Merge remote-tracking branches 'asoc/topic/sgtl5000', 'asoc/topic/simple', 'asoc...

[mirror_ubuntu-bionic-kernel.git] / drivers / nvme / host / rdma.c

/*
 * 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/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/string.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 <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

/*
 * 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;
        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),
        NVME_RDMA_IB_QUEUE_ALLOCATED = (1 << 1),
        NVME_RDMA_Q_DELETING = (1 << 2),
};

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 */
        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);

/* 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->mr->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)) {
                ret = PTR_ERR(req->mr);
                req->mr = NULL;
                goto out;
        }

        req->mr->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;
        struct ib_device *ibdev;

        if (!test_and_clear_bit(NVME_RDMA_IB_QUEUE_ALLOCATED, &queue->flags))
                return;

        dev = queue->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;
        }
        set_bit(NVME_RDMA_IB_QUEUE_ALLOCATED, &queue->flags);

        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;
        }

        clear_bit(NVME_RDMA_Q_DELETING, &queue->flags);
        set_bit(NVME_RDMA_Q_CONNECTED, &queue->flags);

        return 0;

out_destroy_cm_id:
        nvme_rdma_destroy_queue_ib(queue);
        rdma_destroy_id(queue->cm_id);
        return ret;
}

static void nvme_rdma_stop_queue(struct nvme_rdma_queue *queue)
{
        rdma_disconnect(queue->cm_id);
        ib_drain_qp(queue->qp);
}

static void nvme_rdma_free_queue(struct nvme_rdma_queue *queue)
{
        nvme_rdma_destroy_queue_ib(queue);
        rdma_destroy_id(queue->cm_id);
}

static void nvme_rdma_stop_and_free_queue(struct nvme_rdma_queue *queue)
{
        if (test_and_set_bit(NVME_RDMA_Q_DELETING, &queue->flags))
                return;
        nvme_rdma_stop_queue(queue);
        nvme_rdma_free_queue(queue);
}

static void nvme_rdma_free_io_queues(struct nvme_rdma_ctrl *ctrl)
{
        int i;

        for (i = 1; i < ctrl->queue_count; i++)
                nvme_rdma_stop_and_free_queue(&ctrl->queues[i]);
}

static int nvme_rdma_connect_io_queues(struct nvme_rdma_ctrl *ctrl)
{
        int i, ret = 0;

        for (i = 1; i < ctrl->queue_count; i++) {
                ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
                if (ret)
                        break;
        }

        return ret;
}

static int nvme_rdma_init_io_queues(struct nvme_rdma_ctrl *ctrl)
{
        int i, ret;

        for (i = 1; i < ctrl->queue_count; i++) {
                ret = nvme_rdma_init_queue(ctrl, i,
                                           ctrl->ctrl.opts->queue_size);
                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--; i >= 1; i--)
                nvme_rdma_stop_and_free_queue(&ctrl->queues[i]);

        return ret;
}

static void nvme_rdma_destroy_admin_queue(struct nvme_rdma_ctrl *ctrl)
{
        nvme_rdma_free_qe(ctrl->queues[0].device->dev, &ctrl->async_event_sqe,
                        sizeof(struct nvme_command), DMA_TO_DEVICE);
        nvme_rdma_stop_and_free_queue(&ctrl->queues[0]);
        blk_cleanup_queue(ctrl->ctrl.admin_q);
        blk_mq_free_tag_set(&ctrl->admin_tag_set);
        nvme_rdma_dev_put(ctrl->device);
}

static void nvme_rdma_free_ctrl(struct nvme_ctrl *nctrl)
{
        struct nvme_rdma_ctrl *ctrl = to_rdma_ctrl(nctrl);

        if (list_empty(&ctrl->list))
                goto free_ctrl;

        mutex_lock(&nvme_rdma_ctrl_mutex);
        list_del(&ctrl->list);
        mutex_unlock(&nvme_rdma_ctrl_mutex);

        kfree(ctrl->queues);
        nvmf_free_options(nctrl->opts);
free_ctrl:
        kfree(ctrl);
}

static void nvme_rdma_reconnect_ctrl_work(struct work_struct *work)
{
        struct nvme_rdma_ctrl *ctrl = container_of(to_delayed_work(work),
                        struct nvme_rdma_ctrl, reconnect_work);
        bool changed;
        int ret;

        if (ctrl->queue_count > 1) {
                nvme_rdma_free_io_queues(ctrl);

                ret = blk_mq_reinit_tagset(&ctrl->tag_set);
                if (ret)
                        goto requeue;
        }

        nvme_rdma_stop_and_free_queue(&ctrl->queues[0]);

        ret = blk_mq_reinit_tagset(&ctrl->admin_tag_set);
        if (ret)
                goto requeue;

        ret = nvme_rdma_init_queue(ctrl, 0, NVMF_AQ_DEPTH);
        if (ret)
                goto requeue;

        blk_mq_start_stopped_hw_queues(ctrl->ctrl.admin_q, true);

        ret = nvmf_connect_admin_queue(&ctrl->ctrl);
        if (ret)
                goto stop_admin_q;

        ret = nvme_enable_ctrl(&ctrl->ctrl, ctrl->cap);
        if (ret)
                goto stop_admin_q;

        nvme_start_keep_alive(&ctrl->ctrl);

        if (ctrl->queue_count > 1) {
                ret = nvme_rdma_init_io_queues(ctrl);
                if (ret)
                        goto stop_admin_q;

                ret = nvme_rdma_connect_io_queues(ctrl);
                if (ret)
                        goto stop_admin_q;
        }

        changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
        WARN_ON_ONCE(!changed);

        if (ctrl->queue_count > 1) {
                nvme_start_queues(&ctrl->ctrl);
                nvme_queue_scan(&ctrl->ctrl);
                nvme_queue_async_events(&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);
        int i;

        nvme_stop_keep_alive(&ctrl->ctrl);

        for (i = 0; i < ctrl->queue_count; i++)
                clear_bit(NVME_RDMA_Q_CONNECTED, &ctrl->queues[i].flags);

        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->mr->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->mr->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->mr->need_inval = false;

        c->common.flags |= NVME_CMD_SGL_METABUF;

        if (!blk_rq_bytes(rq))
                return nvme_rdma_set_sg_null(c);

        req->sg_table.sgl = req->first_sgl;
        ret = sg_alloc_table_chained(&req->sg_table, rq->nr_phys_segments,
                                req->sg_table.sgl);
        if (ret)
                return -ENOMEM;

        nents = blk_rq_map_sg(rq->q, rq, req->sg_table.sgl);
        BUG_ON(nents > rq->nr_phys_segments);
        req->nents = nents;

        count = ib_dma_map_sg(ibdev, req->sg_table.sgl, nents,
                    rq_data_dir(rq) == WRITE ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
        if (unlikely(count <= 0)) {
                sg_free_table_chained(&req->sg_table, true);
                return -EIO;
        }

        if (count == 1) {
                if (rq_data_dir(rq) == WRITE &&
                    map_len <= nvme_rdma_inline_data_size(queue) &&
                    nvme_rdma_queue_idx(queue))
                        return nvme_rdma_map_sg_inline(queue, req, c);

                if (!register_always)
                        return nvme_rdma_map_sg_single(queue, req, c);
        }

        return nvme_rdma_map_sg_fr(queue, req, c, count);
}

static void nvme_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc)
{
        if (unlikely(wc->status != IB_WC_SUCCESS))
                nvme_rdma_wr_error(cq, wc, "SEND");
}

static int nvme_rdma_post_send(struct nvme_rdma_queue *queue,
                struct nvme_rdma_qe *qe, struct ib_sge *sge, u32 num_sge,
                struct ib_send_wr *first, bool flush)
{
        struct ib_send_wr wr, *bad_wr;
        int ret;

        sge->addr   = qe->dma;
        sge->length = sizeof(struct nvme_command),
        sge->lkey   = queue->device->pd->local_dma_lkey;

        qe->cqe.done = nvme_rdma_send_done;

        wr.next       = NULL;
        wr.wr_cqe     = &qe->cqe;
        wr.sg_list    = sge;
        wr.num_sge    = num_sge;
        wr.opcode     = IB_WR_SEND;
        wr.send_flags = 0;

        /*
         * Unsignalled send completions are another giant desaster in the
         * IB Verbs spec:  If we don't regularly post signalled sends
         * the send queue will fill up and only a QP reset will rescue us.
         * Would have been way to obvious to handle this in hardware or
         * at least the RDMA stack..
         *
         * This messy and racy code sniplet is copy and pasted from the iSER
         * initiator, and the magic '32' comes from there as well.
         *
         * Always signal the flushes. The magic request used for the flush
         * sequencer is not allocated in our driver's tagset and it's
         * triggered to be freed by blk_cleanup_queue(). So we need to
         * always mark it as signaled to ensure that the "wr_cqe", which is
         * embeded in request's payload, is not freed when __ib_process_cq()
         * calls wr_cqe->done().
         */
        if ((++queue->sig_count % 32) == 0 || flush)
                wr.send_flags |= IB_SEND_SIGNALED;

        if (first)
                first->next = &wr;
        else
                first = &wr;

        ret = ib_post_send(queue->qp, first, &bad_wr);
        if (ret) {
                dev_err(queue->ctrl->ctrl.device,
                             "%s failed with error code %d\n", __func__, ret);
        }
        return ret;
}

static int nvme_rdma_post_recv(struct nvme_rdma_queue *queue,
                struct nvme_rdma_qe *qe)
{
        struct ib_recv_wr wr, *bad_wr;
        struct ib_sge list;
        int ret;

        list.addr   = qe->dma;
        list.length = sizeof(struct nvme_completion);
        list.lkey   = queue->device->pd->local_dma_lkey;

        qe->cqe.done = nvme_rdma_recv_done;

        wr.next     = NULL;
        wr.wr_cqe   = &qe->cqe;
        wr.sg_list  = &list;
        wr.num_sge  = 1;

        ret = ib_post_recv(queue->qp, &wr, &bad_wr);
        if (ret) {
                dev_err(queue->ctrl->ctrl.device,
                        "%s failed with error code %d\n", __func__, ret);
        }
        return ret;
}

static struct blk_mq_tags *nvme_rdma_tagset(struct nvme_rdma_queue *queue)
{
        u32 queue_idx = nvme_rdma_queue_idx(queue);

        if (queue_idx == 0)
                return queue->ctrl->admin_tag_set.tags[queue_idx];
        return queue->ctrl->tag_set.tags[queue_idx - 1];
}

static void nvme_rdma_submit_async_event(struct nvme_ctrl *arg, int aer_idx)
{
        struct nvme_rdma_ctrl *ctrl = to_rdma_ctrl(arg);
        struct nvme_rdma_queue *queue = &ctrl->queues[0];
        struct ib_device *dev = queue->device->dev;
        struct nvme_rdma_qe *sqe = &ctrl->async_event_sqe;
        struct nvme_command *cmd = sqe->data;
        struct ib_sge sge;
        int ret;

        if (WARN_ON_ONCE(aer_idx != 0))
                return;

        ib_dma_sync_single_for_cpu(dev, sqe->dma, sizeof(*cmd), DMA_TO_DEVICE);

        memset(cmd, 0, sizeof(*cmd));
        cmd->common.opcode = nvme_admin_async_event;
        cmd->common.command_id = NVME_RDMA_AQ_BLKMQ_DEPTH;
        cmd->common.flags |= NVME_CMD_SGL_METABUF;
        nvme_rdma_set_sg_null(cmd);

        ib_dma_sync_single_for_device(dev, sqe->dma, sizeof(*cmd),
                        DMA_TO_DEVICE);

        ret = nvme_rdma_post_send(queue, sqe, &sge, 1, NULL, false);
        WARN_ON_ONCE(ret);
}

static int nvme_rdma_process_nvme_rsp(struct nvme_rdma_queue *queue,
                struct nvme_completion *cqe, struct ib_wc *wc, int tag)
{
        u16 status = le16_to_cpu(cqe->status);
        struct request *rq;
        struct nvme_rdma_request *req;
        int ret = 0;

        status >>= 1;

        rq = blk_mq_tag_to_rq(nvme_rdma_tagset(queue), cqe->command_id);
        if (!rq) {
                dev_err(queue->ctrl->ctrl.device,
                        "tag 0x%x on QP %#x not found\n",
                        cqe->command_id, queue->qp->qp_num);
                nvme_rdma_error_recovery(queue->ctrl);
                return ret;
        }
        req = blk_mq_rq_to_pdu(rq);

        if (rq->cmd_type == REQ_TYPE_DRV_PRIV && rq->special)
                memcpy(rq->special, cqe, sizeof(*cqe));

        if (rq->tag == tag)
                ret = 1;

        if ((wc->wc_flags & IB_WC_WITH_INVALIDATE) &&
            wc->ex.invalidate_rkey == req->mr->rkey)
                req->mr->need_inval = false;

        blk_mq_complete_request(rq, status);

        return ret;
}

static int __nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc, int tag)
{
        struct nvme_rdma_qe *qe =
                container_of(wc->wr_cqe, struct nvme_rdma_qe, cqe);
        struct nvme_rdma_queue *queue = cq->cq_context;
        struct ib_device *ibdev = queue->device->dev;
        struct nvme_completion *cqe = qe->data;
        const size_t len = sizeof(struct nvme_completion);
        int ret = 0;

        if (unlikely(wc->status != IB_WC_SUCCESS)) {
                nvme_rdma_wr_error(cq, wc, "RECV");
                return 0;
        }

        ib_dma_sync_single_for_cpu(ibdev, qe->dma, len, DMA_FROM_DEVICE);
        /*
         * AEN requests are special as they don't time out and can
         * survive any kind of queue freeze and often don't respond to
         * aborts.  We don't even bother to allocate a struct request
         * for them but rather special case them here.
         */
        if (unlikely(nvme_rdma_queue_idx(queue) == 0 &&
                        cqe->command_id >= NVME_RDMA_AQ_BLKMQ_DEPTH))
                nvme_complete_async_event(&queue->ctrl->ctrl, cqe);
        else
                ret = nvme_rdma_process_nvme_rsp(queue, cqe, wc, tag);
        ib_dma_sync_single_for_device(ibdev, qe->dma, len, DMA_FROM_DEVICE);

        nvme_rdma_post_recv(queue, qe);
        return ret;
}

static void nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
{
        __nvme_rdma_recv_done(cq, wc, -1);
}

static int nvme_rdma_conn_established(struct nvme_rdma_queue *queue)
{
        int ret, i;

        for (i = 0; i < queue->queue_size; i++) {
                ret = nvme_rdma_post_recv(queue, &queue->rsp_ring[i]);
                if (ret)
                        goto out_destroy_queue_ib;
        }

        return 0;

out_destroy_queue_ib:
        nvme_rdma_destroy_queue_ib(queue);
        return ret;
}

static int nvme_rdma_conn_rejected(struct nvme_rdma_queue *queue,
                struct rdma_cm_event *ev)
{
        if (ev->param.conn.private_data_len) {
                struct nvme_rdma_cm_rej *rej =
                        (struct nvme_rdma_cm_rej *)ev->param.conn.private_data;

                dev_err(queue->ctrl->ctrl.device,
                        "Connect rejected, status %d.", le16_to_cpu(rej->sts));
                /* XXX: Think of something clever to do here... */
        } else {
                dev_err(queue->ctrl->ctrl.device,
                        "Connect rejected, no private data.\n");
        }

        return -ECONNRESET;
}

static int nvme_rdma_addr_resolved(struct nvme_rdma_queue *queue)
{
        struct nvme_rdma_device *dev;
        int ret;

        dev = nvme_rdma_find_get_device(queue->cm_id);
        if (!dev) {
                dev_err(queue->cm_id->device->dma_device,
                        "no client data found!\n");
                return -ECONNREFUSED;
        }

        ret = nvme_rdma_create_queue_ib(queue, dev);
        if (ret) {
                nvme_rdma_dev_put(dev);
                goto out;
        }

        ret = rdma_resolve_route(queue->cm_id, NVME_RDMA_CONNECT_TIMEOUT_MS);
        if (ret) {
                dev_err(queue->ctrl->ctrl.device,
                        "rdma_resolve_route failed (%d).\n",
                        queue->cm_error);
                goto out_destroy_queue;
        }

        return 0;

out_destroy_queue:
        nvme_rdma_destroy_queue_ib(queue);
out:
        return ret;
}

static int nvme_rdma_route_resolved(struct nvme_rdma_queue *queue)
{
        struct nvme_rdma_ctrl *ctrl = queue->ctrl;
        struct rdma_conn_param param = { };
        struct nvme_rdma_cm_req priv = { };
        int ret;

        param.qp_num = queue->qp->qp_num;
        param.flow_control = 1;

        param.responder_resources = queue->device->dev->attrs.max_qp_rd_atom;
        /* maximum retry count */
        param.retry_count = 7;
        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));
        /*
         * set the admin queue depth to the minimum size
         * specified by the Fabrics standard.
         */
        if (priv.qid == 0) {
                priv.hrqsize = cpu_to_le16(NVMF_AQ_DEPTH);
                priv.hsqsize = cpu_to_le16(NVMF_AQ_DEPTH - 1);
        } else {
                /*
                 * current interpretation of the fabrics spec
                 * is at minimum you make hrqsize sqsize+1, or a
                 * 1's based representation of sqsize.
                 */
                priv.hrqsize = cpu_to_le16(queue->queue_size);
                priv.hsqsize = cpu_to_le16(queue->ctrl->ctrl.sqsize);
        }

        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;
}

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:
                /* device removal is handled via the ib_client API */
                break;
        default:
                dev_err(queue->ctrl->ctrl.device,
                        "Unexpected RDMA CM event (%d)\n", ev->event);
                nvme_rdma_error_recovery(queue->ctrl);
                break;
        }

        if (cm_error) {
                queue->cm_error = cm_error;
                complete(&queue->cm_done);
        }

        return 0;
}

static enum blk_eh_timer_return
nvme_rdma_timeout(struct request *rq, bool reserved)
{
        struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);

        /* queue error recovery */
        nvme_rdma_error_recovery(req->queue->ctrl);

        /* fail with DNR on cmd timeout */
        rq->errors = NVME_SC_ABORT_REQ | NVME_SC_DNR;

        return BLK_EH_HANDLED;
}

static int nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
                const struct blk_mq_queue_data *bd)
{
        struct nvme_ns *ns = hctx->queue->queuedata;
        struct nvme_rdma_queue *queue = hctx->driver_data;
        struct request *rq = bd->rq;
        struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
        struct nvme_rdma_qe *sqe = &req->sqe;
        struct nvme_command *c = sqe->data;
        bool flush = false;
        struct ib_device *dev;
        unsigned int map_len;
        int ret;

        WARN_ON_ONCE(rq->tag < 0);

        dev = queue->device->dev;
        ib_dma_sync_single_for_cpu(dev, sqe->dma,
                        sizeof(struct nvme_command), DMA_TO_DEVICE);

        ret = nvme_setup_cmd(ns, rq, c);
        if (ret)
                return ret;

        c->common.command_id = rq->tag;
        blk_mq_start_request(rq);

        map_len = nvme_map_len(rq);
        ret = nvme_rdma_map_data(queue, rq, map_len, c);
        if (ret < 0) {
                dev_err(queue->ctrl->ctrl.device,
                             "Failed to map data (%d)\n", ret);
                nvme_cleanup_cmd(rq);
                goto err;
        }

        ib_dma_sync_single_for_device(dev, sqe->dma,
                        sizeof(struct nvme_command), DMA_TO_DEVICE);

        if (rq->cmd_type == REQ_TYPE_FS && req_op(rq) == REQ_OP_FLUSH)
                flush = true;
        ret = nvme_rdma_post_send(queue, sqe, req->sge, req->num_sge,
                        req->mr->need_inval ? &req->reg_wr.wr : NULL, flush);
        if (ret) {
                nvme_rdma_unmap_data(queue, rq);
                goto err;
        }

        return BLK_MQ_RQ_QUEUE_OK;
err:
        return (ret == -ENOMEM || ret == -EAGAIN) ?
                BLK_MQ_RQ_QUEUE_BUSY : BLK_MQ_RQ_QUEUE_ERROR;
}

static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag)
{
        struct nvme_rdma_queue *queue = hctx->driver_data;
        struct ib_cq *cq = queue->ib_cq;
        struct ib_wc wc;
        int found = 0;

        ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
        while (ib_poll_cq(cq, 1, &wc) > 0) {
                struct ib_cqe *cqe = wc.wr_cqe;

                if (cqe) {
                        if (cqe->done == nvme_rdma_recv_done)
                                found |= __nvme_rdma_recv_done(cq, &wc, tag);
                        else
                                cqe->done(cq, &wc);
                }
        }

        return found;
}

static void nvme_rdma_complete_rq(struct request *rq)
{
        struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
        struct nvme_rdma_queue *queue = req->queue;
        int error = 0;

        nvme_rdma_unmap_data(queue, rq);

        if (unlikely(rq->errors)) {
                if (nvme_req_needs_retry(rq, rq->errors)) {
                        nvme_requeue_req(rq);
                        return;
                }

                if (rq->cmd_type == REQ_TYPE_DRV_PRIV)
                        error = rq->errors;
                else
                        error = nvme_error_status(rq->errors);
        }

        blk_mq_end_request(rq, error);
}

static struct blk_mq_ops nvme_rdma_mq_ops = {
        .queue_rq       = nvme_rdma_queue_rq,
        .complete       = nvme_rdma_complete_rq,
        .map_queue      = blk_mq_map_queue,
        .init_request   = nvme_rdma_init_request,
        .exit_request   = nvme_rdma_exit_request,
        .reinit_request = nvme_rdma_reinit_request,
        .init_hctx      = nvme_rdma_init_hctx,
        .poll           = nvme_rdma_poll,
        .timeout        = nvme_rdma_timeout,
};

static struct blk_mq_ops nvme_rdma_admin_mq_ops = {
        .queue_rq       = nvme_rdma_queue_rq,
        .complete       = nvme_rdma_complete_rq,
        .map_queue      = blk_mq_map_queue,
        .init_request   = nvme_rdma_init_admin_request,
        .exit_request   = nvme_rdma_exit_admin_request,
        .reinit_request = nvme_rdma_reinit_request,
        .init_hctx      = nvme_rdma_init_admin_hctx,
        .timeout        = nvme_rdma_timeout,
};

static int nvme_rdma_configure_admin_queue(struct nvme_rdma_ctrl *ctrl)
{
        int error;

        error = nvme_rdma_init_queue(ctrl, 0, NVMF_AQ_DEPTH);
        if (error)
                return error;

        ctrl->device = ctrl->queues[0].device;

        /*
         * We need a reference on the device as long as the tag_set is alive,
         * as the MRs in the request structures need a valid ib_device.
         */
        error = -EINVAL;
        if (!nvme_rdma_dev_get(ctrl->device))
                goto out_free_queue;

        ctrl->max_fr_pages = min_t(u32, NVME_RDMA_MAX_SEGMENTS,
                ctrl->device->dev->attrs.max_fast_reg_page_list_len);

        memset(&ctrl->admin_tag_set, 0, sizeof(ctrl->admin_tag_set));
        ctrl->admin_tag_set.ops = &nvme_rdma_admin_mq_ops;
        ctrl->admin_tag_set.queue_depth = NVME_RDMA_AQ_BLKMQ_DEPTH;
        ctrl->admin_tag_set.reserved_tags = 2; /* connect + keep-alive */
        ctrl->admin_tag_set.numa_node = NUMA_NO_NODE;
        ctrl->admin_tag_set.cmd_size = sizeof(struct nvme_rdma_request) +
                SG_CHUNK_SIZE * sizeof(struct scatterlist);
        ctrl->admin_tag_set.driver_data = ctrl;
        ctrl->admin_tag_set.nr_hw_queues = 1;
        ctrl->admin_tag_set.timeout = ADMIN_TIMEOUT;

        error = blk_mq_alloc_tag_set(&ctrl->admin_tag_set);
        if (error)
                goto out_put_dev;

        ctrl->ctrl.admin_q = blk_mq_init_queue(&ctrl->admin_tag_set);
        if (IS_ERR(ctrl->ctrl.admin_q)) {
                error = PTR_ERR(ctrl->ctrl.admin_q);
                goto out_free_tagset;
        }

        error = nvmf_connect_admin_queue(&ctrl->ctrl);
        if (error)
                goto out_cleanup_queue;

        error = nvmf_reg_read64(&ctrl->ctrl, NVME_REG_CAP, &ctrl->cap);
        if (error) {
                dev_err(ctrl->ctrl.device,
                        "prop_get NVME_REG_CAP failed\n");
                goto out_cleanup_queue;
        }

        ctrl->ctrl.sqsize =
                min_t(int, NVME_CAP_MQES(ctrl->cap) + 1, ctrl->ctrl.sqsize);

        error = nvme_enable_ctrl(&ctrl->ctrl, ctrl->cap);
        if (error)
                goto out_cleanup_queue;

        ctrl->ctrl.max_hw_sectors =
                (ctrl->max_fr_pages - 1) << (PAGE_SHIFT - 9);

        error = nvme_init_identify(&ctrl->ctrl);
        if (error)
                goto out_cleanup_queue;

        error = nvme_rdma_alloc_qe(ctrl->queues[0].device->dev,
                        &ctrl->async_event_sqe, sizeof(struct nvme_command),
                        DMA_TO_DEVICE);
        if (error)
                goto out_cleanup_queue;

        nvme_start_keep_alive(&ctrl->ctrl);

        return 0;

out_cleanup_queue:
        blk_cleanup_queue(ctrl->ctrl.admin_q);
out_free_tagset:
        /* disconnect and drain the queue before freeing the tagset */
        nvme_rdma_stop_queue(&ctrl->queues[0]);
        blk_mq_free_tag_set(&ctrl->admin_tag_set);
out_put_dev:
        nvme_rdma_dev_put(ctrl->device);
out_free_queue:
        nvme_rdma_free_queue(&ctrl->queues[0]);
        return error;
}

static void nvme_rdma_shutdown_ctrl(struct nvme_rdma_ctrl *ctrl)
{
        nvme_stop_keep_alive(&ctrl->ctrl);
        cancel_work_sync(&ctrl->err_work);
        cancel_delayed_work_sync(&ctrl->reconnect_work);

        if (ctrl->queue_count > 1) {
                nvme_stop_queues(&ctrl->ctrl);
                blk_mq_tagset_busy_iter(&ctrl->tag_set,
                                        nvme_cancel_request, &ctrl->ctrl);
                nvme_rdma_free_io_queues(ctrl);
        }

        if (test_bit(NVME_RDMA_Q_CONNECTED, &ctrl->queues[0].flags))
                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_remove_ctrl(struct nvme_rdma_ctrl *ctrl, bool shutdown)
{
        nvme_uninit_ctrl(&ctrl->ctrl);
        if (shutdown)
                nvme_rdma_shutdown_ctrl(ctrl);

        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);
        }

        nvme_put_ctrl(&ctrl->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_rdma_remove_ctrl(ctrl, true);
}

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 = 0;

        /*
         * Keep a reference until all work is flushed since
         * __nvme_rdma_del_ctrl can free the ctrl mem
         */
        if (!kref_get_unless_zero(&ctrl->ctrl.kref))
                return -EBUSY;
        ret = __nvme_rdma_del_ctrl(ctrl);
        if (!ret)
                flush_work(&ctrl->delete_work);
        nvme_put_ctrl(&ctrl->ctrl);
        return ret;
}

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_rdma_remove_ctrl(ctrl, false);
}

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);
                nvme_queue_async_events(&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.opts->queue_size;
        ctrl->tag_set.reserved_tags = 1; /* fabric connect */
        ctrl->tag_set.numa_node = NUMA_NO_NODE;
        ctrl->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
        ctrl->tag_set.cmd_size = sizeof(struct nvme_rdma_request) +
                SG_CHUNK_SIZE * sizeof(struct scatterlist);
        ctrl->tag_set.driver_data = ctrl;
        ctrl->tag_set.nr_hw_queues = ctrl->queue_count - 1;
        ctrl->tag_set.timeout = NVME_IO_TIMEOUT;

        ret = blk_mq_alloc_tag_set(&ctrl->tag_set);
        if (ret)
                goto out_put_dev;
        ctrl->ctrl.tagset = &ctrl->tag_set;

        ctrl->ctrl.connect_q = blk_mq_init_queue(&ctrl->tag_set);
        if (IS_ERR(ctrl->ctrl.connect_q)) {
                ret = PTR_ERR(ctrl->ctrl.connect_q);
                goto out_free_tag_set;
        }

        ret = nvme_rdma_connect_io_queues(ctrl);
        if (ret)
                goto out_cleanup_connect_q;

        return 0;

out_cleanup_connect_q:
        blk_cleanup_queue(ctrl->ctrl.connect_q);
out_free_tag_set:
        blk_mq_free_tag_set(&ctrl->tag_set);
out_put_dev:
        nvme_rdma_dev_put(ctrl->device);
out_free_io_queues:
        nvme_rdma_free_io_queues(ctrl);
        return ret;
}

static int nvme_rdma_parse_ipaddr(struct sockaddr_in *in_addr, char *p)
{
        u8 *addr = (u8 *)&in_addr->sin_addr.s_addr;
        size_t buflen = strlen(p);

        /* XXX: handle IPv6 addresses */

        if (buflen > INET_ADDRSTRLEN)
                return -EINVAL;
        if (in4_pton(p, buflen, addr, '\0', NULL) == 0)
                return -EINVAL;
        in_addr->sin_family = AF_INET;
        return 0;
}

static struct nvme_ctrl *nvme_rdma_create_ctrl(struct device *dev,
                struct nvmf_ctrl_options *opts)
{
        struct nvme_rdma_ctrl *ctrl;
        int ret;
        bool changed;

        ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
        if (!ctrl)
                return ERR_PTR(-ENOMEM);
        ctrl->ctrl.opts = opts;
        INIT_LIST_HEAD(&ctrl->list);

        ret = nvme_rdma_parse_ipaddr(&ctrl->addr_in, opts->traddr);
        if (ret) {
                pr_err("malformed IP address passed: %s\n", opts->traddr);
                goto out_free_ctrl;
        }

        if (opts->mask & NVMF_OPT_TRSVCID) {
                u16 port;

                ret = kstrtou16(opts->trsvcid, 0, &port);
                if (ret)
                        goto out_free_ctrl;

                ctrl->addr_in.sin_port = cpu_to_be16(port);
        } else {
                ctrl->addr_in.sin_port = cpu_to_be16(NVME_RDMA_IP_PORT);
        }

        ret = nvme_init_ctrl(&ctrl->ctrl, dev, &nvme_rdma_ctrl_ops,
                                0 /* no quirks, we're perfect! */);
        if (ret)
                goto out_free_ctrl;

        ctrl->reconnect_delay = opts->reconnect_delay;
        INIT_DELAYED_WORK(&ctrl->reconnect_work,
                        nvme_rdma_reconnect_ctrl_work);
        INIT_WORK(&ctrl->err_work, nvme_rdma_error_recovery_work);
        INIT_WORK(&ctrl->delete_work, nvme_rdma_del_ctrl_work);
        INIT_WORK(&ctrl->reset_work, nvme_rdma_reset_ctrl_work);
        spin_lock_init(&ctrl->lock);

        ctrl->queue_count = opts->nr_io_queues + 1; /* +1 for admin queue */
        ctrl->ctrl.sqsize = opts->queue_size - 1;
        ctrl->ctrl.kato = opts->kato;

        ret = -ENOMEM;
        ctrl->queues = kcalloc(ctrl->queue_count, sizeof(*ctrl->queues),
                                GFP_KERNEL);
        if (!ctrl->queues)
                goto out_uninit_ctrl;

        ret = nvme_rdma_configure_admin_queue(ctrl);
        if (ret)
                goto out_kfree_queues;

        /* sanity check icdoff */
        if (ctrl->ctrl.icdoff) {
                dev_err(ctrl->ctrl.device, "icdoff is not supported!\n");
                goto out_remove_admin_queue;
        }

        /* sanity check keyed sgls */
        if (!(ctrl->ctrl.sgls & (1 << 20))) {
                dev_err(ctrl->ctrl.device, "Mandatory keyed sgls are not support\n");
                goto out_remove_admin_queue;
        }

        if (opts->queue_size > ctrl->ctrl.maxcmd) {
                /* warn if maxcmd is lower than queue_size */
                dev_warn(ctrl->ctrl.device,
                        "queue_size %zu > ctrl maxcmd %u, clamping down\n",
                        opts->queue_size, ctrl->ctrl.maxcmd);
                opts->queue_size = ctrl->ctrl.maxcmd;
        }

        if (opts->nr_io_queues) {
                ret = nvme_rdma_create_io_queues(ctrl);
                if (ret)
                        goto out_remove_admin_queue;
        }

        changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
        WARN_ON_ONCE(!changed);

        dev_info(ctrl->ctrl.device, "new ctrl: NQN \"%s\", addr %pISp\n",
                ctrl->ctrl.opts->subsysnqn, &ctrl->addr);

        kref_get(&ctrl->ctrl.kref);

        mutex_lock(&nvme_rdma_ctrl_mutex);
        list_add_tail(&ctrl->list, &nvme_rdma_ctrl_list);
        mutex_unlock(&nvme_rdma_ctrl_mutex);

        if (opts->nr_io_queues) {
                nvme_queue_scan(&ctrl->ctrl);
                nvme_queue_async_events(&ctrl->ctrl);
        }

        return &ctrl->ctrl;

out_remove_admin_queue:
        nvme_stop_keep_alive(&ctrl->ctrl);
        nvme_rdma_destroy_admin_queue(ctrl);
out_kfree_queues:
        kfree(ctrl->queues);
out_uninit_ctrl:
        nvme_uninit_ctrl(&ctrl->ctrl);
        nvme_put_ctrl(&ctrl->ctrl);
        if (ret > 0)
                ret = -EIO;
        return ERR_PTR(ret);
out_free_ctrl:
        kfree(ctrl);
        return ERR_PTR(ret);
}

static struct nvmf_transport_ops nvme_rdma_transport = {
        .name           = "rdma",
        .required_opts  = NVMF_OPT_TRADDR,
        .allowed_opts   = NVMF_OPT_TRSVCID | NVMF_OPT_RECONNECT_DELAY,
        .create_ctrl    = nvme_rdma_create_ctrl,
};

static void nvme_rdma_add_one(struct ib_device *ib_device)
{
}

static void nvme_rdma_remove_one(struct ib_device *ib_device, void *client_data)
{
        struct nvme_rdma_ctrl *ctrl;

        /* Delete all controllers using this device */
        mutex_lock(&nvme_rdma_ctrl_mutex);
        list_for_each_entry(ctrl, &nvme_rdma_ctrl_list, list) {
                if (ctrl->device->dev != ib_device)
                        continue;
                dev_info(ctrl->ctrl.device,
                        "Removing ctrl: NQN \"%s\", addr %pISp\n",
                        ctrl->ctrl.opts->subsysnqn, &ctrl->addr);
                __nvme_rdma_del_ctrl(ctrl);
        }
        mutex_unlock(&nvme_rdma_ctrl_mutex);

        flush_workqueue(nvme_rdma_wq);
}

static struct ib_client nvme_rdma_ib_client = {
        .name   = "nvme_rdma",
        .add = nvme_rdma_add_one,
        .remove = nvme_rdma_remove_one
};

static int __init nvme_rdma_init_module(void)
{
        int ret;

        nvme_rdma_wq = create_workqueue("nvme_rdma_wq");
        if (!nvme_rdma_wq)
                return -ENOMEM;

        ret = ib_register_client(&nvme_rdma_ib_client);
        if (ret) {
                destroy_workqueue(nvme_rdma_wq);
                return ret;
        }

        nvmf_register_transport(&nvme_rdma_transport);
        return 0;
}

static void __exit nvme_rdma_cleanup_module(void)
{
        nvmf_unregister_transport(&nvme_rdma_transport);
        ib_unregister_client(&nvme_rdma_ib_client);
        destroy_workqueue(nvme_rdma_wq);
}

module_init(nvme_rdma_init_module);
module_exit(nvme_rdma_cleanup_module);

MODULE_LICENSE("GPL v2");