NVMe over Fabrics RDMA transport drivers

NVMe over Fabrics RDMA transport drivers

[Christoph Hellwig]

This patch set implements the NVMe over Fabrics RDMA host and the target
drivers.

The host driver is tied into the NVMe host stack and implements the RDMA
transport under the NVMe core and Fabrics modules. The NVMe over Fabrics
RDMA host module is responsible for establishing a connection against a
given target/controller, RDMA event handling and data-plane command
processing.

The target driver hooks into the NVMe target core stack and implements
the RDMA transport. The module is responsible for RDMA connection
establishment, RDMA event handling and data-plane RDMA commands
processing.

RDMA connection establishment is done using RDMA/CM and IP resolution.
The data-plane command sequence follows the classic storage model where
the target pushes/pulls the data.

[PATCH 1/5] blk-mq: Introduce blk_mq_reinit_tagset

[Christoph Hellwig]

From: Sagi Grimberg <sagi@grimberg.me>

The new nvme-rdma driver will need to reinitialize all the tags as part of
the error recovery procedure (realloc the tag memory region). Add a helper
in blk-mq for it that can iterate over all requests in a tagset to make
this easier.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: Ming Lin <ming.l@ssi.samsung.com>
Reviewed-by: Stephen Bates <Stephen.Bates@pmcs.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-mq-tag.c     | 26 ++++++++++++++++++++++++++
 include/linux/blk-mq.h |  3 +++
 2 files changed, 29 insertions(+)

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 56a0c37..729bac3 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -485,6 +485,32 @@ void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
 }
 EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
 
+int blk_mq_reinit_tagset(struct blk_mq_tag_set *set)
+{
+	int i, j, ret = 0;
+
+	if (!set->ops->reinit_request)
+		goto out;
+
+	for (i = 0; i < set->nr_hw_queues; i++) {
+		struct blk_mq_tags *tags = set->tags[i];
+
+		for (j = 0; j < tags->nr_tags; j++) {
+			if (!tags->rqs[j])
+				continue;
+
+			ret = set->ops->reinit_request(set->driver_data,
+						tags->rqs[j]);
+			if (ret)
+				goto out;
+		}
+	}
+
+out:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(blk_mq_reinit_tagset);
+
 void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
 		void *priv)
 {
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 6bf8735..9a5d581 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -96,6 +96,7 @@ typedef int (init_request_fn)(void *, struct request *, unsigned int,
 		unsigned int, unsigned int);
 typedef void (exit_request_fn)(void *, struct request *, unsigned int,
 		unsigned int);
+typedef int (reinit_request_fn)(void *, struct request *);
 
 typedef void (busy_iter_fn)(struct blk_mq_hw_ctx *, struct request *, void *,
 		bool);
@@ -145,6 +146,7 @@ struct blk_mq_ops {
 	 */
 	init_request_fn		*init_request;
 	exit_request_fn		*exit_request;
+	reinit_request_fn	*reinit_request;
 };
 
 enum {
@@ -245,6 +247,7 @@ void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
 void blk_mq_freeze_queue(struct request_queue *q);
 void blk_mq_unfreeze_queue(struct request_queue *q);
 void blk_mq_freeze_queue_start(struct request_queue *q);
+int blk_mq_reinit_tagset(struct blk_mq_tag_set *set);
 
 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);
 
-- 
2.1.4

[PATCH 2/5] nvme: add new reconnecting controller state

[Christoph Hellwig]

The nvme fabric (RDMA, FC, etc...) can introduce port, link or node
failures that may require a reconnect to re-establish the connection.

Add a new reconnecting state that will initially be used by the RDMA
driver.

Reviewed-by: Jay Freyensee <james.p.freyensee@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/nvme/host/core.c | 12 ++++++++++++
 drivers/nvme/host/nvme.h |  1 +
 2 files changed, 13 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 6f4361b..5bd5de1 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -88,6 +88,7 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 		switch (old_state) {
 		case NVME_CTRL_NEW:
 		case NVME_CTRL_RESETTING:
+		case NVME_CTRL_RECONNECTING:
 			changed = true;
 			/* FALLTHRU */
 		default:
@@ -98,6 +99,16 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 		switch (old_state) {
 		case NVME_CTRL_NEW:
 		case NVME_CTRL_LIVE:
+		case NVME_CTRL_RECONNECTING:
+			changed = true;
+			/* FALLTHRU */
+		default:
+			break;
+		}
+		break;
+	case NVME_CTRL_RECONNECTING:
+		switch (old_state) {
+		case NVME_CTRL_LIVE:
 			changed = true;
 			/* FALLTHRU */
 		default:
@@ -108,6 +119,7 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 		switch (old_state) {
 		case NVME_CTRL_LIVE:
 		case NVME_CTRL_RESETTING:
+		case NVME_CTRL_RECONNECTING:
 			changed = true;
 			/* FALLTHRU */
 		default:
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index d25eaab..a288974 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -74,6 +74,7 @@ enum nvme_ctrl_state {
 	NVME_CTRL_NEW,
 	NVME_CTRL_LIVE,
 	NVME_CTRL_RESETTING,
+	NVME_CTRL_RECONNECTING,
 	NVME_CTRL_DELETING,
 	NVME_CTRL_DEAD,
 };
-- 
2.1.4

[PATCH 3/5] nvme-rdma.h: Add includes for nvme rdma_cm negotiation

[Christoph Hellwig]

From: Sagi Grimberg <sagi@grimberg.me>

NVMe over Fabrics RDMA transport defines a connection establishment
protocol over the RDMA connection manager. This header will be used by
both the host and target drivers to negotiate the connection
establishment parameters.

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>
---
 include/linux/nvme-rdma.h | 71 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 include/linux/nvme-rdma.h

diff --git a/include/linux/nvme-rdma.h b/include/linux/nvme-rdma.h
new file mode 100644
index 0000000..bf240a3
--- /dev/null
+++ b/include/linux/nvme-rdma.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2015 Mellanox Technologies. All rights reserved.
+ *
+ * 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.
+ */
+
+#ifndef _LINUX_NVME_RDMA_H
+#define _LINUX_NVME_RDMA_H
+
+enum nvme_rdma_cm_fmt {
+	NVME_RDMA_CM_FMT_1_0 = 0x0,
+};
+
+enum nvme_rdma_cm_status {
+	NVME_RDMA_CM_INVALID_LEN	= 0x01,
+	NVME_RDMA_CM_INVALID_RECFMT	= 0x02,
+	NVME_RDMA_CM_INVALID_QID	= 0x03,
+	NVME_RDMA_CM_INVALID_HSQSIZE	= 0x04,
+	NVME_RDMA_CM_INVALID_HRQSIZE	= 0x05,
+	NVME_RDMA_CM_NO_RSC		= 0x06,
+	NVME_RDMA_CM_INVALID_IRD	= 0x07,
+	NVME_RDMA_CM_INVALID_ORD	= 0x08,
+};
+
+/**
+ * struct nvme_rdma_cm_req - rdma connect request
+ *
+ * @recfmt:        format of the RDMA Private Data
+ * @qid:           queue Identifier for the Admin or I/O Queue
+ * @hrqsize:       host receive queue size to be created
+ * @hsqsize:       host send queue size to be created
+ */
+struct nvme_rdma_cm_req {
+	__le16		recfmt;
+	__le16		qid;
+	__le16		hrqsize;
+	__le16		hsqsize;
+	u8		rsvd[24];
+};
+
+/**
+ * struct nvme_rdma_cm_rep - rdma connect reply
+ *
+ * @recfmt:        format of the RDMA Private Data
+ * @crqsize:       controller receive queue size
+ */
+struct nvme_rdma_cm_rep {
+	__le16		recfmt;
+	__le16		crqsize;
+	u8		rsvd[28];
+};
+
+/**
+ * struct nvme_rdma_cm_rej - rdma connect reject
+ *
+ * @recfmt:        format of the RDMA Private Data
+ * @fsts:          error status for the associated connect request
+ */
+struct nvme_rdma_cm_rej {
+	__le16		recfmt;
+	__le16		sts;
+};
+
+#endif /* _LINUX_NVME_RDMA_H */
-- 
2.1.4

[PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Christoph Hellwig]

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>
---
 drivers/nvme/target/Kconfig  |   10 +
 drivers/nvme/target/Makefile |    2 +
 drivers/nvme/target/rdma.c   | 1404 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1416 insertions(+)
 create mode 100644 drivers/nvme/target/rdma.c

diff --git a/drivers/nvme/target/Kconfig b/drivers/nvme/target/Kconfig
index b77ce43..6aa7be0 100644
--- a/drivers/nvme/target/Kconfig
+++ b/drivers/nvme/target/Kconfig
@@ -24,3 +24,13 @@ 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 e49ba60..b7a0623 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 0000000..fccb01d
--- /dev/null
+++ b/drivers/nvme/target/rdma.c
@@ -0,0 +1,1404 @@
+/*
+ * 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 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_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);
+}
+
+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 &&
+		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_req_complete(&rsp->req, NVME_SC_DATA_XFER_ERROR);
+		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))
+		return;
+
+	if (unlikely(wc->byte_len < sizeof(struct nvme_command))) {
+		pr_err("Ctrl Fatal Error: capsule size less than 64 bytes\n");
+		if (queue->nvme_sq.ctrl)
+			nvmet_ctrl_fatal_error(queue->nvme_sq.ctrl);
+		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);
+		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_cmds;
+		}
+	}
+
+	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_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, *next;
+	static LIST_HEAD(del_list);
+
+	mutex_lock(&nvmet_rdma_queue_mutex);
+	list_for_each_entry_safe(queue, next,
+			&nvmet_rdma_queue_list, queue_list) {
+		if (queue->nvme_sq.ctrl->cntlid == ctrl->cntlid)
+			list_move_tail(&queue->queue_list, &del_list);
+	}
+	mutex_unlock(&nvmet_rdma_queue_mutex);
+
+	list_for_each_entry_safe(queue, next, &del_list, queue_list)
+		nvmet_rdma_queue_disconnect(queue);
+}
+
+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;
+
+	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 */
-- 
2.1.4

[PATCH 5/5] nvme-rdma: add a NVMe over Fabrics RDMA host driver

[Christoph Hellwig]

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>
---
 drivers/nvme/host/Kconfig  |   16 +
 drivers/nvme/host/Makefile |    3 +
 drivers/nvme/host/rdma.c   | 2009 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 2028 insertions(+)
 create mode 100644 drivers/nvme/host/rdma.c

diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig
index 3397651..db39d53 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 5f8648f..47abcec 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 0000000..4edc912
--- /dev/null
+++ b/drivers/nvme/host/rdma.c
@@ -0,0 +1,2009 @@
+/*
+ * 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_free_queue(struct nvme_rdma_queue *queue)
+{
+	if (!test_and_clear_bit(NVME_RDMA_Q_CONNECTED, &queue->flags))
+		return;
+
+	rdma_disconnect(queue->cm_id);
+	ib_drain_qp(queue->qp);
+	nvme_rdma_destroy_queue_ib(queue);
+	rdma_destroy_id(queue->cm_id);
+}
+
+static void nvme_rdma_free_io_queues(struct nvme_rdma_ctrl *ctrl)
+{
+	int i;
+
+	for (i = 1; i < ctrl->queue_count; i++)
+		nvme_rdma_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_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_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_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;
+	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->status == IB_CM_REJ_CONSUMER_DEFINED) {
+		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 && (rq->cmd_flags & REQ_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;
+
+	nvme_start_keep_alive(&ctrl->ctrl);
+
+	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;
+
+	return 0;
+
+out_cleanup_queue:
+	blk_cleanup_queue(ctrl->ctrl.admin_q);
+out_free_tagset:
+	blk_mq_free_tag_set(&ctrl->admin_tag_set);
+out_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:
+	nvme_stop_keep_alive(&ctrl->ctrl);
+	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_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");
-- 
2.1.4

Re: NVMe over Fabrics RDMA transport drivers

[Sagi Grimberg]

We forgot to CC Linux-rdma, CC'ing...

On 07/06/16 00:23, Christoph Hellwig wrote:
> This patch set implements the NVMe over Fabrics RDMA host and the target
> drivers.
>
> The host driver is tied into the NVMe host stack and implements the RDMA
> transport under the NVMe core and Fabrics modules. The NVMe over Fabrics
> RDMA host module is responsible for establishing a connection against a
> given target/controller, RDMA event handling and data-plane command
> processing.
>
> The target driver hooks into the NVMe target core stack and implements
> the RDMA transport. The module is responsible for RDMA connection
> establishment, RDMA event handling and data-plane RDMA commands
> processing.
>
> RDMA connection establishment is done using RDMA/CM and IP resolution.
> The data-plane command sequence follows the classic storage model where
> the target pushes/pulls the data.
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-block" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: [PATCH 3/5] nvme-rdma.h: Add includes for nvme rdma_cm negotiation

[Sagi Grimberg]

We forgot to CC Linux-rdma, CC'ing...

On 07/06/16 00:23, Christoph Hellwig wrote:
> From: Sagi Grimberg <sagi@grimberg.me>
>
> NVMe over Fabrics RDMA transport defines a connection establishment
> protocol over the RDMA connection manager. This header will be used by
> both the host and target drivers to negotiate the connection
> establishment parameters.
>
> 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>
> ---
>   include/linux/nvme-rdma.h | 71 +++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 71 insertions(+)
>   create mode 100644 include/linux/nvme-rdma.h
>
> diff --git a/include/linux/nvme-rdma.h b/include/linux/nvme-rdma.h
> new file mode 100644
> index 0000000..bf240a3
> --- /dev/null
> +++ b/include/linux/nvme-rdma.h
> @@ -0,0 +1,71 @@
> +/*
> + * Copyright (c) 2015 Mellanox Technologies. All rights reserved.
> + *
> + * 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.
> + */
> +
> +#ifndef _LINUX_NVME_RDMA_H
> +#define _LINUX_NVME_RDMA_H
> +
> +enum nvme_rdma_cm_fmt {
> +	NVME_RDMA_CM_FMT_1_0 = 0x0,
> +};
> +
> +enum nvme_rdma_cm_status {
> +	NVME_RDMA_CM_INVALID_LEN	= 0x01,
> +	NVME_RDMA_CM_INVALID_RECFMT	= 0x02,
> +	NVME_RDMA_CM_INVALID_QID	= 0x03,
> +	NVME_RDMA_CM_INVALID_HSQSIZE	= 0x04,
> +	NVME_RDMA_CM_INVALID_HRQSIZE	= 0x05,
> +	NVME_RDMA_CM_NO_RSC		= 0x06,
> +	NVME_RDMA_CM_INVALID_IRD	= 0x07,
> +	NVME_RDMA_CM_INVALID_ORD	= 0x08,
> +};
> +
> +/**
> + * struct nvme_rdma_cm_req - rdma connect request
> + *
> + * @recfmt:        format of the RDMA Private Data
> + * @qid:           queue Identifier for the Admin or I/O Queue
> + * @hrqsize:       host receive queue size to be created
> + * @hsqsize:       host send queue size to be created
> + */
> +struct nvme_rdma_cm_req {
> +	__le16		recfmt;
> +	__le16		qid;
> +	__le16		hrqsize;
> +	__le16		hsqsize;
> +	u8		rsvd[24];
> +};
> +
> +/**
> + * struct nvme_rdma_cm_rep - rdma connect reply
> + *
> + * @recfmt:        format of the RDMA Private Data
> + * @crqsize:       controller receive queue size
> + */
> +struct nvme_rdma_cm_rep {
> +	__le16		recfmt;
> +	__le16		crqsize;
> +	u8		rsvd[28];
> +};
> +
> +/**
> + * struct nvme_rdma_cm_rej - rdma connect reject
> + *
> + * @recfmt:        format of the RDMA Private Data
> + * @fsts:          error status for the associated connect request
> + */
> +struct nvme_rdma_cm_rej {
> +	__le16		recfmt;
> +	__le16		sts;
> +};
> +
> +#endif /* _LINUX_NVME_RDMA_H */
>

Re: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Sagi Grimberg]

We forgot to CC Linux-rdma, CC'ing...

On 07/06/16 00:23, Christoph Hellwig wrote:
> 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>
> ---
>   drivers/nvme/target/Kconfig  |   10 +
>   drivers/nvme/target/Makefile |    2 +
>   drivers/nvme/target/rdma.c   | 1404 ++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 1416 insertions(+)
>   create mode 100644 drivers/nvme/target/rdma.c
>
> diff --git a/drivers/nvme/target/Kconfig b/drivers/nvme/target/Kconfig
> index b77ce43..6aa7be0 100644
> --- a/drivers/nvme/target/Kconfig
> +++ b/drivers/nvme/target/Kconfig
> @@ -24,3 +24,13 @@ 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 e49ba60..b7a0623 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 0000000..fccb01d
> --- /dev/null
> +++ b/drivers/nvme/target/rdma.c
> @@ -0,0 +1,1404 @@
> +/*
> + * 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 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_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);
> +}
> +
> +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 &&
> +		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_req_complete(&rsp->req, NVME_SC_DATA_XFER_ERROR);
> +		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))
> +		return;
> +
> +	if (unlikely(wc->byte_len < sizeof(struct nvme_command))) {
> +		pr_err("Ctrl Fatal Error: capsule size less than 64 bytes\n");
> +		if (queue->nvme_sq.ctrl)
> +			nvmet_ctrl_fatal_error(queue->nvme_sq.ctrl);
> +		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);
> +		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_cmds;
> +		}
> +	}
> +
> +	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_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, *next;
> +	static LIST_HEAD(del_list);
> +
> +	mutex_lock(&nvmet_rdma_queue_mutex);
> +	list_for_each_entry_safe(queue, next,
> +			&nvmet_rdma_queue_list, queue_list) {
> +		if (queue->nvme_sq.ctrl->cntlid == ctrl->cntlid)
> +			list_move_tail(&queue->queue_list, &del_list);
> +	}
> +	mutex_unlock(&nvmet_rdma_queue_mutex);
> +
> +	list_for_each_entry_safe(queue, next, &del_list, queue_list)
> +		nvmet_rdma_queue_disconnect(queue);
> +}
> +
> +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;
> +
> +	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 */
>

Re: [PATCH 5/5] nvme-rdma: add a NVMe over Fabrics RDMA host driver

[Sagi Grimberg]

We forgot to CC Linux-rdma, CC'ing...

On 07/06/16 00:23, Christoph Hellwig wrote:
> 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 $IPADDR
>
> This requires the latest version of nvme-cli with Fabrics support.
>
> Signed-off-by: Jay Freyensee <james.p.freyensee@intel.com>
> Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
> Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/nvme/host/Kconfig  |   16 +
>   drivers/nvme/host/Makefile |    3 +
>   drivers/nvme/host/rdma.c   | 2009 ++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 2028 insertions(+)
>   create mode 100644 drivers/nvme/host/rdma.c
>
> diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig
> index 3397651..db39d53 100644
> --- a/drivers/nvme/host/Kconfig
> +++ b/drivers/nvme/host/Kconfig
> @@ -27,3 +27,19 @@ config BLK_DEV_NVME_SCSI
>
>   config NVME_FABRICS
>   	tristate
> +
> +config NVME_RDMA
> +	tristate "NVM Express over Fabrics RDMA host driver"
> +	depends on INFINIBAND
> +	depends on BLK_DEV_NVME
> +	select NVME_FABRICS
> +	select SG_POOL
> +	help
> +	  This provides support for the NVMe over Fabrics protocol using
> +	  the RDMA (Infiniband, RoCE, iWarp) transport.  This allows you
> +	  to use remote block devices exported using the NVMe protocol set.
> +
> +	  To configure a NVMe over Fabrics controller use the nvme-cli tool
> +	  from https://github.com/linux-nvme/nvme-cli.
> +
> +	  If unsure, say N.
> diff --git a/drivers/nvme/host/Makefile b/drivers/nvme/host/Makefile
> index 5f8648f..47abcec 100644
> --- a/drivers/nvme/host/Makefile
> +++ b/drivers/nvme/host/Makefile
> @@ -1,6 +1,7 @@
>   obj-$(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 0000000..4edc912
> --- /dev/null
> +++ b/drivers/nvme/host/rdma.c
> @@ -0,0 +1,2009 @@
> +/*
> + * 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_free_queue(struct nvme_rdma_queue *queue)
> +{
> +	if (!test_and_clear_bit(NVME_RDMA_Q_CONNECTED, &queue->flags))
> +		return;
> +
> +	rdma_disconnect(queue->cm_id);
> +	ib_drain_qp(queue->qp);
> +	nvme_rdma_destroy_queue_ib(queue);
> +	rdma_destroy_id(queue->cm_id);
> +}
> +
> +static void nvme_rdma_free_io_queues(struct nvme_rdma_ctrl *ctrl)
> +{
> +	int i;
> +
> +	for (i = 1; i < ctrl->queue_count; i++)
> +		nvme_rdma_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_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_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_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;
> +	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->status == IB_CM_REJ_CONSUMER_DEFINED) {
> +		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 && (rq->cmd_flags & REQ_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;
> +
> +	nvme_start_keep_alive(&ctrl->ctrl);
> +
> +	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;
> +
> +	return 0;
> +
> +out_cleanup_queue:
> +	blk_cleanup_queue(ctrl->ctrl.admin_q);
> +out_free_tagset:
> +	blk_mq_free_tag_set(&ctrl->admin_tag_set);
> +out_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:
> +	nvme_stop_keep_alive(&ctrl->ctrl);
> +	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_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");
>

Re: NVMe over Fabrics RDMA transport drivers

[Christoph Hellwig]

On Tue, Jun 07, 2016 at 02:57:09PM +0300, Sagi Grimberg wrote:
> We forgot to CC Linux-rdma, CC'ing...

D'oh - thanks for catching this.

Re: [PATCH 5/5] nvme-rdma: add a NVMe over Fabrics RDMA host driver

[Keith Busch]

On Mon, Jun 06, 2016 at 11:23:35PM +0200, Christoph Hellwig wrote:
> 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.

Is there a public fork or patch set available for the user tools? I'd
be happy to merge that in.

Overall, this whole series is looking really good. I'll try this out on
some machines today.

RE: NVMe over Fabrics RDMA transport drivers

[Woodruff, Robert J]

Sagi Grimberg wrote,

>We forgot to CC Linux-rdma, CC'ing...

Are you planning on sending the patch set to the linux-rdma list for comments as well ?
It might be good to do so if you want review from the rdma subsystem experts, as many of them do not subscribe to the other
lists.

Re: [PATCH 5/5] nvme-rdma: add a NVMe over Fabrics RDMA host driver

[Freyensee, James P]

On Tue, 2016-06-07 at 10:47 -0400, Keith Busch wrote:
> On Mon, Jun 06, 2016 at 11:23:35PM +0200, Christoph Hellwig wrote:
> > 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.
> 
> Is there a public fork or patch set available for the user tools? I'd
> be happy to merge that in.
> 
> Overall, this whole series is looking really good. 

Special thanks to Sagi and Christoph for organizing all the patches of
this code project into a dynamite submission series for these mailing
lists.

> I'll try this out on
> some machines today.

Re: NVMe over Fabrics RDMA transport drivers

[Steve Wise]

On 6/7/2016 9:55 AM, Woodruff, Robert J wrote:
> Sagi Grimberg wrote,
>
>> We forgot to CC Linux-rdma, CC'ing...
> Are you planning on sending the patch set to the linux-rdma list for comments as well ?
> It might be good to do so if you want review from the rdma subsystem experts, as many of them do not subscribe to the other
> lists.

It would be great to make sure and CC linux-rdma on v2 of all 4 series, 
so interested folks can review and/or test out the whole enchilada.

Anyway, today I used the github tree at 
git://git.infradead.org/nvme-fabrics.git, branch nvmf-all for testing 
NVME/Fabrics over RDMA.  I used nvme-cli from 
https://github.com/linux-nvme/nvme-cli.git, and nvmetcli from 
git://git.infradead.org/users/hch/nvmetcli.git for configuring.  I ran 
some xfs, fio and iozone tests over both iw_cxgb4 and mlx4, using ram 
disks and an NVME ssd.  Checks out good so far!

Tested-by: Steve Wise <swise@opengridcomputing.com>

Re: NVMe over Fabrics RDMA transport drivers

[Christoph Hellwig]

On Tue, Jun 07, 2016 at 03:14:22PM -0500, Steve Wise wrote:
> It would be great to make sure and CC linux-rdma on v2 of all 4 series, so 
> interested folks can review and/or test out the whole enchilada.

Just go for the git tree at

	git://git.infradead.org/nvme-fabrics.git nvmf-all

to make your life easier for that..  I'll include the list on the next
repost, although I hope the first series with it's mostly protocol header
changes can go in before needing to repost the rest, they are all pretty
trivial.

RE: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Steve Wise]

<snip>

> > +
> > +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_cmds;
> > +		}
> > +	}
> > +

Should the above error path actually goto a block that frees the rsps?  Like
this?

diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index c184ee5..8aaa36f 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -1053,7 +1053,7 @@ nvmet_rdma_alloc_queue(struct nvmet_rdma_device *ndev,
                                !queue->host_qid);
                if (IS_ERR(queue->cmds)) {
                        ret = NVME_RDMA_CM_NO_RSC;
-                       goto out_free_cmds;
+                       goto out_free_responses;
                }
        }

@@ -1073,6 +1073,8 @@ out_free_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:

Re: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Ming Lin]

On Thu, Jun 9, 2016 at 2:42 PM, Steve Wise <swise@opengridcomputing.com> wrote:

> Should the above error path actually goto a block that frees the rsps?  Like
> this?
>
> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
> index c184ee5..8aaa36f 100644
> --- a/drivers/nvme/target/rdma.c
> +++ b/drivers/nvme/target/rdma.c
> @@ -1053,7 +1053,7 @@ nvmet_rdma_alloc_queue(struct nvmet_rdma_device *ndev,
>                                 !queue->host_qid);
>                 if (IS_ERR(queue->cmds)) {
>                         ret = NVME_RDMA_CM_NO_RSC;
> -                       goto out_free_cmds;
> +                       goto out_free_responses;
>                 }
>         }
>
> @@ -1073,6 +1073,8 @@ out_free_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:

Yes. Nice catch.

RE: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Steve Wise]

<snip>

> > +
> > +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);

The above nvmet cm event handler, nvmet_rdma_cm_handler(), calls
nvmet_rdma_queue_connect() for CONNECT_REQUEST events, which calls
nvmet_rdma_alloc_queue (), which, if it encounters a failure (like creating
the qp), calls nvmet_rdma_cm_reject () which calls rdma_reject().  The
non-zero error, however, gets returned back here and this function returns
the error to the RDMA_CM which will also reject the connection as well as
destroy the cm_id.  So there are two rejects happening, I think.  Either
nvmet should reject and destroy the cm_id, or it should do neither and
return non-zero to the RDMA_CM to reject/destroy.

Steve.

Re: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Christoph Hellwig]

On Thu, Jun 09, 2016 at 06:03:51PM -0500, Steve Wise wrote:
> The above nvmet cm event handler, nvmet_rdma_cm_handler(), calls
> nvmet_rdma_queue_connect() for CONNECT_REQUEST events, which calls
> nvmet_rdma_alloc_queue (), which, if it encounters a failure (like creating
> the qp), calls nvmet_rdma_cm_reject () which calls rdma_reject().  The
> non-zero error, however, gets returned back here and this function returns
> the error to the RDMA_CM which will also reject the connection as well as
> destroy the cm_id.  So there are two rejects happening, I think.  Either
> nvmet should reject and destroy the cm_id, or it should do neither and
> return non-zero to the RDMA_CM to reject/destroy.

Can you just send a patch?

Re: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Christoph Hellwig]

On Thu, Jun 09, 2016 at 04:42:11PM -0500, Steve Wise wrote:
> 
> <snip>
> 
> > > +
> > > +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_cmds;
> > > +		}
> > > +	}
> > > +
> 
> Should the above error path actually goto a block that frees the rsps?  Like
> this?

Yes, this looks good.  Thanks a lot, I'll include it in when reposting.

RE: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Steve Wise]

> On Thu, Jun 09, 2016 at 06:03:51PM -0500, Steve Wise wrote:
> > The above nvmet cm event handler, nvmet_rdma_cm_handler(), calls
> > nvmet_rdma_queue_connect() for CONNECT_REQUEST events, which calls
> > nvmet_rdma_alloc_queue (), which, if it encounters a failure (like creating
> > the qp), calls nvmet_rdma_cm_reject () which calls rdma_reject().  The
> > non-zero error, however, gets returned back here and this function returns
> > the error to the RDMA_CM which will also reject the connection as well as
> > destroy the cm_id.  So there are two rejects happening, I think.  Either
> > nvmet should reject and destroy the cm_id, or it should do neither and
> > return non-zero to the RDMA_CM to reject/destroy.
> 
> Can you just send a patch?

Yes, I'll send it out in a separate email.

RE: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Steve Wise]

> Either
> > > nvmet should reject and destroy the cm_id, or it should do neither and
> > > return non-zero to the RDMA_CM to reject/destroy.
> >
> > Can you just send a patch?
> 
> Yes, I'll send it out in a separate email.

Before I do, what do you think of this (untested)?

diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index b1c6e5b..6f0c335 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -1255,7 +1255,8 @@ static int nvmet_rdma_cm_handler(struct rdma_cm_id *cm_id,

        switch (event->event) {
        case RDMA_CM_EVENT_CONNECT_REQUEST:
-               ret = nvmet_rdma_queue_connect(cm_id, event);
+               if (nvmet_rdma_queue_connect(cm_id, event))
+                       rdma_destroy_id(cm_id);
                break;
        case RDMA_CM_EVENT_ESTABLISHED:
                nvmet_rdma_queue_established(queue);

RE: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Steve Wise]

> 
> The above nvmet cm event handler, nvmet_rdma_cm_handler(), calls
> nvmet_rdma_queue_connect() for CONNECT_REQUEST events, which calls
> nvmet_rdma_alloc_queue (), which, if it encounters a failure (like creating
> the qp), calls nvmet_rdma_cm_reject () which calls rdma_reject().  The
> non-zero error, however, gets returned back here and this function returns
> the error to the RDMA_CM which will also reject the connection as well as
> destroy the cm_id.  So there are two rejects happening, I think.  Either
> nvmet should reject and destroy the cm_id, or it should do neither and
> return non-zero to the RDMA_CM to reject/destroy.
> 
> Steve.
> 

Hey Sean, 

Am I correct here?  IE: Is it ok for the rdma application to rdma_reject() and
rmda_destroy_id() the CONNECT_REQUEST cm_id _inside_ its event handler as long
as it returns 0? 

Thanks,

Steve.

RE: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Steve Wise]

> 
> Hey Sean,
> 
> Am I correct here?  IE: Is it ok for the rdma application to rdma_reject() and
> rmda_destroy_id() the CONNECT_REQUEST cm_id _inside_ its event handler as
> long
> as it returns 0?
> 
> Thanks,
> 
> Steve.


Looking at rdma_destroy_id(), I think it is invalid to call it from the event
handler:

void rdma_destroy_id(struct rdma_cm_id *id)
{

<snip>

        /*
         * Wait for any active callback to finish.  New callbacks will find
         * the id_priv state set to destroying and abort.
         */
        mutex_lock(&id_priv->handler_mutex);
        mutex_unlock(&id_priv->handler_mutex);

And indeed when I tried to destroy the CONNECT request cm_id in the nvmet event
handler, I see the event handler thread is stuck:

INFO: task kworker/u32:0:6275 blocked for more than 120 seconds.
      Tainted: G            E   4.7.0-rc2-nvmf-all.3+ #81
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u32:0   D ffff880f90737768     0  6275      2 0x10000080
Workqueue: iw_cm_wq cm_work_handler [iw_cm]
 ffff880f90737768 ffff880f907376d8 ffffffff81c0b500 0000000000000005
 ffff8810226a4940 ffff88102b894490 ffffffffa02cf4cd ffff880f00000000
 ffff880fcd917c00 ffff880f00000000 0000000000000004 ffff880f00000000
Call Trace:
 [<ffffffffa02cf4cd>] ? stop_ep_timer+0x2d/0xe0 [iw_cxgb4]
 [<ffffffff8163e6a7>] schedule+0x47/0xc0
 [<ffffffffa024d276>] ? iw_cm_reject+0x96/0xe0 [iw_cm]
 [<ffffffff8163e8e5>] schedule_preempt_disabled+0x15/0x20
 [<ffffffff8163fd78>] __mutex_lock_slowpath+0x108/0x310
 [<ffffffff8163ffb1>] mutex_lock+0x31/0x50
 [<ffffffffa0261498>] rdma_destroy_id+0x38/0x200 [rdma_cm]
 [<ffffffffa03145f0>] ? nvmet_rdma_queue_connect+0x1a0/0x1a0 [nvmet_rdma]
 [<ffffffffa0262fe1>] ? rdma_create_id+0x171/0x1a0 [rdma_cm]
 [<ffffffffa03146f8>] nvmet_rdma_cm_handler+0x108/0x168 [nvmet_rdma]
 [<ffffffffa026407a>] iw_conn_req_handler+0x1ca/0x240 [rdma_cm]
 [<ffffffffa024efc6>] cm_conn_req_handler+0x606/0x680 [iw_cm]
 [<ffffffffa024f109>] process_event+0xc9/0xf0 [iw_cm]
 [<ffffffffa024f277>] cm_work_handler+0x147/0x1c0 [iw_cm]
 [<ffffffff8107d4f6>] ? trace_event_raw_event_workqueue_execute_start+0x66/0xa0
 [<ffffffff81081736>] process_one_work+0x1c6/0x550
...

So I withdraw my comment about nvmet.  I think the code is fine as-is.  The 2nd
reject results in a no-op since the connection request was rejected by nvmet.

Steve. 

RE: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Hefty, Sean]

> Am I correct here?  IE: Is it ok for the rdma application to
> rdma_reject()

yes

> rmda_destroy_id() the CONNECT_REQUEST cm_id _inside_ its event handler

no

> as long
> as it returns 0?

The user can return a non-zero value from the cm handler to destroy the id.

- Sean

Re: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Sagi Grimberg]

> Looking at rdma_destroy_id(), I think it is invalid to call it from the event
> handler:

...

>
> So I withdraw my comment about nvmet.  I think the code is fine as-is.  The 2nd
> reject results in a no-op since the connection request was rejected by nvmet.

I was just catching up on this after a short vacation, just what I was
about to comment, thanks Steve :)