nvmet-rdma: add a NVMe over Fabrics RDMA target driver
[cascardo/linux.git] / drivers / nvme / target / rdma.c
diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
new file mode 100644 (file)
index 0000000..e06d504
--- /dev/null
@@ -0,0 +1,1448 @@
+/*
+ * NVMe over Fabrics RDMA target.
+ * Copyright (c) 2015-2016 HGST, a Western Digital Company.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/atomic.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/nvme.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/wait.h>
+#include <linux/inet.h>
+#include <asm/unaligned.h>
+
+#include <rdma/ib_verbs.h>
+#include <rdma/rdma_cm.h>
+#include <rdma/rw.h>
+
+#include <linux/nvme-rdma.h>
+#include "nvmet.h"
+
+/*
+ * We allow up to a page of inline data to go with the SQE
+ */
+#define NVMET_RDMA_INLINE_DATA_SIZE    PAGE_SIZE
+
+struct nvmet_rdma_cmd {
+       struct ib_sge           sge[2];
+       struct ib_cqe           cqe;
+       struct ib_recv_wr       wr;
+       struct scatterlist      inline_sg;
+       struct page             *inline_page;
+       struct nvme_command     *nvme_cmd;
+       struct nvmet_rdma_queue *queue;
+};
+
+enum {
+       NVMET_RDMA_REQ_INLINE_DATA      = (1 << 0),
+       NVMET_RDMA_REQ_INVALIDATE_RKEY  = (1 << 1),
+};
+
+struct nvmet_rdma_rsp {
+       struct ib_sge           send_sge;
+       struct ib_cqe           send_cqe;
+       struct ib_send_wr       send_wr;
+
+       struct nvmet_rdma_cmd   *cmd;
+       struct nvmet_rdma_queue *queue;
+
+       struct ib_cqe           read_cqe;
+       struct rdma_rw_ctx      rw;
+
+       struct nvmet_req        req;
+
+       u8                      n_rdma;
+       u32                     flags;
+       u32                     invalidate_rkey;
+
+       struct list_head        wait_list;
+       struct list_head        free_list;
+};
+
+enum nvmet_rdma_queue_state {
+       NVMET_RDMA_Q_CONNECTING,
+       NVMET_RDMA_Q_LIVE,
+       NVMET_RDMA_Q_DISCONNECTING,
+};
+
+struct nvmet_rdma_queue {
+       struct rdma_cm_id       *cm_id;
+       struct nvmet_port       *port;
+       struct ib_cq            *cq;
+       atomic_t                sq_wr_avail;
+       struct nvmet_rdma_device *dev;
+       spinlock_t              state_lock;
+       enum nvmet_rdma_queue_state state;
+       struct nvmet_cq         nvme_cq;
+       struct nvmet_sq         nvme_sq;
+
+       struct nvmet_rdma_rsp   *rsps;
+       struct list_head        free_rsps;
+       spinlock_t              rsps_lock;
+       struct nvmet_rdma_cmd   *cmds;
+
+       struct work_struct      release_work;
+       struct list_head        rsp_wait_list;
+       struct list_head        rsp_wr_wait_list;
+       spinlock_t              rsp_wr_wait_lock;
+
+       int                     idx;
+       int                     host_qid;
+       int                     recv_queue_size;
+       int                     send_queue_size;
+
+       struct list_head        queue_list;
+};
+
+struct nvmet_rdma_device {
+       struct ib_device        *device;
+       struct ib_pd            *pd;
+       struct ib_srq           *srq;
+       struct nvmet_rdma_cmd   *srq_cmds;
+       size_t                  srq_size;
+       struct kref             ref;
+       struct list_head        entry;
+};
+
+static bool nvmet_rdma_use_srq;
+module_param_named(use_srq, nvmet_rdma_use_srq, bool, 0444);
+MODULE_PARM_DESC(use_srq, "Use shared receive queue.");
+
+static DEFINE_IDA(nvmet_rdma_queue_ida);
+static LIST_HEAD(nvmet_rdma_queue_list);
+static DEFINE_MUTEX(nvmet_rdma_queue_mutex);
+
+static LIST_HEAD(device_list);
+static DEFINE_MUTEX(device_list_mutex);
+
+static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp);
+static void nvmet_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc);
+static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc);
+static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc);
+static void nvmet_rdma_qp_event(struct ib_event *event, void *priv);
+static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue);
+
+static struct nvmet_fabrics_ops nvmet_rdma_ops;
+
+/* XXX: really should move to a generic header sooner or later.. */
+static inline u32 get_unaligned_le24(const u8 *p)
+{
+       return (u32)p[0] | (u32)p[1] << 8 | (u32)p[2] << 16;
+}
+
+static inline bool nvmet_rdma_need_data_in(struct nvmet_rdma_rsp *rsp)
+{
+       return nvme_is_write(rsp->req.cmd) &&
+               rsp->req.data_len &&
+               !(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
+}
+
+static inline bool nvmet_rdma_need_data_out(struct nvmet_rdma_rsp *rsp)
+{
+       return !nvme_is_write(rsp->req.cmd) &&
+               rsp->req.data_len &&
+               !rsp->req.rsp->status &&
+               !(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
+}
+
+static inline struct nvmet_rdma_rsp *
+nvmet_rdma_get_rsp(struct nvmet_rdma_queue *queue)
+{
+       struct nvmet_rdma_rsp *rsp;
+       unsigned long flags;
+
+       spin_lock_irqsave(&queue->rsps_lock, flags);
+       rsp = list_first_entry(&queue->free_rsps,
+                               struct nvmet_rdma_rsp, free_list);
+       list_del(&rsp->free_list);
+       spin_unlock_irqrestore(&queue->rsps_lock, flags);
+
+       return rsp;
+}
+
+static inline void
+nvmet_rdma_put_rsp(struct nvmet_rdma_rsp *rsp)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&rsp->queue->rsps_lock, flags);
+       list_add_tail(&rsp->free_list, &rsp->queue->free_rsps);
+       spin_unlock_irqrestore(&rsp->queue->rsps_lock, flags);
+}
+
+static void nvmet_rdma_free_sgl(struct scatterlist *sgl, unsigned int nents)
+{
+       struct scatterlist *sg;
+       int count;
+
+       if (!sgl || !nents)
+               return;
+
+       for_each_sg(sgl, sg, nents, count)
+               __free_page(sg_page(sg));
+       kfree(sgl);
+}
+
+static int nvmet_rdma_alloc_sgl(struct scatterlist **sgl, unsigned int *nents,
+               u32 length)
+{
+       struct scatterlist *sg;
+       struct page *page;
+       unsigned int nent;
+       int i = 0;
+
+       nent = DIV_ROUND_UP(length, PAGE_SIZE);
+       sg = kmalloc_array(nent, sizeof(struct scatterlist), GFP_KERNEL);
+       if (!sg)
+               goto out;
+
+       sg_init_table(sg, nent);
+
+       while (length) {
+               u32 page_len = min_t(u32, length, PAGE_SIZE);
+
+               page = alloc_page(GFP_KERNEL);
+               if (!page)
+                       goto out_free_pages;
+
+               sg_set_page(&sg[i], page, page_len, 0);
+               length -= page_len;
+               i++;
+       }
+       *sgl = sg;
+       *nents = nent;
+       return 0;
+
+out_free_pages:
+       while (i > 0) {
+               i--;
+               __free_page(sg_page(&sg[i]));
+       }
+       kfree(sg);
+out:
+       return NVME_SC_INTERNAL;
+}
+
+static int nvmet_rdma_alloc_cmd(struct nvmet_rdma_device *ndev,
+                       struct nvmet_rdma_cmd *c, bool admin)
+{
+       /* NVMe command / RDMA RECV */
+       c->nvme_cmd = kmalloc(sizeof(*c->nvme_cmd), GFP_KERNEL);
+       if (!c->nvme_cmd)
+               goto out;
+
+       c->sge[0].addr = ib_dma_map_single(ndev->device, c->nvme_cmd,
+                       sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
+       if (ib_dma_mapping_error(ndev->device, c->sge[0].addr))
+               goto out_free_cmd;
+
+       c->sge[0].length = sizeof(*c->nvme_cmd);
+       c->sge[0].lkey = ndev->pd->local_dma_lkey;
+
+       if (!admin) {
+               c->inline_page = alloc_pages(GFP_KERNEL,
+                               get_order(NVMET_RDMA_INLINE_DATA_SIZE));
+               if (!c->inline_page)
+                       goto out_unmap_cmd;
+               c->sge[1].addr = ib_dma_map_page(ndev->device,
+                               c->inline_page, 0, NVMET_RDMA_INLINE_DATA_SIZE,
+                               DMA_FROM_DEVICE);
+               if (ib_dma_mapping_error(ndev->device, c->sge[1].addr))
+                       goto out_free_inline_page;
+               c->sge[1].length = NVMET_RDMA_INLINE_DATA_SIZE;
+               c->sge[1].lkey = ndev->pd->local_dma_lkey;
+       }
+
+       c->cqe.done = nvmet_rdma_recv_done;
+
+       c->wr.wr_cqe = &c->cqe;
+       c->wr.sg_list = c->sge;
+       c->wr.num_sge = admin ? 1 : 2;
+
+       return 0;
+
+out_free_inline_page:
+       if (!admin) {
+               __free_pages(c->inline_page,
+                               get_order(NVMET_RDMA_INLINE_DATA_SIZE));
+       }
+out_unmap_cmd:
+       ib_dma_unmap_single(ndev->device, c->sge[0].addr,
+                       sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
+out_free_cmd:
+       kfree(c->nvme_cmd);
+
+out:
+       return -ENOMEM;
+}
+
+static void nvmet_rdma_free_cmd(struct nvmet_rdma_device *ndev,
+               struct nvmet_rdma_cmd *c, bool admin)
+{
+       if (!admin) {
+               ib_dma_unmap_page(ndev->device, c->sge[1].addr,
+                               NVMET_RDMA_INLINE_DATA_SIZE, DMA_FROM_DEVICE);
+               __free_pages(c->inline_page,
+                               get_order(NVMET_RDMA_INLINE_DATA_SIZE));
+       }
+       ib_dma_unmap_single(ndev->device, c->sge[0].addr,
+                               sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
+       kfree(c->nvme_cmd);
+}
+
+static struct nvmet_rdma_cmd *
+nvmet_rdma_alloc_cmds(struct nvmet_rdma_device *ndev,
+               int nr_cmds, bool admin)
+{
+       struct nvmet_rdma_cmd *cmds;
+       int ret = -EINVAL, i;
+
+       cmds = kcalloc(nr_cmds, sizeof(struct nvmet_rdma_cmd), GFP_KERNEL);
+       if (!cmds)
+               goto out;
+
+       for (i = 0; i < nr_cmds; i++) {
+               ret = nvmet_rdma_alloc_cmd(ndev, cmds + i, admin);
+               if (ret)
+                       goto out_free;
+       }
+
+       return cmds;
+
+out_free:
+       while (--i >= 0)
+               nvmet_rdma_free_cmd(ndev, cmds + i, admin);
+       kfree(cmds);
+out:
+       return ERR_PTR(ret);
+}
+
+static void nvmet_rdma_free_cmds(struct nvmet_rdma_device *ndev,
+               struct nvmet_rdma_cmd *cmds, int nr_cmds, bool admin)
+{
+       int i;
+
+       for (i = 0; i < nr_cmds; i++)
+               nvmet_rdma_free_cmd(ndev, cmds + i, admin);
+       kfree(cmds);
+}
+
+static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
+               struct nvmet_rdma_rsp *r)
+{
+       /* NVMe CQE / RDMA SEND */
+       r->req.rsp = kmalloc(sizeof(*r->req.rsp), GFP_KERNEL);
+       if (!r->req.rsp)
+               goto out;
+
+       r->send_sge.addr = ib_dma_map_single(ndev->device, r->req.rsp,
+                       sizeof(*r->req.rsp), DMA_TO_DEVICE);
+       if (ib_dma_mapping_error(ndev->device, r->send_sge.addr))
+               goto out_free_rsp;
+
+       r->send_sge.length = sizeof(*r->req.rsp);
+       r->send_sge.lkey = ndev->pd->local_dma_lkey;
+
+       r->send_cqe.done = nvmet_rdma_send_done;
+
+       r->send_wr.wr_cqe = &r->send_cqe;
+       r->send_wr.sg_list = &r->send_sge;
+       r->send_wr.num_sge = 1;
+       r->send_wr.send_flags = IB_SEND_SIGNALED;
+
+       /* Data In / RDMA READ */
+       r->read_cqe.done = nvmet_rdma_read_data_done;
+       return 0;
+
+out_free_rsp:
+       kfree(r->req.rsp);
+out:
+       return -ENOMEM;
+}
+
+static void nvmet_rdma_free_rsp(struct nvmet_rdma_device *ndev,
+               struct nvmet_rdma_rsp *r)
+{
+       ib_dma_unmap_single(ndev->device, r->send_sge.addr,
+                               sizeof(*r->req.rsp), DMA_TO_DEVICE);
+       kfree(r->req.rsp);
+}
+
+static int
+nvmet_rdma_alloc_rsps(struct nvmet_rdma_queue *queue)
+{
+       struct nvmet_rdma_device *ndev = queue->dev;
+       int nr_rsps = queue->recv_queue_size * 2;
+       int ret = -EINVAL, i;
+
+       queue->rsps = kcalloc(nr_rsps, sizeof(struct nvmet_rdma_rsp),
+                       GFP_KERNEL);
+       if (!queue->rsps)
+               goto out;
+
+       for (i = 0; i < nr_rsps; i++) {
+               struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
+
+               ret = nvmet_rdma_alloc_rsp(ndev, rsp);
+               if (ret)
+                       goto out_free;
+
+               list_add_tail(&rsp->free_list, &queue->free_rsps);
+       }
+
+       return 0;
+
+out_free:
+       while (--i >= 0) {
+               struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
+
+               list_del(&rsp->free_list);
+               nvmet_rdma_free_rsp(ndev, rsp);
+       }
+       kfree(queue->rsps);
+out:
+       return ret;
+}
+
+static void nvmet_rdma_free_rsps(struct nvmet_rdma_queue *queue)
+{
+       struct nvmet_rdma_device *ndev = queue->dev;
+       int i, nr_rsps = queue->recv_queue_size * 2;
+
+       for (i = 0; i < nr_rsps; i++) {
+               struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
+
+               list_del(&rsp->free_list);
+               nvmet_rdma_free_rsp(ndev, rsp);
+       }
+       kfree(queue->rsps);
+}
+
+static int nvmet_rdma_post_recv(struct nvmet_rdma_device *ndev,
+               struct nvmet_rdma_cmd *cmd)
+{
+       struct ib_recv_wr *bad_wr;
+
+       if (ndev->srq)
+               return ib_post_srq_recv(ndev->srq, &cmd->wr, &bad_wr);
+       return ib_post_recv(cmd->queue->cm_id->qp, &cmd->wr, &bad_wr);
+}
+
+static void nvmet_rdma_process_wr_wait_list(struct nvmet_rdma_queue *queue)
+{
+       spin_lock(&queue->rsp_wr_wait_lock);
+       while (!list_empty(&queue->rsp_wr_wait_list)) {
+               struct nvmet_rdma_rsp *rsp;
+               bool ret;
+
+               rsp = list_entry(queue->rsp_wr_wait_list.next,
+                               struct nvmet_rdma_rsp, wait_list);
+               list_del(&rsp->wait_list);
+
+               spin_unlock(&queue->rsp_wr_wait_lock);
+               ret = nvmet_rdma_execute_command(rsp);
+               spin_lock(&queue->rsp_wr_wait_lock);
+
+               if (!ret) {
+                       list_add(&rsp->wait_list, &queue->rsp_wr_wait_list);
+                       break;
+               }
+       }
+       spin_unlock(&queue->rsp_wr_wait_lock);
+}
+
+
+static void nvmet_rdma_release_rsp(struct nvmet_rdma_rsp *rsp)
+{
+       struct nvmet_rdma_queue *queue = rsp->queue;
+
+       atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);
+
+       if (rsp->n_rdma) {
+               rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
+                               queue->cm_id->port_num, rsp->req.sg,
+                               rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
+       }
+
+       if (rsp->req.sg != &rsp->cmd->inline_sg)
+               nvmet_rdma_free_sgl(rsp->req.sg, rsp->req.sg_cnt);
+
+       if (unlikely(!list_empty_careful(&queue->rsp_wr_wait_list)))
+               nvmet_rdma_process_wr_wait_list(queue);
+
+       nvmet_rdma_put_rsp(rsp);
+}
+
+static void nvmet_rdma_error_comp(struct nvmet_rdma_queue *queue)
+{
+       if (queue->nvme_sq.ctrl) {
+               nvmet_ctrl_fatal_error(queue->nvme_sq.ctrl);
+       } else {
+               /*
+                * we didn't setup the controller yet in case
+                * of admin connect error, just disconnect and
+                * cleanup the queue
+                */
+               nvmet_rdma_queue_disconnect(queue);
+       }
+}
+
+static void nvmet_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+       struct nvmet_rdma_rsp *rsp =
+               container_of(wc->wr_cqe, struct nvmet_rdma_rsp, send_cqe);
+
+       nvmet_rdma_release_rsp(rsp);
+
+       if (unlikely(wc->status != IB_WC_SUCCESS &&
+                    wc->status != IB_WC_WR_FLUSH_ERR)) {
+               pr_err("SEND for CQE 0x%p failed with status %s (%d).\n",
+                       wc->wr_cqe, ib_wc_status_msg(wc->status), wc->status);
+               nvmet_rdma_error_comp(rsp->queue);
+       }
+}
+
+static void nvmet_rdma_queue_response(struct nvmet_req *req)
+{
+       struct nvmet_rdma_rsp *rsp =
+               container_of(req, struct nvmet_rdma_rsp, req);
+       struct rdma_cm_id *cm_id = rsp->queue->cm_id;
+       struct ib_send_wr *first_wr, *bad_wr;
+
+       if (rsp->flags & NVMET_RDMA_REQ_INVALIDATE_RKEY) {
+               rsp->send_wr.opcode = IB_WR_SEND_WITH_INV;
+               rsp->send_wr.ex.invalidate_rkey = rsp->invalidate_rkey;
+       } else {
+               rsp->send_wr.opcode = IB_WR_SEND;
+       }
+
+       if (nvmet_rdma_need_data_out(rsp))
+               first_wr = rdma_rw_ctx_wrs(&rsp->rw, cm_id->qp,
+                               cm_id->port_num, NULL, &rsp->send_wr);
+       else
+               first_wr = &rsp->send_wr;
+
+       nvmet_rdma_post_recv(rsp->queue->dev, rsp->cmd);
+       if (ib_post_send(cm_id->qp, first_wr, &bad_wr)) {
+               pr_err("sending cmd response failed\n");
+               nvmet_rdma_release_rsp(rsp);
+       }
+}
+
+static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+       struct nvmet_rdma_rsp *rsp =
+               container_of(wc->wr_cqe, struct nvmet_rdma_rsp, read_cqe);
+       struct nvmet_rdma_queue *queue = cq->cq_context;
+
+       WARN_ON(rsp->n_rdma <= 0);
+       atomic_add(rsp->n_rdma, &queue->sq_wr_avail);
+       rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
+                       queue->cm_id->port_num, rsp->req.sg,
+                       rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
+       rsp->n_rdma = 0;
+
+       if (unlikely(wc->status != IB_WC_SUCCESS)) {
+               nvmet_rdma_release_rsp(rsp);
+               if (wc->status != IB_WC_WR_FLUSH_ERR) {
+                       pr_info("RDMA READ for CQE 0x%p failed with status %s (%d).\n",
+                               wc->wr_cqe, ib_wc_status_msg(wc->status), wc->status);
+                       nvmet_rdma_error_comp(queue);
+               }
+               return;
+       }
+
+       rsp->req.execute(&rsp->req);
+}
+
+static void nvmet_rdma_use_inline_sg(struct nvmet_rdma_rsp *rsp, u32 len,
+               u64 off)
+{
+       sg_init_table(&rsp->cmd->inline_sg, 1);
+       sg_set_page(&rsp->cmd->inline_sg, rsp->cmd->inline_page, len, off);
+       rsp->req.sg = &rsp->cmd->inline_sg;
+       rsp->req.sg_cnt = 1;
+}
+
+static u16 nvmet_rdma_map_sgl_inline(struct nvmet_rdma_rsp *rsp)
+{
+       struct nvme_sgl_desc *sgl = &rsp->req.cmd->common.dptr.sgl;
+       u64 off = le64_to_cpu(sgl->addr);
+       u32 len = le32_to_cpu(sgl->length);
+
+       if (!nvme_is_write(rsp->req.cmd))
+               return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+
+       if (off + len > NVMET_RDMA_INLINE_DATA_SIZE) {
+               pr_err("invalid inline data offset!\n");
+               return NVME_SC_SGL_INVALID_OFFSET | NVME_SC_DNR;
+       }
+
+       /* no data command? */
+       if (!len)
+               return 0;
+
+       nvmet_rdma_use_inline_sg(rsp, len, off);
+       rsp->flags |= NVMET_RDMA_REQ_INLINE_DATA;
+       return 0;
+}
+
+static u16 nvmet_rdma_map_sgl_keyed(struct nvmet_rdma_rsp *rsp,
+               struct nvme_keyed_sgl_desc *sgl, bool invalidate)
+{
+       struct rdma_cm_id *cm_id = rsp->queue->cm_id;
+       u64 addr = le64_to_cpu(sgl->addr);
+       u32 len = get_unaligned_le24(sgl->length);
+       u32 key = get_unaligned_le32(sgl->key);
+       int ret;
+       u16 status;
+
+       /* no data command? */
+       if (!len)
+               return 0;
+
+       /* use the already allocated data buffer if possible */
+       if (len <= NVMET_RDMA_INLINE_DATA_SIZE && rsp->queue->host_qid) {
+               nvmet_rdma_use_inline_sg(rsp, len, 0);
+       } else {
+               status = nvmet_rdma_alloc_sgl(&rsp->req.sg, &rsp->req.sg_cnt,
+                               len);
+               if (status)
+                       return status;
+       }
+
+       ret = rdma_rw_ctx_init(&rsp->rw, cm_id->qp, cm_id->port_num,
+                       rsp->req.sg, rsp->req.sg_cnt, 0, addr, key,
+                       nvmet_data_dir(&rsp->req));
+       if (ret < 0)
+               return NVME_SC_INTERNAL;
+       rsp->n_rdma += ret;
+
+       if (invalidate) {
+               rsp->invalidate_rkey = key;
+               rsp->flags |= NVMET_RDMA_REQ_INVALIDATE_RKEY;
+       }
+
+       return 0;
+}
+
+static u16 nvmet_rdma_map_sgl(struct nvmet_rdma_rsp *rsp)
+{
+       struct nvme_keyed_sgl_desc *sgl = &rsp->req.cmd->common.dptr.ksgl;
+
+       switch (sgl->type >> 4) {
+       case NVME_SGL_FMT_DATA_DESC:
+               switch (sgl->type & 0xf) {
+               case NVME_SGL_FMT_OFFSET:
+                       return nvmet_rdma_map_sgl_inline(rsp);
+               default:
+                       pr_err("invalid SGL subtype: %#x\n", sgl->type);
+                       return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+               }
+       case NVME_KEY_SGL_FMT_DATA_DESC:
+               switch (sgl->type & 0xf) {
+               case NVME_SGL_FMT_ADDRESS | NVME_SGL_FMT_INVALIDATE:
+                       return nvmet_rdma_map_sgl_keyed(rsp, sgl, true);
+               case NVME_SGL_FMT_ADDRESS:
+                       return nvmet_rdma_map_sgl_keyed(rsp, sgl, false);
+               default:
+                       pr_err("invalid SGL subtype: %#x\n", sgl->type);
+                       return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+               }
+       default:
+               pr_err("invalid SGL type: %#x\n", sgl->type);
+               return NVME_SC_SGL_INVALID_TYPE | NVME_SC_DNR;
+       }
+}
+
+static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp)
+{
+       struct nvmet_rdma_queue *queue = rsp->queue;
+
+       if (unlikely(atomic_sub_return(1 + rsp->n_rdma,
+                       &queue->sq_wr_avail) < 0)) {
+               pr_debug("IB send queue full (needed %d): queue %u cntlid %u\n",
+                               1 + rsp->n_rdma, queue->idx,
+                               queue->nvme_sq.ctrl->cntlid);
+               atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);
+               return false;
+       }
+
+       if (nvmet_rdma_need_data_in(rsp)) {
+               if (rdma_rw_ctx_post(&rsp->rw, queue->cm_id->qp,
+                               queue->cm_id->port_num, &rsp->read_cqe, NULL))
+                       nvmet_req_complete(&rsp->req, NVME_SC_DATA_XFER_ERROR);
+       } else {
+               rsp->req.execute(&rsp->req);
+       }
+
+       return true;
+}
+
+static void nvmet_rdma_handle_command(struct nvmet_rdma_queue *queue,
+               struct nvmet_rdma_rsp *cmd)
+{
+       u16 status;
+
+       cmd->queue = queue;
+       cmd->n_rdma = 0;
+       cmd->req.port = queue->port;
+
+       if (!nvmet_req_init(&cmd->req, &queue->nvme_cq,
+                       &queue->nvme_sq, &nvmet_rdma_ops))
+               return;
+
+       status = nvmet_rdma_map_sgl(cmd);
+       if (status)
+               goto out_err;
+
+       if (unlikely(!nvmet_rdma_execute_command(cmd))) {
+               spin_lock(&queue->rsp_wr_wait_lock);
+               list_add_tail(&cmd->wait_list, &queue->rsp_wr_wait_list);
+               spin_unlock(&queue->rsp_wr_wait_lock);
+       }
+
+       return;
+
+out_err:
+       nvmet_req_complete(&cmd->req, status);
+}
+
+static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+       struct nvmet_rdma_cmd *cmd =
+               container_of(wc->wr_cqe, struct nvmet_rdma_cmd, cqe);
+       struct nvmet_rdma_queue *queue = cq->cq_context;
+       struct nvmet_rdma_rsp *rsp;
+
+       if (unlikely(wc->status != IB_WC_SUCCESS)) {
+               if (wc->status != IB_WC_WR_FLUSH_ERR) {
+                       pr_err("RECV for CQE 0x%p failed with status %s (%d)\n",
+                               wc->wr_cqe, ib_wc_status_msg(wc->status),
+                               wc->status);
+                       nvmet_rdma_error_comp(queue);
+               }
+               return;
+       }
+
+       if (unlikely(wc->byte_len < sizeof(struct nvme_command))) {
+               pr_err("Ctrl Fatal Error: capsule size less than 64 bytes\n");
+               nvmet_rdma_error_comp(queue);
+               return;
+       }
+
+       cmd->queue = queue;
+       rsp = nvmet_rdma_get_rsp(queue);
+       rsp->cmd = cmd;
+       rsp->flags = 0;
+       rsp->req.cmd = cmd->nvme_cmd;
+
+       if (unlikely(queue->state != NVMET_RDMA_Q_LIVE)) {
+               unsigned long flags;
+
+               spin_lock_irqsave(&queue->state_lock, flags);
+               if (queue->state == NVMET_RDMA_Q_CONNECTING)
+                       list_add_tail(&rsp->wait_list, &queue->rsp_wait_list);
+               else
+                       nvmet_rdma_put_rsp(rsp);
+               spin_unlock_irqrestore(&queue->state_lock, flags);
+               return;
+       }
+
+       nvmet_rdma_handle_command(queue, rsp);
+}
+
+static void nvmet_rdma_destroy_srq(struct nvmet_rdma_device *ndev)
+{
+       if (!ndev->srq)
+               return;
+
+       nvmet_rdma_free_cmds(ndev, ndev->srq_cmds, ndev->srq_size, false);
+       ib_destroy_srq(ndev->srq);
+}
+
+static int nvmet_rdma_init_srq(struct nvmet_rdma_device *ndev)
+{
+       struct ib_srq_init_attr srq_attr = { NULL, };
+       struct ib_srq *srq;
+       size_t srq_size;
+       int ret, i;
+
+       srq_size = 4095;        /* XXX: tune */
+
+       srq_attr.attr.max_wr = srq_size;
+       srq_attr.attr.max_sge = 2;
+       srq_attr.attr.srq_limit = 0;
+       srq_attr.srq_type = IB_SRQT_BASIC;
+       srq = ib_create_srq(ndev->pd, &srq_attr);
+       if (IS_ERR(srq)) {
+               /*
+                * If SRQs aren't supported we just go ahead and use normal
+                * non-shared receive queues.
+                */
+               pr_info("SRQ requested but not supported.\n");
+               return 0;
+       }
+
+       ndev->srq_cmds = nvmet_rdma_alloc_cmds(ndev, srq_size, false);
+       if (IS_ERR(ndev->srq_cmds)) {
+               ret = PTR_ERR(ndev->srq_cmds);
+               goto out_destroy_srq;
+       }
+
+       ndev->srq = srq;
+       ndev->srq_size = srq_size;
+
+       for (i = 0; i < srq_size; i++)
+               nvmet_rdma_post_recv(ndev, &ndev->srq_cmds[i]);
+
+       return 0;
+
+out_destroy_srq:
+       ib_destroy_srq(srq);
+       return ret;
+}
+
+static void nvmet_rdma_free_dev(struct kref *ref)
+{
+       struct nvmet_rdma_device *ndev =
+               container_of(ref, struct nvmet_rdma_device, ref);
+
+       mutex_lock(&device_list_mutex);
+       list_del(&ndev->entry);
+       mutex_unlock(&device_list_mutex);
+
+       nvmet_rdma_destroy_srq(ndev);
+       ib_dealloc_pd(ndev->pd);
+
+       kfree(ndev);
+}
+
+static struct nvmet_rdma_device *
+nvmet_rdma_find_get_device(struct rdma_cm_id *cm_id)
+{
+       struct nvmet_rdma_device *ndev;
+       int ret;
+
+       mutex_lock(&device_list_mutex);
+       list_for_each_entry(ndev, &device_list, entry) {
+               if (ndev->device->node_guid == cm_id->device->node_guid &&
+                   kref_get_unless_zero(&ndev->ref))
+                       goto out_unlock;
+       }
+
+       ndev = kzalloc(sizeof(*ndev), GFP_KERNEL);
+       if (!ndev)
+               goto out_err;
+
+       ndev->device = cm_id->device;
+       kref_init(&ndev->ref);
+
+       ndev->pd = ib_alloc_pd(ndev->device);
+       if (IS_ERR(ndev->pd))
+               goto out_free_dev;
+
+       if (nvmet_rdma_use_srq) {
+               ret = nvmet_rdma_init_srq(ndev);
+               if (ret)
+                       goto out_free_pd;
+       }
+
+       list_add(&ndev->entry, &device_list);
+out_unlock:
+       mutex_unlock(&device_list_mutex);
+       pr_debug("added %s.\n", ndev->device->name);
+       return ndev;
+
+out_free_pd:
+       ib_dealloc_pd(ndev->pd);
+out_free_dev:
+       kfree(ndev);
+out_err:
+       mutex_unlock(&device_list_mutex);
+       return NULL;
+}
+
+static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
+{
+       struct ib_qp_init_attr qp_attr;
+       struct nvmet_rdma_device *ndev = queue->dev;
+       int comp_vector, nr_cqe, ret, i;
+
+       /*
+        * Spread the io queues across completion vectors,
+        * but still keep all admin queues on vector 0.
+        */
+       comp_vector = !queue->host_qid ? 0 :
+               queue->idx % ndev->device->num_comp_vectors;
+
+       /*
+        * Reserve CQ slots for RECV + RDMA_READ/RDMA_WRITE + RDMA_SEND.
+        */
+       nr_cqe = queue->recv_queue_size + 2 * queue->send_queue_size;
+
+       queue->cq = ib_alloc_cq(ndev->device, queue,
+                       nr_cqe + 1, comp_vector,
+                       IB_POLL_WORKQUEUE);
+       if (IS_ERR(queue->cq)) {
+               ret = PTR_ERR(queue->cq);
+               pr_err("failed to create CQ cqe= %d ret= %d\n",
+                      nr_cqe + 1, ret);
+               goto out;
+       }
+
+       memset(&qp_attr, 0, sizeof(qp_attr));
+       qp_attr.qp_context = queue;
+       qp_attr.event_handler = nvmet_rdma_qp_event;
+       qp_attr.send_cq = queue->cq;
+       qp_attr.recv_cq = queue->cq;
+       qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
+       qp_attr.qp_type = IB_QPT_RC;
+       /* +1 for drain */
+       qp_attr.cap.max_send_wr = queue->send_queue_size + 1;
+       qp_attr.cap.max_rdma_ctxs = queue->send_queue_size;
+       qp_attr.cap.max_send_sge = max(ndev->device->attrs.max_sge_rd,
+                                       ndev->device->attrs.max_sge);
+
+       if (ndev->srq) {
+               qp_attr.srq = ndev->srq;
+       } else {
+               /* +1 for drain */
+               qp_attr.cap.max_recv_wr = 1 + queue->recv_queue_size;
+               qp_attr.cap.max_recv_sge = 2;
+       }
+
+       ret = rdma_create_qp(queue->cm_id, ndev->pd, &qp_attr);
+       if (ret) {
+               pr_err("failed to create_qp ret= %d\n", ret);
+               goto err_destroy_cq;
+       }
+
+       atomic_set(&queue->sq_wr_avail, qp_attr.cap.max_send_wr);
+
+       pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
+                __func__, queue->cq->cqe, qp_attr.cap.max_send_sge,
+                qp_attr.cap.max_send_wr, queue->cm_id);
+
+       if (!ndev->srq) {
+               for (i = 0; i < queue->recv_queue_size; i++) {
+                       queue->cmds[i].queue = queue;
+                       nvmet_rdma_post_recv(ndev, &queue->cmds[i]);
+               }
+       }
+
+out:
+       return ret;
+
+err_destroy_cq:
+       ib_free_cq(queue->cq);
+       goto out;
+}
+
+static void nvmet_rdma_destroy_queue_ib(struct nvmet_rdma_queue *queue)
+{
+       rdma_destroy_qp(queue->cm_id);
+       ib_free_cq(queue->cq);
+}
+
+static void nvmet_rdma_free_queue(struct nvmet_rdma_queue *queue)
+{
+       pr_info("freeing queue %d\n", queue->idx);
+
+       nvmet_sq_destroy(&queue->nvme_sq);
+
+       nvmet_rdma_destroy_queue_ib(queue);
+       if (!queue->dev->srq) {
+               nvmet_rdma_free_cmds(queue->dev, queue->cmds,
+                               queue->recv_queue_size,
+                               !queue->host_qid);
+       }
+       nvmet_rdma_free_rsps(queue);
+       ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
+       kfree(queue);
+}
+
+static void nvmet_rdma_release_queue_work(struct work_struct *w)
+{
+       struct nvmet_rdma_queue *queue =
+               container_of(w, struct nvmet_rdma_queue, release_work);
+       struct rdma_cm_id *cm_id = queue->cm_id;
+       struct nvmet_rdma_device *dev = queue->dev;
+
+       nvmet_rdma_free_queue(queue);
+       rdma_destroy_id(cm_id);
+       kref_put(&dev->ref, nvmet_rdma_free_dev);
+}
+
+static int
+nvmet_rdma_parse_cm_connect_req(struct rdma_conn_param *conn,
+                               struct nvmet_rdma_queue *queue)
+{
+       struct nvme_rdma_cm_req *req;
+
+       req = (struct nvme_rdma_cm_req *)conn->private_data;
+       if (!req || conn->private_data_len == 0)
+               return NVME_RDMA_CM_INVALID_LEN;
+
+       if (le16_to_cpu(req->recfmt) != NVME_RDMA_CM_FMT_1_0)
+               return NVME_RDMA_CM_INVALID_RECFMT;
+
+       queue->host_qid = le16_to_cpu(req->qid);
+
+       /*
+        * req->hsqsize corresponds to our recv queue size
+        * req->hrqsize corresponds to our send queue size
+        */
+       queue->recv_queue_size = le16_to_cpu(req->hsqsize);
+       queue->send_queue_size = le16_to_cpu(req->hrqsize);
+
+       if (!queue->host_qid && queue->recv_queue_size > NVMF_AQ_DEPTH)
+               return NVME_RDMA_CM_INVALID_HSQSIZE;
+
+       /* XXX: Should we enforce some kind of max for IO queues? */
+
+       return 0;
+}
+
+static int nvmet_rdma_cm_reject(struct rdma_cm_id *cm_id,
+                               enum nvme_rdma_cm_status status)
+{
+       struct nvme_rdma_cm_rej rej;
+
+       rej.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
+       rej.sts = cpu_to_le16(status);
+
+       return rdma_reject(cm_id, (void *)&rej, sizeof(rej));
+}
+
+static struct nvmet_rdma_queue *
+nvmet_rdma_alloc_queue(struct nvmet_rdma_device *ndev,
+               struct rdma_cm_id *cm_id,
+               struct rdma_cm_event *event)
+{
+       struct nvmet_rdma_queue *queue;
+       int ret;
+
+       queue = kzalloc(sizeof(*queue), GFP_KERNEL);
+       if (!queue) {
+               ret = NVME_RDMA_CM_NO_RSC;
+               goto out_reject;
+       }
+
+       ret = nvmet_sq_init(&queue->nvme_sq);
+       if (ret)
+               goto out_free_queue;
+
+       ret = nvmet_rdma_parse_cm_connect_req(&event->param.conn, queue);
+       if (ret)
+               goto out_destroy_sq;
+
+       /*
+        * Schedules the actual release because calling rdma_destroy_id from
+        * inside a CM callback would trigger a deadlock. (great API design..)
+        */
+       INIT_WORK(&queue->release_work, nvmet_rdma_release_queue_work);
+       queue->dev = ndev;
+       queue->cm_id = cm_id;
+
+       spin_lock_init(&queue->state_lock);
+       queue->state = NVMET_RDMA_Q_CONNECTING;
+       INIT_LIST_HEAD(&queue->rsp_wait_list);
+       INIT_LIST_HEAD(&queue->rsp_wr_wait_list);
+       spin_lock_init(&queue->rsp_wr_wait_lock);
+       INIT_LIST_HEAD(&queue->free_rsps);
+       spin_lock_init(&queue->rsps_lock);
+
+       queue->idx = ida_simple_get(&nvmet_rdma_queue_ida, 0, 0, GFP_KERNEL);
+       if (queue->idx < 0) {
+               ret = NVME_RDMA_CM_NO_RSC;
+               goto out_free_queue;
+       }
+
+       ret = nvmet_rdma_alloc_rsps(queue);
+       if (ret) {
+               ret = NVME_RDMA_CM_NO_RSC;
+               goto out_ida_remove;
+       }
+
+       if (!ndev->srq) {
+               queue->cmds = nvmet_rdma_alloc_cmds(ndev,
+                               queue->recv_queue_size,
+                               !queue->host_qid);
+               if (IS_ERR(queue->cmds)) {
+                       ret = NVME_RDMA_CM_NO_RSC;
+                       goto out_free_responses;
+               }
+       }
+
+       ret = nvmet_rdma_create_queue_ib(queue);
+       if (ret) {
+               pr_err("%s: creating RDMA queue failed (%d).\n",
+                       __func__, ret);
+               ret = NVME_RDMA_CM_NO_RSC;
+               goto out_free_cmds;
+       }
+
+       return queue;
+
+out_free_cmds:
+       if (!ndev->srq) {
+               nvmet_rdma_free_cmds(queue->dev, queue->cmds,
+                               queue->recv_queue_size,
+                               !queue->host_qid);
+       }
+out_free_responses:
+       nvmet_rdma_free_rsps(queue);
+out_ida_remove:
+       ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
+out_destroy_sq:
+       nvmet_sq_destroy(&queue->nvme_sq);
+out_free_queue:
+       kfree(queue);
+out_reject:
+       nvmet_rdma_cm_reject(cm_id, ret);
+       return NULL;
+}
+
+static void nvmet_rdma_qp_event(struct ib_event *event, void *priv)
+{
+       struct nvmet_rdma_queue *queue = priv;
+
+       switch (event->event) {
+       case IB_EVENT_COMM_EST:
+               rdma_notify(queue->cm_id, event->event);
+               break;
+       default:
+               pr_err("received unrecognized IB QP event %d\n", event->event);
+               break;
+       }
+}
+
+static int nvmet_rdma_cm_accept(struct rdma_cm_id *cm_id,
+               struct nvmet_rdma_queue *queue,
+               struct rdma_conn_param *p)
+{
+       struct rdma_conn_param  param = { };
+       struct nvme_rdma_cm_rep priv = { };
+       int ret = -ENOMEM;
+
+       param.rnr_retry_count = 7;
+       param.flow_control = 1;
+       param.initiator_depth = min_t(u8, p->initiator_depth,
+               queue->dev->device->attrs.max_qp_init_rd_atom);
+       param.private_data = &priv;
+       param.private_data_len = sizeof(priv);
+       priv.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
+       priv.crqsize = cpu_to_le16(queue->recv_queue_size);
+
+       ret = rdma_accept(cm_id, &param);
+       if (ret)
+               pr_err("rdma_accept failed (error code = %d)\n", ret);
+
+       return ret;
+}
+
+static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id,
+               struct rdma_cm_event *event)
+{
+       struct nvmet_rdma_device *ndev;
+       struct nvmet_rdma_queue *queue;
+       int ret = -EINVAL;
+
+       ndev = nvmet_rdma_find_get_device(cm_id);
+       if (!ndev) {
+               pr_err("no client data!\n");
+               nvmet_rdma_cm_reject(cm_id, NVME_RDMA_CM_NO_RSC);
+               return -ECONNREFUSED;
+       }
+
+       queue = nvmet_rdma_alloc_queue(ndev, cm_id, event);
+       if (!queue) {
+               ret = -ENOMEM;
+               goto put_device;
+       }
+       queue->port = cm_id->context;
+
+       ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn);
+       if (ret)
+               goto release_queue;
+
+       mutex_lock(&nvmet_rdma_queue_mutex);
+       list_add_tail(&queue->queue_list, &nvmet_rdma_queue_list);
+       mutex_unlock(&nvmet_rdma_queue_mutex);
+
+       return 0;
+
+release_queue:
+       nvmet_rdma_free_queue(queue);
+put_device:
+       kref_put(&ndev->ref, nvmet_rdma_free_dev);
+
+       return ret;
+}
+
+static void nvmet_rdma_queue_established(struct nvmet_rdma_queue *queue)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&queue->state_lock, flags);
+       if (queue->state != NVMET_RDMA_Q_CONNECTING) {
+               pr_warn("trying to establish a connected queue\n");
+               goto out_unlock;
+       }
+       queue->state = NVMET_RDMA_Q_LIVE;
+
+       while (!list_empty(&queue->rsp_wait_list)) {
+               struct nvmet_rdma_rsp *cmd;
+
+               cmd = list_first_entry(&queue->rsp_wait_list,
+                                       struct nvmet_rdma_rsp, wait_list);
+               list_del(&cmd->wait_list);
+
+               spin_unlock_irqrestore(&queue->state_lock, flags);
+               nvmet_rdma_handle_command(queue, cmd);
+               spin_lock_irqsave(&queue->state_lock, flags);
+       }
+
+out_unlock:
+       spin_unlock_irqrestore(&queue->state_lock, flags);
+}
+
+static void __nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
+{
+       bool disconnect = false;
+       unsigned long flags;
+
+       pr_debug("cm_id= %p queue->state= %d\n", queue->cm_id, queue->state);
+
+       spin_lock_irqsave(&queue->state_lock, flags);
+       switch (queue->state) {
+       case NVMET_RDMA_Q_CONNECTING:
+       case NVMET_RDMA_Q_LIVE:
+               disconnect = true;
+               queue->state = NVMET_RDMA_Q_DISCONNECTING;
+               break;
+       case NVMET_RDMA_Q_DISCONNECTING:
+               break;
+       }
+       spin_unlock_irqrestore(&queue->state_lock, flags);
+
+       if (disconnect) {
+               rdma_disconnect(queue->cm_id);
+               ib_drain_qp(queue->cm_id->qp);
+               schedule_work(&queue->release_work);
+       }
+}
+
+static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
+{
+       bool disconnect = false;
+
+       mutex_lock(&nvmet_rdma_queue_mutex);
+       if (!list_empty(&queue->queue_list)) {
+               list_del_init(&queue->queue_list);
+               disconnect = true;
+       }
+       mutex_unlock(&nvmet_rdma_queue_mutex);
+
+       if (disconnect)
+               __nvmet_rdma_queue_disconnect(queue);
+}
+
+static void nvmet_rdma_queue_connect_fail(struct rdma_cm_id *cm_id,
+               struct nvmet_rdma_queue *queue)
+{
+       WARN_ON_ONCE(queue->state != NVMET_RDMA_Q_CONNECTING);
+
+       pr_err("failed to connect queue\n");
+       schedule_work(&queue->release_work);
+}
+
+static int nvmet_rdma_cm_handler(struct rdma_cm_id *cm_id,
+               struct rdma_cm_event *event)
+{
+       struct nvmet_rdma_queue *queue = NULL;
+       int ret = 0;
+
+       if (cm_id->qp)
+               queue = cm_id->qp->qp_context;
+
+       pr_debug("%s (%d): status %d id %p\n",
+               rdma_event_msg(event->event), event->event,
+               event->status, cm_id);
+
+       switch (event->event) {
+       case RDMA_CM_EVENT_CONNECT_REQUEST:
+               ret = nvmet_rdma_queue_connect(cm_id, event);
+               break;
+       case RDMA_CM_EVENT_ESTABLISHED:
+               nvmet_rdma_queue_established(queue);
+               break;
+       case RDMA_CM_EVENT_ADDR_CHANGE:
+       case RDMA_CM_EVENT_DISCONNECTED:
+       case RDMA_CM_EVENT_DEVICE_REMOVAL:
+       case RDMA_CM_EVENT_TIMEWAIT_EXIT:
+               /*
+                * We can get the device removal callback even for a
+                * CM ID that we aren't actually using.  In that case
+                * the context pointer is NULL, so we shouldn't try
+                * to disconnect a non-existing queue.  But we also
+                * need to return 1 so that the core will destroy
+                * it's own ID.  What a great API design..
+                */
+               if (queue)
+                       nvmet_rdma_queue_disconnect(queue);
+               else
+                       ret = 1;
+               break;
+       case RDMA_CM_EVENT_REJECTED:
+       case RDMA_CM_EVENT_UNREACHABLE:
+       case RDMA_CM_EVENT_CONNECT_ERROR:
+               nvmet_rdma_queue_connect_fail(cm_id, queue);
+               break;
+       default:
+               pr_err("received unrecognized RDMA CM event %d\n",
+                       event->event);
+               break;
+       }
+
+       return ret;
+}
+
+static void nvmet_rdma_delete_ctrl(struct nvmet_ctrl *ctrl)
+{
+       struct nvmet_rdma_queue *queue;
+
+restart:
+       mutex_lock(&nvmet_rdma_queue_mutex);
+       list_for_each_entry(queue, &nvmet_rdma_queue_list, queue_list) {
+               if (queue->nvme_sq.ctrl == ctrl) {
+                       list_del_init(&queue->queue_list);
+                       mutex_unlock(&nvmet_rdma_queue_mutex);
+
+                       __nvmet_rdma_queue_disconnect(queue);
+                       goto restart;
+               }
+       }
+       mutex_unlock(&nvmet_rdma_queue_mutex);
+}
+
+static int nvmet_rdma_add_port(struct nvmet_port *port)
+{
+       struct rdma_cm_id *cm_id;
+       struct sockaddr_in addr_in;
+       u16 port_in;
+       int ret;
+
+       switch (port->disc_addr.adrfam) {
+       case NVMF_ADDR_FAMILY_IP4:
+               break;
+       default:
+               pr_err("address family %d not supported\n",
+                               port->disc_addr.adrfam);
+               return -EINVAL;
+       }
+
+       ret = kstrtou16(port->disc_addr.trsvcid, 0, &port_in);
+       if (ret)
+               return ret;
+
+       addr_in.sin_family = AF_INET;
+       addr_in.sin_addr.s_addr = in_aton(port->disc_addr.traddr);
+       addr_in.sin_port = htons(port_in);
+
+       cm_id = rdma_create_id(&init_net, nvmet_rdma_cm_handler, port,
+                       RDMA_PS_TCP, IB_QPT_RC);
+       if (IS_ERR(cm_id)) {
+               pr_err("CM ID creation failed\n");
+               return PTR_ERR(cm_id);
+       }
+
+       ret = rdma_bind_addr(cm_id, (struct sockaddr *)&addr_in);
+       if (ret) {
+               pr_err("binding CM ID to %pISpc failed (%d)\n", &addr_in, ret);
+               goto out_destroy_id;
+       }
+
+       ret = rdma_listen(cm_id, 128);
+       if (ret) {
+               pr_err("listening to %pISpc failed (%d)\n", &addr_in, ret);
+               goto out_destroy_id;
+       }
+
+       pr_info("enabling port %d (%pISpc)\n",
+               le16_to_cpu(port->disc_addr.portid), &addr_in);
+       port->priv = cm_id;
+       return 0;
+
+out_destroy_id:
+       rdma_destroy_id(cm_id);
+       return ret;
+}
+
+static void nvmet_rdma_remove_port(struct nvmet_port *port)
+{
+       struct rdma_cm_id *cm_id = port->priv;
+
+       rdma_destroy_id(cm_id);
+}
+
+static struct nvmet_fabrics_ops nvmet_rdma_ops = {
+       .owner                  = THIS_MODULE,
+       .type                   = NVMF_TRTYPE_RDMA,
+       .sqe_inline_size        = NVMET_RDMA_INLINE_DATA_SIZE,
+       .msdbd                  = 1,
+       .has_keyed_sgls         = 1,
+       .add_port               = nvmet_rdma_add_port,
+       .remove_port            = nvmet_rdma_remove_port,
+       .queue_response         = nvmet_rdma_queue_response,
+       .delete_ctrl            = nvmet_rdma_delete_ctrl,
+};
+
+static int __init nvmet_rdma_init(void)
+{
+       return nvmet_register_transport(&nvmet_rdma_ops);
+}
+
+static void __exit nvmet_rdma_exit(void)
+{
+       struct nvmet_rdma_queue *queue;
+
+       nvmet_unregister_transport(&nvmet_rdma_ops);
+
+       flush_scheduled_work();
+
+       mutex_lock(&nvmet_rdma_queue_mutex);
+       while ((queue = list_first_entry_or_null(&nvmet_rdma_queue_list,
+                       struct nvmet_rdma_queue, queue_list))) {
+               list_del_init(&queue->queue_list);
+
+               mutex_unlock(&nvmet_rdma_queue_mutex);
+               __nvmet_rdma_queue_disconnect(queue);
+               mutex_lock(&nvmet_rdma_queue_mutex);
+       }
+       mutex_unlock(&nvmet_rdma_queue_mutex);
+
+       flush_scheduled_work();
+       ida_destroy(&nvmet_rdma_queue_ida);
+}
+
+module_init(nvmet_rdma_init);
+module_exit(nvmet_rdma_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("nvmet-transport-1"); /* 1 == NVMF_TRTYPE_RDMA */