nvmet-rdma: add a NVMe over Fabrics RDMA target driver

This patch implements the RDMA transport for the NVMe over Fabrics target,
which allows exporting NVMe over Fabrics functionality over RDMA fabrics
(Infiniband, RoCE, iWARP).

All NVMe logic is in the generic target and this module just provides a
small glue between it and the generic code in the RDMA subsystem.

Signed-off-by: Armen Baloyan <armenx.baloyan@intel.com>,
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, 1460 insertions, 0 deletions

diff --git a/drivers/nvme/target/Kconfig b/drivers/nvme/target/Kconfig
index 6bbd7890c3ad..0be9e3d4c352 100644
--- a/drivers/nvme/target/Kconfig
+++ b/drivers/nvme/target/Kconfig
@@ -25,3 +25,13 @@ config NVME_TARGET_LOOP
 	  to test NVMe host and target side features.
 
 	  If unsure, say N.
+
+config NVME_TARGET_RDMA
+	tristate "NVMe over Fabrics RDMA target support"
+	depends on INFINIBAND
+	select NVME_TARGET
+	help
+	  This enables the NVMe RDMA target support, which allows exporting NVMe
+	  devices over RDMA.
+
+	  If unsure, say N.
diff --git a/drivers/nvme/target/Makefile b/drivers/nvme/target/Makefile
index e49ba60756d4..b7a06232c9da 100644
--- a/drivers/nvme/target/Makefile
+++ b/drivers/nvme/target/Makefile
@@ -1,7 +1,9 @@
 
 obj-$(CONFIG_NVME_TARGET)		+= nvmet.o
 obj-$(CONFIG_NVME_TARGET_LOOP)		+= nvme-loop.o
+obj-$(CONFIG_NVME_TARGET_RDMA)		+= nvmet-rdma.o
 
 nvmet-y		+= core.o configfs.o admin-cmd.o io-cmd.o fabrics-cmd.o \
 			discovery.o
 nvme-loop-y	+= loop.o
+nvmet-rdma-y	+= rdma.o
diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
new file mode 100644
index 000000000000..e06d504bdf0c
--- /dev/null
+++ b/drivers/nvme/target/rdma.c
@@ -0,0 +1,1448 @@
+/*
+ * NVMe over Fabrics RDMA target.
+ * 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/atomic.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/nvme.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/wait.h>
+#include <linux/inet.h>
+#include <asm/unaligned.h>
+
+#include <rdma/ib_verbs.h>
+#include <rdma/rdma_cm.h>
+#include <rdma/rw.h>
+
+#include <linux/nvme-rdma.h>
+#include "nvmet.h"
+
+/*
+ * We allow up to a page of inline data to go with the SQE
+ */
+#define NVMET_RDMA_INLINE_DATA_SIZE	PAGE_SIZE
+
+struct nvmet_rdma_cmd {
+	struct ib_sge		sge[2];
+	struct ib_cqe		cqe;
+	struct ib_recv_wr	wr;
+	struct scatterlist	inline_sg;
+	struct page		*inline_page;
+	struct nvme_command     *nvme_cmd;
+	struct nvmet_rdma_queue	*queue;
+};
+
+enum {
+	NVMET_RDMA_REQ_INLINE_DATA	= (1 << 0),
+	NVMET_RDMA_REQ_INVALIDATE_RKEY	= (1 << 1),
+};
+
+struct nvmet_rdma_rsp {
+	struct ib_sge		send_sge;
+	struct ib_cqe		send_cqe;
+	struct ib_send_wr	send_wr;
+
+	struct nvmet_rdma_cmd	*cmd;
+	struct nvmet_rdma_queue	*queue;
+
+	struct ib_cqe		read_cqe;
+	struct rdma_rw_ctx	rw;
+
+	struct nvmet_req	req;
+
+	u8			n_rdma;
+	u32			flags;
+	u32			invalidate_rkey;
+
+	struct list_head	wait_list;
+	struct list_head	free_list;
+};
+
+enum nvmet_rdma_queue_state {
+	NVMET_RDMA_Q_CONNECTING,
+	NVMET_RDMA_Q_LIVE,
+	NVMET_RDMA_Q_DISCONNECTING,
+};
+
+struct nvmet_rdma_queue {
+	struct rdma_cm_id	*cm_id;
+	struct nvmet_port	*port;
+	struct ib_cq		*cq;
+	atomic_t		sq_wr_avail;
+	struct nvmet_rdma_device *dev;
+	spinlock_t		state_lock;
+	enum nvmet_rdma_queue_state state;
+	struct nvmet_cq		nvme_cq;
+	struct nvmet_sq		nvme_sq;
+
+	struct nvmet_rdma_rsp	*rsps;
+	struct list_head	free_rsps;
+	spinlock_t		rsps_lock;
+	struct nvmet_rdma_cmd	*cmds;
+
+	struct work_struct	release_work;
+	struct list_head	rsp_wait_list;
+	struct list_head	rsp_wr_wait_list;
+	spinlock_t		rsp_wr_wait_lock;
+
+	int			idx;
+	int			host_qid;
+	int			recv_queue_size;
+	int			send_queue_size;
+
+	struct list_head	queue_list;
+};
+
+struct nvmet_rdma_device {
+	struct ib_device	*device;
+	struct ib_pd		*pd;
+	struct ib_srq		*srq;
+	struct nvmet_rdma_cmd	*srq_cmds;
+	size_t			srq_size;
+	struct kref		ref;
+	struct list_head	entry;
+};
+
+static bool nvmet_rdma_use_srq;
+module_param_named(use_srq, nvmet_rdma_use_srq, bool, 0444);
+MODULE_PARM_DESC(use_srq, "Use shared receive queue.");
+
+static DEFINE_IDA(nvmet_rdma_queue_ida);
+static LIST_HEAD(nvmet_rdma_queue_list);
+static DEFINE_MUTEX(nvmet_rdma_queue_mutex);
+
+static LIST_HEAD(device_list);
+static DEFINE_MUTEX(device_list_mutex);
+
+static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp);
+static void nvmet_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc);
+static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc);
+static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc);
+static void nvmet_rdma_qp_event(struct ib_event *event, void *priv);
+static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue);
+
+static struct nvmet_fabrics_ops nvmet_rdma_ops;
+
+/* XXX: really should move to a generic header sooner or later.. */
+static inline u32 get_unaligned_le24(const u8 *p)
+{
+	return (u32)p[0] | (u32)p[1] << 8 | (u32)p[2] << 16;
+}
+
+static inline bool nvmet_rdma_need_data_in(struct nvmet_rdma_rsp *rsp)
+{
+	return nvme_is_write(rsp->req.cmd) &&
+		rsp->req.data_len &&
+		!(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
+}
+
+static inline bool nvmet_rdma_need_data_out(struct nvmet_rdma_rsp *rsp)
+{
+	return !nvme_is_write(rsp->req.cmd) &&
+		rsp->req.data_len &&
+		!rsp->req.rsp->status &&
+		!(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
+}
+
+static inline struct nvmet_rdma_rsp *
+nvmet_rdma_get_rsp(struct nvmet_rdma_queue *queue)
+{
+	struct nvmet_rdma_rsp *rsp;
+	unsigned long flags;
+
+	spin_lock_irqsave(&queue->rsps_lock, flags);
+	rsp = list_first_entry(&queue->free_rsps,
+				struct nvmet_rdma_rsp, free_list);
+	list_del(&rsp->free_list);
+	spin_unlock_irqrestore(&queue->rsps_lock, flags);
+
+	return rsp;
+}
+
+static inline void
+nvmet_rdma_put_rsp(struct nvmet_rdma_rsp *rsp)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&rsp->queue->rsps_lock, flags);
+	list_add_tail(&rsp->free_list, &rsp->queue->free_rsps);
+	spin_unlock_irqrestore(&rsp->queue->rsps_lock, flags);
+}
+
+static void nvmet_rdma_free_sgl(struct scatterlist *sgl, unsigned int nents)
+{
+	struct scatterlist *sg;
+	int count;
+
+	if (!sgl || !nents)
+		return;
+
+	for_each_sg(sgl, sg, nents, count)
+		__free_page(sg_page(sg));
+	kfree(sgl);
+}
+
+static int nvmet_rdma_alloc_sgl(struct scatterlist **sgl, unsigned int *nents,
+		u32 length)
+{
+	struct scatterlist *sg;
+	struct page *page;
+	unsigned int nent;
+	int i = 0;
+
+	nent = DIV_ROUND_UP(length, PAGE_SIZE);
+	sg = kmalloc_array(nent, sizeof(struct scatterlist), GFP_KERNEL);
+	if (!sg)
+		goto out;
+
+	sg_init_table(sg, nent);
+
+	while (length) {
+		u32 page_len = min_t(u32, length, PAGE_SIZE);
+
+		page = alloc_page(GFP_KERNEL);
+		if (!page)
+			goto out_free_pages;
+
+		sg_set_page(&sg[i], page, page_len, 0);
+		length -= page_len;
+		i++;
+	}
+	*sgl = sg;
+	*nents = nent;
+	return 0;
+
+out_free_pages:
+	while (i > 0) {
+		i--;
+		__free_page(sg_page(&sg[i]));
+	}
+	kfree(sg);
+out:
+	return NVME_SC_INTERNAL;
+}
+
+static int nvmet_rdma_alloc_cmd(struct nvmet_rdma_device *ndev,
+			struct nvmet_rdma_cmd *c, bool admin)
+{
+	/* NVMe command / RDMA RECV */
+	c->nvme_cmd = kmalloc(sizeof(*c->nvme_cmd), GFP_KERNEL);
+	if (!c->nvme_cmd)
+		goto out;
+
+	c->sge[0].addr = ib_dma_map_single(ndev->device, c->nvme_cmd,
+			sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
+	if (ib_dma_mapping_error(ndev->device, c->sge[0].addr))
+		goto out_free_cmd;
+
+	c->sge[0].length = sizeof(*c->nvme_cmd);
+	c->sge[0].lkey = ndev->pd->local_dma_lkey;
+
+	if (!admin) {
+		c->inline_page = alloc_pages(GFP_KERNEL,
+				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
+		if (!c->inline_page)
+			goto out_unmap_cmd;
+		c->sge[1].addr = ib_dma_map_page(ndev->device,
+				c->inline_page, 0, NVMET_RDMA_INLINE_DATA_SIZE,
+				DMA_FROM_DEVICE);
+		if (ib_dma_mapping_error(ndev->device, c->sge[1].addr))
+			goto out_free_inline_page;
+		c->sge[1].length = NVMET_RDMA_INLINE_DATA_SIZE;
+		c->sge[1].lkey = ndev->pd->local_dma_lkey;
+	}
+
+	c->cqe.done = nvmet_rdma_recv_done;
+
+	c->wr.wr_cqe = &c->cqe;
+	c->wr.sg_list = c->sge;
+	c->wr.num_sge = admin ? 1 : 2;
+
+	return 0;
+
+out_free_inline_page:
+	if (!admin) {
+		__free_pages(c->inline_page,
+				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
+	}
+out_unmap_cmd:
+	ib_dma_unmap_single(ndev->device, c->sge[0].addr,
+			sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
+out_free_cmd:
+	kfree(c->nvme_cmd);
+
+out:
+	return -ENOMEM;
+}
+
+static void nvmet_rdma_free_cmd(struct nvmet_rdma_device *ndev,
+		struct nvmet_rdma_cmd *c, bool admin)
+{
+	if (!admin) {
+		ib_dma_unmap_page(ndev->device, c->sge[1].addr,
+				NVMET_RDMA_INLINE_DATA_SIZE, DMA_FROM_DEVICE);
+		__free_pages(c->inline_page,
+				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
+	}
+	ib_dma_unmap_single(ndev->device, c->sge[0].addr,
+				sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
+	kfree(c->nvme_cmd);
+}
+
+static struct nvmet_rdma_cmd *
+nvmet_rdma_alloc_cmds(struct nvmet_rdma_device *ndev,
+		int nr_cmds, bool admin)
+{
+	struct nvmet_rdma_cmd *cmds;
+	int ret = -EINVAL, i;
+
+	cmds = kcalloc(nr_cmds, sizeof(struct nvmet_rdma_cmd), GFP_KERNEL);
+	if (!cmds)
+		goto out;
+
+	for (i = 0; i < nr_cmds; i++) {
+		ret = nvmet_rdma_alloc_cmd(ndev, cmds + i, admin);
+		if (ret)
+			goto out_free;
+	}
+
+	return cmds;
+
+out_free:
+	while (--i >= 0)
+		nvmet_rdma_free_cmd(ndev, cmds + i, admin);
+	kfree(cmds);
+out:
+	return ERR_PTR(ret);
+}
+
+static void nvmet_rdma_free_cmds(struct nvmet_rdma_device *ndev,
+		struct nvmet_rdma_cmd *cmds, int nr_cmds, bool admin)
+{
+	int i;
+
+	for (i = 0; i < nr_cmds; i++)
+		nvmet_rdma_free_cmd(ndev, cmds + i, admin);
+	kfree(cmds);
+}
+
+static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
+		struct nvmet_rdma_rsp *r)
+{
+	/* NVMe CQE / RDMA SEND */
+	r->req.rsp = kmalloc(sizeof(*r->req.rsp), GFP_KERNEL);
+	if (!r->req.rsp)
+		goto out;
+
+	r->send_sge.addr = ib_dma_map_single(ndev->device, r->req.rsp,
+			sizeof(*r->req.rsp), DMA_TO_DEVICE);
+	if (ib_dma_mapping_error(ndev->device, r->send_sge.addr))
+		goto out_free_rsp;
+
+	r->send_sge.length = sizeof(*r->req.rsp);
+	r->send_sge.lkey = ndev->pd->local_dma_lkey;
+
+	r->send_cqe.done = nvmet_rdma_send_done;
+
+	r->send_wr.wr_cqe = &r->send_cqe;
+	r->send_wr.sg_list = &r->send_sge;
+	r->send_wr.num_sge = 1;
+	r->send_wr.send_flags = IB_SEND_SIGNALED;
+
+	/* Data In / RDMA READ */
+	r->read_cqe.done = nvmet_rdma_read_data_done;
+	return 0;
+
+out_free_rsp:
+	kfree(r->req.rsp);
+out:
+	return -ENOMEM;
+}
+
+static void nvmet_rdma_free_rsp(struct nvmet_rdma_device *ndev,
+		struct nvmet_rdma_rsp *r)
+{
+	ib_dma_unmap_single(ndev->device, r->send_sge.addr,
+				sizeof(*r->req.rsp), DMA_TO_DEVICE);
+	kfree(r->req.rsp);
+}
+
+static int
+nvmet_rdma_alloc_rsps(struct nvmet_rdma_queue *queue)
+{
+	struct nvmet_rdma_device *ndev = queue->dev;
+	int nr_rsps = queue->recv_queue_size * 2;
+	int ret = -EINVAL, i;
+
+	queue->rsps = kcalloc(nr_rsps, sizeof(struct nvmet_rdma_rsp),
+			GFP_KERNEL);
+	if (!queue->rsps)
+		goto out;
+
+	for (i = 0; i < nr_rsps; i++) {
+		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
+
+		ret = nvmet_rdma_alloc_rsp(ndev, rsp);
+		if (ret)
+			goto out_free;
+
+		list_add_tail(&rsp->free_list, &queue->free_rsps);
+	}
+
+	return 0;
+
+out_free:
+	while (--i >= 0) {
+		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
+
+		list_del(&rsp->free_list);
+		nvmet_rdma_free_rsp(ndev, rsp);
+	}
+	kfree(queue->rsps);
+out:
+	return ret;
+}
+
+static void nvmet_rdma_free_rsps(struct nvmet_rdma_queue *queue)
+{
+	struct nvmet_rdma_device *ndev = queue->dev;
+	int i, nr_rsps = queue->recv_queue_size * 2;
+
+	for (i = 0; i < nr_rsps; i++) {
+		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
+
+		list_del(&rsp->free_list);
+		nvmet_rdma_free_rsp(ndev, rsp);
+	}
+	kfree(queue->rsps);
+}
+
+static int nvmet_rdma_post_recv(struct nvmet_rdma_device *ndev,
+		struct nvmet_rdma_cmd *cmd)
+{
+	struct ib_recv_wr *bad_wr;
+
+	if (ndev->srq)
+		return ib_post_srq_recv(ndev->srq, &cmd->wr, &bad_wr);
+	return ib_post_recv(cmd->queue->cm_id->qp, &cmd->wr, &bad_wr);
+}
+
+static void nvmet_rdma_process_wr_wait_list(struct nvmet_rdma_queue *queue)
+{
+	spin_lock(&queue->rsp_wr_wait_lock);
+	while (!list_empty(&queue->rsp_wr_wait_list)) {
+		struct nvmet_rdma_rsp *rsp;
+		bool ret;
+
+		rsp = list_entry(queue->rsp_wr_wait_list.next,
+				struct nvmet_rdma_rsp, wait_list);
+		list_del(&rsp->wait_list);
+
+		spin_unlock(&queue->rsp_wr_wait_lock);
+		ret = nvmet_rdma_execute_command(rsp);
+		spin_lock(&queue->rsp_wr_wait_lock);
+
+		if (!ret) {
+			list_add(&rsp->wait_list, &queue->rsp_wr_wait_list);
+			break;
+		}
+	}
+	spin_unlock(&queue->rsp_wr_wait_lock);
+}
+
+
+static void nvmet_rdma_release_rsp(struct nvmet_rdma_rsp *rsp)
+{
+	struct nvmet_rdma_queue *queue = rsp->queue;
+
+	atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);
+
+	if (rsp->n_rdma) {
+		rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
+				queue->cm_id->port_num, rsp->req.sg,
+				rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
+	}
+
+	if (rsp->req.sg != &rsp->cmd->inline_sg)
+		nvmet_rdma_free_sgl(rsp->req.sg, rsp->req.sg_cnt);
+
+	if (unlikely(!list_empty_careful(&queue->rsp_wr_wait_list)))
+		nvmet_rdma_process_wr_wait_list(queue);
+
+	nvmet_rdma_put_rsp(rsp);
+}
+
+static void nvmet_rdma_error_comp(struct nvmet_rdma_queue *queue)
+{
+	if (queue->nvme_sq.ctrl) {
+		nvmet_ctrl_fatal_error(queue->nvme_sq.ctrl);
+	} else {
+		/*
+		 * we didn't setup the controller yet in case
+		 * of admin connect error, just disconnect and
+		 * cleanup the queue
+		 */
+		nvmet_rdma_queue_disconnect(queue);
+	}
+}
+
+static void nvmet_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct nvmet_rdma_rsp *rsp =
+		container_of(wc->wr_cqe, struct nvmet_rdma_rsp, send_cqe);
+
+	nvmet_rdma_release_rsp(rsp);
+
+	if (unlikely(wc->status != IB_WC_SUCCESS &&
+		     wc->status != IB_WC_WR_FLUSH_ERR)) {
+		pr_err("SEND for CQE 0x%p failed with status %s (%d).\n",
+			wc->wr_cqe, ib_wc_status_msg(wc->status), wc->status);
+		nvmet_rdma_error_comp(rsp->queue);
+	}
+}
+
+static void nvmet_rdma_queue_response(struct nvmet_req *req)
+{
+	struct nvmet_rdma_rsp *rsp =
+		container_of(req, struct nvmet_rdma_rsp, req);
+	struct rdma_cm_id *cm_id = rsp->queue->cm_id;
+	struct ib_send_wr *first_wr, *bad_wr;
+
+	if (rsp->flags & NVMET_RDMA_REQ_INVALIDATE_RKEY) {
+		rsp->send_wr.opcode = IB_WR_SEND_WITH_INV;
+		rsp->send_wr.ex.invalidate_rkey = rsp->invalidate_rkey;
+	} else {
+		rsp->send_wr.opcode = IB_WR_SEND;
+	}
+
+	if (nvmet_rdma_need_data_out(rsp))
+		first_wr = rdma_rw_ctx_wrs(&rsp->rw, cm_id->qp,
+				cm_id->port_num, NULL, &rsp->send_wr);
+	else
+		first_wr = &rsp->send_wr;
+
+	nvmet_rdma_post_recv(rsp->queue->dev, rsp->cmd);
+	if (ib_post_send(cm_id->qp, first_wr, &bad_wr)) {
+		pr_err("sending cmd response failed\n");
+		nvmet_rdma_release_rsp(rsp);
+	}
+}
+
+static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct nvmet_rdma_rsp *rsp =
+		container_of(wc->wr_cqe, struct nvmet_rdma_rsp, read_cqe);
+	struct nvmet_rdma_queue *queue = cq->cq_context;
+
+	WARN_ON(rsp->n_rdma <= 0);
+	atomic_add(rsp->n_rdma, &queue->sq_wr_avail);
+	rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
+			queue->cm_id->port_num, rsp->req.sg,
+			rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
+	rsp->n_rdma = 0;
+
+	if (unlikely(wc->status != IB_WC_SUCCESS)) {
+		nvmet_rdma_release_rsp(rsp);
+		if (wc->status != IB_WC_WR_FLUSH_ERR) {
+			pr_info("RDMA READ for CQE 0x%p failed with status %s (%d).\n",
+				wc->wr_cqe, ib_wc_status_msg(wc->status), wc->status);
+			nvmet_rdma_error_comp(queue);
+		}
+		return;
+	}
+
+	rsp->req.execute(&rsp->req);
+}
+
+static void nvmet_rdma_use_inline_sg(struct nvmet_rdma_rsp *rsp, u32 len,
+		u64 off)
+{
+	sg_init_table(&rsp->cmd->inline_sg, 1);
+	sg_set_page(&rsp->cmd->inline_sg, rsp->cmd->inline_page, len, off);
+	rsp->req.sg = &rsp->cmd->inline_sg;
+	rsp->req.sg_cnt = 1;
+}
+
+static u16 nvmet_rdma_map_sgl_inline(struct nvmet_rdma_rsp *rsp)
+{
+	struct nvme_sgl_desc *sgl = &rsp->req.cmd->common.dptr.sgl;
+	u64 off = le64_to_cpu(sgl->addr);
+	u32 len = le32_to_cpu(sgl->length);
+
+	if (!nvme_is_write(rsp->req.cmd))
+		return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+
+	if (off + len > NVMET_RDMA_INLINE_DATA_SIZE) {
+		pr_err("invalid inline data offset!\n");
+		return NVME_SC_SGL_INVALID_OFFSET | NVME_SC_DNR;
+	}
+
+	/* no data command? */
+	if (!len)
+		return 0;
+
+	nvmet_rdma_use_inline_sg(rsp, len, off);
+	rsp->flags |= NVMET_RDMA_REQ_INLINE_DATA;
+	return 0;
+}
+
+static u16 nvmet_rdma_map_sgl_keyed(struct nvmet_rdma_rsp *rsp,
+		struct nvme_keyed_sgl_desc *sgl, bool invalidate)
+{
+	struct rdma_cm_id *cm_id = rsp->queue->cm_id;
+	u64 addr = le64_to_cpu(sgl->addr);
+	u32 len = get_unaligned_le24(sgl->length);
+	u32 key = get_unaligned_le32(sgl->key);
+	int ret;
+	u16 status;
+
+	/* no data command? */
+	if (!len)
+		return 0;
+
+	/* use the already allocated data buffer if possible */
+	if (len <= NVMET_RDMA_INLINE_DATA_SIZE && rsp->queue->host_qid) {
+		nvmet_rdma_use_inline_sg(rsp, len, 0);
+	} else {
+		status = nvmet_rdma_alloc_sgl(&rsp->req.sg, &rsp->req.sg_cnt,
+				len);
+		if (status)
+			return status;
+	}
+
+	ret = rdma_rw_ctx_init(&rsp->rw, cm_id->qp, cm_id->port_num,
+			rsp->req.sg, rsp->req.sg_cnt, 0, addr, key,
+			nvmet_data_dir(&rsp->req));
+	if (ret < 0)
+		return NVME_SC_INTERNAL;
+	rsp->n_rdma += ret;
+
+	if (invalidate) {
+		rsp->invalidate_rkey = key;
+		rsp->flags |= NVMET_RDMA_REQ_INVALIDATE_RKEY;
+	}
+
+	return 0;
+}
+
+static u16 nvmet_rdma_map_sgl(struct nvmet_rdma_rsp *rsp)
+{
+	struct nvme_keyed_sgl_desc *sgl = &rsp->req.cmd->common.dptr.ksgl;
+
+	switch (sgl->type >> 4) {
+	case NVME_SGL_FMT_DATA_DESC:
+		switch (sgl->type & 0xf) {
+		case NVME_SGL_FMT_OFFSET:
+			return nvmet_rdma_map_sgl_inline(rsp);
+		default:
+			pr_err("invalid SGL subtype: %#x\n", sgl->type);
+			return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+		}
+	case NVME_KEY_SGL_FMT_DATA_DESC:
+		switch (sgl->type & 0xf) {
+		case NVME_SGL_FMT_ADDRESS | NVME_SGL_FMT_INVALIDATE:
+			return nvmet_rdma_map_sgl_keyed(rsp, sgl, true);
+		case NVME_SGL_FMT_ADDRESS:
+			return nvmet_rdma_map_sgl_keyed(rsp, sgl, false);
+		default:
+			pr_err("invalid SGL subtype: %#x\n", sgl->type);
+			return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+		}
+	default:
+		pr_err("invalid SGL type: %#x\n", sgl->type);
+		return NVME_SC_SGL_INVALID_TYPE | NVME_SC_DNR;
+	}
+}
+
+static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp)
+{
+	struct nvmet_rdma_queue *queue = rsp->queue;
+
+	if (unlikely(atomic_sub_return(1 + rsp->n_rdma,
+			&queue->sq_wr_avail) < 0)) {
+		pr_debug("IB send queue full (needed %d): queue %u cntlid %u\n",
+				1 + rsp->n_rdma, queue->idx,
+				queue->nvme_sq.ctrl->cntlid);
+		atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);
+		return false;
+	}
+
+	if (nvmet_rdma_need_data_in(rsp)) {
+		if (rdma_rw_ctx_post(&rsp->rw, queue->cm_id->qp,
+				queue->cm_id->port_num, &rsp->read_cqe, NULL))
+			nvmet_req_complete(&rsp->req, NVME_SC_DATA_XFER_ERROR);
+	} else {
+		rsp->req.execute(&rsp->req);
+	}
+
+	return true;
+}
+
+static void nvmet_rdma_handle_command(struct nvmet_rdma_queue *queue,
+		struct nvmet_rdma_rsp *cmd)
+{
+	u16 status;
+
+	cmd->queue = queue;
+	cmd->n_rdma = 0;
+	cmd->req.port = queue->port;
+
+	if (!nvmet_req_init(&cmd->req, &queue->nvme_cq,
+			&queue->nvme_sq, &nvmet_rdma_ops))
+		return;
+
+	status = nvmet_rdma_map_sgl(cmd);
+	if (status)
+		goto out_err;
+
+	if (unlikely(!nvmet_rdma_execute_command(cmd))) {
+		spin_lock(&queue->rsp_wr_wait_lock);
+		list_add_tail(&cmd->wait_list, &queue->rsp_wr_wait_list);
+		spin_unlock(&queue->rsp_wr_wait_lock);
+	}
+
+	return;
+
+out_err:
+	nvmet_req_complete(&cmd->req, status);
+}
+
+static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+	struct nvmet_rdma_cmd *cmd =
+		container_of(wc->wr_cqe, struct nvmet_rdma_cmd, cqe);
+	struct nvmet_rdma_queue *queue = cq->cq_context;
+	struct nvmet_rdma_rsp *rsp;
+
+	if (unlikely(wc->status != IB_WC_SUCCESS)) {
+		if (wc->status != IB_WC_WR_FLUSH_ERR) {
+			pr_err("RECV for CQE 0x%p failed with status %s (%d)\n",
+				wc->wr_cqe, ib_wc_status_msg(wc->status),
+				wc->status);
+			nvmet_rdma_error_comp(queue);
+		}
+		return;
+	}
+
+	if (unlikely(wc->byte_len < sizeof(struct nvme_command))) {
+		pr_err("Ctrl Fatal Error: capsule size less than 64 bytes\n");
+		nvmet_rdma_error_comp(queue);
+		return;
+	}
+
+	cmd->queue = queue;
+	rsp = nvmet_rdma_get_rsp(queue);
+	rsp->cmd = cmd;
+	rsp->flags = 0;
+	rsp->req.cmd = cmd->nvme_cmd;
+
+	if (unlikely(queue->state != NVMET_RDMA_Q_LIVE)) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&queue->state_lock, flags);
+		if (queue->state == NVMET_RDMA_Q_CONNECTING)
+			list_add_tail(&rsp->wait_list, &queue->rsp_wait_list);
+		else
+			nvmet_rdma_put_rsp(rsp);
+		spin_unlock_irqrestore(&queue->state_lock, flags);
+		return;
+	}
+
+	nvmet_rdma_handle_command(queue, rsp);
+}
+
+static void nvmet_rdma_destroy_srq(struct nvmet_rdma_device *ndev)
+{
+	if (!ndev->srq)
+		return;
+
+	nvmet_rdma_free_cmds(ndev, ndev->srq_cmds, ndev->srq_size, false);
+	ib_destroy_srq(ndev->srq);
+}
+
+static int nvmet_rdma_init_srq(struct nvmet_rdma_device *ndev)
+{
+	struct ib_srq_init_attr srq_attr = { NULL, };
+	struct ib_srq *srq;
+	size_t srq_size;
+	int ret, i;
+
+	srq_size = 4095;	/* XXX: tune */
+
+	srq_attr.attr.max_wr = srq_size;
+	srq_attr.attr.max_sge = 2;
+	srq_attr.attr.srq_limit = 0;
+	srq_attr.srq_type = IB_SRQT_BASIC;
+	srq = ib_create_srq(ndev->pd, &srq_attr);
+	if (IS_ERR(srq)) {
+		/*
+		 * If SRQs aren't supported we just go ahead and use normal
+		 * non-shared receive queues.
+		 */
+		pr_info("SRQ requested but not supported.\n");
+		return 0;
+	}
+
+	ndev->srq_cmds = nvmet_rdma_alloc_cmds(ndev, srq_size, false);
+	if (IS_ERR(ndev->srq_cmds)) {
+		ret = PTR_ERR(ndev->srq_cmds);
+		goto out_destroy_srq;
+	}
+
+	ndev->srq = srq;
+	ndev->srq_size = srq_size;
+
+	for (i = 0; i < srq_size; i++)
+		nvmet_rdma_post_recv(ndev, &ndev->srq_cmds[i]);
+
+	return 0;
+
+out_destroy_srq:
+	ib_destroy_srq(srq);
+	return ret;
+}
+
+static void nvmet_rdma_free_dev(struct kref *ref)
+{
+	struct nvmet_rdma_device *ndev =
+		container_of(ref, struct nvmet_rdma_device, ref);
+
+	mutex_lock(&device_list_mutex);
+	list_del(&ndev->entry);
+	mutex_unlock(&device_list_mutex);
+
+	nvmet_rdma_destroy_srq(ndev);
+	ib_dealloc_pd(ndev->pd);
+
+	kfree(ndev);
+}
+
+static struct nvmet_rdma_device *
+nvmet_rdma_find_get_device(struct rdma_cm_id *cm_id)
+{
+	struct nvmet_rdma_device *ndev;
+	int ret;
+
+	mutex_lock(&device_list_mutex);
+	list_for_each_entry(ndev, &device_list, entry) {
+		if (ndev->device->node_guid == cm_id->device->node_guid &&
+		    kref_get_unless_zero(&ndev->ref))
+			goto out_unlock;
+	}
+
+	ndev = kzalloc(sizeof(*ndev), GFP_KERNEL);
+	if (!ndev)
+		goto out_err;
+
+	ndev->device = cm_id->device;
+	kref_init(&ndev->ref);
+
+	ndev->pd = ib_alloc_pd(ndev->device);
+	if (IS_ERR(ndev->pd))
+		goto out_free_dev;
+
+	if (nvmet_rdma_use_srq) {
+		ret = nvmet_rdma_init_srq(ndev);
+		if (ret)
+			goto out_free_pd;
+	}
+
+	list_add(&ndev->entry, &device_list);
+out_unlock:
+	mutex_unlock(&device_list_mutex);
+	pr_debug("added %s.\n", ndev->device->name);
+	return ndev;
+
+out_free_pd:
+	ib_dealloc_pd(ndev->pd);
+out_free_dev:
+	kfree(ndev);
+out_err:
+	mutex_unlock(&device_list_mutex);
+	return NULL;
+}
+
+static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
+{
+	struct ib_qp_init_attr qp_attr;
+	struct nvmet_rdma_device *ndev = queue->dev;
+	int comp_vector, nr_cqe, ret, i;
+
+	/*
+	 * Spread the io queues across completion vectors,
+	 * but still keep all admin queues on vector 0.
+	 */
+	comp_vector = !queue->host_qid ? 0 :
+		queue->idx % ndev->device->num_comp_vectors;
+
+	/*
+	 * Reserve CQ slots for RECV + RDMA_READ/RDMA_WRITE + RDMA_SEND.
+	 */
+	nr_cqe = queue->recv_queue_size + 2 * queue->send_queue_size;
+
+	queue->cq = ib_alloc_cq(ndev->device, queue,
+			nr_cqe + 1, comp_vector,
+			IB_POLL_WORKQUEUE);
+	if (IS_ERR(queue->cq)) {
+		ret = PTR_ERR(queue->cq);
+		pr_err("failed to create CQ cqe= %d ret= %d\n",
+		       nr_cqe + 1, ret);
+		goto out;
+	}
+
+	memset(&qp_attr, 0, sizeof(qp_attr));
+	qp_attr.qp_context = queue;
+	qp_attr.event_handler = nvmet_rdma_qp_event;
+	qp_attr.send_cq = queue->cq;
+	qp_attr.recv_cq = queue->cq;
+	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
+	qp_attr.qp_type = IB_QPT_RC;
+	/* +1 for drain */
+	qp_attr.cap.max_send_wr = queue->send_queue_size + 1;
+	qp_attr.cap.max_rdma_ctxs = queue->send_queue_size;
+	qp_attr.cap.max_send_sge = max(ndev->device->attrs.max_sge_rd,
+					ndev->device->attrs.max_sge);
+
+	if (ndev->srq) {
+		qp_attr.srq = ndev->srq;
+	} else {
+		/* +1 for drain */
+		qp_attr.cap.max_recv_wr = 1 + queue->recv_queue_size;
+		qp_attr.cap.max_recv_sge = 2;
+	}
+
+	ret = rdma_create_qp(queue->cm_id, ndev->pd, &qp_attr);
+	if (ret) {
+		pr_err("failed to create_qp ret= %d\n", ret);
+		goto err_destroy_cq;
+	}
+
+	atomic_set(&queue->sq_wr_avail, qp_attr.cap.max_send_wr);
+
+	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
+		 __func__, queue->cq->cqe, qp_attr.cap.max_send_sge,
+		 qp_attr.cap.max_send_wr, queue->cm_id);
+
+	if (!ndev->srq) {
+		for (i = 0; i < queue->recv_queue_size; i++) {
+			queue->cmds[i].queue = queue;
+			nvmet_rdma_post_recv(ndev, &queue->cmds[i]);
+		}
+	}
+
+out:
+	return ret;
+
+err_destroy_cq:
+	ib_free_cq(queue->cq);
+	goto out;
+}
+
+static void nvmet_rdma_destroy_queue_ib(struct nvmet_rdma_queue *queue)
+{
+	rdma_destroy_qp(queue->cm_id);
+	ib_free_cq(queue->cq);
+}
+
+static void nvmet_rdma_free_queue(struct nvmet_rdma_queue *queue)
+{
+	pr_info("freeing queue %d\n", queue->idx);
+
+	nvmet_sq_destroy(&queue->nvme_sq);
+
+	nvmet_rdma_destroy_queue_ib(queue);
+	if (!queue->dev->srq) {
+		nvmet_rdma_free_cmds(queue->dev, queue->cmds,
+				queue->recv_queue_size,
+				!queue->host_qid);
+	}
+	nvmet_rdma_free_rsps(queue);
+	ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
+	kfree(queue);
+}
+
+static void nvmet_rdma_release_queue_work(struct work_struct *w)
+{
+	struct nvmet_rdma_queue *queue =
+		container_of(w, struct nvmet_rdma_queue, release_work);
+	struct rdma_cm_id *cm_id = queue->cm_id;
+	struct nvmet_rdma_device *dev = queue->dev;
+
+	nvmet_rdma_free_queue(queue);
+	rdma_destroy_id(cm_id);
+	kref_put(&dev->ref, nvmet_rdma_free_dev);
+}
+
+static int
+nvmet_rdma_parse_cm_connect_req(struct rdma_conn_param *conn,
+				struct nvmet_rdma_queue *queue)
+{
+	struct nvme_rdma_cm_req *req;
+
+	req = (struct nvme_rdma_cm_req *)conn->private_data;
+	if (!req || conn->private_data_len == 0)
+		return NVME_RDMA_CM_INVALID_LEN;
+
+	if (le16_to_cpu(req->recfmt) != NVME_RDMA_CM_FMT_1_0)
+		return NVME_RDMA_CM_INVALID_RECFMT;
+
+	queue->host_qid = le16_to_cpu(req->qid);
+
+	/*
+	 * req->hsqsize corresponds to our recv queue size
+	 * req->hrqsize corresponds to our send queue size
+	 */
+	queue->recv_queue_size = le16_to_cpu(req->hsqsize);
+	queue->send_queue_size = le16_to_cpu(req->hrqsize);
+
+	if (!queue->host_qid && queue->recv_queue_size > NVMF_AQ_DEPTH)
+		return NVME_RDMA_CM_INVALID_HSQSIZE;
+
+	/* XXX: Should we enforce some kind of max for IO queues? */
+
+	return 0;
+}
+
+static int nvmet_rdma_cm_reject(struct rdma_cm_id *cm_id,
+				enum nvme_rdma_cm_status status)
+{
+	struct nvme_rdma_cm_rej rej;
+
+	rej.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
+	rej.sts = cpu_to_le16(status);
+
+	return rdma_reject(cm_id, (void *)&rej, sizeof(rej));
+}
+
+static struct nvmet_rdma_queue *
+nvmet_rdma_alloc_queue(struct nvmet_rdma_device *ndev,
+		struct rdma_cm_id *cm_id,
+		struct rdma_cm_event *event)
+{
+	struct nvmet_rdma_queue *queue;
+	int ret;
+
+	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
+	if (!queue) {
+		ret = NVME_RDMA_CM_NO_RSC;
+		goto out_reject;
+	}
+
+	ret = nvmet_sq_init(&queue->nvme_sq);
+	if (ret)
+		goto out_free_queue;
+
+	ret = nvmet_rdma_parse_cm_connect_req(&event->param.conn, queue);
+	if (ret)
+		goto out_destroy_sq;
+
+	/*
+	 * Schedules the actual release because calling rdma_destroy_id from
+	 * inside a CM callback would trigger a deadlock. (great API design..)
+	 */
+	INIT_WORK(&queue->release_work, nvmet_rdma_release_queue_work);
+	queue->dev = ndev;
+	queue->cm_id = cm_id;
+
+	spin_lock_init(&queue->state_lock);
+	queue->state = NVMET_RDMA_Q_CONNECTING;
+	INIT_LIST_HEAD(&queue->rsp_wait_list);
+	INIT_LIST_HEAD(&queue->rsp_wr_wait_list);
+	spin_lock_init(&queue->rsp_wr_wait_lock);
+	INIT_LIST_HEAD(&queue->free_rsps);
+	spin_lock_init(&queue->rsps_lock);
+
+	queue->idx = ida_simple_get(&nvmet_rdma_queue_ida, 0, 0, GFP_KERNEL);
+	if (queue->idx < 0) {
+		ret = NVME_RDMA_CM_NO_RSC;
+		goto out_free_queue;
+	}
+
+	ret = nvmet_rdma_alloc_rsps(queue);
+	if (ret) {
+		ret = NVME_RDMA_CM_NO_RSC;
+		goto out_ida_remove;
+	}
+
+	if (!ndev->srq) {
+		queue->cmds = nvmet_rdma_alloc_cmds(ndev,
+				queue->recv_queue_size,
+				!queue->host_qid);
+		if (IS_ERR(queue->cmds)) {
+			ret = NVME_RDMA_CM_NO_RSC;
+			goto out_free_responses;
+		}
+	}
+
+	ret = nvmet_rdma_create_queue_ib(queue);
+	if (ret) {
+		pr_err("%s: creating RDMA queue failed (%d).\n",
+			__func__, ret);
+		ret = NVME_RDMA_CM_NO_RSC;
+		goto out_free_cmds;
+	}
+
+	return queue;
+
+out_free_cmds:
+	if (!ndev->srq) {
+		nvmet_rdma_free_cmds(queue->dev, queue->cmds,
+				queue->recv_queue_size,
+				!queue->host_qid);
+	}
+out_free_responses:
+	nvmet_rdma_free_rsps(queue);
+out_ida_remove:
+	ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
+out_destroy_sq:
+	nvmet_sq_destroy(&queue->nvme_sq);
+out_free_queue:
+	kfree(queue);
+out_reject:
+	nvmet_rdma_cm_reject(cm_id, ret);
+	return NULL;
+}
+
+static void nvmet_rdma_qp_event(struct ib_event *event, void *priv)
+{
+	struct nvmet_rdma_queue *queue = priv;
+
+	switch (event->event) {
+	case IB_EVENT_COMM_EST:
+		rdma_notify(queue->cm_id, event->event);
+		break;
+	default:
+		pr_err("received unrecognized IB QP event %d\n", event->event);
+		break;
+	}
+}
+
+static int nvmet_rdma_cm_accept(struct rdma_cm_id *cm_id,
+		struct nvmet_rdma_queue *queue,
+		struct rdma_conn_param *p)
+{
+	struct rdma_conn_param  param = { };
+	struct nvme_rdma_cm_rep priv = { };
+	int ret = -ENOMEM;
+
+	param.rnr_retry_count = 7;
+	param.flow_control = 1;
+	param.initiator_depth = min_t(u8, p->initiator_depth,
+		queue->dev->device->attrs.max_qp_init_rd_atom);
+	param.private_data = &priv;
+	param.private_data_len = sizeof(priv);
+	priv.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
+	priv.crqsize = cpu_to_le16(queue->recv_queue_size);
+
+	ret = rdma_accept(cm_id, &param);
+	if (ret)
+		pr_err("rdma_accept failed (error code = %d)\n", ret);
+
+	return ret;
+}
+
+static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id,
+		struct rdma_cm_event *event)
+{
+	struct nvmet_rdma_device *ndev;
+	struct nvmet_rdma_queue *queue;
+	int ret = -EINVAL;
+
+	ndev = nvmet_rdma_find_get_device(cm_id);
+	if (!ndev) {
+		pr_err("no client data!\n");
+		nvmet_rdma_cm_reject(cm_id, NVME_RDMA_CM_NO_RSC);
+		return -ECONNREFUSED;
+	}
+
+	queue = nvmet_rdma_alloc_queue(ndev, cm_id, event);
+	if (!queue) {
+		ret = -ENOMEM;
+		goto put_device;
+	}
+	queue->port = cm_id->context;
+
+	ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn);
+	if (ret)
+		goto release_queue;
+
+	mutex_lock(&nvmet_rdma_queue_mutex);
+	list_add_tail(&queue->queue_list, &nvmet_rdma_queue_list);
+	mutex_unlock(&nvmet_rdma_queue_mutex);
+
+	return 0;
+
+release_queue:
+	nvmet_rdma_free_queue(queue);
+put_device:
+	kref_put(&ndev->ref, nvmet_rdma_free_dev);
+
+	return ret;
+}
+
+static void nvmet_rdma_queue_established(struct nvmet_rdma_queue *queue)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&queue->state_lock, flags);
+	if (queue->state != NVMET_RDMA_Q_CONNECTING) {
+		pr_warn("trying to establish a connected queue\n");
+		goto out_unlock;
+	}
+	queue->state = NVMET_RDMA_Q_LIVE;
+
+	while (!list_empty(&queue->rsp_wait_list)) {
+		struct nvmet_rdma_rsp *cmd;
+
+		cmd = list_first_entry(&queue->rsp_wait_list,
+					struct nvmet_rdma_rsp, wait_list);
+		list_del(&cmd->wait_list);
+
+		spin_unlock_irqrestore(&queue->state_lock, flags);
+		nvmet_rdma_handle_command(queue, cmd);
+		spin_lock_irqsave(&queue->state_lock, flags);
+	}
+
+out_unlock:
+	spin_unlock_irqrestore(&queue->state_lock, flags);
+}
+
+static void __nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
+{
+	bool disconnect = false;
+	unsigned long flags;
+
+	pr_debug("cm_id= %p queue->state= %d\n", queue->cm_id, queue->state);
+
+	spin_lock_irqsave(&queue->state_lock, flags);
+	switch (queue->state) {
+	case NVMET_RDMA_Q_CONNECTING:
+	case NVMET_RDMA_Q_LIVE:
+		disconnect = true;
+		queue->state = NVMET_RDMA_Q_DISCONNECTING;
+		break;
+	case NVMET_RDMA_Q_DISCONNECTING:
+		break;
+	}
+	spin_unlock_irqrestore(&queue->state_lock, flags);
+
+	if (disconnect) {
+		rdma_disconnect(queue->cm_id);
+		ib_drain_qp(queue->cm_id->qp);
+		schedule_work(&queue->release_work);
+	}
+}
+
+static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
+{
+	bool disconnect = false;
+
+	mutex_lock(&nvmet_rdma_queue_mutex);
+	if (!list_empty(&queue->queue_list)) {
+		list_del_init(&queue->queue_list);
+		disconnect = true;
+	}
+	mutex_unlock(&nvmet_rdma_queue_mutex);
+
+	if (disconnect)
+		__nvmet_rdma_queue_disconnect(queue);
+}
+
+static void nvmet_rdma_queue_connect_fail(struct rdma_cm_id *cm_id,
+		struct nvmet_rdma_queue *queue)
+{
+	WARN_ON_ONCE(queue->state != NVMET_RDMA_Q_CONNECTING);
+
+	pr_err("failed to connect queue\n");
+	schedule_work(&queue->release_work);
+}
+
+static int nvmet_rdma_cm_handler(struct rdma_cm_id *cm_id,
+		struct rdma_cm_event *event)
+{
+	struct nvmet_rdma_queue *queue = NULL;
+	int ret = 0;
+
+	if (cm_id->qp)
+		queue = cm_id->qp->qp_context;
+
+	pr_debug("%s (%d): status %d id %p\n",
+		rdma_event_msg(event->event), event->event,
+		event->status, cm_id);
+
+	switch (event->event) {
+	case RDMA_CM_EVENT_CONNECT_REQUEST:
+		ret = nvmet_rdma_queue_connect(cm_id, event);
+		break;
+	case RDMA_CM_EVENT_ESTABLISHED:
+		nvmet_rdma_queue_established(queue);
+		break;
+	case RDMA_CM_EVENT_ADDR_CHANGE:
+	case RDMA_CM_EVENT_DISCONNECTED:
+	case RDMA_CM_EVENT_DEVICE_REMOVAL:
+	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
+		/*
+		 * We can get the device removal callback even for a
+		 * CM ID that we aren't actually using.  In that case
+		 * the context pointer is NULL, so we shouldn't try
+		 * to disconnect a non-existing queue.  But we also
+		 * need to return 1 so that the core will destroy
+		 * it's own ID.  What a great API design..
+		 */
+		if (queue)
+			nvmet_rdma_queue_disconnect(queue);
+		else
+			ret = 1;
+		break;
+	case RDMA_CM_EVENT_REJECTED:
+	case RDMA_CM_EVENT_UNREACHABLE:
+	case RDMA_CM_EVENT_CONNECT_ERROR:
+		nvmet_rdma_queue_connect_fail(cm_id, queue);
+		break;
+	default:
+		pr_err("received unrecognized RDMA CM event %d\n",
+			event->event);
+		break;
+	}
+
+	return ret;
+}
+
+static void nvmet_rdma_delete_ctrl(struct nvmet_ctrl *ctrl)
+{
+	struct nvmet_rdma_queue *queue;
+
+restart:
+	mutex_lock(&nvmet_rdma_queue_mutex);
+	list_for_each_entry(queue, &nvmet_rdma_queue_list, queue_list) {
+		if (queue->nvme_sq.ctrl == ctrl) {
+			list_del_init(&queue->queue_list);
+			mutex_unlock(&nvmet_rdma_queue_mutex);
+
+			__nvmet_rdma_queue_disconnect(queue);
+			goto restart;
+		}
+	}
+	mutex_unlock(&nvmet_rdma_queue_mutex);
+}
+
+static int nvmet_rdma_add_port(struct nvmet_port *port)
+{
+	struct rdma_cm_id *cm_id;
+	struct sockaddr_in addr_in;
+	u16 port_in;
+	int ret;
+
+	switch (port->disc_addr.adrfam) {
+	case NVMF_ADDR_FAMILY_IP4:
+		break;
+	default:
+		pr_err("address family %d not supported\n",
+				port->disc_addr.adrfam);
+		return -EINVAL;
+	}
+
+	ret = kstrtou16(port->disc_addr.trsvcid, 0, &port_in);
+	if (ret)
+		return ret;
+
+	addr_in.sin_family = AF_INET;
+	addr_in.sin_addr.s_addr = in_aton(port->disc_addr.traddr);
+	addr_in.sin_port = htons(port_in);
+
+	cm_id = rdma_create_id(&init_net, nvmet_rdma_cm_handler, port,
+			RDMA_PS_TCP, IB_QPT_RC);
+	if (IS_ERR(cm_id)) {
+		pr_err("CM ID creation failed\n");
+		return PTR_ERR(cm_id);
+	}
+
+	ret = rdma_bind_addr(cm_id, (struct sockaddr *)&addr_in);
+	if (ret) {
+		pr_err("binding CM ID to %pISpc failed (%d)\n", &addr_in, ret);
+		goto out_destroy_id;
+	}
+
+	ret = rdma_listen(cm_id, 128);
+	if (ret) {
+		pr_err("listening to %pISpc failed (%d)\n", &addr_in, ret);
+		goto out_destroy_id;
+	}
+
+	pr_info("enabling port %d (%pISpc)\n",
+		le16_to_cpu(port->disc_addr.portid), &addr_in);
+	port->priv = cm_id;
+	return 0;
+
+out_destroy_id:
+	rdma_destroy_id(cm_id);
+	return ret;
+}
+
+static void nvmet_rdma_remove_port(struct nvmet_port *port)
+{
+	struct rdma_cm_id *cm_id = port->priv;
+
+	rdma_destroy_id(cm_id);
+}
+
+static struct nvmet_fabrics_ops nvmet_rdma_ops = {
+	.owner			= THIS_MODULE,
+	.type			= NVMF_TRTYPE_RDMA,
+	.sqe_inline_size	= NVMET_RDMA_INLINE_DATA_SIZE,
+	.msdbd			= 1,
+	.has_keyed_sgls		= 1,
+	.add_port		= nvmet_rdma_add_port,
+	.remove_port		= nvmet_rdma_remove_port,
+	.queue_response		= nvmet_rdma_queue_response,
+	.delete_ctrl		= nvmet_rdma_delete_ctrl,
+};
+
+static int __init nvmet_rdma_init(void)
+{
+	return nvmet_register_transport(&nvmet_rdma_ops);
+}
+
+static void __exit nvmet_rdma_exit(void)
+{
+	struct nvmet_rdma_queue *queue;
+
+	nvmet_unregister_transport(&nvmet_rdma_ops);
+
+	flush_scheduled_work();
+
+	mutex_lock(&nvmet_rdma_queue_mutex);
+	while ((queue = list_first_entry_or_null(&nvmet_rdma_queue_list,
+			struct nvmet_rdma_queue, queue_list))) {
+		list_del_init(&queue->queue_list);
+
+		mutex_unlock(&nvmet_rdma_queue_mutex);
+		__nvmet_rdma_queue_disconnect(queue);
+		mutex_lock(&nvmet_rdma_queue_mutex);
+	}
+	mutex_unlock(&nvmet_rdma_queue_mutex);
+
+	flush_scheduled_work();
+	ida_destroy(&nvmet_rdma_queue_ida);
+}
+
+module_init(nvmet_rdma_init);
+module_exit(nvmet_rdma_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("nvmet-transport-1"); /* 1 == NVMF_TRTYPE_RDMA */