nvme-rdma: add a NVMe over Fabrics RDMA host driver

This patch implements the RDMA host (initiator in SCSI speak) driver.  It
can be used to connect to remote NVMe over Fabrics controllers over
Infiniband, RoCE or iWarp, and uses the existing NVMe core driver as well
a the new fabrics library.

To connect to all NVMe over Fabrics controller reachable on a given taget
port using RDMA/CM use the following command:

	nvme connect-all -t rdma -a $IPADDR

This requires the latest version of nvme-cli with Fabrics support.

Signed-off-by: Jay Freyensee <james.p.freyensee@intel.com>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

3 files changed, 2040 insertions, 0 deletions

diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig
index 3397651cc144..db39d53cdfb9 100644
--- a/drivers/nvme/host/Kconfig
+++ b/drivers/nvme/host/Kconfig
@@ -27,3 +27,19 @@ config BLK_DEV_NVME_SCSI
 
 config NVME_FABRICS
 	tristate
+
+config NVME_RDMA
+	tristate "NVM Express over Fabrics RDMA host driver"
+	depends on INFINIBAND
+	depends on BLK_DEV_NVME
+	select NVME_FABRICS
+	select SG_POOL
+	help
+	  This provides support for the NVMe over Fabrics protocol using
+	  the RDMA (Infiniband, RoCE, iWarp) transport.  This allows you
+	  to use remote block devices exported using the NVMe protocol set.
+
+	  To configure a NVMe over Fabrics controller use the nvme-cli tool
+	  from https://github.com/linux-nvme/nvme-cli.
+
+	  If unsure, say N.
diff --git a/drivers/nvme/host/Makefile b/drivers/nvme/host/Makefile
index 5f8648faf4e0..47abcec23514 100644
--- a/drivers/nvme/host/Makefile
+++ b/drivers/nvme/host/Makefile
@@ -1,6 +1,7 @@
 obj-$(CONFIG_NVME_CORE)			+= nvme-core.o
 obj-$(CONFIG_BLK_DEV_NVME)		+= nvme.o
 obj-$(CONFIG_NVME_FABRICS)		+= nvme-fabrics.o
+obj-$(CONFIG_NVME_RDMA)			+= nvme-rdma.o
 
 nvme-core-y				:= core.o
 nvme-core-$(CONFIG_BLK_DEV_NVME_SCSI)	+= scsi.o
@@ -9,3 +10,5 @@ nvme-core-$(CONFIG_NVM)			+= lightnvm.o
 nvme-y					+= pci.o
 
 nvme-fabrics-y				+= fabrics.o
+
+nvme-rdma-y				+= rdma.o
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
new file mode 100644
index 000000000000..278551bcd5c7
--- /dev/null
+++ b/drivers/nvme/host/rdma.c
@@ -0,0 +1,2021 @@
+/*
+ * NVMe over Fabrics RDMA host code.
+ * 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/delay.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/jiffies.h>
+#include <linux/atomic.h>
+#include <linux/blk-mq.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/scatterlist.h>
+#include <linux/nvme.h>
+#include <linux/t10-pi.h>
+#include <asm/unaligned.h>
+
+#include <rdma/ib_verbs.h>
+#include <rdma/rdma_cm.h>
+#include <rdma/ib_cm.h>
+#include <linux/nvme-rdma.h>
+
+#include "nvme.h"
+#include "fabrics.h"
+
+
+#define NVME_RDMA_CONNECT_TIMEOUT_MS	1000		/* 1 second */
+
+#define NVME_RDMA_MAX_SEGMENT_SIZE	0xffffff	/* 24-bit SGL field */
+
+#define NVME_RDMA_MAX_SEGMENTS		256
+
+#define NVME_RDMA_MAX_INLINE_SEGMENTS	1
+
+#define NVME_RDMA_MAX_PAGES_PER_MR	512
+
+#define NVME_RDMA_DEF_RECONNECT_DELAY	20
+
+/*
+ * We handle AEN commands ourselves and don't even let the
+ * block layer know about them.
+ */
+#define NVME_RDMA_NR_AEN_COMMANDS      1
+#define NVME_RDMA_AQ_BLKMQ_DEPTH       \
+	(NVMF_AQ_DEPTH - NVME_RDMA_NR_AEN_COMMANDS)
+
+struct nvme_rdma_device {
+	struct ib_device       *dev;
+	struct ib_pd	       *pd;
+	struct ib_mr	       *mr;
+	struct kref		ref;
+	struct list_head	entry;
+};
+
+struct nvme_rdma_qe {
+	struct ib_cqe		cqe;
+	void			*data;
+	u64			dma;
+};
+
+struct nvme_rdma_queue;
+struct nvme_rdma_request {
+	struct ib_mr		*mr;
+	struct nvme_rdma_qe	sqe;
+	struct ib_sge		sge[1 + NVME_RDMA_MAX_INLINE_SEGMENTS];
+	u32			num_sge;
+	int			nents;
+	bool			inline_data;
+	bool			need_inval;
+	struct ib_reg_wr	reg_wr;
+	struct ib_cqe		reg_cqe;
+	struct nvme_rdma_queue  *queue;
+	struct sg_table		sg_table;
+	struct scatterlist	first_sgl[];
+};
+
+enum nvme_rdma_queue_flags {
+	NVME_RDMA_Q_CONNECTED = (1 << 0),
+};
+
+struct nvme_rdma_queue {
+	struct nvme_rdma_qe	*rsp_ring;
+	u8			sig_count;
+	int			queue_size;
+	size_t			cmnd_capsule_len;
+	struct nvme_rdma_ctrl	*ctrl;
+	struct nvme_rdma_device	*device;
+	struct ib_cq		*ib_cq;
+	struct ib_qp		*qp;
+
+	unsigned long		flags;
+	struct rdma_cm_id	*cm_id;
+	int			cm_error;
+	struct completion	cm_done;
+};
+
+struct nvme_rdma_ctrl {
+	/* read and written in the hot path */
+	spinlock_t		lock;
+
+	/* read only in the hot path */
+	struct nvme_rdma_queue	*queues;
+	u32			queue_count;
+
+	/* other member variables */
+	unsigned short		tl_retry_count;
+	struct blk_mq_tag_set	tag_set;
+	struct work_struct	delete_work;
+	struct work_struct	reset_work;
+	struct work_struct	err_work;
+
+	struct nvme_rdma_qe	async_event_sqe;
+
+	int			reconnect_delay;
+	struct delayed_work	reconnect_work;
+
+	struct list_head	list;
+
+	struct blk_mq_tag_set	admin_tag_set;
+	struct nvme_rdma_device	*device;
+
+	u64			cap;
+	u32			max_fr_pages;
+
+	union {
+		struct sockaddr addr;
+		struct sockaddr_in addr_in;
+	};
+
+	struct nvme_ctrl	ctrl;
+};
+
+static inline struct nvme_rdma_ctrl *to_rdma_ctrl(struct nvme_ctrl *ctrl)
+{
+	return container_of(ctrl, struct nvme_rdma_ctrl, ctrl);
+}
+
+static LIST_HEAD(device_list);
+static DEFINE_MUTEX(device_list_mutex);
+
+static LIST_HEAD(nvme_rdma_ctrl_list);
+static DEFINE_MUTEX(nvme_rdma_ctrl_mutex);
+
+static struct workqueue_struct *nvme_rdma_wq;
+
+/*
+ * Disabling this option makes small I/O goes faster, but is fundamentally
+ * unsafe.  With it turned off we will have to register a global rkey that
+ * allows read and write access to all physical memory.
+ */
+static bool register_always = true;
+module_param(register_always, bool, 0444);
+MODULE_PARM_DESC(register_always,
+	 "Use memory registration even for contiguous memory regions");
+
+static int nvme_rdma_cm_handler(struct rdma_cm_id *cm_id,
+		struct rdma_cm_event *event);
+static void nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc);
+static int __nvme_rdma_del_ctrl(struct nvme_rdma_ctrl *ctrl);
+
+/* XXX: really should move to a generic header sooner or later.. */
+static inline void put_unaligned_le24(u32 val, u8 *p)
+{
+	*p++ = val;
+	*p++ = val >> 8;
+	*p++ = val >> 16;
+}
+
+static inline int nvme_rdma_queue_idx(struct nvme_rdma_queue *queue)
+{
+	return queue - queue->ctrl->queues;
+}
+
+static inline size_t nvme_rdma_inline_data_size(struct nvme_rdma_queue *queue)
+{
+	return queue->cmnd_capsule_len - sizeof(struct nvme_command);
+}
+
+static void nvme_rdma_free_qe(struct ib_device *ibdev, struct nvme_rdma_qe *qe,
+		size_t capsule_size, enum dma_data_direction dir)
+{
+	ib_dma_unmap_single(ibdev, qe->dma, capsule_size, dir);
+	kfree(qe->data);
+}
+
+static int nvme_rdma_alloc_qe(struct ib_device *ibdev, struct nvme_rdma_qe *qe,
+		size_t capsule_size, enum dma_data_direction dir)
+{
+	qe->data = kzalloc(capsule_size, GFP_KERNEL);
+	if (!qe->data)
+		return -ENOMEM;
+
+	qe->dma = ib_dma_map_single(ibdev, qe->data, capsule_size, dir);
+	if (ib_dma_mapping_error(ibdev, qe->dma)) {
+		kfree(qe->data);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void nvme_rdma_free_ring(struct ib_device *ibdev,
+		struct nvme_rdma_qe *ring, size_t ib_queue_size,
+		size_t capsule_size, enum dma_data_direction dir)
+{
+	int i;
+
+	for (i = 0; i < ib_queue_size; i++)
+		nvme_rdma_free_qe(ibdev, &ring[i], capsule_size, dir);
+	kfree(ring);
+}
+
+static struct nvme_rdma_qe *nvme_rdma_alloc_ring(struct ib_device *ibdev,
+		size_t ib_queue_size, size_t capsule_size,
+		enum dma_data_direction dir)
+{
+	struct nvme_rdma_qe *ring;
+	int i;
+
+	ring = kcalloc(ib_queue_size, sizeof(struct nvme_rdma_qe), GFP_KERNEL);
+	if (!ring)
+		return NULL;
+
+	for (i = 0; i < ib_queue_size; i++) {
+		if (nvme_rdma_alloc_qe(ibdev, &ring[i], capsule_size, dir))
+			goto out_free_ring;
+	}
+
+	return ring;
+
+out_free_ring:
+	nvme_rdma_free_ring(ibdev, ring, i, capsule_size, dir);
+	return NULL;
+}
+
+static void nvme_rdma_qp_event(struct ib_event *event, void *context)
+{
+	pr_debug("QP event %d\n", event->event);
+}
+
+static int nvme_rdma_wait_for_cm(struct nvme_rdma_queue *queue)
+{
+	wait_for_completion_interruptible_timeout(&queue->cm_done,
+			msecs_to_jiffies(NVME_RDMA_CONNECT_TIMEOUT_MS) + 1);
+	return queue->cm_error;
+}
+
+static int nvme_rdma_create_qp(struct nvme_rdma_queue *queue, const int factor)
+{
+	struct nvme_rdma_device *dev = queue->device;
+	struct ib_qp_init_attr init_attr;
+	int ret;
+
+	memset(&init_attr, 0, sizeof(init_attr));
+	init_attr.event_handler = nvme_rdma_qp_event;
+	/* +1 for drain */
+	init_attr.cap.max_send_wr = factor * queue->queue_size + 1;
+	/* +1 for drain */
+	init_attr.cap.max_recv_wr = queue->queue_size + 1;
+	init_attr.cap.max_recv_sge = 1;
+	init_attr.cap.max_send_sge = 1 + NVME_RDMA_MAX_INLINE_SEGMENTS;
+	init_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
+	init_attr.qp_type = IB_QPT_RC;
+	init_attr.send_cq = queue->ib_cq;
+	init_attr.recv_cq = queue->ib_cq;
+
+	ret = rdma_create_qp(queue->cm_id, dev->pd, &init_attr);
+
+	queue->qp = queue->cm_id->qp;
+	return ret;
+}
+
+static int nvme_rdma_reinit_request(void *data, struct request *rq)
+{
+	struct nvme_rdma_ctrl *ctrl = data;
+	struct nvme_rdma_device *dev = ctrl->device;
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	int ret = 0;
+
+	if (!req->need_inval)
+		goto out;
+
+	ib_dereg_mr(req->mr);
+
+	req->mr = ib_alloc_mr(dev->pd, IB_MR_TYPE_MEM_REG,
+			ctrl->max_fr_pages);
+	if (IS_ERR(req->mr)) {
+		req->mr = NULL;
+		ret = PTR_ERR(req->mr);
+	}
+
+	req->need_inval = false;
+
+out:
+	return ret;
+}
+
+static void __nvme_rdma_exit_request(struct nvme_rdma_ctrl *ctrl,
+		struct request *rq, unsigned int queue_idx)
+{
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	struct nvme_rdma_queue *queue = &ctrl->queues[queue_idx];
+	struct nvme_rdma_device *dev = queue->device;
+
+	if (req->mr)
+		ib_dereg_mr(req->mr);
+
+	nvme_rdma_free_qe(dev->dev, &req->sqe, sizeof(struct nvme_command),
+			DMA_TO_DEVICE);
+}
+
+static void nvme_rdma_exit_request(void *data, struct request *rq,
+				unsigned int hctx_idx, unsigned int rq_idx)
+{
+	return __nvme_rdma_exit_request(data, rq, hctx_idx + 1);
+}
+
+static void nvme_rdma_exit_admin_request(void *data, struct request *rq,
+				unsigned int hctx_idx, unsigned int rq_idx)
+{
+	return __nvme_rdma_exit_request(data, rq, 0);
+}
+
+static int __nvme_rdma_init_request(struct nvme_rdma_ctrl *ctrl,
+		struct request *rq, unsigned int queue_idx)
+{
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	struct nvme_rdma_queue *queue = &ctrl->queues[queue_idx];
+	struct nvme_rdma_device *dev = queue->device;
+	struct ib_device *ibdev = dev->dev;
+	int ret;
+
+	BUG_ON(queue_idx >= ctrl->queue_count);
+
+	ret = nvme_rdma_alloc_qe(ibdev, &req->sqe, sizeof(struct nvme_command),
+			DMA_TO_DEVICE);
+	if (ret)
+		return ret;
+
+	req->mr = ib_alloc_mr(dev->pd, IB_MR_TYPE_MEM_REG,
+			ctrl->max_fr_pages);
+	if (IS_ERR(req->mr)) {
+		ret = PTR_ERR(req->mr);
+		goto out_free_qe;
+	}
+
+	req->queue = queue;
+
+	return 0;
+
+out_free_qe:
+	nvme_rdma_free_qe(dev->dev, &req->sqe, sizeof(struct nvme_command),
+			DMA_TO_DEVICE);
+	return -ENOMEM;
+}
+
+static int nvme_rdma_init_request(void *data, struct request *rq,
+				unsigned int hctx_idx, unsigned int rq_idx,
+				unsigned int numa_node)
+{
+	return __nvme_rdma_init_request(data, rq, hctx_idx + 1);
+}
+
+static int nvme_rdma_init_admin_request(void *data, struct request *rq,
+				unsigned int hctx_idx, unsigned int rq_idx,
+				unsigned int numa_node)
+{
+	return __nvme_rdma_init_request(data, rq, 0);
+}
+
+static int nvme_rdma_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
+		unsigned int hctx_idx)
+{
+	struct nvme_rdma_ctrl *ctrl = data;
+	struct nvme_rdma_queue *queue = &ctrl->queues[hctx_idx + 1];
+
+	BUG_ON(hctx_idx >= ctrl->queue_count);
+
+	hctx->driver_data = queue;
+	return 0;
+}
+
+static int nvme_rdma_init_admin_hctx(struct blk_mq_hw_ctx *hctx, void *data,
+		unsigned int hctx_idx)
+{
+	struct nvme_rdma_ctrl *ctrl = data;
+	struct nvme_rdma_queue *queue = &ctrl->queues[0];
+
+	BUG_ON(hctx_idx != 0);
+
+	hctx->driver_data = queue;
+	return 0;
+}
+
+static void nvme_rdma_free_dev(struct kref *ref)
+{
+	struct nvme_rdma_device *ndev =
+		container_of(ref, struct nvme_rdma_device, ref);
+
+	mutex_lock(&device_list_mutex);
+	list_del(&ndev->entry);
+	mutex_unlock(&device_list_mutex);
+
+	if (!register_always)
+		ib_dereg_mr(ndev->mr);
+	ib_dealloc_pd(ndev->pd);
+
+	kfree(ndev);
+}
+
+static void nvme_rdma_dev_put(struct nvme_rdma_device *dev)
+{
+	kref_put(&dev->ref, nvme_rdma_free_dev);
+}
+
+static int nvme_rdma_dev_get(struct nvme_rdma_device *dev)
+{
+	return kref_get_unless_zero(&dev->ref);
+}
+
+static struct nvme_rdma_device *
+nvme_rdma_find_get_device(struct rdma_cm_id *cm_id)
+{
+	struct nvme_rdma_device *ndev;
+
+	mutex_lock(&device_list_mutex);
+	list_for_each_entry(ndev, &device_list, entry) {
+		if (ndev->dev->node_guid == cm_id->device->node_guid &&
+		    nvme_rdma_dev_get(ndev))
+			goto out_unlock;
+	}
+
+	ndev = kzalloc(sizeof(*ndev), GFP_KERNEL);
+	if (!ndev)
+		goto out_err;
+
+	ndev->dev = cm_id->device;
+	kref_init(&ndev->ref);
+
+	ndev->pd = ib_alloc_pd(ndev->dev);
+	if (IS_ERR(ndev->pd))
+		goto out_free_dev;
+
+	if (!register_always) {
+		ndev->mr = ib_get_dma_mr(ndev->pd,
+					    IB_ACCESS_LOCAL_WRITE |
+					    IB_ACCESS_REMOTE_READ |
+					    IB_ACCESS_REMOTE_WRITE);
+		if (IS_ERR(ndev->mr))
+			goto out_free_pd;
+	}
+
+	if (!(ndev->dev->attrs.device_cap_flags &
+	      IB_DEVICE_MEM_MGT_EXTENSIONS)) {
+		dev_err(&ndev->dev->dev,
+			"Memory registrations not supported.\n");
+		goto out_free_mr;
+	}
+
+	list_add(&ndev->entry, &device_list);
+out_unlock:
+	mutex_unlock(&device_list_mutex);
+	return ndev;
+
+out_free_mr:
+	if (!register_always)
+		ib_dereg_mr(ndev->mr);
+out_free_pd:
+	ib_dealloc_pd(ndev->pd);
+out_free_dev:
+	kfree(ndev);
+out_err:
+	mutex_unlock(&device_list_mutex);
+	return NULL;
+}
+
+static void nvme_rdma_destroy_queue_ib(struct nvme_rdma_queue *queue)
+{
+	struct nvme_rdma_device *dev = queue->device;
+	struct ib_device *ibdev = dev->dev;
+
+	rdma_destroy_qp(queue->cm_id);
+	ib_free_cq(queue->ib_cq);
+
+	nvme_rdma_free_ring(ibdev, queue->rsp_ring, queue->queue_size,
+			sizeof(struct nvme_completion), DMA_FROM_DEVICE);
+
+	nvme_rdma_dev_put(dev);
+}
+
+static int nvme_rdma_create_queue_ib(struct nvme_rdma_queue *queue,
+		struct nvme_rdma_device *dev)
+{
+	struct ib_device *ibdev = dev->dev;
+	const int send_wr_factor = 3;			/* MR, SEND, INV */
+	const int cq_factor = send_wr_factor + 1;	/* + RECV */
+	int comp_vector, idx = nvme_rdma_queue_idx(queue);
+
+	int ret;
+
+	queue->device = dev;
+
+	/*
+	 * The admin queue is barely used once the controller is live, so don't
+	 * bother to spread it out.
+	 */
+	if (idx == 0)
+		comp_vector = 0;
+	else
+		comp_vector = idx % ibdev->num_comp_vectors;
+
+
+	/* +1 for ib_stop_cq */
+	queue->ib_cq = ib_alloc_cq(dev->dev, queue,
+				cq_factor * queue->queue_size + 1, comp_vector,
+				IB_POLL_SOFTIRQ);
+	if (IS_ERR(queue->ib_cq)) {
+		ret = PTR_ERR(queue->ib_cq);
+		goto out;
+	}
+
+	ret = nvme_rdma_create_qp(queue, send_wr_factor);
+	if (ret)
+		goto out_destroy_ib_cq;
+
+	queue->rsp_ring = nvme_rdma_alloc_ring(ibdev, queue->queue_size,
+			sizeof(struct nvme_completion), DMA_FROM_DEVICE);
+	if (!queue->rsp_ring) {
+		ret = -ENOMEM;
+		goto out_destroy_qp;
+	}
+
+	return 0;
+
+out_destroy_qp:
+	ib_destroy_qp(queue->qp);
+out_destroy_ib_cq:
+	ib_free_cq(queue->ib_cq);
+out:
+	return ret;
+}
+
+static int nvme_rdma_init_queue(struct nvme_rdma_ctrl *ctrl,
+		int idx, size_t queue_size)
+{
+	struct nvme_rdma_queue *queue;
+	int ret;
+
+	queue = &ctrl->queues[idx];
+	queue->ctrl = ctrl;
+	init_completion(&queue->cm_done);
+
+	if (idx > 0)
+		queue->cmnd_capsule_len = ctrl->ctrl.ioccsz * 16;
+	else
+		queue->cmnd_capsule_len = sizeof(struct nvme_command);
+
+	queue->queue_size = queue_size;
+
+	queue->cm_id = rdma_create_id(&init_net, nvme_rdma_cm_handler, queue,
+			RDMA_PS_TCP, IB_QPT_RC);
+	if (IS_ERR(queue->cm_id)) {
+		dev_info(ctrl->ctrl.device,
+			"failed to create CM ID: %ld\n", PTR_ERR(queue->cm_id));
+		return PTR_ERR(queue->cm_id);
+	}
+
+	queue->cm_error = -ETIMEDOUT;
+	ret = rdma_resolve_addr(queue->cm_id, NULL, &ctrl->addr,
+			NVME_RDMA_CONNECT_TIMEOUT_MS);
+	if (ret) {
+		dev_info(ctrl->ctrl.device,
+			"rdma_resolve_addr failed (%d).\n", ret);
+		goto out_destroy_cm_id;
+	}
+
+	ret = nvme_rdma_wait_for_cm(queue);
+	if (ret) {
+		dev_info(ctrl->ctrl.device,
+			"rdma_resolve_addr wait failed (%d).\n", ret);
+		goto out_destroy_cm_id;
+	}
+
+	set_bit(NVME_RDMA_Q_CONNECTED, &queue->flags);
+
+	return 0;
+
+out_destroy_cm_id:
+	rdma_destroy_id(queue->cm_id);
+	return ret;
+}
+
+static void nvme_rdma_stop_queue(struct nvme_rdma_queue *queue)
+{
+	rdma_disconnect(queue->cm_id);
+	ib_drain_qp(queue->qp);
+}
+
+static void nvme_rdma_free_queue(struct nvme_rdma_queue *queue)
+{
+	nvme_rdma_destroy_queue_ib(queue);
+	rdma_destroy_id(queue->cm_id);
+}
+
+static void nvme_rdma_stop_and_free_queue(struct nvme_rdma_queue *queue)
+{
+	if (!test_and_clear_bit(NVME_RDMA_Q_CONNECTED, &queue->flags))
+		return;
+	nvme_rdma_stop_queue(queue);
+	nvme_rdma_free_queue(queue);
+}
+
+static void nvme_rdma_free_io_queues(struct nvme_rdma_ctrl *ctrl)
+{
+	int i;
+
+	for (i = 1; i < ctrl->queue_count; i++)
+		nvme_rdma_stop_and_free_queue(&ctrl->queues[i]);
+}
+
+static int nvme_rdma_connect_io_queues(struct nvme_rdma_ctrl *ctrl)
+{
+	int i, ret = 0;
+
+	for (i = 1; i < ctrl->queue_count; i++) {
+		ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static int nvme_rdma_init_io_queues(struct nvme_rdma_ctrl *ctrl)
+{
+	int i, ret;
+
+	for (i = 1; i < ctrl->queue_count; i++) {
+		ret = nvme_rdma_init_queue(ctrl, i, ctrl->ctrl.sqsize);
+		if (ret) {
+			dev_info(ctrl->ctrl.device,
+				"failed to initialize i/o queue: %d\n", ret);
+			goto out_free_queues;
+		}
+	}
+
+	return 0;
+
+out_free_queues:
+	for (; i >= 1; i--)
+		nvme_rdma_stop_and_free_queue(&ctrl->queues[i]);
+
+	return ret;
+}
+
+static void nvme_rdma_destroy_admin_queue(struct nvme_rdma_ctrl *ctrl)
+{
+	nvme_rdma_free_qe(ctrl->queues[0].device->dev, &ctrl->async_event_sqe,
+			sizeof(struct nvme_command), DMA_TO_DEVICE);
+	nvme_rdma_stop_and_free_queue(&ctrl->queues[0]);
+	blk_cleanup_queue(ctrl->ctrl.admin_q);
+	blk_mq_free_tag_set(&ctrl->admin_tag_set);
+	nvme_rdma_dev_put(ctrl->device);
+}
+
+static void nvme_rdma_free_ctrl(struct nvme_ctrl *nctrl)
+{
+	struct nvme_rdma_ctrl *ctrl = to_rdma_ctrl(nctrl);
+
+	if (list_empty(&ctrl->list))
+		goto free_ctrl;
+
+	mutex_lock(&nvme_rdma_ctrl_mutex);
+	list_del(&ctrl->list);
+	mutex_unlock(&nvme_rdma_ctrl_mutex);
+
+	if (ctrl->ctrl.tagset) {
+		blk_cleanup_queue(ctrl->ctrl.connect_q);
+		blk_mq_free_tag_set(&ctrl->tag_set);
+		nvme_rdma_dev_put(ctrl->device);
+	}
+	kfree(ctrl->queues);
+	nvmf_free_options(nctrl->opts);
+free_ctrl:
+	kfree(ctrl);
+}
+
+static void nvme_rdma_reconnect_ctrl_work(struct work_struct *work)
+{
+	struct nvme_rdma_ctrl *ctrl = container_of(to_delayed_work(work),
+			struct nvme_rdma_ctrl, reconnect_work);
+	bool changed;
+	int ret;
+
+	if (ctrl->queue_count > 1) {
+		nvme_rdma_free_io_queues(ctrl);
+
+		ret = blk_mq_reinit_tagset(&ctrl->tag_set);
+		if (ret)
+			goto requeue;
+	}
+
+	nvme_rdma_stop_and_free_queue(&ctrl->queues[0]);
+
+	ret = blk_mq_reinit_tagset(&ctrl->admin_tag_set);
+	if (ret)
+		goto requeue;
+
+	ret = nvme_rdma_init_queue(ctrl, 0, NVMF_AQ_DEPTH);
+	if (ret)
+		goto requeue;
+
+	blk_mq_start_stopped_hw_queues(ctrl->ctrl.admin_q, true);
+
+	ret = nvmf_connect_admin_queue(&ctrl->ctrl);
+	if (ret)
+		goto stop_admin_q;
+
+	ret = nvme_enable_ctrl(&ctrl->ctrl, ctrl->cap);
+	if (ret)
+		goto stop_admin_q;
+
+	nvme_start_keep_alive(&ctrl->ctrl);
+
+	if (ctrl->queue_count > 1) {
+		ret = nvme_rdma_init_io_queues(ctrl);
+		if (ret)
+			goto stop_admin_q;
+
+		ret = nvme_rdma_connect_io_queues(ctrl);
+		if (ret)
+			goto stop_admin_q;
+	}
+
+	changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
+	WARN_ON_ONCE(!changed);
+
+	if (ctrl->queue_count > 1)
+		nvme_start_queues(&ctrl->ctrl);
+
+	dev_info(ctrl->ctrl.device, "Successfully reconnected\n");
+
+	return;
+
+stop_admin_q:
+	blk_mq_stop_hw_queues(ctrl->ctrl.admin_q);
+requeue:
+	/* Make sure we are not resetting/deleting */
+	if (ctrl->ctrl.state == NVME_CTRL_RECONNECTING) {
+		dev_info(ctrl->ctrl.device,
+			"Failed reconnect attempt, requeueing...\n");
+		queue_delayed_work(nvme_rdma_wq, &ctrl->reconnect_work,
+					ctrl->reconnect_delay * HZ);
+	}
+}
+
+static void nvme_rdma_error_recovery_work(struct work_struct *work)
+{
+	struct nvme_rdma_ctrl *ctrl = container_of(work,
+			struct nvme_rdma_ctrl, err_work);
+
+	nvme_stop_keep_alive(&ctrl->ctrl);
+	if (ctrl->queue_count > 1)
+		nvme_stop_queues(&ctrl->ctrl);
+	blk_mq_stop_hw_queues(ctrl->ctrl.admin_q);
+
+	/* We must take care of fastfail/requeue all our inflight requests */
+	if (ctrl->queue_count > 1)
+		blk_mq_tagset_busy_iter(&ctrl->tag_set,
+					nvme_cancel_request, &ctrl->ctrl);
+	blk_mq_tagset_busy_iter(&ctrl->admin_tag_set,
+				nvme_cancel_request, &ctrl->ctrl);
+
+	dev_info(ctrl->ctrl.device, "reconnecting in %d seconds\n",
+		ctrl->reconnect_delay);
+
+	queue_delayed_work(nvme_rdma_wq, &ctrl->reconnect_work,
+				ctrl->reconnect_delay * HZ);
+}
+
+static void nvme_rdma_error_recovery(struct nvme_rdma_ctrl *ctrl)
+{
+	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_RECONNECTING))
+		return;
+
+	queue_work(nvme_rdma_wq, &ctrl->err_work);
+}
+
+static void nvme_rdma_wr_error(struct ib_cq *cq, struct ib_wc *wc,
+		const char *op)
+{
+	struct nvme_rdma_queue *queue = cq->cq_context;
+	struct nvme_rdma_ctrl *ctrl = queue->ctrl;
+
+	if (ctrl->ctrl.state == NVME_CTRL_LIVE)
+		dev_info(ctrl->ctrl.device,
+			     "%s for CQE 0x%p failed with status %s (%d)\n",
+			     op, wc->wr_cqe,
+			     ib_wc_status_msg(wc->status), wc->status);
+	nvme_rdma_error_recovery(ctrl);
+}
+
+static void nvme_rdma_memreg_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	if (unlikely(wc->status != IB_WC_SUCCESS))
+		nvme_rdma_wr_error(cq, wc, "MEMREG");
+}
+
+static void nvme_rdma_inv_rkey_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	if (unlikely(wc->status != IB_WC_SUCCESS))
+		nvme_rdma_wr_error(cq, wc, "LOCAL_INV");
+}
+
+static int nvme_rdma_inv_rkey(struct nvme_rdma_queue *queue,
+		struct nvme_rdma_request *req)
+{
+	struct ib_send_wr *bad_wr;
+	struct ib_send_wr wr = {
+		.opcode		    = IB_WR_LOCAL_INV,
+		.next		    = NULL,
+		.num_sge	    = 0,
+		.send_flags	    = 0,
+		.ex.invalidate_rkey = req->mr->rkey,
+	};
+
+	req->reg_cqe.done = nvme_rdma_inv_rkey_done;
+	wr.wr_cqe = &req->reg_cqe;
+
+	return ib_post_send(queue->qp, &wr, &bad_wr);
+}
+
+static void nvme_rdma_unmap_data(struct nvme_rdma_queue *queue,
+		struct request *rq)
+{
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	struct nvme_rdma_ctrl *ctrl = queue->ctrl;
+	struct nvme_rdma_device *dev = queue->device;
+	struct ib_device *ibdev = dev->dev;
+	int res;
+
+	if (!blk_rq_bytes(rq))
+		return;
+
+	if (req->need_inval) {
+		res = nvme_rdma_inv_rkey(queue, req);
+		if (res < 0) {
+			dev_err(ctrl->ctrl.device,
+				"Queueing INV WR for rkey %#x failed (%d)\n",
+				req->mr->rkey, res);
+			nvme_rdma_error_recovery(queue->ctrl);
+		}
+	}
+
+	ib_dma_unmap_sg(ibdev, req->sg_table.sgl,
+			req->nents, rq_data_dir(rq) ==
+				    WRITE ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+
+	nvme_cleanup_cmd(rq);
+	sg_free_table_chained(&req->sg_table, true);
+}
+
+static int nvme_rdma_set_sg_null(struct nvme_command *c)
+{
+	struct nvme_keyed_sgl_desc *sg = &c->common.dptr.ksgl;
+
+	sg->addr = 0;
+	put_unaligned_le24(0, sg->length);
+	put_unaligned_le32(0, sg->key);
+	sg->type = NVME_KEY_SGL_FMT_DATA_DESC << 4;
+	return 0;
+}
+
+static int nvme_rdma_map_sg_inline(struct nvme_rdma_queue *queue,
+		struct nvme_rdma_request *req, struct nvme_command *c)
+{
+	struct nvme_sgl_desc *sg = &c->common.dptr.sgl;
+
+	req->sge[1].addr = sg_dma_address(req->sg_table.sgl);
+	req->sge[1].length = sg_dma_len(req->sg_table.sgl);
+	req->sge[1].lkey = queue->device->pd->local_dma_lkey;
+
+	sg->addr = cpu_to_le64(queue->ctrl->ctrl.icdoff);
+	sg->length = cpu_to_le32(sg_dma_len(req->sg_table.sgl));
+	sg->type = (NVME_SGL_FMT_DATA_DESC << 4) | NVME_SGL_FMT_OFFSET;
+
+	req->inline_data = true;
+	req->num_sge++;
+	return 0;
+}
+
+static int nvme_rdma_map_sg_single(struct nvme_rdma_queue *queue,
+		struct nvme_rdma_request *req, struct nvme_command *c)
+{
+	struct nvme_keyed_sgl_desc *sg = &c->common.dptr.ksgl;
+
+	sg->addr = cpu_to_le64(sg_dma_address(req->sg_table.sgl));
+	put_unaligned_le24(sg_dma_len(req->sg_table.sgl), sg->length);
+	put_unaligned_le32(queue->device->mr->rkey, sg->key);
+	sg->type = NVME_KEY_SGL_FMT_DATA_DESC << 4;
+	return 0;
+}
+
+static int nvme_rdma_map_sg_fr(struct nvme_rdma_queue *queue,
+		struct nvme_rdma_request *req, struct nvme_command *c,
+		int count)
+{
+	struct nvme_keyed_sgl_desc *sg = &c->common.dptr.ksgl;
+	int nr;
+
+	nr = ib_map_mr_sg(req->mr, req->sg_table.sgl, count, NULL, PAGE_SIZE);
+	if (nr < count) {
+		if (nr < 0)
+			return nr;
+		return -EINVAL;
+	}
+
+	ib_update_fast_reg_key(req->mr, ib_inc_rkey(req->mr->rkey));
+
+	req->reg_cqe.done = nvme_rdma_memreg_done;
+	memset(&req->reg_wr, 0, sizeof(req->reg_wr));
+	req->reg_wr.wr.opcode = IB_WR_REG_MR;
+	req->reg_wr.wr.wr_cqe = &req->reg_cqe;
+	req->reg_wr.wr.num_sge = 0;
+	req->reg_wr.mr = req->mr;
+	req->reg_wr.key = req->mr->rkey;
+	req->reg_wr.access = IB_ACCESS_LOCAL_WRITE |
+			     IB_ACCESS_REMOTE_READ |
+			     IB_ACCESS_REMOTE_WRITE;
+
+	req->need_inval = true;
+
+	sg->addr = cpu_to_le64(req->mr->iova);
+	put_unaligned_le24(req->mr->length, sg->length);
+	put_unaligned_le32(req->mr->rkey, sg->key);
+	sg->type = (NVME_KEY_SGL_FMT_DATA_DESC << 4) |
+			NVME_SGL_FMT_INVALIDATE;
+
+	return 0;
+}
+
+static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
+		struct request *rq, unsigned int map_len,
+		struct nvme_command *c)
+{
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	struct nvme_rdma_device *dev = queue->device;
+	struct ib_device *ibdev = dev->dev;
+	int nents, count;
+	int ret;
+
+	req->num_sge = 1;
+	req->inline_data = false;
+	req->need_inval = false;
+
+	c->common.flags |= NVME_CMD_SGL_METABUF;
+
+	if (!blk_rq_bytes(rq))
+		return nvme_rdma_set_sg_null(c);
+
+	req->sg_table.sgl = req->first_sgl;
+	ret = sg_alloc_table_chained(&req->sg_table, rq->nr_phys_segments,
+				req->sg_table.sgl);
+	if (ret)
+		return -ENOMEM;
+
+	nents = blk_rq_map_sg(rq->q, rq, req->sg_table.sgl);
+	BUG_ON(nents > rq->nr_phys_segments);
+	req->nents = nents;
+
+	count = ib_dma_map_sg(ibdev, req->sg_table.sgl, nents,
+		    rq_data_dir(rq) == WRITE ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+	if (unlikely(count <= 0)) {
+		sg_free_table_chained(&req->sg_table, true);
+		return -EIO;
+	}
+
+	if (count == 1) {
+		if (rq_data_dir(rq) == WRITE &&
+		    map_len <= nvme_rdma_inline_data_size(queue) &&
+		    nvme_rdma_queue_idx(queue))
+			return nvme_rdma_map_sg_inline(queue, req, c);
+
+		if (!register_always)
+			return nvme_rdma_map_sg_single(queue, req, c);
+	}
+
+	return nvme_rdma_map_sg_fr(queue, req, c, count);
+}
+
+static void nvme_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	if (unlikely(wc->status != IB_WC_SUCCESS))
+		nvme_rdma_wr_error(cq, wc, "SEND");
+}
+
+static int nvme_rdma_post_send(struct nvme_rdma_queue *queue,
+		struct nvme_rdma_qe *qe, struct ib_sge *sge, u32 num_sge,
+		struct ib_send_wr *first, bool flush)
+{
+	struct ib_send_wr wr, *bad_wr;
+	int ret;
+
+	sge->addr   = qe->dma;
+	sge->length = sizeof(struct nvme_command),
+	sge->lkey   = queue->device->pd->local_dma_lkey;
+
+	qe->cqe.done = nvme_rdma_send_done;
+
+	wr.next       = NULL;
+	wr.wr_cqe     = &qe->cqe;
+	wr.sg_list    = sge;
+	wr.num_sge    = num_sge;
+	wr.opcode     = IB_WR_SEND;
+	wr.send_flags = 0;
+
+	/*
+	 * Unsignalled send completions are another giant desaster in the
+	 * IB Verbs spec:  If we don't regularly post signalled sends
+	 * the send queue will fill up and only a QP reset will rescue us.
+	 * Would have been way to obvious to handle this in hardware or
+	 * at least the RDMA stack..
+	 *
+	 * This messy and racy code sniplet is copy and pasted from the iSER
+	 * initiator, and the magic '32' comes from there as well.
+	 *
+	 * Always signal the flushes. The magic request used for the flush
+	 * sequencer is not allocated in our driver's tagset and it's
+	 * triggered to be freed by blk_cleanup_queue(). So we need to
+	 * always mark it as signaled to ensure that the "wr_cqe", which is
+	 * embeded in request's payload, is not freed when __ib_process_cq()
+	 * calls wr_cqe->done().
+	 */
+	if ((++queue->sig_count % 32) == 0 || flush)
+		wr.send_flags |= IB_SEND_SIGNALED;
+
+	if (first)
+		first->next = &wr;
+	else
+		first = &wr;
+
+	ret = ib_post_send(queue->qp, first, &bad_wr);
+	if (ret) {
+		dev_err(queue->ctrl->ctrl.device,
+			     "%s failed with error code %d\n", __func__, ret);
+	}
+	return ret;
+}
+
+static int nvme_rdma_post_recv(struct nvme_rdma_queue *queue,
+		struct nvme_rdma_qe *qe)
+{
+	struct ib_recv_wr wr, *bad_wr;
+	struct ib_sge list;
+	int ret;
+
+	list.addr   = qe->dma;
+	list.length = sizeof(struct nvme_completion);
+	list.lkey   = queue->device->pd->local_dma_lkey;
+
+	qe->cqe.done = nvme_rdma_recv_done;
+
+	wr.next     = NULL;
+	wr.wr_cqe   = &qe->cqe;
+	wr.sg_list  = &list;
+	wr.num_sge  = 1;
+
+	ret = ib_post_recv(queue->qp, &wr, &bad_wr);
+	if (ret) {
+		dev_err(queue->ctrl->ctrl.device,
+			"%s failed with error code %d\n", __func__, ret);
+	}
+	return ret;
+}
+
+static struct blk_mq_tags *nvme_rdma_tagset(struct nvme_rdma_queue *queue)
+{
+	u32 queue_idx = nvme_rdma_queue_idx(queue);
+
+	if (queue_idx == 0)
+		return queue->ctrl->admin_tag_set.tags[queue_idx];
+	return queue->ctrl->tag_set.tags[queue_idx - 1];
+}
+
+static void nvme_rdma_submit_async_event(struct nvme_ctrl *arg, int aer_idx)
+{
+	struct nvme_rdma_ctrl *ctrl = to_rdma_ctrl(arg);
+	struct nvme_rdma_queue *queue = &ctrl->queues[0];
+	struct ib_device *dev = queue->device->dev;
+	struct nvme_rdma_qe *sqe = &ctrl->async_event_sqe;
+	struct nvme_command *cmd = sqe->data;
+	struct ib_sge sge;
+	int ret;
+
+	if (WARN_ON_ONCE(aer_idx != 0))
+		return;
+
+	ib_dma_sync_single_for_cpu(dev, sqe->dma, sizeof(*cmd), DMA_TO_DEVICE);
+
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->common.opcode = nvme_admin_async_event;
+	cmd->common.command_id = NVME_RDMA_AQ_BLKMQ_DEPTH;
+	cmd->common.flags |= NVME_CMD_SGL_METABUF;
+	nvme_rdma_set_sg_null(cmd);
+
+	ib_dma_sync_single_for_device(dev, sqe->dma, sizeof(*cmd),
+			DMA_TO_DEVICE);
+
+	ret = nvme_rdma_post_send(queue, sqe, &sge, 1, NULL, false);
+	WARN_ON_ONCE(ret);
+}
+
+static int nvme_rdma_process_nvme_rsp(struct nvme_rdma_queue *queue,
+		struct nvme_completion *cqe, struct ib_wc *wc, int tag)
+{
+	u16 status = le16_to_cpu(cqe->status);
+	struct request *rq;
+	struct nvme_rdma_request *req;
+	int ret = 0;
+
+	status >>= 1;
+
+	rq = blk_mq_tag_to_rq(nvme_rdma_tagset(queue), cqe->command_id);
+	if (!rq) {
+		dev_err(queue->ctrl->ctrl.device,
+			"tag 0x%x on QP %#x not found\n",
+			cqe->command_id, queue->qp->qp_num);
+		nvme_rdma_error_recovery(queue->ctrl);
+		return ret;
+	}
+	req = blk_mq_rq_to_pdu(rq);
+
+	if (rq->cmd_type == REQ_TYPE_DRV_PRIV && rq->special)
+		memcpy(rq->special, cqe, sizeof(*cqe));
+
+	if (rq->tag == tag)
+		ret = 1;
+
+	if ((wc->wc_flags & IB_WC_WITH_INVALIDATE) &&
+	    wc->ex.invalidate_rkey == req->mr->rkey)
+		req->need_inval = false;
+
+	blk_mq_complete_request(rq, status);
+
+	return ret;
+}
+
+static int __nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc, int tag)
+{
+	struct nvme_rdma_qe *qe =
+		container_of(wc->wr_cqe, struct nvme_rdma_qe, cqe);
+	struct nvme_rdma_queue *queue = cq->cq_context;
+	struct ib_device *ibdev = queue->device->dev;
+	struct nvme_completion *cqe = qe->data;
+	const size_t len = sizeof(struct nvme_completion);
+	int ret = 0;
+
+	if (unlikely(wc->status != IB_WC_SUCCESS)) {
+		nvme_rdma_wr_error(cq, wc, "RECV");
+		return 0;
+	}
+
+	ib_dma_sync_single_for_cpu(ibdev, qe->dma, len, DMA_FROM_DEVICE);
+	/*
+	 * 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_rdma_queue_idx(queue) == 0 &&
+			cqe->command_id >= NVME_RDMA_AQ_BLKMQ_DEPTH))
+		nvme_complete_async_event(&queue->ctrl->ctrl, cqe);
+	else
+		ret = nvme_rdma_process_nvme_rsp(queue, cqe, wc, tag);
+	ib_dma_sync_single_for_device(ibdev, qe->dma, len, DMA_FROM_DEVICE);
+
+	nvme_rdma_post_recv(queue, qe);
+	return ret;
+}
+
+static void nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	__nvme_rdma_recv_done(cq, wc, -1);
+}
+
+static int nvme_rdma_conn_established(struct nvme_rdma_queue *queue)
+{
+	int ret, i;
+
+	for (i = 0; i < queue->queue_size; i++) {
+		ret = nvme_rdma_post_recv(queue, &queue->rsp_ring[i]);
+		if (ret)
+			goto out_destroy_queue_ib;
+	}
+
+	return 0;
+
+out_destroy_queue_ib:
+	nvme_rdma_destroy_queue_ib(queue);
+	return ret;
+}
+
+static int nvme_rdma_conn_rejected(struct nvme_rdma_queue *queue,
+		struct rdma_cm_event *ev)
+{
+	if (ev->param.conn.private_data_len) {
+		struct nvme_rdma_cm_rej *rej =
+			(struct nvme_rdma_cm_rej *)ev->param.conn.private_data;
+
+		dev_err(queue->ctrl->ctrl.device,
+			"Connect rejected, status %d.", le16_to_cpu(rej->sts));
+		/* XXX: Think of something clever to do here... */
+	} else {
+		dev_err(queue->ctrl->ctrl.device,
+			"Connect rejected, no private data.\n");
+	}
+
+	return -ECONNRESET;
+}
+
+static int nvme_rdma_addr_resolved(struct nvme_rdma_queue *queue)
+{
+	struct nvme_rdma_device *dev;
+	int ret;
+
+	dev = nvme_rdma_find_get_device(queue->cm_id);
+	if (!dev) {
+		dev_err(queue->cm_id->device->dma_device,
+			"no client data found!\n");
+		return -ECONNREFUSED;
+	}
+
+	ret = nvme_rdma_create_queue_ib(queue, dev);
+	if (ret) {
+		nvme_rdma_dev_put(dev);
+		goto out;
+	}
+
+	ret = rdma_resolve_route(queue->cm_id, NVME_RDMA_CONNECT_TIMEOUT_MS);
+	if (ret) {
+		dev_err(queue->ctrl->ctrl.device,
+			"rdma_resolve_route failed (%d).\n",
+			queue->cm_error);
+		goto out_destroy_queue;
+	}
+
+	return 0;
+
+out_destroy_queue:
+	nvme_rdma_destroy_queue_ib(queue);
+out:
+	return ret;
+}
+
+static int nvme_rdma_route_resolved(struct nvme_rdma_queue *queue)
+{
+	struct nvme_rdma_ctrl *ctrl = queue->ctrl;
+	struct rdma_conn_param param = { };
+	struct nvme_rdma_cm_req priv;
+	int ret;
+
+	param.qp_num = queue->qp->qp_num;
+	param.flow_control = 1;
+
+	param.responder_resources = queue->device->dev->attrs.max_qp_rd_atom;
+	/* rdma_cm will clamp down to max QP retry count (7) */
+	param.retry_count = ctrl->tl_retry_count;
+	param.rnr_retry_count = 7;
+	param.private_data = &priv;
+	param.private_data_len = sizeof(priv);
+
+	priv.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
+	priv.qid = cpu_to_le16(nvme_rdma_queue_idx(queue));
+	priv.hrqsize = cpu_to_le16(queue->queue_size);
+	priv.hsqsize = cpu_to_le16(queue->queue_size);
+
+	ret = rdma_connect(queue->cm_id, &param);
+	if (ret) {
+		dev_err(ctrl->ctrl.device,
+			"rdma_connect failed (%d).\n", ret);
+		goto out_destroy_queue_ib;
+	}
+
+	return 0;
+
+out_destroy_queue_ib:
+	nvme_rdma_destroy_queue_ib(queue);
+	return ret;
+}
+
+/**
+ * nvme_rdma_device_unplug() - Handle RDMA device unplug
+ * @queue:      Queue that owns the cm_id that caught the event
+ *
+ * DEVICE_REMOVAL event notifies us that the RDMA device is about
+ * to unplug so we should take care of destroying our RDMA resources.
+ * This event will be generated for each allocated cm_id.
+ *
+ * In our case, the RDMA resources are managed per controller and not
+ * only per queue. So the way we handle this is we trigger an implicit
+ * controller deletion upon the first DEVICE_REMOVAL event we see, and
+ * hold the event inflight until the controller deletion is completed.
+ *
+ * One exception that we need to handle is the destruction of the cm_id
+ * that caught the event. Since we hold the callout until the controller
+ * deletion is completed, we'll deadlock if the controller deletion will
+ * call rdma_destroy_id on this queue's cm_id. Thus, we claim ownership
+ * of destroying this queue before-hand, destroy the queue resources
+ * after the controller deletion completed with the exception of destroying
+ * the cm_id implicitely by returning a non-zero rc to the callout.
+ */
+static int nvme_rdma_device_unplug(struct nvme_rdma_queue *queue)
+{
+	struct nvme_rdma_ctrl *ctrl = queue->ctrl;
+	int ret, ctrl_deleted = 0;
+
+	/* First disable the queue so ctrl delete won't free it */
+	if (!test_and_clear_bit(NVME_RDMA_Q_CONNECTED, &queue->flags))
+		goto out;
+
+	/* delete the controller */
+	ret = __nvme_rdma_del_ctrl(ctrl);
+	if (!ret) {
+		dev_warn(ctrl->ctrl.device,
+			"Got rdma device removal event, deleting ctrl\n");
+		flush_work(&ctrl->delete_work);
+
+		/* Return non-zero so the cm_id will destroy implicitly */
+		ctrl_deleted = 1;
+
+		/* Free this queue ourselves */
+		rdma_disconnect(queue->cm_id);
+		ib_drain_qp(queue->qp);
+		nvme_rdma_destroy_queue_ib(queue);
+	}
+
+out:
+	return ctrl_deleted;
+}
+
+static int nvme_rdma_cm_handler(struct rdma_cm_id *cm_id,
+		struct rdma_cm_event *ev)
+{
+	struct nvme_rdma_queue *queue = cm_id->context;
+	int cm_error = 0;
+
+	dev_dbg(queue->ctrl->ctrl.device, "%s (%d): status %d id %p\n",
+		rdma_event_msg(ev->event), ev->event,
+		ev->status, cm_id);
+
+	switch (ev->event) {
+	case RDMA_CM_EVENT_ADDR_RESOLVED:
+		cm_error = nvme_rdma_addr_resolved(queue);
+		break;
+	case RDMA_CM_EVENT_ROUTE_RESOLVED:
+		cm_error = nvme_rdma_route_resolved(queue);
+		break;
+	case RDMA_CM_EVENT_ESTABLISHED:
+		queue->cm_error = nvme_rdma_conn_established(queue);
+		/* complete cm_done regardless of success/failure */
+		complete(&queue->cm_done);
+		return 0;
+	case RDMA_CM_EVENT_REJECTED:
+		cm_error = nvme_rdma_conn_rejected(queue, ev);
+		break;
+	case RDMA_CM_EVENT_ADDR_ERROR:
+	case RDMA_CM_EVENT_ROUTE_ERROR:
+	case RDMA_CM_EVENT_CONNECT_ERROR:
+	case RDMA_CM_EVENT_UNREACHABLE:
+		dev_dbg(queue->ctrl->ctrl.device,
+			"CM error event %d\n", ev->event);
+		cm_error = -ECONNRESET;
+		break;
+	case RDMA_CM_EVENT_DISCONNECTED:
+	case RDMA_CM_EVENT_ADDR_CHANGE:
+	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
+		dev_dbg(queue->ctrl->ctrl.device,
+			"disconnect received - connection closed\n");
+		nvme_rdma_error_recovery(queue->ctrl);
+		break;
+	case RDMA_CM_EVENT_DEVICE_REMOVAL:
+		/* return 1 means impliciy CM ID destroy */
+		return nvme_rdma_device_unplug(queue);
+	default:
+		dev_err(queue->ctrl->ctrl.device,
+			"Unexpected RDMA CM event (%d)\n", ev->event);
+		nvme_rdma_error_recovery(queue->ctrl);
+		break;
+	}
+
+	if (cm_error) {
+		queue->cm_error = cm_error;
+		complete(&queue->cm_done);
+	}
+
+	return 0;
+}
+
+static enum blk_eh_timer_return
+nvme_rdma_timeout(struct request *rq, bool reserved)
+{
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+
+	/* queue error recovery */
+	nvme_rdma_error_recovery(req->queue->ctrl);
+
+	/* fail with DNR on cmd timeout */
+	rq->errors = NVME_SC_ABORT_REQ | NVME_SC_DNR;
+
+	return BLK_EH_HANDLED;
+}
+
+static int nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
+		const struct blk_mq_queue_data *bd)
+{
+	struct nvme_ns *ns = hctx->queue->queuedata;
+	struct nvme_rdma_queue *queue = hctx->driver_data;
+	struct request *rq = bd->rq;
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	struct nvme_rdma_qe *sqe = &req->sqe;
+	struct nvme_command *c = sqe->data;
+	bool flush = false;
+	struct ib_device *dev;
+	unsigned int map_len;
+	int ret;
+
+	WARN_ON_ONCE(rq->tag < 0);
+
+	dev = queue->device->dev;
+	ib_dma_sync_single_for_cpu(dev, sqe->dma,
+			sizeof(struct nvme_command), DMA_TO_DEVICE);
+
+	ret = nvme_setup_cmd(ns, rq, c);
+	if (ret)
+		return ret;
+
+	c->common.command_id = rq->tag;
+	blk_mq_start_request(rq);
+
+	map_len = nvme_map_len(rq);
+	ret = nvme_rdma_map_data(queue, rq, map_len, c);
+	if (ret < 0) {
+		dev_err(queue->ctrl->ctrl.device,
+			     "Failed to map data (%d)\n", ret);
+		nvme_cleanup_cmd(rq);
+		goto err;
+	}
+
+	ib_dma_sync_single_for_device(dev, sqe->dma,
+			sizeof(struct nvme_command), DMA_TO_DEVICE);
+
+	if (rq->cmd_type == REQ_TYPE_FS && req_op(rq) == REQ_OP_FLUSH)
+		flush = true;
+	ret = nvme_rdma_post_send(queue, sqe, req->sge, req->num_sge,
+			req->need_inval ? &req->reg_wr.wr : NULL, flush);
+	if (ret) {
+		nvme_rdma_unmap_data(queue, rq);
+		goto err;
+	}
+
+	return BLK_MQ_RQ_QUEUE_OK;
+err:
+	return (ret == -ENOMEM || ret == -EAGAIN) ?
+		BLK_MQ_RQ_QUEUE_BUSY : BLK_MQ_RQ_QUEUE_ERROR;
+}
+
+static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag)
+{
+	struct nvme_rdma_queue *queue = hctx->driver_data;
+	struct ib_cq *cq = queue->ib_cq;
+	struct ib_wc wc;
+	int found = 0;
+
+	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
+	while (ib_poll_cq(cq, 1, &wc) > 0) {
+		struct ib_cqe *cqe = wc.wr_cqe;
+
+		if (cqe) {
+			if (cqe->done == nvme_rdma_recv_done)
+				found |= __nvme_rdma_recv_done(cq, &wc, tag);
+			else
+				cqe->done(cq, &wc);
+		}
+	}
+
+	return found;
+}
+
+static void nvme_rdma_complete_rq(struct request *rq)
+{
+	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
+	struct nvme_rdma_queue *queue = req->queue;
+	int error = 0;
+
+	nvme_rdma_unmap_data(queue, rq);
+
+	if (unlikely(rq->errors)) {
+		if (nvme_req_needs_retry(rq, rq->errors)) {
+			nvme_requeue_req(rq);
+			return;
+		}
+
+		if (rq->cmd_type == REQ_TYPE_DRV_PRIV)
+			error = rq->errors;
+		else
+			error = nvme_error_status(rq->errors);
+	}
+
+	blk_mq_end_request(rq, error);
+}
+
+static struct blk_mq_ops nvme_rdma_mq_ops = {
+	.queue_rq	= nvme_rdma_queue_rq,
+	.complete	= nvme_rdma_complete_rq,
+	.map_queue	= blk_mq_map_queue,
+	.init_request	= nvme_rdma_init_request,
+	.exit_request	= nvme_rdma_exit_request,
+	.reinit_request	= nvme_rdma_reinit_request,
+	.init_hctx	= nvme_rdma_init_hctx,
+	.poll		= nvme_rdma_poll,
+	.timeout	= nvme_rdma_timeout,
+};
+
+static struct blk_mq_ops nvme_rdma_admin_mq_ops = {
+	.queue_rq	= nvme_rdma_queue_rq,
+	.complete	= nvme_rdma_complete_rq,
+	.map_queue	= blk_mq_map_queue,
+	.init_request	= nvme_rdma_init_admin_request,
+	.exit_request	= nvme_rdma_exit_admin_request,
+	.reinit_request	= nvme_rdma_reinit_request,
+	.init_hctx	= nvme_rdma_init_admin_hctx,
+	.timeout	= nvme_rdma_timeout,
+};
+
+static int nvme_rdma_configure_admin_queue(struct nvme_rdma_ctrl *ctrl)
+{
+	int error;
+
+	error = nvme_rdma_init_queue(ctrl, 0, NVMF_AQ_DEPTH);
+	if (error)
+		return error;
+
+	ctrl->device = ctrl->queues[0].device;
+
+	/*
+	 * We need a reference on the device as long as the tag_set is alive,
+	 * as the MRs in the request structures need a valid ib_device.
+	 */
+	error = -EINVAL;
+	if (!nvme_rdma_dev_get(ctrl->device))
+		goto out_free_queue;
+
+	ctrl->max_fr_pages = min_t(u32, NVME_RDMA_MAX_SEGMENTS,
+		ctrl->device->dev->attrs.max_fast_reg_page_list_len);
+
+	memset(&ctrl->admin_tag_set, 0, sizeof(ctrl->admin_tag_set));
+	ctrl->admin_tag_set.ops = &nvme_rdma_admin_mq_ops;
+	ctrl->admin_tag_set.queue_depth = NVME_RDMA_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_rdma_request) +
+		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;
+
+	error = blk_mq_alloc_tag_set(&ctrl->admin_tag_set);
+	if (error)
+		goto out_put_dev;
+
+	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 =
+		(ctrl->max_fr_pages - 1) << (PAGE_SHIFT - 9);
+
+	error = nvme_init_identify(&ctrl->ctrl);
+	if (error)
+		goto out_cleanup_queue;
+
+	error = nvme_rdma_alloc_qe(ctrl->queues[0].device->dev,
+			&ctrl->async_event_sqe, sizeof(struct nvme_command),
+			DMA_TO_DEVICE);
+	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:
+	/* disconnect and drain the queue before freeing the tagset */
+	nvme_rdma_stop_queue(&ctrl->queues[0]);
+	blk_mq_free_tag_set(&ctrl->admin_tag_set);
+out_put_dev:
+	nvme_rdma_dev_put(ctrl->device);
+out_free_queue:
+	nvme_rdma_free_queue(&ctrl->queues[0]);
+	return error;
+}
+
+static void nvme_rdma_shutdown_ctrl(struct nvme_rdma_ctrl *ctrl)
+{
+	nvme_stop_keep_alive(&ctrl->ctrl);
+	cancel_work_sync(&ctrl->err_work);
+	cancel_delayed_work_sync(&ctrl->reconnect_work);
+
+	if (ctrl->queue_count > 1) {
+		nvme_stop_queues(&ctrl->ctrl);
+		blk_mq_tagset_busy_iter(&ctrl->tag_set,
+					nvme_cancel_request, &ctrl->ctrl);
+		nvme_rdma_free_io_queues(ctrl);
+	}
+
+	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_rdma_destroy_admin_queue(ctrl);
+}
+
+static void nvme_rdma_del_ctrl_work(struct work_struct *work)
+{
+	struct nvme_rdma_ctrl *ctrl = container_of(work,
+				struct nvme_rdma_ctrl, delete_work);
+
+	nvme_remove_namespaces(&ctrl->ctrl);
+	nvme_rdma_shutdown_ctrl(ctrl);
+	nvme_uninit_ctrl(&ctrl->ctrl);
+	nvme_put_ctrl(&ctrl->ctrl);
+}
+
+static int __nvme_rdma_del_ctrl(struct nvme_rdma_ctrl *ctrl)
+{
+	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_DELETING))
+		return -EBUSY;
+
+	if (!queue_work(nvme_rdma_wq, &ctrl->delete_work))
+		return -EBUSY;
+
+	return 0;
+}
+
+static int nvme_rdma_del_ctrl(struct nvme_ctrl *nctrl)
+{
+	struct nvme_rdma_ctrl *ctrl = to_rdma_ctrl(nctrl);
+	int ret;
+
+	ret = __nvme_rdma_del_ctrl(ctrl);
+	if (ret)
+		return ret;
+
+	flush_work(&ctrl->delete_work);
+
+	return 0;
+}
+
+static void nvme_rdma_remove_ctrl_work(struct work_struct *work)
+{
+	struct nvme_rdma_ctrl *ctrl = container_of(work,
+				struct nvme_rdma_ctrl, delete_work);
+
+	nvme_remove_namespaces(&ctrl->ctrl);
+	nvme_uninit_ctrl(&ctrl->ctrl);
+	nvme_put_ctrl(&ctrl->ctrl);
+}
+
+static void nvme_rdma_reset_ctrl_work(struct work_struct *work)
+{
+	struct nvme_rdma_ctrl *ctrl = container_of(work,
+					struct nvme_rdma_ctrl, reset_work);
+	int ret;
+	bool changed;
+
+	nvme_rdma_shutdown_ctrl(ctrl);
+
+	ret = nvme_rdma_configure_admin_queue(ctrl);
+	if (ret) {
+		/* ctrl is already shutdown, just remove the ctrl */
+		INIT_WORK(&ctrl->delete_work, nvme_rdma_remove_ctrl_work);
+		goto del_dead_ctrl;
+	}
+
+	if (ctrl->queue_count > 1) {
+		ret = blk_mq_reinit_tagset(&ctrl->tag_set);
+		if (ret)
+			goto del_dead_ctrl;
+
+		ret = nvme_rdma_init_io_queues(ctrl);
+		if (ret)
+			goto del_dead_ctrl;
+
+		ret = nvme_rdma_connect_io_queues(ctrl);
+		if (ret)
+			goto del_dead_ctrl;
+	}
+
+	changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
+	WARN_ON_ONCE(!changed);
+
+	if (ctrl->queue_count > 1) {
+		nvme_start_queues(&ctrl->ctrl);
+		nvme_queue_scan(&ctrl->ctrl);
+	}
+
+	return;
+
+del_dead_ctrl:
+	/* Deleting this dead controller... */
+	dev_warn(ctrl->ctrl.device, "Removing after reset failure\n");
+	WARN_ON(!queue_work(nvme_rdma_wq, &ctrl->delete_work));
+}
+
+static int nvme_rdma_reset_ctrl(struct nvme_ctrl *nctrl)
+{
+	struct nvme_rdma_ctrl *ctrl = to_rdma_ctrl(nctrl);
+
+	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_RESETTING))
+		return -EBUSY;
+
+	if (!queue_work(nvme_rdma_wq, &ctrl->reset_work))
+		return -EBUSY;
+
+	flush_work(&ctrl->reset_work);
+
+	return 0;
+}
+
+static const struct nvme_ctrl_ops nvme_rdma_ctrl_ops = {
+	.name			= "rdma",
+	.module			= THIS_MODULE,
+	.is_fabrics		= true,
+	.reg_read32		= nvmf_reg_read32,
+	.reg_read64		= nvmf_reg_read64,
+	.reg_write32		= nvmf_reg_write32,
+	.reset_ctrl		= nvme_rdma_reset_ctrl,
+	.free_ctrl		= nvme_rdma_free_ctrl,
+	.submit_async_event	= nvme_rdma_submit_async_event,
+	.delete_ctrl		= nvme_rdma_del_ctrl,
+	.get_subsysnqn		= nvmf_get_subsysnqn,
+	.get_address		= nvmf_get_address,
+};
+
+static int nvme_rdma_create_io_queues(struct nvme_rdma_ctrl *ctrl)
+{
+	struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;
+	int ret;
+
+	ret = nvme_set_queue_count(&ctrl->ctrl, &opts->nr_io_queues);
+	if (ret)
+		return ret;
+
+	ctrl->queue_count = opts->nr_io_queues + 1;
+	if (ctrl->queue_count < 2)
+		return 0;
+
+	dev_info(ctrl->ctrl.device,
+		"creating %d I/O queues.\n", opts->nr_io_queues);
+
+	ret = nvme_rdma_init_io_queues(ctrl);
+	if (ret)
+		return ret;
+
+	/*
+	 * We need a reference on the device as long as the tag_set is alive,
+	 * as the MRs in the request structures need a valid ib_device.
+	 */
+	ret = -EINVAL;
+	if (!nvme_rdma_dev_get(ctrl->device))
+		goto out_free_io_queues;
+
+	memset(&ctrl->tag_set, 0, sizeof(ctrl->tag_set));
+	ctrl->tag_set.ops = &nvme_rdma_mq_ops;
+	ctrl->tag_set.queue_depth = ctrl->ctrl.sqsize;
+	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_rdma_request) +
+		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;
+
+	ret = blk_mq_alloc_tag_set(&ctrl->tag_set);
+	if (ret)
+		goto out_put_dev;
+	ctrl->ctrl.tagset = &ctrl->tag_set;
+
+	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_tag_set;
+	}
+
+	ret = nvme_rdma_connect_io_queues(ctrl);
+	if (ret)
+		goto out_cleanup_connect_q;
+
+	return 0;
+
+out_cleanup_connect_q:
+	blk_cleanup_queue(ctrl->ctrl.connect_q);
+out_free_tag_set:
+	blk_mq_free_tag_set(&ctrl->tag_set);
+out_put_dev:
+	nvme_rdma_dev_put(ctrl->device);
+out_free_io_queues:
+	nvme_rdma_free_io_queues(ctrl);
+	return ret;
+}
+
+static int nvme_rdma_parse_ipaddr(struct sockaddr_in *in_addr, char *p)
+{
+	u8 *addr = (u8 *)&in_addr->sin_addr.s_addr;
+	size_t buflen = strlen(p);
+
+	/* XXX: handle IPv6 addresses */
+
+	if (buflen > INET_ADDRSTRLEN)
+		return -EINVAL;
+	if (in4_pton(p, buflen, addr, '\0', NULL) == 0)
+		return -EINVAL;
+	in_addr->sin_family = AF_INET;
+	return 0;
+}
+
+static struct nvme_ctrl *nvme_rdma_create_ctrl(struct device *dev,
+		struct nvmf_ctrl_options *opts)
+{
+	struct nvme_rdma_ctrl *ctrl;
+	int ret;
+	bool changed;
+
+	ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
+	if (!ctrl)
+		return ERR_PTR(-ENOMEM);
+	ctrl->ctrl.opts = opts;
+	INIT_LIST_HEAD(&ctrl->list);
+
+	ret = nvme_rdma_parse_ipaddr(&ctrl->addr_in, opts->traddr);
+	if (ret) {
+		pr_err("malformed IP address passed: %s\n", opts->traddr);
+		goto out_free_ctrl;
+	}
+
+	if (opts->mask & NVMF_OPT_TRSVCID) {
+		u16 port;
+
+		ret = kstrtou16(opts->trsvcid, 0, &port);
+		if (ret)
+			goto out_free_ctrl;
+
+		ctrl->addr_in.sin_port = cpu_to_be16(port);
+	} else {
+		ctrl->addr_in.sin_port = cpu_to_be16(NVME_RDMA_IP_PORT);
+	}
+
+	ret = nvme_init_ctrl(&ctrl->ctrl, dev, &nvme_rdma_ctrl_ops,
+				0 /* no quirks, we're perfect! */);
+	if (ret)
+		goto out_free_ctrl;
+
+	ctrl->reconnect_delay = opts->reconnect_delay;
+	INIT_DELAYED_WORK(&ctrl->reconnect_work,
+			nvme_rdma_reconnect_ctrl_work);
+	INIT_WORK(&ctrl->err_work, nvme_rdma_error_recovery_work);
+	INIT_WORK(&ctrl->delete_work, nvme_rdma_del_ctrl_work);
+	INIT_WORK(&ctrl->reset_work, nvme_rdma_reset_ctrl_work);
+	spin_lock_init(&ctrl->lock);
+
+	ctrl->queue_count = opts->nr_io_queues + 1; /* +1 for admin queue */
+	ctrl->ctrl.sqsize = opts->queue_size;
+	ctrl->tl_retry_count = opts->tl_retry_count;
+	ctrl->ctrl.kato = opts->kato;
+
+	ret = -ENOMEM;
+	ctrl->queues = kcalloc(ctrl->queue_count, sizeof(*ctrl->queues),
+				GFP_KERNEL);
+	if (!ctrl->queues)
+		goto out_uninit_ctrl;
+
+	ret = nvme_rdma_configure_admin_queue(ctrl);
+	if (ret)
+		goto out_kfree_queues;
+
+	/* sanity check icdoff */
+	if (ctrl->ctrl.icdoff) {
+		dev_err(ctrl->ctrl.device, "icdoff is not supported!\n");
+		goto out_remove_admin_queue;
+	}
+
+	/* sanity check keyed sgls */
+	if (!(ctrl->ctrl.sgls & (1 << 20))) {
+		dev_err(ctrl->ctrl.device, "Mandatory keyed sgls are not support\n");
+		goto out_remove_admin_queue;
+	}
+
+	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_rdma_create_io_queues(ctrl);
+		if (ret)
+			goto out_remove_admin_queue;
+	}
+
+	changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
+	WARN_ON_ONCE(!changed);
+
+	dev_info(ctrl->ctrl.device, "new ctrl: NQN \"%s\", addr %pISp\n",
+		ctrl->ctrl.opts->subsysnqn, &ctrl->addr);
+
+	kref_get(&ctrl->ctrl.kref);
+
+	mutex_lock(&nvme_rdma_ctrl_mutex);
+	list_add_tail(&ctrl->list, &nvme_rdma_ctrl_list);
+	mutex_unlock(&nvme_rdma_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_stop_keep_alive(&ctrl->ctrl);
+	nvme_rdma_destroy_admin_queue(ctrl);
+out_kfree_queues:
+	kfree(ctrl->queues);
+out_uninit_ctrl:
+	nvme_uninit_ctrl(&ctrl->ctrl);
+	nvme_put_ctrl(&ctrl->ctrl);
+	if (ret > 0)
+		ret = -EIO;
+	return ERR_PTR(ret);
+out_free_ctrl:
+	kfree(ctrl);
+	return ERR_PTR(ret);
+}
+
+static struct nvmf_transport_ops nvme_rdma_transport = {
+	.name		= "rdma",
+	.required_opts	= NVMF_OPT_TRADDR,
+	.allowed_opts	= NVMF_OPT_TRSVCID | NVMF_OPT_TL_RETRY_COUNT |
+			  NVMF_OPT_RECONNECT_DELAY,
+	.create_ctrl	= nvme_rdma_create_ctrl,
+};
+
+static int __init nvme_rdma_init_module(void)
+{
+	nvme_rdma_wq = create_workqueue("nvme_rdma_wq");
+	if (!nvme_rdma_wq)
+		return -ENOMEM;
+
+	nvmf_register_transport(&nvme_rdma_transport);
+	return 0;
+}
+
+static void __exit nvme_rdma_cleanup_module(void)
+{
+	struct nvme_rdma_ctrl *ctrl;
+
+	nvmf_unregister_transport(&nvme_rdma_transport);
+
+	mutex_lock(&nvme_rdma_ctrl_mutex);
+	list_for_each_entry(ctrl, &nvme_rdma_ctrl_list, list)
+		__nvme_rdma_del_ctrl(ctrl);
+	mutex_unlock(&nvme_rdma_ctrl_mutex);
+
+	destroy_workqueue(nvme_rdma_wq);
+}
+
+module_init(nvme_rdma_init_module);
+module_exit(nvme_rdma_cleanup_module);
+
+MODULE_LICENSE("GPL v2");