&nvme_loop_ops)) {
  		dev_err(ctrl->ctrl.device, "failed async event work\n");
  		return;
  	}
  
  	schedule_work(&iod->work);
  }
  
  static int nvme_loop_init_iod(struct nvme_loop_ctrl *ctrl,
  		struct nvme_loop_iod *iod, unsigned int queue_idx)
  {
  	BUG_ON(queue_idx >= ctrl->queue_count);
  
  	iod->req.cmd = &iod->cmd;
  	iod->req.rsp = &iod->rsp;
  	iod->queue = &ctrl->queues[queue_idx];
  	INIT_WORK(&iod->work, nvme_loop_execute_work);
  	return 0;
  }
  
  static int nvme_loop_init_request(void *data, struct request *req,
  				unsigned int hctx_idx, unsigned int rq_idx,
  				unsigned int numa_node)
  {
  	return nvme_loop_init_iod(data, blk_mq_rq_to_pdu(req), hctx_idx + 1);
  }
  
  static int nvme_loop_init_admin_request(void *data, struct request *req,
  				unsigned int hctx_idx, unsigned int rq_idx,
  				unsigned int numa_node)
  {
  	return nvme_loop_init_iod(data, blk_mq_rq_to_pdu(req), 0);
  }
  
  static int nvme_loop_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
  		unsigned int hctx_idx)
  {
  	struct nvme_loop_ctrl *ctrl = data;
  	struct nvme_loop_queue *queue = &ctrl->queues[hctx_idx + 1];
  
  	BUG_ON(hctx_idx >= ctrl->queue_count);
  
  	hctx->driver_data = queue;
  	return 0;
  }
  
  static int nvme_loop_init_admin_hctx(struct blk_mq_hw_ctx *hctx, void *data,
  		unsigned int hctx_idx)
  {
  	struct nvme_loop_ctrl *ctrl = data;
  	struct nvme_loop_queue *queue = &ctrl->queues[0];
  
  	BUG_ON(hctx_idx != 0);
  
  	hctx->driver_data = queue;
  	return 0;
  }
  
  static struct blk_mq_ops nvme_loop_mq_ops = {
  	.queue_rq	= nvme_loop_queue_rq,
  	.complete	= nvme_loop_complete_rq,
  	.init_request	= nvme_loop_init_request,
  	.init_hctx	= nvme_loop_init_hctx,
  	.timeout	= nvme_loop_timeout,
  };
  
  static struct blk_mq_ops nvme_loop_admin_mq_ops = {
  	.queue_rq	= nvme_loop_queue_rq,
  	.complete	= nvme_loop_complete_rq,
  	.init_request	= nvme_loop_init_admin_request,
  	.init_hctx	= nvme_loop_init_admin_hctx,
  	.timeout	= nvme_loop_timeout,
  };
  
  static void nvme_loop_destroy_admin_queue(struct nvme_loop_ctrl *ctrl)
  {
  	blk_cleanup_queue(ctrl->ctrl.admin_q);
  	blk_mq_free_tag_set(&ctrl->admin_tag_set);
  	nvmet_sq_destroy(&ctrl->queues[0].nvme_sq);
  }
  
  static void nvme_loop_free_ctrl(struct nvme_ctrl *nctrl)
  {
  	struct nvme_loop_ctrl *ctrl = to_loop_ctrl(nctrl);
  
  	if (list_empty(&ctrl->list))
  		goto free_ctrl;
  
  	mutex_lock(&nvme_loop_ctrl_mutex);
  	list_del(&ctrl->list);
  	mutex_unlock(&nvme_loop_ctrl_mutex);
  
  	if (nctrl->tagset) {
  		blk_cleanup_queue(ctrl->ctrl.connect_q);
  		blk_mq_free_tag_set(&ctrl->tag_set);
  	}
  	kfree(ctrl->queues);
  	nvmf_free_options(nctrl->opts);
  free_ctrl:
  	kfree(ctrl);
  }
  
  static int nvme_loop_configure_admin_queue(struct nvme_loop_ctrl *ctrl)
  {
  	int error;
  
  	memset(&ctrl->admin_tag_set, 0, sizeof(ctrl->admin_tag_set));
  	ctrl->admin_tag_set.ops = &nvme_loop_admin_mq_ops;
  	ctrl->admin_tag_set.queue_depth = NVME_LOOP_AQ_BLKMQ_DEPTH;
  	ctrl->admin_tag_set.reserved_tags = 2; /* connect + keep-alive */
  	ctrl->admin_tag_set.numa_node = NUMA_NO_NODE;
  	ctrl->admin_tag_set.cmd_size = sizeof(struct nvme_loop_iod) +
  		SG_CHUNK_SIZE * sizeof(struct scatterlist);
  	ctrl->admin_tag_set.driver_data = ctrl;
  	ctrl->admin_tag_set.nr_hw_queues = 1;
  	ctrl->admin_tag_set.timeout = ADMIN_TIMEOUT;
  
  	ctrl->queues[0].ctrl = ctrl;
  	error = nvmet_sq_init(&ctrl->queues[0].nvme_sq);
  	if (error)
  		return error;
  	ctrl->queue_count = 1;
  
  	error = blk_mq_alloc_tag_set(&ctrl->admin_tag_set);
  	if (error)
  		goto out_free_sq;
  
  	ctrl->ctrl.admin_q = blk_mq_init_queue(&ctrl->admin_tag_set);
  	if (IS_ERR(ctrl->ctrl.admin_q)) {
  		error = PTR_ERR(ctrl->ctrl.admin_q);
  		goto out_free_tagset;
  	}
  
  	error = nvmf_connect_admin_queue(&ctrl->ctrl);
  	if (error)
  		goto out_cleanup_queue;
  
  	error = nvmf_reg_read64(&ctrl->ctrl, NVME_REG_CAP, &ctrl->cap);
  	if (error) {
  		dev_err(ctrl->ctrl.device,
  			"prop_get NVME_REG_CAP failed\n");
  		goto out_cleanup_queue;
  	}
  
  	ctrl->ctrl.sqsize =
  		min_t(int, NVME_CAP_MQES(ctrl->cap) + 1, ctrl->ctrl.sqsize);
  
  	error = nvme_enable_ctrl(&ctrl->ctrl, ctrl->cap);
  	if (error)
  		goto out_cleanup_queue;
  
  	ctrl->ctrl.max_hw_sectors =
  		(NVME_LOOP_MAX_SEGMENTS - 1) << (PAGE_SHIFT - 9);
  
  	error = nvme_init_identify(&ctrl->ctrl);
  	if (error)
  		goto out_cleanup_queue;
  
  	nvme_start_keep_alive(&ctrl->ctrl);
  
  	return 0;
  
  out_cleanup_queue:
  	blk_cleanup_queue(ctrl->ctrl.admin_q);
  out_free_tagset:
  	blk_mq_free_tag_set(&ctrl->admin_tag_set);
  out_free_sq:
  	nvmet_sq_destroy(&ctrl->queues[0].nvme_sq);
  	return error;
  }
  
  static void nvme_loop_shutdown_ctrl(struct nvme_loop_ctrl *ctrl)
  {
  	int i;
  
  	nvme_stop_keep_alive(&ctrl->ctrl);
  
  	if (ctrl->queue_count > 1) {
  		nvme_stop_queues(&ctrl->ctrl);
  		blk_mq_tagset_busy_iter(&ctrl->tag_set,
  					nvme_cancel_request, &ctrl->ctrl);
  
  		for (i = 1; i < ctrl->queue_count; i++)
  			nvmet_sq_destroy(&ctrl->queues[i].nvme_sq);
  	}
  
  	if (ctrl->ctrl.state == NVME_CTRL_LIVE)
  		nvme_shutdown_ctrl(&ctrl->ctrl);
  
  	blk_mq_stop_hw_queues(ctrl->ctrl.admin_q);
  	blk_mq_tagset_busy_iter(&ctrl->admin_tag_set,
  				nvme_cancel_request, &ctrl->ctrl);
  	nvme_loop_destroy_admin_queue(ctrl);
  }
  
  static void nvme_loop_del_ctrl_work(struct work_struct *work)
  {
  	struct nvme_loop_ctrl *ctrl = container_of(work,
  				struct nvme_loop_ctrl, delete_work);
  
  	nvme_uninit_ctrl(&ctrl->ctrl);
  	nvme_loop_shutdown_ctrl(ctrl);
  	nvme_put_ctrl(&ctrl->ctrl);
  }
  
  static int __nvme_loop_del_ctrl(struct nvme_loop_ctrl *ctrl)
  {
  	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_DELETING))
  		return -EBUSY;
  
  	if (!schedule_work(&ctrl->delete_work))
  		return -EBUSY;
  
  	return 0;
  }
  
  static int nvme_loop_del_ctrl(struct nvme_ctrl *nctrl)
  {
  	struct nvme_loop_ctrl *ctrl = to_loop_ctrl(nctrl);
  	int ret;
  
  	ret = __nvme_loop_del_ctrl(ctrl);
  	if (ret)
  		return ret;
  
  	flush_work(&ctrl->delete_work);
  
  	return 0;
  }
  
  static void nvme_loop_delete_ctrl(struct nvmet_ctrl *nctrl)
  {
  	struct nvme_loop_ctrl *ctrl;
  
  	mutex_lock(&nvme_loop_ctrl_mutex);
  	list_for_each_entry(ctrl, &nvme_loop_ctrl_list, list) {
  		if (ctrl->ctrl.cntlid == nctrl->cntlid)
  			__nvme_loop_del_ctrl(ctrl);
  	}
  	mutex_unlock(&nvme_loop_ctrl_mutex);
  }
  
  static void nvme_loop_reset_ctrl_work(struct work_struct *work)
  {
  	struct nvme_loop_ctrl *ctrl = container_of(work,
  					struct nvme_loop_ctrl, reset_work);
  	bool changed;
  	int i, ret;
  
  	nvme_loop_shutdown_ctrl(ctrl);
  
  	ret = nvme_loop_configure_admin_queue(ctrl);
  	if (ret)
  		goto out_disable;
  
  	for (i = 1; i <= ctrl->ctrl.opts->nr_io_queues; i++) {
  		ctrl->queues[i].ctrl = ctrl;
  		ret = nvmet_sq_init(&ctrl->queues[i].nvme_sq);
  		if (ret)
  			goto out_free_queues;
  
  		ctrl->queue_count++;
  	}
  
  	for (i = 1; i <= ctrl->ctrl.opts->nr_io_queues; i++) {
  		ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
  		if (ret)
  			goto out_free_queues;
  	}
  
  	changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
  	WARN_ON_ONCE(!changed);
  
  	nvme_queue_scan(&ctrl->ctrl);
  	nvme_queue_async_events(&ctrl->ctrl);
  
  	nvme_start_queues(&ctrl->ctrl);
  
  	return;
  
  out_free_queues:
  	for (i = 1; i < ctrl->queue_count; i++)
  		nvmet_sq_destroy(&ctrl->queues[i].nvme_sq);
  	nvme_loop_destroy_admin_queue(ctrl);
  out_disable:
  	dev_warn(ctrl->ctrl.device, "Removing after reset failure\n");
  	nvme_uninit_ctrl(&ctrl->ctrl);
  	nvme_put_ctrl(&ctrl->ctrl);
  }
  
  static int nvme_loop_reset_ctrl(struct nvme_ctrl *nctrl)
  {
  	struct nvme_loop_ctrl *ctrl = to_loop_ctrl(nctrl);
  
  	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_RESETTING))
  		return -EBUSY;
  
  	if (!schedule_work(&ctrl->reset_work))
  		return -EBUSY;
  
  	flush_work(&ctrl->reset_work);
  
  	return 0;
  }
  
  static const struct nvme_ctrl_ops nvme_loop_ctrl_ops = {
  	.name			= "loop",
  	.module			= THIS_MODULE,
  	.is_fabrics		= true,
  	.reg_read32		= nvmf_reg_read32,
  	.reg_read64		= nvmf_reg_read64,
  	.reg_write32		= nvmf_reg_write32,
  	.reset_ctrl		= nvme_loop_reset_ctrl,
  	.free_ctrl		= nvme_loop_free_ctrl,
  	.submit_async_event	= nvme_loop_submit_async_event,
  	.delete_ctrl		= nvme_loop_del_ctrl,
  	.get_subsysnqn		= nvmf_get_subsysnqn,
  };
  
  static int nvme_loop_create_io_queues(struct nvme_loop_ctrl *ctrl)
  {
  	struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;
  	int ret, i;
  
  	ret = nvme_set_queue_count(&ctrl->ctrl, &opts->nr_io_queues);
  	if (ret || !opts->nr_io_queues)
  		return ret;
  
  	dev_info(ctrl->ctrl.device, "creating %d I/O queues.\n",
  		opts->nr_io_queues);
  
  	for (i = 1; i <= opts->nr_io_queues; i++) {
  		ctrl->queues[i].ctrl = ctrl;
  		ret = nvmet_sq_init(&ctrl->queues[i].nvme_sq);
  		if (ret)
  			goto out_destroy_queues;
  
  		ctrl->queue_count++;
  	}
  
  	memset(&ctrl->tag_set, 0, sizeof(ctrl->tag_set));
  	ctrl->tag_set.ops = &nvme_loop_mq_ops;
  	ctrl->tag_set.queue_depth = ctrl->ctrl.opts->queue_size;
  	ctrl->tag_set.reserved_tags = 1; /* fabric connect */
  	ctrl->tag_set.numa_node = NUMA_NO_NODE;
  	ctrl->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
  	ctrl->tag_set.cmd_size = sizeof(struct nvme_loop_iod) +
  		SG_CHUNK_SIZE * sizeof(struct scatterlist);
  	ctrl->tag_set.driver_data = ctrl;
  	ctrl->tag_set.nr_hw_queues = ctrl->queue_count - 1;
  	ctrl->tag_set.timeout = NVME_IO_TIMEOUT;
  	ctrl->ctrl.tagset = &ctrl->tag_set;
  
  	ret = blk_mq_alloc_tag_set(&ctrl->tag_set);
  	if (ret)
  		goto out_destroy_queues;
  
  	ctrl->ctrl.connect_q = blk_mq_init_queue(&ctrl->tag_set);
  	if (IS_ERR(ctrl->ctrl.connect_q)) {
  		ret = PTR_ERR(ctrl->ctrl.connect_q);
  		goto out_free_tagset;
  	}
  
  	for (i = 1; i <= opts->nr_io_queues; i++) {
  		ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
  		if (ret)
  			goto out_cleanup_connect_q;
  	}
  
  	return 0;
  
  out_cleanup_connect_q:
  	blk_cleanup_queue(ctrl->ctrl.connect_q);
  out_free_tagset:
  	blk_mq_free_tag_set(&ctrl->tag_set);
  out_destroy_queues:
  	for (i = 1; i < ctrl->queue_count; i++)
  		nvmet_sq_destroy(&ctrl->queues[i].nvme_sq);
  	return ret;
  }
  
  static struct nvme_ctrl *nvme_loop_create_ctrl(struct device *dev,
  		struct nvmf_ctrl_options *opts)
  {
  	struct nvme_loop_ctrl *ctrl;
  	bool changed;
  	int ret;
  
  	ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
  	if (!ctrl)
  		return ERR_PTR(-ENOMEM);
  	ctrl->ctrl.opts = opts;
  	INIT_LIST_HEAD(&ctrl->list);
  
  	INIT_WORK(&ctrl->delete_work, nvme_loop_del_ctrl_work);
  	INIT_WORK(&ctrl->reset_work, nvme_loop_reset_ctrl_work);
  
  	ret = nvme_init_ctrl(&ctrl->ctrl, dev, &nvme_loop_ctrl_ops,
  				0 /* no quirks, we're perfect! */);
  	if (ret)
  		goto out_put_ctrl;
  
  	spin_lock_init(&ctrl->lock);
  
  	ret = -ENOMEM;
  
  	ctrl->ctrl.sqsize = opts->queue_size - 1;
  	ctrl->ctrl.kato = opts->kato;
  
  	ctrl->queues = kcalloc(opts->nr_io_queues + 1, sizeof(*ctrl->queues),
  			GFP_KERNEL);
  	if (!ctrl->queues)
  		goto out_uninit_ctrl;
  
  	ret = nvme_loop_configure_admin_queue(ctrl);
  	if (ret)
  		goto out_free_queues;
  
  	if (opts->queue_size > ctrl->ctrl.maxcmd) {
  		/* warn if maxcmd is lower than queue_size */
  		dev_warn(ctrl->ctrl.device,
  			"queue_size %zu > ctrl maxcmd %u, clamping down\n",
  			opts->queue_size, ctrl->ctrl.maxcmd);
  		opts->queue_size = ctrl->ctrl.maxcmd;
  	}
  
  	if (opts->nr_io_queues) {
  		ret = nvme_loop_create_io_queues(ctrl);
  		if (ret)
  			goto out_remove_admin_queue;
  	}
  
  	nvme_loop_init_iod(ctrl, &ctrl->async_event_iod, 0);
  
  	dev_info(ctrl->ctrl.device,
  		 "new ctrl: \"%s\"\n", ctrl->ctrl.opts->subsysnqn);
  
  	kref_get(&ctrl->ctrl.kref);
  
  	changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
  	WARN_ON_ONCE(!changed);
  
  	mutex_lock(&nvme_loop_ctrl_mutex);
  	list_add_tail(&ctrl->list, &nvme_loop_ctrl_list);
  	mutex_unlock(&nvme_loop_ctrl_mutex);
  
  	if (opts->nr_io_queues) {
  		nvme_queue_scan(&ctrl->ctrl);
  		nvme_queue_async_events(&ctrl->ctrl);
  	}
  
  	return &ctrl->ctrl;
  
  out_remove_admin_queue:
  	nvme_loop_destroy_admin_queue(ctrl);
  out_free_queues:
  	kfree(ctrl->queues);
  out_uninit_ctrl:
  	nvme_uninit_ctrl(&ctrl->ctrl);
  out_put_ctrl:
  	nvme_put_ctrl(&ctrl->ctrl);
  	if (ret > 0)
  		ret = -EIO;
  	return ERR_PTR(ret);
  }
  
  static int nvme_loop_add_port(struct nvmet_port *port)
  {
  	/*
  	 * XXX: disalow adding more than one port so
  	 * there is no connection rejections when a
  	 * a subsystem is assigned to a port for which
  	 * loop doesn't have a pointer.
  	 * This scenario would be possible if we allowed
  	 * more than one port to be added and a subsystem
  	 * was assigned to a port other than nvmet_loop_port.
  	 */
  
  	if (nvmet_loop_port)
  		return -EPERM;
  
  	nvmet_loop_port = port;
  	return 0;
  }
  
  static void nvme_loop_remove_port(struct nvmet_port *port)
  {
  	if (port == nvmet_loop_port)
  		nvmet_loop_port = NULL;
  }
  
  static struct nvmet_fabrics_ops nvme_loop_ops = {
  	.owner		= THIS_MODULE,
  	.type		= NVMF_TRTYPE_LOOP,
  	.add_port	= nvme_loop_add_port,
  	.remove_port	= nvme_loop_remove_port,
  	.queue_response = nvme_loop_queue_response,
  	.delete_ctrl	= nvme_loop_delete_ctrl,
  };
  
  static struct nvmf_transport_ops nvme_loop_transport = {
  	.name		= "loop",
  	.create_ctrl	= nvme_loop_create_ctrl,
  };
  
  static int __init nvme_loop_init_module(void)
  {
  	int ret;
  
  	ret = nvmet_register_transport(&nvme_loop_ops);
  	if (ret)
  		return ret;
  	return nvmf_register_transport(&nvme_loop_transport);
  }
  
  static void __exit nvme_loop_cleanup_module(void)
  {
  	struct nvme_loop_ctrl *ctrl, *next;
  
  	nvmf_unregister_transport(&nvme_loop_transport);
  	nvmet_unregister_transport(&nvme_loop_ops);
  
  	mutex_lock(&nvme_loop_ctrl_mutex);
  	list_for_each_entry_safe(ctrl, next, &nvme_loop_ctrl_list, list)
  		__nvme_loop_del_ctrl(ctrl);
  	mutex_unlock(&nvme_loop_ctrl_mutex);
  
  	flush_scheduled_work();
  }
  
  module_init(nvme_loop_init_module);
  module_exit(nvme_loop_cleanup_module);
  
  MODULE_LICENSE("GPL v2");
  MODULE_ALIAS("nvmet-transport-254"); /* 254 == NVMF_TRTYPE_LOOP */
  