Re: NVMe over Fabrics RDMA transport drivers

Re: NVMe over Fabrics RDMA transport drivers

[Sagi Grimberg]

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

On 07/06/16 00:23, Christoph Hellwig wrote:
> This patch set implements the NVMe over Fabrics RDMA host and the target
> drivers.
>
> The host driver is tied into the NVMe host stack and implements the RDMA
> transport under the NVMe core and Fabrics modules. The NVMe over Fabrics
> RDMA host module is responsible for establishing a connection against a
> given target/controller, RDMA event handling and data-plane command
> processing.
>
> The target driver hooks into the NVMe target core stack and implements
> the RDMA transport. The module is responsible for RDMA connection
> establishment, RDMA event handling and data-plane RDMA commands
> processing.
>
> RDMA connection establishment is done using RDMA/CM and IP resolution.
> The data-plane command sequence follows the classic storage model where
> the target pushes/pulls the data.
>
> --
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>

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

[Sagi Grimberg]

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

On 07/06/16 00:23, Christoph Hellwig wrote:
> From: Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
>
> NVMe over Fabrics RDMA transport defines a connection establishment
> protocol over the RDMA connection manager. This header will be used by
> both the host and target drivers to negotiate the connection
> establishment parameters.
>
> Signed-off-by: Jay Freyensee <james.p.freyensee-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Ming Lin <ming.l-Vzezgt5dB6uUEJcrhfAQsw@public.gmane.org>
> Signed-off-by: Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
> Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
> ---
>   include/linux/nvme-rdma.h | 71 +++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 71 insertions(+)
>   create mode 100644 include/linux/nvme-rdma.h
>
> diff --git a/include/linux/nvme-rdma.h b/include/linux/nvme-rdma.h
> new file mode 100644
> index 0000000..bf240a3
> --- /dev/null
> +++ b/include/linux/nvme-rdma.h
> @@ -0,0 +1,71 @@
> +/*
> + * Copyright (c) 2015 Mellanox Technologies. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +
> +#ifndef _LINUX_NVME_RDMA_H
> +#define _LINUX_NVME_RDMA_H
> +
> +enum nvme_rdma_cm_fmt {
> +	NVME_RDMA_CM_FMT_1_0 = 0x0,
> +};
> +
> +enum nvme_rdma_cm_status {
> +	NVME_RDMA_CM_INVALID_LEN	= 0x01,
> +	NVME_RDMA_CM_INVALID_RECFMT	= 0x02,
> +	NVME_RDMA_CM_INVALID_QID	= 0x03,
> +	NVME_RDMA_CM_INVALID_HSQSIZE	= 0x04,
> +	NVME_RDMA_CM_INVALID_HRQSIZE	= 0x05,
> +	NVME_RDMA_CM_NO_RSC		= 0x06,
> +	NVME_RDMA_CM_INVALID_IRD	= 0x07,
> +	NVME_RDMA_CM_INVALID_ORD	= 0x08,
> +};
> +
> +/**
> + * struct nvme_rdma_cm_req - rdma connect request
> + *
> + * @recfmt:        format of the RDMA Private Data
> + * @qid:           queue Identifier for the Admin or I/O Queue
> + * @hrqsize:       host receive queue size to be created
> + * @hsqsize:       host send queue size to be created
> + */
> +struct nvme_rdma_cm_req {
> +	__le16		recfmt;
> +	__le16		qid;
> +	__le16		hrqsize;
> +	__le16		hsqsize;
> +	u8		rsvd[24];
> +};
> +
> +/**
> + * struct nvme_rdma_cm_rep - rdma connect reply
> + *
> + * @recfmt:        format of the RDMA Private Data
> + * @crqsize:       controller receive queue size
> + */
> +struct nvme_rdma_cm_rep {
> +	__le16		recfmt;
> +	__le16		crqsize;
> +	u8		rsvd[28];
> +};
> +
> +/**
> + * struct nvme_rdma_cm_rej - rdma connect reject
> + *
> + * @recfmt:        format of the RDMA Private Data
> + * @fsts:          error status for the associated connect request
> + */
> +struct nvme_rdma_cm_rej {
> +	__le16		recfmt;
> +	__le16		sts;
> +};
> +
> +#endif /* _LINUX_NVME_RDMA_H */
>
--
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Re: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Sagi Grimberg]

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

On 07/06/16 00:23, Christoph Hellwig wrote:
> This patch implements the RDMA transport for the NVMe over Fabrics target,
> which allows exporting NVMe over Fabrics functionality over RDMA fabrics
> (Infiniband, RoCE, iWARP).
>
> All NVMe logic is in the generic target and this module just provides a
> small glue between it and the generic code in the RDMA subsystem.
>
> Signed-off-by: Armen Baloyan <armenx.baloyan@intel.com>,
> Signed-off-by: Jay Freyensee <james.p.freyensee@intel.com>
> Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
> Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/nvme/target/Kconfig  |   10 +
>   drivers/nvme/target/Makefile |    2 +
>   drivers/nvme/target/rdma.c   | 1404 ++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 1416 insertions(+)
>   create mode 100644 drivers/nvme/target/rdma.c
>
> diff --git a/drivers/nvme/target/Kconfig b/drivers/nvme/target/Kconfig
> index b77ce43..6aa7be0 100644
> --- a/drivers/nvme/target/Kconfig
> +++ b/drivers/nvme/target/Kconfig
> @@ -24,3 +24,13 @@ config NVME_TARGET_LOOP
>   	  to test NVMe host and target side features.
>
>   	  If unsure, say N.
> +
> +config NVME_TARGET_RDMA
> +	tristate "NVMe over Fabrics RDMA target support"
> +	depends on INFINIBAND
> +	select NVME_TARGET
> +	help
> +	  This enables the NVMe RDMA target support, which allows exporting NVMe
> +	  devices over RDMA.
> +
> +	  If unsure, say N.
> diff --git a/drivers/nvme/target/Makefile b/drivers/nvme/target/Makefile
> index e49ba60..b7a0623 100644
> --- a/drivers/nvme/target/Makefile
> +++ b/drivers/nvme/target/Makefile
> @@ -1,7 +1,9 @@
>
>   obj-$(CONFIG_NVME_TARGET)		+= nvmet.o
>   obj-$(CONFIG_NVME_TARGET_LOOP)		+= nvme-loop.o
> +obj-$(CONFIG_NVME_TARGET_RDMA)		+= nvmet-rdma.o
>
>   nvmet-y		+= core.o configfs.o admin-cmd.o io-cmd.o fabrics-cmd.o \
>   			discovery.o
>   nvme-loop-y	+= loop.o
> +nvmet-rdma-y	+= rdma.o
> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
> new file mode 100644
> index 0000000..fccb01d
> --- /dev/null
> +++ b/drivers/nvme/target/rdma.c
> @@ -0,0 +1,1404 @@
> +/*
> + * NVMe over Fabrics RDMA target.
> + * Copyright (c) 2015-2016 HGST, a Western Digital Company.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +#include <linux/atomic.h>
> +#include <linux/ctype.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/nvme.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>
> +#include <linux/wait.h>
> +#include <linux/inet.h>
> +#include <asm/unaligned.h>
> +
> +#include <rdma/ib_verbs.h>
> +#include <rdma/rdma_cm.h>
> +#include <rdma/rw.h>
> +
> +#include <linux/nvme-rdma.h>
> +#include "nvmet.h"
> +
> +/*
> + * We allow up to a page of inline data to go with the SQE
> + */
> +#define NVMET_RDMA_INLINE_DATA_SIZE	PAGE_SIZE
> +
> +struct nvmet_rdma_cmd {
> +	struct ib_sge		sge[2];
> +	struct ib_cqe		cqe;
> +	struct ib_recv_wr	wr;
> +	struct scatterlist	inline_sg;
> +	struct page		*inline_page;
> +	struct nvme_command     *nvme_cmd;
> +	struct nvmet_rdma_queue	*queue;
> +};
> +
> +enum {
> +	NVMET_RDMA_REQ_INLINE_DATA	= (1 << 0),
> +	NVMET_RDMA_REQ_INVALIDATE_RKEY	= (1 << 1),
> +};
> +
> +struct nvmet_rdma_rsp {
> +	struct ib_sge		send_sge;
> +	struct ib_cqe		send_cqe;
> +	struct ib_send_wr	send_wr;
> +
> +	struct nvmet_rdma_cmd	*cmd;
> +	struct nvmet_rdma_queue	*queue;
> +
> +	struct ib_cqe		read_cqe;
> +	struct rdma_rw_ctx	rw;
> +
> +	struct nvmet_req	req;
> +
> +	u8			n_rdma;
> +	u32			flags;
> +	u32			invalidate_rkey;
> +
> +	struct list_head	wait_list;
> +	struct list_head	free_list;
> +};
> +
> +enum nvmet_rdma_queue_state {
> +	NVMET_RDMA_Q_CONNECTING,
> +	NVMET_RDMA_Q_LIVE,
> +	NVMET_RDMA_Q_DISCONNECTING,
> +};
> +
> +struct nvmet_rdma_queue {
> +	struct rdma_cm_id	*cm_id;
> +	struct nvmet_port	*port;
> +	struct ib_cq		*cq;
> +	atomic_t		sq_wr_avail;
> +	struct nvmet_rdma_device *dev;
> +	spinlock_t		state_lock;
> +	enum nvmet_rdma_queue_state state;
> +	struct nvmet_cq		nvme_cq;
> +	struct nvmet_sq		nvme_sq;
> +
> +	struct nvmet_rdma_rsp	*rsps;
> +	struct list_head	free_rsps;
> +	spinlock_t		rsps_lock;
> +	struct nvmet_rdma_cmd	*cmds;
> +
> +	struct work_struct	release_work;
> +	struct list_head	rsp_wait_list;
> +	struct list_head	rsp_wr_wait_list;
> +	spinlock_t		rsp_wr_wait_lock;
> +
> +	int			idx;
> +	int			host_qid;
> +	int			recv_queue_size;
> +	int			send_queue_size;
> +
> +	struct list_head	queue_list;
> +};
> +
> +struct nvmet_rdma_device {
> +	struct ib_device	*device;
> +	struct ib_pd		*pd;
> +	struct ib_srq		*srq;
> +	struct nvmet_rdma_cmd	*srq_cmds;
> +	size_t			srq_size;
> +	struct kref		ref;
> +	struct list_head	entry;
> +};
> +
> +static bool nvmet_rdma_use_srq;
> +module_param_named(use_srq, nvmet_rdma_use_srq, bool, 0444);
> +MODULE_PARM_DESC(use_srq, "Use shared receive queue.");
> +
> +static DEFINE_IDA(nvmet_rdma_queue_ida);
> +static LIST_HEAD(nvmet_rdma_queue_list);
> +static DEFINE_MUTEX(nvmet_rdma_queue_mutex);
> +
> +static LIST_HEAD(device_list);
> +static DEFINE_MUTEX(device_list_mutex);
> +
> +static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp);
> +static void nvmet_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc);
> +static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc);
> +static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc);
> +static void nvmet_rdma_qp_event(struct ib_event *event, void *priv);
> +
> +static struct nvmet_fabrics_ops nvmet_rdma_ops;
> +
> +/* XXX: really should move to a generic header sooner or later.. */
> +static inline u32 get_unaligned_le24(const u8 *p)
> +{
> +	return (u32)p[0] | (u32)p[1] << 8 | (u32)p[2] << 16;
> +}
> +
> +static inline bool nvmet_rdma_need_data_in(struct nvmet_rdma_rsp *rsp)
> +{
> +	return nvme_is_write(rsp->req.cmd) &&
> +		rsp->req.data_len &&
> +		!(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
> +}
> +
> +static inline bool nvmet_rdma_need_data_out(struct nvmet_rdma_rsp *rsp)
> +{
> +	return !nvme_is_write(rsp->req.cmd) &&
> +		rsp->req.data_len &&
> +		!rsp->req.rsp->status &&
> +		!(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
> +}
> +
> +static inline struct nvmet_rdma_rsp *
> +nvmet_rdma_get_rsp(struct nvmet_rdma_queue *queue)
> +{
> +	struct nvmet_rdma_rsp *rsp;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&queue->rsps_lock, flags);
> +	rsp = list_first_entry(&queue->free_rsps,
> +				struct nvmet_rdma_rsp, free_list);
> +	list_del(&rsp->free_list);
> +	spin_unlock_irqrestore(&queue->rsps_lock, flags);
> +
> +	return rsp;
> +}
> +
> +static inline void
> +nvmet_rdma_put_rsp(struct nvmet_rdma_rsp *rsp)
> +{
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&rsp->queue->rsps_lock, flags);
> +	list_add_tail(&rsp->free_list, &rsp->queue->free_rsps);
> +	spin_unlock_irqrestore(&rsp->queue->rsps_lock, flags);
> +}
> +
> +static void nvmet_rdma_free_sgl(struct scatterlist *sgl, unsigned int nents)
> +{
> +	struct scatterlist *sg;
> +	int count;
> +
> +	if (!sgl || !nents)
> +		return;
> +
> +	for_each_sg(sgl, sg, nents, count)
> +		__free_page(sg_page(sg));
> +	kfree(sgl);
> +}
> +
> +static int nvmet_rdma_alloc_sgl(struct scatterlist **sgl, unsigned int *nents,
> +		u32 length)
> +{
> +	struct scatterlist *sg;
> +	struct page *page;
> +	unsigned int nent;
> +	int i = 0;
> +
> +	nent = DIV_ROUND_UP(length, PAGE_SIZE);
> +	sg = kmalloc_array(nent, sizeof(struct scatterlist), GFP_KERNEL);
> +	if (!sg)
> +		goto out;
> +
> +	sg_init_table(sg, nent);
> +
> +	while (length) {
> +		u32 page_len = min_t(u32, length, PAGE_SIZE);
> +
> +		page = alloc_page(GFP_KERNEL);
> +		if (!page)
> +			goto out_free_pages;
> +
> +		sg_set_page(&sg[i], page, page_len, 0);
> +		length -= page_len;
> +		i++;
> +	}
> +	*sgl = sg;
> +	*nents = nent;
> +	return 0;
> +
> +out_free_pages:
> +	while (i > 0) {
> +		i--;
> +		__free_page(sg_page(&sg[i]));
> +	}
> +	kfree(sg);
> +out:
> +	return NVME_SC_INTERNAL;
> +}
> +
> +static int nvmet_rdma_alloc_cmd(struct nvmet_rdma_device *ndev,
> +			struct nvmet_rdma_cmd *c, bool admin)
> +{
> +	/* NVMe command / RDMA RECV */
> +	c->nvme_cmd = kmalloc(sizeof(*c->nvme_cmd), GFP_KERNEL);
> +	if (!c->nvme_cmd)
> +		goto out;
> +
> +	c->sge[0].addr = ib_dma_map_single(ndev->device, c->nvme_cmd,
> +			sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
> +	if (ib_dma_mapping_error(ndev->device, c->sge[0].addr))
> +		goto out_free_cmd;
> +
> +	c->sge[0].length = sizeof(*c->nvme_cmd);
> +	c->sge[0].lkey = ndev->pd->local_dma_lkey;
> +
> +	if (!admin) {
> +		c->inline_page = alloc_pages(GFP_KERNEL,
> +				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
> +		if (!c->inline_page)
> +			goto out_unmap_cmd;
> +		c->sge[1].addr = ib_dma_map_page(ndev->device,
> +				c->inline_page, 0, NVMET_RDMA_INLINE_DATA_SIZE,
> +				DMA_FROM_DEVICE);
> +		if (ib_dma_mapping_error(ndev->device, c->sge[1].addr))
> +			goto out_free_inline_page;
> +		c->sge[1].length = NVMET_RDMA_INLINE_DATA_SIZE;
> +		c->sge[1].lkey = ndev->pd->local_dma_lkey;
> +	}
> +
> +	c->cqe.done = nvmet_rdma_recv_done;
> +
> +	c->wr.wr_cqe = &c->cqe;
> +	c->wr.sg_list = c->sge;
> +	c->wr.num_sge = admin ? 1 : 2;
> +
> +	return 0;
> +
> +out_free_inline_page:
> +	if (!admin) {
> +		__free_pages(c->inline_page,
> +				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
> +	}
> +out_unmap_cmd:
> +	ib_dma_unmap_single(ndev->device, c->sge[0].addr,
> +			sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
> +out_free_cmd:
> +	kfree(c->nvme_cmd);
> +
> +out:
> +	return -ENOMEM;
> +}
> +
> +static void nvmet_rdma_free_cmd(struct nvmet_rdma_device *ndev,
> +		struct nvmet_rdma_cmd *c, bool admin)
> +{
> +	if (!admin) {
> +		ib_dma_unmap_page(ndev->device, c->sge[1].addr,
> +				NVMET_RDMA_INLINE_DATA_SIZE, DMA_FROM_DEVICE);
> +		__free_pages(c->inline_page,
> +				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
> +	}
> +	ib_dma_unmap_single(ndev->device, c->sge[0].addr,
> +				sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
> +	kfree(c->nvme_cmd);
> +}
> +
> +static struct nvmet_rdma_cmd *
> +nvmet_rdma_alloc_cmds(struct nvmet_rdma_device *ndev,
> +		int nr_cmds, bool admin)
> +{
> +	struct nvmet_rdma_cmd *cmds;
> +	int ret = -EINVAL, i;
> +
> +	cmds = kcalloc(nr_cmds, sizeof(struct nvmet_rdma_cmd), GFP_KERNEL);
> +	if (!cmds)
> +		goto out;
> +
> +	for (i = 0; i < nr_cmds; i++) {
> +		ret = nvmet_rdma_alloc_cmd(ndev, cmds + i, admin);
> +		if (ret)
> +			goto out_free;
> +	}
> +
> +	return cmds;
> +
> +out_free:
> +	while (--i >= 0)
> +		nvmet_rdma_free_cmd(ndev, cmds + i, admin);
> +	kfree(cmds);
> +out:
> +	return ERR_PTR(ret);
> +}
> +
> +static void nvmet_rdma_free_cmds(struct nvmet_rdma_device *ndev,
> +		struct nvmet_rdma_cmd *cmds, int nr_cmds, bool admin)
> +{
> +	int i;
> +
> +	for (i = 0; i < nr_cmds; i++)
> +		nvmet_rdma_free_cmd(ndev, cmds + i, admin);
> +	kfree(cmds);
> +}
> +
> +static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
> +		struct nvmet_rdma_rsp *r)
> +{
> +	/* NVMe CQE / RDMA SEND */
> +	r->req.rsp = kmalloc(sizeof(*r->req.rsp), GFP_KERNEL);
> +	if (!r->req.rsp)
> +		goto out;
> +
> +	r->send_sge.addr = ib_dma_map_single(ndev->device, r->req.rsp,
> +			sizeof(*r->req.rsp), DMA_TO_DEVICE);
> +	if (ib_dma_mapping_error(ndev->device, r->send_sge.addr))
> +		goto out_free_rsp;
> +
> +	r->send_sge.length = sizeof(*r->req.rsp);
> +	r->send_sge.lkey = ndev->pd->local_dma_lkey;
> +
> +	r->send_cqe.done = nvmet_rdma_send_done;
> +
> +	r->send_wr.wr_cqe = &r->send_cqe;
> +	r->send_wr.sg_list = &r->send_sge;
> +	r->send_wr.num_sge = 1;
> +	r->send_wr.send_flags = IB_SEND_SIGNALED;
> +
> +	/* Data In / RDMA READ */
> +	r->read_cqe.done = nvmet_rdma_read_data_done;
> +	return 0;
> +
> +out_free_rsp:
> +	kfree(r->req.rsp);
> +out:
> +	return -ENOMEM;
> +}
> +
> +static void nvmet_rdma_free_rsp(struct nvmet_rdma_device *ndev,
> +		struct nvmet_rdma_rsp *r)
> +{
> +	ib_dma_unmap_single(ndev->device, r->send_sge.addr,
> +				sizeof(*r->req.rsp), DMA_TO_DEVICE);
> +	kfree(r->req.rsp);
> +}
> +
> +static int
> +nvmet_rdma_alloc_rsps(struct nvmet_rdma_queue *queue)
> +{
> +	struct nvmet_rdma_device *ndev = queue->dev;
> +	int nr_rsps = queue->recv_queue_size * 2;
> +	int ret = -EINVAL, i;
> +
> +	queue->rsps = kcalloc(nr_rsps, sizeof(struct nvmet_rdma_rsp),
> +			GFP_KERNEL);
> +	if (!queue->rsps)
> +		goto out;
> +
> +	for (i = 0; i < nr_rsps; i++) {
> +		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
> +
> +		ret = nvmet_rdma_alloc_rsp(ndev, rsp);
> +		if (ret)
> +			goto out_free;
> +
> +		list_add_tail(&rsp->free_list, &queue->free_rsps);
> +	}
> +
> +	return 0;
> +
> +out_free:
> +	while (--i >= 0) {
> +		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
> +
> +		list_del(&rsp->free_list);
> +		nvmet_rdma_free_rsp(ndev, rsp);
> +	}
> +	kfree(queue->rsps);
> +out:
> +	return ret;
> +}
> +
> +static void nvmet_rdma_free_rsps(struct nvmet_rdma_queue *queue)
> +{
> +	struct nvmet_rdma_device *ndev = queue->dev;
> +	int i, nr_rsps = queue->recv_queue_size * 2;
> +
> +	for (i = 0; i < nr_rsps; i++) {
> +		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
> +
> +		list_del(&rsp->free_list);
> +		nvmet_rdma_free_rsp(ndev, rsp);
> +	}
> +	kfree(queue->rsps);
> +}
> +
> +static int nvmet_rdma_post_recv(struct nvmet_rdma_device *ndev,
> +		struct nvmet_rdma_cmd *cmd)
> +{
> +	struct ib_recv_wr *bad_wr;
> +
> +	if (ndev->srq)
> +		return ib_post_srq_recv(ndev->srq, &cmd->wr, &bad_wr);
> +	return ib_post_recv(cmd->queue->cm_id->qp, &cmd->wr, &bad_wr);
> +}
> +
> +static void nvmet_rdma_process_wr_wait_list(struct nvmet_rdma_queue *queue)
> +{
> +	spin_lock(&queue->rsp_wr_wait_lock);
> +	while (!list_empty(&queue->rsp_wr_wait_list)) {
> +		struct nvmet_rdma_rsp *rsp;
> +		bool ret;
> +
> +		rsp = list_entry(queue->rsp_wr_wait_list.next,
> +				struct nvmet_rdma_rsp, wait_list);
> +		list_del(&rsp->wait_list);
> +
> +		spin_unlock(&queue->rsp_wr_wait_lock);
> +		ret = nvmet_rdma_execute_command(rsp);
> +		spin_lock(&queue->rsp_wr_wait_lock);
> +
> +		if (!ret) {
> +			list_add(&rsp->wait_list, &queue->rsp_wr_wait_list);
> +			break;
> +		}
> +	}
> +	spin_unlock(&queue->rsp_wr_wait_lock);
> +}
> +
> +
> +static void nvmet_rdma_release_rsp(struct nvmet_rdma_rsp *rsp)
> +{
> +	struct nvmet_rdma_queue *queue = rsp->queue;
> +
> +	atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);
> +
> +	if (rsp->n_rdma) {
> +		rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
> +				queue->cm_id->port_num, rsp->req.sg,
> +				rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
> +	}
> +
> +	if (rsp->req.sg != &rsp->cmd->inline_sg)
> +		nvmet_rdma_free_sgl(rsp->req.sg, rsp->req.sg_cnt);
> +
> +	if (unlikely(!list_empty_careful(&queue->rsp_wr_wait_list)))
> +		nvmet_rdma_process_wr_wait_list(queue);
> +
> +	nvmet_rdma_put_rsp(rsp);
> +}
> +
> +static void nvmet_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc)
> +{
> +	struct nvmet_rdma_rsp *rsp =
> +		container_of(wc->wr_cqe, struct nvmet_rdma_rsp, send_cqe);
> +
> +	nvmet_rdma_release_rsp(rsp);
> +}
> +
> +static void nvmet_rdma_queue_response(struct nvmet_req *req)
> +{
> +	struct nvmet_rdma_rsp *rsp =
> +		container_of(req, struct nvmet_rdma_rsp, req);
> +	struct rdma_cm_id *cm_id = rsp->queue->cm_id;
> +	struct ib_send_wr *first_wr, *bad_wr;
> +
> +	if (rsp->flags & NVMET_RDMA_REQ_INVALIDATE_RKEY) {
> +		rsp->send_wr.opcode = IB_WR_SEND_WITH_INV;
> +		rsp->send_wr.ex.invalidate_rkey = rsp->invalidate_rkey;
> +	} else {
> +		rsp->send_wr.opcode = IB_WR_SEND;
> +	}
> +
> +	if (nvmet_rdma_need_data_out(rsp))
> +		first_wr = rdma_rw_ctx_wrs(&rsp->rw, cm_id->qp,
> +				cm_id->port_num, NULL, &rsp->send_wr);
> +	else
> +		first_wr = &rsp->send_wr;
> +
> +	nvmet_rdma_post_recv(rsp->queue->dev, rsp->cmd);
> +	if (ib_post_send(cm_id->qp, first_wr, &bad_wr)) {
> +		pr_err("sending cmd response failed\n");
> +		nvmet_rdma_release_rsp(rsp);
> +	}
> +}
> +
> +static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc)
> +{
> +	struct nvmet_rdma_rsp *rsp =
> +		container_of(wc->wr_cqe, struct nvmet_rdma_rsp, read_cqe);
> +	struct nvmet_rdma_queue *queue = cq->cq_context;
> +
> +	WARN_ON(rsp->n_rdma <= 0);
> +	atomic_add(rsp->n_rdma, &queue->sq_wr_avail);
> +	rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
> +			queue->cm_id->port_num, rsp->req.sg,
> +			rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
> +	rsp->n_rdma = 0;
> +
> +	if (unlikely(wc->status != IB_WC_SUCCESS &&
> +		wc->status != IB_WC_WR_FLUSH_ERR)) {
> +		pr_info("RDMA READ for CQE 0x%p failed with status %s (%d).\n",
> +			wc->wr_cqe, ib_wc_status_msg(wc->status), wc->status);
> +		nvmet_req_complete(&rsp->req, NVME_SC_DATA_XFER_ERROR);
> +		return;
> +	}
> +
> +	rsp->req.execute(&rsp->req);
> +}
> +
> +static void nvmet_rdma_use_inline_sg(struct nvmet_rdma_rsp *rsp, u32 len,
> +		u64 off)
> +{
> +	sg_init_table(&rsp->cmd->inline_sg, 1);
> +	sg_set_page(&rsp->cmd->inline_sg, rsp->cmd->inline_page, len, off);
> +	rsp->req.sg = &rsp->cmd->inline_sg;
> +	rsp->req.sg_cnt = 1;
> +}
> +
> +static u16 nvmet_rdma_map_sgl_inline(struct nvmet_rdma_rsp *rsp)
> +{
> +	struct nvme_sgl_desc *sgl = &rsp->req.cmd->common.dptr.sgl;
> +	u64 off = le64_to_cpu(sgl->addr);
> +	u32 len = le32_to_cpu(sgl->length);
> +
> +	if (!nvme_is_write(rsp->req.cmd))
> +		return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
> +
> +	if (off + len > NVMET_RDMA_INLINE_DATA_SIZE) {
> +		pr_err("invalid inline data offset!\n");
> +		return NVME_SC_SGL_INVALID_OFFSET | NVME_SC_DNR;
> +	}
> +
> +	/* no data command? */
> +	if (!len)
> +		return 0;
> +
> +	nvmet_rdma_use_inline_sg(rsp, len, off);
> +	rsp->flags |= NVMET_RDMA_REQ_INLINE_DATA;
> +	return 0;
> +}
> +
> +static u16 nvmet_rdma_map_sgl_keyed(struct nvmet_rdma_rsp *rsp,
> +		struct nvme_keyed_sgl_desc *sgl, bool invalidate)
> +{
> +	struct rdma_cm_id *cm_id = rsp->queue->cm_id;
> +	u64 addr = le64_to_cpu(sgl->addr);
> +	u32 len = get_unaligned_le24(sgl->length);
> +	u32 key = get_unaligned_le32(sgl->key);
> +	int ret;
> +	u16 status;
> +
> +	/* no data command? */
> +	if (!len)
> +		return 0;
> +
> +	/* use the already allocated data buffer if possible */
> +	if (len <= NVMET_RDMA_INLINE_DATA_SIZE && rsp->queue->host_qid) {
> +		nvmet_rdma_use_inline_sg(rsp, len, 0);
> +	} else {
> +		status = nvmet_rdma_alloc_sgl(&rsp->req.sg, &rsp->req.sg_cnt,
> +				len);
> +		if (status)
> +			return status;
> +	}
> +
> +	ret = rdma_rw_ctx_init(&rsp->rw, cm_id->qp, cm_id->port_num,
> +			rsp->req.sg, rsp->req.sg_cnt, 0, addr, key,
> +			nvmet_data_dir(&rsp->req));
> +	if (ret < 0)
> +		return NVME_SC_INTERNAL;
> +	rsp->n_rdma += ret;
> +
> +	if (invalidate) {
> +		rsp->invalidate_rkey = key;
> +		rsp->flags |= NVMET_RDMA_REQ_INVALIDATE_RKEY;
> +	}
> +
> +	return 0;
> +}
> +
> +static u16 nvmet_rdma_map_sgl(struct nvmet_rdma_rsp *rsp)
> +{
> +	struct nvme_keyed_sgl_desc *sgl = &rsp->req.cmd->common.dptr.ksgl;
> +
> +	switch (sgl->type >> 4) {
> +	case NVME_SGL_FMT_DATA_DESC:
> +		switch (sgl->type & 0xf) {
> +		case NVME_SGL_FMT_OFFSET:
> +			return nvmet_rdma_map_sgl_inline(rsp);
> +		default:
> +			pr_err("invalid SGL subtype: %#x\n", sgl->type);
> +			return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
> +		}
> +	case NVME_KEY_SGL_FMT_DATA_DESC:
> +		switch (sgl->type & 0xf) {
> +		case NVME_SGL_FMT_ADDRESS | NVME_SGL_FMT_INVALIDATE:
> +			return nvmet_rdma_map_sgl_keyed(rsp, sgl, true);
> +		case NVME_SGL_FMT_ADDRESS:
> +			return nvmet_rdma_map_sgl_keyed(rsp, sgl, false);
> +		default:
> +			pr_err("invalid SGL subtype: %#x\n", sgl->type);
> +			return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
> +		}
> +	default:
> +		pr_err("invalid SGL type: %#x\n", sgl->type);
> +		return NVME_SC_SGL_INVALID_TYPE | NVME_SC_DNR;
> +	}
> +}
> +
> +static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp)
> +{
> +	struct nvmet_rdma_queue *queue = rsp->queue;
> +
> +	if (unlikely(atomic_sub_return(1 + rsp->n_rdma,
> +			&queue->sq_wr_avail) < 0)) {
> +		pr_debug("IB send queue full (needed %d): queue %u cntlid %u\n",
> +				1 + rsp->n_rdma, queue->idx,
> +				queue->nvme_sq.ctrl->cntlid);
> +		atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);
> +		return false;
> +	}
> +
> +	if (nvmet_rdma_need_data_in(rsp)) {
> +		if (rdma_rw_ctx_post(&rsp->rw, queue->cm_id->qp,
> +				queue->cm_id->port_num, &rsp->read_cqe, NULL))
> +			nvmet_req_complete(&rsp->req, NVME_SC_DATA_XFER_ERROR);
> +	} else {
> +		rsp->req.execute(&rsp->req);
> +	}
> +
> +	return true;
> +}
> +
> +static void nvmet_rdma_handle_command(struct nvmet_rdma_queue *queue,
> +		struct nvmet_rdma_rsp *cmd)
> +{
> +	u16 status;
> +
> +	cmd->queue = queue;
> +	cmd->n_rdma = 0;
> +	cmd->req.port = queue->port;
> +
> +	if (!nvmet_req_init(&cmd->req, &queue->nvme_cq,
> +			&queue->nvme_sq, &nvmet_rdma_ops))
> +		return;
> +
> +	status = nvmet_rdma_map_sgl(cmd);
> +	if (status)
> +		goto out_err;
> +
> +	if (unlikely(!nvmet_rdma_execute_command(cmd))) {
> +		spin_lock(&queue->rsp_wr_wait_lock);
> +		list_add_tail(&cmd->wait_list, &queue->rsp_wr_wait_list);
> +		spin_unlock(&queue->rsp_wr_wait_lock);
> +	}
> +
> +	return;
> +
> +out_err:
> +	nvmet_req_complete(&cmd->req, status);
> +}
> +
> +static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
> +{
> +	struct nvmet_rdma_cmd *cmd =
> +		container_of(wc->wr_cqe, struct nvmet_rdma_cmd, cqe);
> +	struct nvmet_rdma_queue *queue = cq->cq_context;
> +	struct nvmet_rdma_rsp *rsp;
> +
> +	if (unlikely(wc->status != IB_WC_SUCCESS))
> +		return;
> +
> +	if (unlikely(wc->byte_len < sizeof(struct nvme_command))) {
> +		pr_err("Ctrl Fatal Error: capsule size less than 64 bytes\n");
> +		if (queue->nvme_sq.ctrl)
> +			nvmet_ctrl_fatal_error(queue->nvme_sq.ctrl);
> +		return;
> +	}
> +
> +	cmd->queue = queue;
> +	rsp = nvmet_rdma_get_rsp(queue);
> +	rsp->cmd = cmd;
> +	rsp->flags = 0;
> +	rsp->req.cmd = cmd->nvme_cmd;
> +
> +	if (unlikely(queue->state != NVMET_RDMA_Q_LIVE)) {
> +		unsigned long flags;
> +
> +		spin_lock_irqsave(&queue->state_lock, flags);
> +		if (queue->state == NVMET_RDMA_Q_CONNECTING)
> +			list_add_tail(&rsp->wait_list, &queue->rsp_wait_list);
> +		spin_unlock_irqrestore(&queue->state_lock, flags);
> +		return;
> +	}
> +
> +	nvmet_rdma_handle_command(queue, rsp);
> +}
> +
> +static void nvmet_rdma_destroy_srq(struct nvmet_rdma_device *ndev)
> +{
> +	if (!ndev->srq)
> +		return;
> +
> +	nvmet_rdma_free_cmds(ndev, ndev->srq_cmds, ndev->srq_size, false);
> +	ib_destroy_srq(ndev->srq);
> +}
> +
> +static int nvmet_rdma_init_srq(struct nvmet_rdma_device *ndev)
> +{
> +	struct ib_srq_init_attr srq_attr = { NULL, };
> +	struct ib_srq *srq;
> +	size_t srq_size;
> +	int ret, i;
> +
> +	srq_size = 4095;	/* XXX: tune */
> +
> +	srq_attr.attr.max_wr = srq_size;
> +	srq_attr.attr.max_sge = 2;
> +	srq_attr.attr.srq_limit = 0;
> +	srq_attr.srq_type = IB_SRQT_BASIC;
> +	srq = ib_create_srq(ndev->pd, &srq_attr);
> +	if (IS_ERR(srq)) {
> +		/*
> +		 * If SRQs aren't supported we just go ahead and use normal
> +		 * non-shared receive queues.
> +		 */
> +		pr_info("SRQ requested but not supported.\n");
> +		return 0;
> +	}
> +
> +	ndev->srq_cmds = nvmet_rdma_alloc_cmds(ndev, srq_size, false);
> +	if (IS_ERR(ndev->srq_cmds)) {
> +		ret = PTR_ERR(ndev->srq_cmds);
> +		goto out_destroy_srq;
> +	}
> +
> +	ndev->srq = srq;
> +	ndev->srq_size = srq_size;
> +
> +	for (i = 0; i < srq_size; i++)
> +		nvmet_rdma_post_recv(ndev, &ndev->srq_cmds[i]);
> +
> +	return 0;
> +
> +out_destroy_srq:
> +	ib_destroy_srq(srq);
> +	return ret;
> +}
> +
> +static void nvmet_rdma_free_dev(struct kref *ref)
> +{
> +	struct nvmet_rdma_device *ndev =
> +		container_of(ref, struct nvmet_rdma_device, ref);
> +
> +	mutex_lock(&device_list_mutex);
> +	list_del(&ndev->entry);
> +	mutex_unlock(&device_list_mutex);
> +
> +	nvmet_rdma_destroy_srq(ndev);
> +	ib_dealloc_pd(ndev->pd);
> +
> +	kfree(ndev);
> +}
> +
> +static struct nvmet_rdma_device *
> +nvmet_rdma_find_get_device(struct rdma_cm_id *cm_id)
> +{
> +	struct nvmet_rdma_device *ndev;
> +	int ret;
> +
> +	mutex_lock(&device_list_mutex);
> +	list_for_each_entry(ndev, &device_list, entry) {
> +		if (ndev->device->node_guid == cm_id->device->node_guid &&
> +		    kref_get_unless_zero(&ndev->ref))
> +			goto out_unlock;
> +	}
> +
> +	ndev = kzalloc(sizeof(*ndev), GFP_KERNEL);
> +	if (!ndev)
> +		goto out_err;
> +
> +	ndev->device = cm_id->device;
> +	kref_init(&ndev->ref);
> +
> +	ndev->pd = ib_alloc_pd(ndev->device);
> +	if (IS_ERR(ndev->pd))
> +		goto out_free_dev;
> +
> +	if (nvmet_rdma_use_srq) {
> +		ret = nvmet_rdma_init_srq(ndev);
> +		if (ret)
> +			goto out_free_pd;
> +	}
> +
> +	list_add(&ndev->entry, &device_list);
> +out_unlock:
> +	mutex_unlock(&device_list_mutex);
> +	pr_debug("added %s.\n", ndev->device->name);
> +	return ndev;
> +
> +out_free_pd:
> +	ib_dealloc_pd(ndev->pd);
> +out_free_dev:
> +	kfree(ndev);
> +out_err:
> +	mutex_unlock(&device_list_mutex);
> +	return NULL;
> +}
> +
> +static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
> +{
> +	struct ib_qp_init_attr qp_attr;
> +	struct nvmet_rdma_device *ndev = queue->dev;
> +	int comp_vector, nr_cqe, ret, i;
> +
> +	/*
> +	 * Spread the io queues across completion vectors,
> +	 * but still keep all admin queues on vector 0.
> +	 */
> +	comp_vector = !queue->host_qid ? 0 :
> +		queue->idx % ndev->device->num_comp_vectors;
> +
> +	/*
> +	 * Reserve CQ slots for RECV + RDMA_READ/RDMA_WRITE + RDMA_SEND.
> +	 */
> +	nr_cqe = queue->recv_queue_size + 2 * queue->send_queue_size;
> +
> +	queue->cq = ib_alloc_cq(ndev->device, queue,
> +			nr_cqe + 1, comp_vector,
> +			IB_POLL_WORKQUEUE);
> +	if (IS_ERR(queue->cq)) {
> +		ret = PTR_ERR(queue->cq);
> +		pr_err("failed to create CQ cqe= %d ret= %d\n",
> +		       nr_cqe + 1, ret);
> +		goto out;
> +	}
> +
> +	memset(&qp_attr, 0, sizeof(qp_attr));
> +	qp_attr.qp_context = queue;
> +	qp_attr.event_handler = nvmet_rdma_qp_event;
> +	qp_attr.send_cq = queue->cq;
> +	qp_attr.recv_cq = queue->cq;
> +	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
> +	qp_attr.qp_type = IB_QPT_RC;
> +	/* +1 for drain */
> +	qp_attr.cap.max_send_wr = queue->send_queue_size + 1;
> +	qp_attr.cap.max_rdma_ctxs = queue->send_queue_size;
> +	qp_attr.cap.max_send_sge = max(ndev->device->attrs.max_sge_rd,
> +					ndev->device->attrs.max_sge);
> +
> +	if (ndev->srq) {
> +		qp_attr.srq = ndev->srq;
> +	} else {
> +		/* +1 for drain */
> +		qp_attr.cap.max_recv_wr = 1 + queue->recv_queue_size;
> +		qp_attr.cap.max_recv_sge = 2;
> +	}
> +
> +	ret = rdma_create_qp(queue->cm_id, ndev->pd, &qp_attr);
> +	if (ret) {
> +		pr_err("failed to create_qp ret= %d\n", ret);
> +		goto err_destroy_cq;
> +	}
> +
> +	atomic_set(&queue->sq_wr_avail, qp_attr.cap.max_send_wr);
> +
> +	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
> +		 __func__, queue->cq->cqe, qp_attr.cap.max_send_sge,
> +		 qp_attr.cap.max_send_wr, queue->cm_id);
> +
> +	if (!ndev->srq) {
> +		for (i = 0; i < queue->recv_queue_size; i++) {
> +			queue->cmds[i].queue = queue;
> +			nvmet_rdma_post_recv(ndev, &queue->cmds[i]);
> +		}
> +	}
> +
> +out:
> +	return ret;
> +
> +err_destroy_cq:
> +	ib_free_cq(queue->cq);
> +	goto out;
> +}
> +
> +static void nvmet_rdma_destroy_queue_ib(struct nvmet_rdma_queue *queue)
> +{
> +	rdma_destroy_qp(queue->cm_id);
> +	ib_free_cq(queue->cq);
> +}
> +
> +static void nvmet_rdma_free_queue(struct nvmet_rdma_queue *queue)
> +{
> +	pr_info("freeing queue %d\n", queue->idx);
> +
> +	nvmet_sq_destroy(&queue->nvme_sq);
> +
> +	nvmet_rdma_destroy_queue_ib(queue);
> +	if (!queue->dev->srq) {
> +		nvmet_rdma_free_cmds(queue->dev, queue->cmds,
> +				queue->recv_queue_size,
> +				!queue->host_qid);
> +	}
> +	nvmet_rdma_free_rsps(queue);
> +	ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
> +	kfree(queue);
> +}
> +
> +static void nvmet_rdma_release_queue_work(struct work_struct *w)
> +{
> +	struct nvmet_rdma_queue *queue =
> +		container_of(w, struct nvmet_rdma_queue, release_work);
> +	struct rdma_cm_id *cm_id = queue->cm_id;
> +	struct nvmet_rdma_device *dev = queue->dev;
> +
> +	nvmet_rdma_free_queue(queue);
> +	rdma_destroy_id(cm_id);
> +	kref_put(&dev->ref, nvmet_rdma_free_dev);
> +}
> +
> +static int
> +nvmet_rdma_parse_cm_connect_req(struct rdma_conn_param *conn,
> +				struct nvmet_rdma_queue *queue)
> +{
> +	struct nvme_rdma_cm_req *req;
> +
> +	req = (struct nvme_rdma_cm_req *)conn->private_data;
> +	if (!req || conn->private_data_len == 0)
> +		return NVME_RDMA_CM_INVALID_LEN;
> +
> +	if (le16_to_cpu(req->recfmt) != NVME_RDMA_CM_FMT_1_0)
> +		return NVME_RDMA_CM_INVALID_RECFMT;
> +
> +	queue->host_qid = le16_to_cpu(req->qid);
> +
> +	/*
> +	 * req->hsqsize corresponds to our recv queue size
> +	 * req->hrqsize corresponds to our send queue size
> +	 */
> +	queue->recv_queue_size = le16_to_cpu(req->hsqsize);
> +	queue->send_queue_size = le16_to_cpu(req->hrqsize);
> +
> +	if (!queue->host_qid && queue->recv_queue_size > NVMF_AQ_DEPTH)
> +		return NVME_RDMA_CM_INVALID_HSQSIZE;
> +
> +	/* XXX: Should we enforce some kind of max for IO queues? */
> +
> +	return 0;
> +}
> +
> +static int nvmet_rdma_cm_reject(struct rdma_cm_id *cm_id,
> +				enum nvme_rdma_cm_status status)
> +{
> +	struct nvme_rdma_cm_rej rej;
> +
> +	rej.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
> +	rej.sts = cpu_to_le16(status);
> +
> +	return rdma_reject(cm_id, (void *)&rej, sizeof(rej));
> +}
> +
> +static struct nvmet_rdma_queue *
> +nvmet_rdma_alloc_queue(struct nvmet_rdma_device *ndev,
> +		struct rdma_cm_id *cm_id,
> +		struct rdma_cm_event *event)
> +{
> +	struct nvmet_rdma_queue *queue;
> +	int ret;
> +
> +	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
> +	if (!queue) {
> +		ret = NVME_RDMA_CM_NO_RSC;
> +		goto out_reject;
> +	}
> +
> +	ret = nvmet_sq_init(&queue->nvme_sq);
> +	if (ret)
> +		goto out_free_queue;
> +
> +	ret = nvmet_rdma_parse_cm_connect_req(&event->param.conn, queue);
> +	if (ret)
> +		goto out_destroy_sq;
> +
> +	/*
> +	 * Schedules the actual release because calling rdma_destroy_id from
> +	 * inside a CM callback would trigger a deadlock. (great API design..)
> +	 */
> +	INIT_WORK(&queue->release_work, nvmet_rdma_release_queue_work);
> +	queue->dev = ndev;
> +	queue->cm_id = cm_id;
> +
> +	spin_lock_init(&queue->state_lock);
> +	queue->state = NVMET_RDMA_Q_CONNECTING;
> +	INIT_LIST_HEAD(&queue->rsp_wait_list);
> +	INIT_LIST_HEAD(&queue->rsp_wr_wait_list);
> +	spin_lock_init(&queue->rsp_wr_wait_lock);
> +	INIT_LIST_HEAD(&queue->free_rsps);
> +	spin_lock_init(&queue->rsps_lock);
> +
> +	queue->idx = ida_simple_get(&nvmet_rdma_queue_ida, 0, 0, GFP_KERNEL);
> +	if (queue->idx < 0) {
> +		ret = NVME_RDMA_CM_NO_RSC;
> +		goto out_free_queue;
> +	}
> +
> +	ret = nvmet_rdma_alloc_rsps(queue);
> +	if (ret) {
> +		ret = NVME_RDMA_CM_NO_RSC;
> +		goto out_ida_remove;
> +	}
> +
> +	if (!ndev->srq) {
> +		queue->cmds = nvmet_rdma_alloc_cmds(ndev,
> +				queue->recv_queue_size,
> +				!queue->host_qid);
> +		if (IS_ERR(queue->cmds)) {
> +			ret = NVME_RDMA_CM_NO_RSC;
> +			goto out_free_cmds;
> +		}
> +	}
> +
> +	ret = nvmet_rdma_create_queue_ib(queue);
> +	if (ret) {
> +		pr_err("%s: creating RDMA queue failed (%d).\n",
> +			__func__, ret);
> +		ret = NVME_RDMA_CM_NO_RSC;
> +		goto out_free_cmds;
> +	}
> +
> +	return queue;
> +
> +out_free_cmds:
> +	if (!ndev->srq) {
> +		nvmet_rdma_free_cmds(queue->dev, queue->cmds,
> +				queue->recv_queue_size,
> +				!queue->host_qid);
> +	}
> +out_ida_remove:
> +	ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
> +out_destroy_sq:
> +	nvmet_sq_destroy(&queue->nvme_sq);
> +out_free_queue:
> +	kfree(queue);
> +out_reject:
> +	nvmet_rdma_cm_reject(cm_id, ret);
> +	return NULL;
> +}
> +
> +static void nvmet_rdma_qp_event(struct ib_event *event, void *priv)
> +{
> +	struct nvmet_rdma_queue *queue = priv;
> +
> +	switch (event->event) {
> +	case IB_EVENT_COMM_EST:
> +		rdma_notify(queue->cm_id, event->event);
> +		break;
> +	default:
> +		pr_err("received unrecognized IB QP event %d\n", event->event);
> +		break;
> +	}
> +}
> +
> +static int nvmet_rdma_cm_accept(struct rdma_cm_id *cm_id,
> +		struct nvmet_rdma_queue *queue,
> +		struct rdma_conn_param *p)
> +{
> +	struct rdma_conn_param  param = { };
> +	struct nvme_rdma_cm_rep priv = { };
> +	int ret = -ENOMEM;
> +
> +	param.rnr_retry_count = 7;
> +	param.flow_control = 1;
> +	param.initiator_depth = min_t(u8, p->initiator_depth,
> +		queue->dev->device->attrs.max_qp_init_rd_atom);
> +	param.private_data = &priv;
> +	param.private_data_len = sizeof(priv);
> +	priv.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
> +	priv.crqsize = cpu_to_le16(queue->recv_queue_size);
> +
> +	ret = rdma_accept(cm_id, &param);
> +	if (ret)
> +		pr_err("rdma_accept failed (error code = %d)\n", ret);
> +
> +	return ret;
> +}
> +
> +static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id,
> +		struct rdma_cm_event *event)
> +{
> +	struct nvmet_rdma_device *ndev;
> +	struct nvmet_rdma_queue *queue;
> +	int ret = -EINVAL;
> +
> +	ndev = nvmet_rdma_find_get_device(cm_id);
> +	if (!ndev) {
> +		pr_err("no client data!\n");
> +		nvmet_rdma_cm_reject(cm_id, NVME_RDMA_CM_NO_RSC);
> +		return -ECONNREFUSED;
> +	}
> +
> +	queue = nvmet_rdma_alloc_queue(ndev, cm_id, event);
> +	if (!queue) {
> +		ret = -ENOMEM;
> +		goto put_device;
> +	}
> +	queue->port = cm_id->context;
> +
> +	ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn);
> +	if (ret)
> +		goto release_queue;
> +
> +	mutex_lock(&nvmet_rdma_queue_mutex);
> +	list_add_tail(&queue->queue_list, &nvmet_rdma_queue_list);
> +	mutex_unlock(&nvmet_rdma_queue_mutex);
> +
> +	return 0;
> +
> +release_queue:
> +	nvmet_rdma_free_queue(queue);
> +put_device:
> +	kref_put(&ndev->ref, nvmet_rdma_free_dev);
> +
> +	return ret;
> +}
> +
> +static void nvmet_rdma_queue_established(struct nvmet_rdma_queue *queue)
> +{
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&queue->state_lock, flags);
> +	if (queue->state != NVMET_RDMA_Q_CONNECTING) {
> +		pr_warn("trying to establish a connected queue\n");
> +		goto out_unlock;
> +	}
> +	queue->state = NVMET_RDMA_Q_LIVE;
> +
> +	while (!list_empty(&queue->rsp_wait_list)) {
> +		struct nvmet_rdma_rsp *cmd;
> +
> +		cmd = list_first_entry(&queue->rsp_wait_list,
> +					struct nvmet_rdma_rsp, wait_list);
> +		list_del(&cmd->wait_list);
> +
> +		spin_unlock_irqrestore(&queue->state_lock, flags);
> +		nvmet_rdma_handle_command(queue, cmd);
> +		spin_lock_irqsave(&queue->state_lock, flags);
> +	}
> +
> +out_unlock:
> +	spin_unlock_irqrestore(&queue->state_lock, flags);
> +}
> +
> +static void __nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
> +{
> +	bool disconnect = false;
> +	unsigned long flags;
> +
> +	pr_debug("cm_id= %p queue->state= %d\n", queue->cm_id, queue->state);
> +
> +	spin_lock_irqsave(&queue->state_lock, flags);
> +	switch (queue->state) {
> +	case NVMET_RDMA_Q_CONNECTING:
> +	case NVMET_RDMA_Q_LIVE:
> +		disconnect = true;
> +		queue->state = NVMET_RDMA_Q_DISCONNECTING;
> +		break;
> +	case NVMET_RDMA_Q_DISCONNECTING:
> +		break;
> +	}
> +	spin_unlock_irqrestore(&queue->state_lock, flags);
> +
> +	if (disconnect) {
> +		rdma_disconnect(queue->cm_id);
> +		ib_drain_qp(queue->cm_id->qp);
> +		schedule_work(&queue->release_work);
> +	}
> +}
> +
> +static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
> +{
> +	bool disconnect = false;
> +
> +	mutex_lock(&nvmet_rdma_queue_mutex);
> +	if (!list_empty(&queue->queue_list)) {
> +		list_del_init(&queue->queue_list);
> +		disconnect = true;
> +	}
> +	mutex_unlock(&nvmet_rdma_queue_mutex);
> +
> +	if (disconnect)
> +		__nvmet_rdma_queue_disconnect(queue);
> +}
> +
> +static void nvmet_rdma_queue_connect_fail(struct rdma_cm_id *cm_id,
> +		struct nvmet_rdma_queue *queue)
> +{
> +	WARN_ON_ONCE(queue->state != NVMET_RDMA_Q_CONNECTING);
> +
> +	pr_err("failed to connect queue\n");
> +	schedule_work(&queue->release_work);
> +}
> +
> +static int nvmet_rdma_cm_handler(struct rdma_cm_id *cm_id,
> +		struct rdma_cm_event *event)
> +{
> +	struct nvmet_rdma_queue *queue = NULL;
> +	int ret = 0;
> +
> +	if (cm_id->qp)
> +		queue = cm_id->qp->qp_context;
> +
> +	pr_debug("%s (%d): status %d id %p\n",
> +		rdma_event_msg(event->event), event->event,
> +		event->status, cm_id);
> +
> +	switch (event->event) {
> +	case RDMA_CM_EVENT_CONNECT_REQUEST:
> +		ret = nvmet_rdma_queue_connect(cm_id, event);
> +		break;
> +	case RDMA_CM_EVENT_ESTABLISHED:
> +		nvmet_rdma_queue_established(queue);
> +		break;
> +	case RDMA_CM_EVENT_ADDR_CHANGE:
> +	case RDMA_CM_EVENT_DISCONNECTED:
> +	case RDMA_CM_EVENT_DEVICE_REMOVAL:
> +	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
> +		/*
> +		 * We can get the device removal callback even for a
> +		 * CM ID that we aren't actually using.  In that case
> +		 * the context pointer is NULL, so we shouldn't try
> +		 * to disconnect a non-existing queue.  But we also
> +		 * need to return 1 so that the core will destroy
> +		 * it's own ID.  What a great API design..
> +		 */
> +		if (queue)
> +			nvmet_rdma_queue_disconnect(queue);
> +		else
> +			ret = 1;
> +		break;
> +	case RDMA_CM_EVENT_REJECTED:
> +	case RDMA_CM_EVENT_UNREACHABLE:
> +	case RDMA_CM_EVENT_CONNECT_ERROR:
> +		nvmet_rdma_queue_connect_fail(cm_id, queue);
> +		break;
> +	default:
> +		pr_err("received unrecognized RDMA CM event %d\n",
> +			event->event);
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static void nvmet_rdma_delete_ctrl(struct nvmet_ctrl *ctrl)
> +{
> +	struct nvmet_rdma_queue *queue, *next;
> +	static LIST_HEAD(del_list);
> +
> +	mutex_lock(&nvmet_rdma_queue_mutex);
> +	list_for_each_entry_safe(queue, next,
> +			&nvmet_rdma_queue_list, queue_list) {
> +		if (queue->nvme_sq.ctrl->cntlid == ctrl->cntlid)
> +			list_move_tail(&queue->queue_list, &del_list);
> +	}
> +	mutex_unlock(&nvmet_rdma_queue_mutex);
> +
> +	list_for_each_entry_safe(queue, next, &del_list, queue_list)
> +		nvmet_rdma_queue_disconnect(queue);
> +}
> +
> +static int nvmet_rdma_add_port(struct nvmet_port *port)
> +{
> +	struct rdma_cm_id *cm_id;
> +	struct sockaddr_in addr_in;
> +	u16 port_in;
> +	int ret;
> +
> +	ret = kstrtou16(port->disc_addr.trsvcid, 0, &port_in);
> +	if (ret)
> +		return ret;
> +
> +	addr_in.sin_family = AF_INET;
> +	addr_in.sin_addr.s_addr = in_aton(port->disc_addr.traddr);
> +	addr_in.sin_port = htons(port_in);
> +
> +	cm_id = rdma_create_id(&init_net, nvmet_rdma_cm_handler, port,
> +			RDMA_PS_TCP, IB_QPT_RC);
> +	if (IS_ERR(cm_id)) {
> +		pr_err("CM ID creation failed\n");
> +		return PTR_ERR(cm_id);
> +	}
> +
> +	ret = rdma_bind_addr(cm_id, (struct sockaddr *)&addr_in);
> +	if (ret) {
> +		pr_err("binding CM ID to %pISpc failed (%d)\n", &addr_in, ret);
> +		goto out_destroy_id;
> +	}
> +
> +	ret = rdma_listen(cm_id, 128);
> +	if (ret) {
> +		pr_err("listening to %pISpc failed (%d)\n", &addr_in, ret);
> +		goto out_destroy_id;
> +	}
> +
> +	pr_info("enabling port %d (%pISpc)\n",
> +		le16_to_cpu(port->disc_addr.portid), &addr_in);
> +	port->priv = cm_id;
> +	return 0;
> +
> +out_destroy_id:
> +	rdma_destroy_id(cm_id);
> +	return ret;
> +}
> +
> +static void nvmet_rdma_remove_port(struct nvmet_port *port)
> +{
> +	struct rdma_cm_id *cm_id = port->priv;
> +
> +	rdma_destroy_id(cm_id);
> +}
> +
> +static struct nvmet_fabrics_ops nvmet_rdma_ops = {
> +	.owner			= THIS_MODULE,
> +	.type			= NVMF_TRTYPE_RDMA,
> +	.sqe_inline_size	= NVMET_RDMA_INLINE_DATA_SIZE,
> +	.msdbd			= 1,
> +	.has_keyed_sgls		= 1,
> +	.add_port		= nvmet_rdma_add_port,
> +	.remove_port		= nvmet_rdma_remove_port,
> +	.queue_response		= nvmet_rdma_queue_response,
> +	.delete_ctrl		= nvmet_rdma_delete_ctrl,
> +};
> +
> +static int __init nvmet_rdma_init(void)
> +{
> +	return nvmet_register_transport(&nvmet_rdma_ops);
> +}
> +
> +static void __exit nvmet_rdma_exit(void)
> +{
> +	struct nvmet_rdma_queue *queue;
> +
> +	nvmet_unregister_transport(&nvmet_rdma_ops);
> +
> +	flush_scheduled_work();
> +
> +	mutex_lock(&nvmet_rdma_queue_mutex);
> +	while ((queue = list_first_entry_or_null(&nvmet_rdma_queue_list,
> +			struct nvmet_rdma_queue, queue_list))) {
> +		list_del_init(&queue->queue_list);
> +
> +		mutex_unlock(&nvmet_rdma_queue_mutex);
> +		__nvmet_rdma_queue_disconnect(queue);
> +		mutex_lock(&nvmet_rdma_queue_mutex);
> +	}
> +	mutex_unlock(&nvmet_rdma_queue_mutex);
> +
> +	flush_scheduled_work();
> +	ida_destroy(&nvmet_rdma_queue_ida);
> +}
> +
> +module_init(nvmet_rdma_init);
> +module_exit(nvmet_rdma_exit);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("nvmet-transport-1"); /* 1 == NVMF_TRTYPE_RDMA */
>

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

[Sagi Grimberg]

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

On 07/06/16 00:23, Christoph Hellwig wrote:
> This patch implements the RDMA host (initiator in SCSI speak) driver.  It
> can be used to connect to remote NVMe over Fabrics controllers over
> Infiniband, RoCE or iWarp, and uses the existing NVMe core driver as well
> a the new fabrics library.
>
> To connect to all NVMe over Fabrics controller reachable on a given taget
> port using RDMA/CM use the following command:
>
> 	nvme connect-all -t rdma -a $IPADDR
>
> This requires the latest version of nvme-cli with Fabrics support.
>
> Signed-off-by: Jay Freyensee <james.p.freyensee-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Ming Lin <ming.l-Vzezgt5dB6uUEJcrhfAQsw@public.gmane.org>
> Signed-off-by: Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
> Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
> ---
>   drivers/nvme/host/Kconfig  |   16 +
>   drivers/nvme/host/Makefile |    3 +
>   drivers/nvme/host/rdma.c   | 2009 ++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 2028 insertions(+)
>   create mode 100644 drivers/nvme/host/rdma.c
>
> diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig
> index 3397651..db39d53 100644
> --- a/drivers/nvme/host/Kconfig
> +++ b/drivers/nvme/host/Kconfig
> @@ -27,3 +27,19 @@ config BLK_DEV_NVME_SCSI
>
>   config NVME_FABRICS
>   	tristate
> +
> +config NVME_RDMA
> +	tristate "NVM Express over Fabrics RDMA host driver"
> +	depends on INFINIBAND
> +	depends on BLK_DEV_NVME
> +	select NVME_FABRICS
> +	select SG_POOL
> +	help
> +	  This provides support for the NVMe over Fabrics protocol using
> +	  the RDMA (Infiniband, RoCE, iWarp) transport.  This allows you
> +	  to use remote block devices exported using the NVMe protocol set.
> +
> +	  To configure a NVMe over Fabrics controller use the nvme-cli tool
> +	  from https://github.com/linux-nvme/nvme-cli.
> +
> +	  If unsure, say N.
> diff --git a/drivers/nvme/host/Makefile b/drivers/nvme/host/Makefile
> index 5f8648f..47abcec 100644
> --- a/drivers/nvme/host/Makefile
> +++ b/drivers/nvme/host/Makefile
> @@ -1,6 +1,7 @@
>   obj-$(CONFIG_NVME_CORE)			+= nvme-core.o
>   obj-$(CONFIG_BLK_DEV_NVME)		+= nvme.o
>   obj-$(CONFIG_NVME_FABRICS)		+= nvme-fabrics.o
> +obj-$(CONFIG_NVME_RDMA)			+= nvme-rdma.o
>
>   nvme-core-y				:= core.o
>   nvme-core-$(CONFIG_BLK_DEV_NVME_SCSI)	+= scsi.o
> @@ -9,3 +10,5 @@ nvme-core-$(CONFIG_NVM)			+= lightnvm.o
>   nvme-y					+= pci.o
>
>   nvme-fabrics-y				+= fabrics.o
> +
> +nvme-rdma-y				+= rdma.o
> diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
> new file mode 100644
> index 0000000..4edc912
> --- /dev/null
> +++ b/drivers/nvme/host/rdma.c
> @@ -0,0 +1,2009 @@
> +/*
> + * NVMe over Fabrics RDMA host code.
> + * Copyright (c) 2015-2016 HGST, a Western Digital Company.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/err.h>
> +#include <linux/string.h>
> +#include <linux/jiffies.h>
> +#include <linux/atomic.h>
> +#include <linux/blk-mq.h>
> +#include <linux/types.h>
> +#include <linux/list.h>
> +#include <linux/mutex.h>
> +#include <linux/scatterlist.h>
> +#include <linux/nvme.h>
> +#include <linux/t10-pi.h>
> +#include <asm/unaligned.h>
> +
> +#include <rdma/ib_verbs.h>
> +#include <rdma/rdma_cm.h>
> +#include <rdma/ib_cm.h>
> +#include <linux/nvme-rdma.h>
> +
> +#include "nvme.h"
> +#include "fabrics.h"
> +
> +
> +#define NVME_RDMA_CONNECT_TIMEOUT_MS	1000		/* 1 second */
> +
> +#define NVME_RDMA_MAX_SEGMENT_SIZE	0xffffff	/* 24-bit SGL field */
> +
> +#define NVME_RDMA_MAX_SEGMENTS		256
> +
> +#define NVME_RDMA_MAX_INLINE_SEGMENTS	1
> +
> +#define NVME_RDMA_MAX_PAGES_PER_MR	512
> +
> +#define NVME_RDMA_DEF_RECONNECT_DELAY	20
> +
> +/*
> + * We handle AEN commands ourselves and don't even let the
> + * block layer know about them.
> + */
> +#define NVME_RDMA_NR_AEN_COMMANDS      1
> +#define NVME_RDMA_AQ_BLKMQ_DEPTH       \
> +	(NVMF_AQ_DEPTH - NVME_RDMA_NR_AEN_COMMANDS)
> +
> +struct nvme_rdma_device {
> +	struct ib_device       *dev;
> +	struct ib_pd	       *pd;
> +	struct ib_mr	       *mr;
> +	struct kref		ref;
> +	struct list_head	entry;
> +};
> +
> +struct nvme_rdma_qe {
> +	struct ib_cqe		cqe;
> +	void			*data;
> +	u64			dma;
> +};
> +
> +struct nvme_rdma_queue;
> +struct nvme_rdma_request {
> +	struct ib_mr		*mr;
> +	struct nvme_rdma_qe	sqe;
> +	struct ib_sge		sge[1 + NVME_RDMA_MAX_INLINE_SEGMENTS];
> +	u32			num_sge;
> +	int			nents;
> +	bool			inline_data;
> +	bool			need_inval;
> +	struct ib_reg_wr	reg_wr;
> +	struct ib_cqe		reg_cqe;
> +	struct nvme_rdma_queue  *queue;
> +	struct sg_table		sg_table;
> +	struct scatterlist	first_sgl[];
> +};
> +
> +enum nvme_rdma_queue_flags {
> +	NVME_RDMA_Q_CONNECTED = (1 << 0),
> +};
> +
> +struct nvme_rdma_queue {
> +	struct nvme_rdma_qe	*rsp_ring;
> +	u8			sig_count;
> +	int			queue_size;
> +	size_t			cmnd_capsule_len;
> +	struct nvme_rdma_ctrl	*ctrl;
> +	struct nvme_rdma_device	*device;
> +	struct ib_cq		*ib_cq;
> +	struct ib_qp		*qp;
> +
> +	unsigned long		flags;
> +	struct rdma_cm_id	*cm_id;
> +	int			cm_error;
> +	struct completion	cm_done;
> +};
> +
> +struct nvme_rdma_ctrl {
> +	/* read and written in the hot path */
> +	spinlock_t		lock;
> +
> +	/* read only in the hot path */
> +	struct nvme_rdma_queue	*queues;
> +	u32			queue_count;
> +
> +	/* other member variables */
> +	unsigned short		tl_retry_count;
> +	struct blk_mq_tag_set	tag_set;
> +	struct work_struct	delete_work;
> +	struct work_struct	reset_work;
> +	struct work_struct	err_work;
> +
> +	struct nvme_rdma_qe	async_event_sqe;
> +
> +	int			reconnect_delay;
> +	struct delayed_work	reconnect_work;
> +
> +	struct list_head	list;
> +
> +	struct blk_mq_tag_set	admin_tag_set;
> +	struct nvme_rdma_device	*device;
> +
> +	u64			cap;
> +	u32			max_fr_pages;
> +
> +	union {
> +		struct sockaddr addr;
> +		struct sockaddr_in addr_in;
> +	};
> +
> +	struct nvme_ctrl	ctrl;
> +};
> +
> +static inline struct nvme_rdma_ctrl *to_rdma_ctrl(struct nvme_ctrl *ctrl)
> +{
> +	return container_of(ctrl, struct nvme_rdma_ctrl, ctrl);
> +}
> +
> +static LIST_HEAD(device_list);
> +static DEFINE_MUTEX(device_list_mutex);
> +
> +static LIST_HEAD(nvme_rdma_ctrl_list);
> +static DEFINE_MUTEX(nvme_rdma_ctrl_mutex);
> +
> +static struct workqueue_struct *nvme_rdma_wq;
> +
> +/*
> + * Disabling this option makes small I/O goes faster, but is fundamentally
> + * unsafe.  With it turned off we will have to register a global rkey that
> + * allows read and write access to all physical memory.
> + */
> +static bool register_always = true;
> +module_param(register_always, bool, 0444);
> +MODULE_PARM_DESC(register_always,
> +	 "Use memory registration even for contiguous memory regions");
> +
> +static int nvme_rdma_cm_handler(struct rdma_cm_id *cm_id,
> +		struct rdma_cm_event *event);
> +static void nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc);
> +static int __nvme_rdma_del_ctrl(struct nvme_rdma_ctrl *ctrl);
> +
> +/* XXX: really should move to a generic header sooner or later.. */
> +static inline void put_unaligned_le24(u32 val, u8 *p)
> +{
> +	*p++ = val;
> +	*p++ = val >> 8;
> +	*p++ = val >> 16;
> +}
> +
> +static inline int nvme_rdma_queue_idx(struct nvme_rdma_queue *queue)
> +{
> +	return queue - queue->ctrl->queues;
> +}
> +
> +static inline size_t nvme_rdma_inline_data_size(struct nvme_rdma_queue *queue)
> +{
> +	return queue->cmnd_capsule_len - sizeof(struct nvme_command);
> +}
> +
> +static void nvme_rdma_free_qe(struct ib_device *ibdev, struct nvme_rdma_qe *qe,
> +		size_t capsule_size, enum dma_data_direction dir)
> +{
> +	ib_dma_unmap_single(ibdev, qe->dma, capsule_size, dir);
> +	kfree(qe->data);
> +}
> +
> +static int nvme_rdma_alloc_qe(struct ib_device *ibdev, struct nvme_rdma_qe *qe,
> +		size_t capsule_size, enum dma_data_direction dir)
> +{
> +	qe->data = kzalloc(capsule_size, GFP_KERNEL);
> +	if (!qe->data)
> +		return -ENOMEM;
> +
> +	qe->dma = ib_dma_map_single(ibdev, qe->data, capsule_size, dir);
> +	if (ib_dma_mapping_error(ibdev, qe->dma)) {
> +		kfree(qe->data);
> +		return -ENOMEM;
> +	}
> +
> +	return 0;
> +}
> +
> +static void nvme_rdma_free_ring(struct ib_device *ibdev,
> +		struct nvme_rdma_qe *ring, size_t ib_queue_size,
> +		size_t capsule_size, enum dma_data_direction dir)
> +{
> +	int i;
> +
> +	for (i = 0; i < ib_queue_size; i++)
> +		nvme_rdma_free_qe(ibdev, &ring[i], capsule_size, dir);
> +	kfree(ring);
> +}
> +
> +static struct nvme_rdma_qe *nvme_rdma_alloc_ring(struct ib_device *ibdev,
> +		size_t ib_queue_size, size_t capsule_size,
> +		enum dma_data_direction dir)
> +{
> +	struct nvme_rdma_qe *ring;
> +	int i;
> +
> +	ring = kcalloc(ib_queue_size, sizeof(struct nvme_rdma_qe), GFP_KERNEL);
> +	if (!ring)
> +		return NULL;
> +
> +	for (i = 0; i < ib_queue_size; i++) {
> +		if (nvme_rdma_alloc_qe(ibdev, &ring[i], capsule_size, dir))
> +			goto out_free_ring;
> +	}
> +
> +	return ring;
> +
> +out_free_ring:
> +	nvme_rdma_free_ring(ibdev, ring, i, capsule_size, dir);
> +	return NULL;
> +}
> +
> +static void nvme_rdma_qp_event(struct ib_event *event, void *context)
> +{
> +	pr_debug("QP event %d\n", event->event);
> +}
> +
> +static int nvme_rdma_wait_for_cm(struct nvme_rdma_queue *queue)
> +{
> +	wait_for_completion_interruptible_timeout(&queue->cm_done,
> +			msecs_to_jiffies(NVME_RDMA_CONNECT_TIMEOUT_MS) + 1);
> +	return queue->cm_error;
> +}
> +
> +static int nvme_rdma_create_qp(struct nvme_rdma_queue *queue, const int factor)
> +{
> +	struct nvme_rdma_device *dev = queue->device;
> +	struct ib_qp_init_attr init_attr;
> +	int ret;
> +
> +	memset(&init_attr, 0, sizeof(init_attr));
> +	init_attr.event_handler = nvme_rdma_qp_event;
> +	/* +1 for drain */
> +	init_attr.cap.max_send_wr = factor * queue->queue_size + 1;
> +	/* +1 for drain */
> +	init_attr.cap.max_recv_wr = queue->queue_size + 1;
> +	init_attr.cap.max_recv_sge = 1;
> +	init_attr.cap.max_send_sge = 1 + NVME_RDMA_MAX_INLINE_SEGMENTS;
> +	init_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
> +	init_attr.qp_type = IB_QPT_RC;
> +	init_attr.send_cq = queue->ib_cq;
> +	init_attr.recv_cq = queue->ib_cq;
> +
> +	ret = rdma_create_qp(queue->cm_id, dev->pd, &init_attr);
> +
> +	queue->qp = queue->cm_id->qp;
> +	return ret;
> +}
> +
> +static int nvme_rdma_reinit_request(void *data, struct request *rq)
> +{
> +	struct nvme_rdma_ctrl *ctrl = data;
> +	struct nvme_rdma_device *dev = ctrl->device;
> +	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
> +	int ret = 0;
> +
> +	if (!req->need_inval)
> +		goto out;
> +
> +	ib_dereg_mr(req->mr);
> +
> +	req->mr = ib_alloc_mr(dev->pd, IB_MR_TYPE_MEM_REG,
> +			ctrl->max_fr_pages);
> +	if (IS_ERR(req->mr)) {
> +		req->mr = NULL;
> +		ret = PTR_ERR(req->mr);
> +	}
> +
> +	req->need_inval = false;
> +
> +out:
> +	return ret;
> +}
> +
> +static void __nvme_rdma_exit_request(struct nvme_rdma_ctrl *ctrl,
> +		struct request *rq, unsigned int queue_idx)
> +{
> +	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
> +	struct nvme_rdma_queue *queue = &ctrl->queues[queue_idx];
> +	struct nvme_rdma_device *dev = queue->device;
> +
> +	if (req->mr)
> +		ib_dereg_mr(req->mr);
> +
> +	nvme_rdma_free_qe(dev->dev, &req->sqe, sizeof(struct nvme_command),
> +			DMA_TO_DEVICE);
> +}
> +
> +static void nvme_rdma_exit_request(void *data, struct request *rq,
> +				unsigned int hctx_idx, unsigned int rq_idx)
> +{
> +	return __nvme_rdma_exit_request(data, rq, hctx_idx + 1);
> +}
> +
> +static void nvme_rdma_exit_admin_request(void *data, struct request *rq,
> +				unsigned int hctx_idx, unsigned int rq_idx)
> +{
> +	return __nvme_rdma_exit_request(data, rq, 0);
> +}
> +
> +static int __nvme_rdma_init_request(struct nvme_rdma_ctrl *ctrl,
> +		struct request *rq, unsigned int queue_idx)
> +{
> +	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
> +	struct nvme_rdma_queue *queue = &ctrl->queues[queue_idx];
> +	struct nvme_rdma_device *dev = queue->device;
> +	struct ib_device *ibdev = dev->dev;
> +	int ret;
> +
> +	BUG_ON(queue_idx >= ctrl->queue_count);
> +
> +	ret = nvme_rdma_alloc_qe(ibdev, &req->sqe, sizeof(struct nvme_command),
> +			DMA_TO_DEVICE);
> +	if (ret)
> +		return ret;
> +
> +	req->mr = ib_alloc_mr(dev->pd, IB_MR_TYPE_MEM_REG,
> +			ctrl->max_fr_pages);
> +	if (IS_ERR(req->mr)) {
> +		ret = PTR_ERR(req->mr);
> +		goto out_free_qe;
> +	}
> +
> +	req->queue = queue;
> +
> +	return 0;
> +
> +out_free_qe:
> +	nvme_rdma_free_qe(dev->dev, &req->sqe, sizeof(struct nvme_command),
> +			DMA_TO_DEVICE);
> +	return -ENOMEM;
> +}
> +
> +static int nvme_rdma_init_request(void *data, struct request *rq,
> +				unsigned int hctx_idx, unsigned int rq_idx,
> +				unsigned int numa_node)
> +{
> +	return __nvme_rdma_init_request(data, rq, hctx_idx + 1);
> +}
> +
> +static int nvme_rdma_init_admin_request(void *data, struct request *rq,
> +				unsigned int hctx_idx, unsigned int rq_idx,
> +				unsigned int numa_node)
> +{
> +	return __nvme_rdma_init_request(data, rq, 0);
> +}
> +
> +static int nvme_rdma_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
> +		unsigned int hctx_idx)
> +{
> +	struct nvme_rdma_ctrl *ctrl = data;
> +	struct nvme_rdma_queue *queue = &ctrl->queues[hctx_idx + 1];
> +
> +	BUG_ON(hctx_idx >= ctrl->queue_count);
> +
> +	hctx->driver_data = queue;
> +	return 0;
> +}
> +
> +static int nvme_rdma_init_admin_hctx(struct blk_mq_hw_ctx *hctx, void *data,
> +		unsigned int hctx_idx)
> +{
> +	struct nvme_rdma_ctrl *ctrl = data;
> +	struct nvme_rdma_queue *queue = &ctrl->queues[0];
> +
> +	BUG_ON(hctx_idx != 0);
> +
> +	hctx->driver_data = queue;
> +	return 0;
> +}
> +
> +static void nvme_rdma_free_dev(struct kref *ref)
> +{
> +	struct nvme_rdma_device *ndev =
> +		container_of(ref, struct nvme_rdma_device, ref);
> +
> +	mutex_lock(&device_list_mutex);
> +	list_del(&ndev->entry);
> +	mutex_unlock(&device_list_mutex);
> +
> +	if (!register_always)
> +		ib_dereg_mr(ndev->mr);
> +	ib_dealloc_pd(ndev->pd);
> +
> +	kfree(ndev);
> +}
> +
> +static void nvme_rdma_dev_put(struct nvme_rdma_device *dev)
> +{
> +	kref_put(&dev->ref, nvme_rdma_free_dev);
> +}
> +
> +static int nvme_rdma_dev_get(struct nvme_rdma_device *dev)
> +{
> +	return kref_get_unless_zero(&dev->ref);
> +}
> +
> +static struct nvme_rdma_device *
> +nvme_rdma_find_get_device(struct rdma_cm_id *cm_id)
> +{
> +	struct nvme_rdma_device *ndev;
> +
> +	mutex_lock(&device_list_mutex);
> +	list_for_each_entry(ndev, &device_list, entry) {
> +		if (ndev->dev->node_guid == cm_id->device->node_guid &&
> +		    nvme_rdma_dev_get(ndev))
> +			goto out_unlock;
> +	}
> +
> +	ndev = kzalloc(sizeof(*ndev), GFP_KERNEL);
> +	if (!ndev)
> +		goto out_err;
> +
> +	ndev->dev = cm_id->device;
> +	kref_init(&ndev->ref);
> +
> +	ndev->pd = ib_alloc_pd(ndev->dev);
> +	if (IS_ERR(ndev->pd))
> +		goto out_free_dev;
> +
> +	if (!register_always) {
> +		ndev->mr = ib_get_dma_mr(ndev->pd,
> +					    IB_ACCESS_LOCAL_WRITE |
> +					    IB_ACCESS_REMOTE_READ |
> +					    IB_ACCESS_REMOTE_WRITE);
> +		if (IS_ERR(ndev->mr))
> +			goto out_free_pd;
> +	}
> +
> +	if (!(ndev->dev->attrs.device_cap_flags &
> +	      IB_DEVICE_MEM_MGT_EXTENSIONS)) {
> +		dev_err(&ndev->dev->dev,
> +			"Memory registrations not supported.\n");
> +		goto out_free_mr;
> +	}
> +
> +	list_add(&ndev->entry, &device_list);
> +out_unlock:
> +	mutex_unlock(&device_list_mutex);
> +	return ndev;
> +
> +out_free_mr:
> +	if (!register_always)
> +		ib_dereg_mr(ndev->mr);
> +out_free_pd:
> +	ib_dealloc_pd(ndev->pd);
> +out_free_dev:
> +	kfree(ndev);
> +out_err:
> +	mutex_unlock(&device_list_mutex);
> +	return NULL;
> +}
> +
> +static void nvme_rdma_destroy_queue_ib(struct nvme_rdma_queue *queue)
> +{
> +	struct nvme_rdma_device *dev = queue->device;
> +	struct ib_device *ibdev = dev->dev;
> +
> +	rdma_destroy_qp(queue->cm_id);
> +	ib_free_cq(queue->ib_cq);
> +
> +	nvme_rdma_free_ring(ibdev, queue->rsp_ring, queue->queue_size,
> +			sizeof(struct nvme_completion), DMA_FROM_DEVICE);
> +
> +	nvme_rdma_dev_put(dev);
> +}
> +
> +static int nvme_rdma_create_queue_ib(struct nvme_rdma_queue *queue,
> +		struct nvme_rdma_device *dev)
> +{
> +	struct ib_device *ibdev = dev->dev;
> +	const int send_wr_factor = 3;			/* MR, SEND, INV */
> +	const int cq_factor = send_wr_factor + 1;	/* + RECV */
> +	int comp_vector, idx = nvme_rdma_queue_idx(queue);
> +
> +	int ret;
> +
> +	queue->device = dev;
> +
> +	/*
> +	 * The admin queue is barely used once the controller is live, so don't
> +	 * bother to spread it out.
> +	 */
> +	if (idx == 0)
> +		comp_vector = 0;
> +	else
> +		comp_vector = idx % ibdev->num_comp_vectors;
> +
> +
> +	/* +1 for ib_stop_cq */
> +	queue->ib_cq = ib_alloc_cq(dev->dev, queue,
> +				cq_factor * queue->queue_size + 1, comp_vector,
> +				IB_POLL_SOFTIRQ);
> +	if (IS_ERR(queue->ib_cq)) {
> +		ret = PTR_ERR(queue->ib_cq);
> +		goto out;
> +	}
> +
> +	ret = nvme_rdma_create_qp(queue, send_wr_factor);
> +	if (ret)
> +		goto out_destroy_ib_cq;
> +
> +	queue->rsp_ring = nvme_rdma_alloc_ring(ibdev, queue->queue_size,
> +			sizeof(struct nvme_completion), DMA_FROM_DEVICE);
> +	if (!queue->rsp_ring) {
> +		ret = -ENOMEM;
> +		goto out_destroy_qp;
> +	}
> +
> +	return 0;
> +
> +out_destroy_qp:
> +	ib_destroy_qp(queue->qp);
> +out_destroy_ib_cq:
> +	ib_free_cq(queue->ib_cq);
> +out:
> +	return ret;
> +}
> +
> +static int nvme_rdma_init_queue(struct nvme_rdma_ctrl *ctrl,
> +		int idx, size_t queue_size)
> +{
> +	struct nvme_rdma_queue *queue;
> +	int ret;
> +
> +	queue = &ctrl->queues[idx];
> +	queue->ctrl = ctrl;
> +	init_completion(&queue->cm_done);
> +
> +	if (idx > 0)
> +		queue->cmnd_capsule_len = ctrl->ctrl.ioccsz * 16;
> +	else
> +		queue->cmnd_capsule_len = sizeof(struct nvme_command);
> +
> +	queue->queue_size = queue_size;
> +
> +	queue->cm_id = rdma_create_id(&init_net, nvme_rdma_cm_handler, queue,
> +			RDMA_PS_TCP, IB_QPT_RC);
> +	if (IS_ERR(queue->cm_id)) {
> +		dev_info(ctrl->ctrl.device,
> +			"failed to create CM ID: %ld\n", PTR_ERR(queue->cm_id));
> +		return PTR_ERR(queue->cm_id);
> +	}
> +
> +	queue->cm_error = -ETIMEDOUT;
> +	ret = rdma_resolve_addr(queue->cm_id, NULL, &ctrl->addr,
> +			NVME_RDMA_CONNECT_TIMEOUT_MS);
> +	if (ret) {
> +		dev_info(ctrl->ctrl.device,
> +			"rdma_resolve_addr failed (%d).\n", ret);
> +		goto out_destroy_cm_id;
> +	}
> +
> +	ret = nvme_rdma_wait_for_cm(queue);
> +	if (ret) {
> +		dev_info(ctrl->ctrl.device,
> +			"rdma_resolve_addr wait failed (%d).\n", ret);
> +		goto out_destroy_cm_id;
> +	}
> +
> +	set_bit(NVME_RDMA_Q_CONNECTED, &queue->flags);
> +
> +	return 0;
> +
> +out_destroy_cm_id:
> +	rdma_destroy_id(queue->cm_id);
> +	return ret;
> +}
> +
> +static void nvme_rdma_free_queue(struct nvme_rdma_queue *queue)
> +{
> +	if (!test_and_clear_bit(NVME_RDMA_Q_CONNECTED, &queue->flags))
> +		return;
> +
> +	rdma_disconnect(queue->cm_id);
> +	ib_drain_qp(queue->qp);
> +	nvme_rdma_destroy_queue_ib(queue);
> +	rdma_destroy_id(queue->cm_id);
> +}
> +
> +static void nvme_rdma_free_io_queues(struct nvme_rdma_ctrl *ctrl)
> +{
> +	int i;
> +
> +	for (i = 1; i < ctrl->queue_count; i++)
> +		nvme_rdma_free_queue(&ctrl->queues[i]);
> +}
> +
> +static int nvme_rdma_connect_io_queues(struct nvme_rdma_ctrl *ctrl)
> +{
> +	int i, ret = 0;
> +
> +	for (i = 1; i < ctrl->queue_count; i++) {
> +		ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
> +		if (ret)
> +			break;
> +	}
> +
> +	return ret;
> +}
> +
> +static int nvme_rdma_init_io_queues(struct nvme_rdma_ctrl *ctrl)
> +{
> +	int i, ret;
> +
> +	for (i = 1; i < ctrl->queue_count; i++) {
> +		ret = nvme_rdma_init_queue(ctrl, i, ctrl->ctrl.sqsize);
> +		if (ret) {
> +			dev_info(ctrl->ctrl.device,
> +				"failed to initialize i/o queue: %d\n", ret);
> +			goto out_free_queues;
> +		}
> +	}
> +
> +	return 0;
> +
> +out_free_queues:
> +	for (; i >= 1; i--)
> +		nvme_rdma_free_queue(&ctrl->queues[i]);
> +
> +	return ret;
> +}
> +
> +static void nvme_rdma_destroy_admin_queue(struct nvme_rdma_ctrl *ctrl)
> +{
> +	nvme_rdma_free_qe(ctrl->queues[0].device->dev, &ctrl->async_event_sqe,
> +			sizeof(struct nvme_command), DMA_TO_DEVICE);
> +	nvme_rdma_free_queue(&ctrl->queues[0]);
> +	blk_cleanup_queue(ctrl->ctrl.admin_q);
> +	blk_mq_free_tag_set(&ctrl->admin_tag_set);
> +	nvme_rdma_dev_put(ctrl->device);
> +}
> +
> +static void nvme_rdma_free_ctrl(struct nvme_ctrl *nctrl)
> +{
> +	struct nvme_rdma_ctrl *ctrl = to_rdma_ctrl(nctrl);
> +
> +	if (list_empty(&ctrl->list))
> +		goto free_ctrl;
> +
> +	mutex_lock(&nvme_rdma_ctrl_mutex);
> +	list_del(&ctrl->list);
> +	mutex_unlock(&nvme_rdma_ctrl_mutex);
> +
> +	if (ctrl->ctrl.tagset) {
> +		blk_cleanup_queue(ctrl->ctrl.connect_q);
> +		blk_mq_free_tag_set(&ctrl->tag_set);
> +		nvme_rdma_dev_put(ctrl->device);
> +	}
> +	kfree(ctrl->queues);
> +	nvmf_free_options(nctrl->opts);
> +free_ctrl:
> +	kfree(ctrl);
> +}
> +
> +static void nvme_rdma_reconnect_ctrl_work(struct work_struct *work)
> +{
> +	struct nvme_rdma_ctrl *ctrl = container_of(to_delayed_work(work),
> +			struct nvme_rdma_ctrl, reconnect_work);
> +	bool changed;
> +	int ret;
> +
> +	if (ctrl->queue_count > 1) {
> +		nvme_rdma_free_io_queues(ctrl);
> +
> +		ret = blk_mq_reinit_tagset(&ctrl->tag_set);
> +		if (ret)
> +			goto requeue;
> +	}
> +
> +	nvme_rdma_free_queue(&ctrl->queues[0]);
> +
> +	ret = blk_mq_reinit_tagset(&ctrl->admin_tag_set);
> +	if (ret)
> +		goto requeue;
> +
> +	ret = nvme_rdma_init_queue(ctrl, 0, NVMF_AQ_DEPTH);
> +	if (ret)
> +		goto requeue;
> +
> +	blk_mq_start_stopped_hw_queues(ctrl->ctrl.admin_q, true);
> +
> +	ret = nvmf_connect_admin_queue(&ctrl->ctrl);
> +	if (ret)
> +		goto stop_admin_q;
> +
> +	ret = nvme_enable_ctrl(&ctrl->ctrl, ctrl->cap);
> +	if (ret)
> +		goto stop_admin_q;
> +
> +	nvme_start_keep_alive(&ctrl->ctrl);
> +
> +	if (ctrl->queue_count > 1) {
> +		ret = nvme_rdma_init_io_queues(ctrl);
> +		if (ret)
> +			goto stop_admin_q;
> +
> +		ret = nvme_rdma_connect_io_queues(ctrl);
> +		if (ret)
> +			goto stop_admin_q;
> +	}
> +
> +	changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
> +	WARN_ON_ONCE(!changed);
> +
> +	if (ctrl->queue_count > 1)
> +		nvme_start_queues(&ctrl->ctrl);
> +
> +	dev_info(ctrl->ctrl.device, "Successfully reconnected\n");
> +
> +	return;
> +
> +stop_admin_q:
> +	blk_mq_stop_hw_queues(ctrl->ctrl.admin_q);
> +requeue:
> +	/* Make sure we are not resetting/deleting */
> +	if (ctrl->ctrl.state == NVME_CTRL_RECONNECTING) {
> +		dev_info(ctrl->ctrl.device,
> +			"Failed reconnect attempt, requeueing...\n");
> +		queue_delayed_work(nvme_rdma_wq, &ctrl->reconnect_work,
> +					ctrl->reconnect_delay * HZ);
> +	}
> +}
> +
> +static void nvme_rdma_error_recovery_work(struct work_struct *work)
> +{
> +	struct nvme_rdma_ctrl *ctrl = container_of(work,
> +			struct nvme_rdma_ctrl, err_work);
> +
> +	nvme_stop_keep_alive(&ctrl->ctrl);
> +	if (ctrl->queue_count > 1)
> +		nvme_stop_queues(&ctrl->ctrl);
> +	blk_mq_stop_hw_queues(ctrl->ctrl.admin_q);
> +
> +	/* We must take care of fastfail/requeue all our inflight requests */
> +	if (ctrl->queue_count > 1)
> +		blk_mq_tagset_busy_iter(&ctrl->tag_set,
> +					nvme_cancel_request, &ctrl->ctrl);
> +	blk_mq_tagset_busy_iter(&ctrl->admin_tag_set,
> +				nvme_cancel_request, &ctrl->ctrl);
> +
> +	dev_info(ctrl->ctrl.device, "reconnecting in %d seconds\n",
> +		ctrl->reconnect_delay);
> +
> +	queue_delayed_work(nvme_rdma_wq, &ctrl->reconnect_work,
> +				ctrl->reconnect_delay * HZ);
> +}
> +
> +static void nvme_rdma_error_recovery(struct nvme_rdma_ctrl *ctrl)
> +{
> +	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_RECONNECTING))
> +		return;
> +
> +	queue_work(nvme_rdma_wq, &ctrl->err_work);
> +}
> +
> +static void nvme_rdma_wr_error(struct ib_cq *cq, struct ib_wc *wc,
> +		const char *op)
> +{
> +	struct nvme_rdma_queue *queue = cq->cq_context;
> +	struct nvme_rdma_ctrl *ctrl = queue->ctrl;
> +
> +	if (ctrl->ctrl.state == NVME_CTRL_LIVE)
> +		dev_info(ctrl->ctrl.device,
> +			     "%s for CQE 0x%p failed with status %s (%d)\n",
> +			     op, wc->wr_cqe,
> +			     ib_wc_status_msg(wc->status), wc->status);
> +	nvme_rdma_error_recovery(ctrl);
> +}
> +
> +static void nvme_rdma_memreg_done(struct ib_cq *cq, struct ib_wc *wc)
> +{
> +	if (unlikely(wc->status != IB_WC_SUCCESS))
> +		nvme_rdma_wr_error(cq, wc, "MEMREG");
> +}
> +
> +static void nvme_rdma_inv_rkey_done(struct ib_cq *cq, struct ib_wc *wc)
> +{
> +	if (unlikely(wc->status != IB_WC_SUCCESS))
> +		nvme_rdma_wr_error(cq, wc, "LOCAL_INV");
> +}
> +
> +static int nvme_rdma_inv_rkey(struct nvme_rdma_queue *queue,
> +		struct nvme_rdma_request *req)
> +{
> +	struct ib_send_wr *bad_wr;
> +	struct ib_send_wr wr = {
> +		.opcode		    = IB_WR_LOCAL_INV,
> +		.next		    = NULL,
> +		.num_sge	    = 0,
> +		.send_flags	    = 0,
> +		.ex.invalidate_rkey = req->mr->rkey,
> +	};
> +
> +	req->reg_cqe.done = nvme_rdma_inv_rkey_done;
> +	wr.wr_cqe = &req->reg_cqe;
> +
> +	return ib_post_send(queue->qp, &wr, &bad_wr);
> +}
> +
> +static void nvme_rdma_unmap_data(struct nvme_rdma_queue *queue,
> +		struct request *rq)
> +{
> +	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
> +	struct nvme_rdma_ctrl *ctrl = queue->ctrl;
> +	struct nvme_rdma_device *dev = queue->device;
> +	struct ib_device *ibdev = dev->dev;
> +	int res;
> +
> +	if (!blk_rq_bytes(rq))
> +		return;
> +
> +	if (req->need_inval) {
> +		res = nvme_rdma_inv_rkey(queue, req);
> +		if (res < 0) {
> +			dev_err(ctrl->ctrl.device,
> +				"Queueing INV WR for rkey %#x failed (%d)\n",
> +				req->mr->rkey, res);
> +			nvme_rdma_error_recovery(queue->ctrl);
> +		}
> +	}
> +
> +	ib_dma_unmap_sg(ibdev, req->sg_table.sgl,
> +			req->nents, rq_data_dir(rq) ==
> +				    WRITE ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
> +
> +	nvme_cleanup_cmd(rq);
> +	sg_free_table_chained(&req->sg_table, true);
> +}
> +
> +static int nvme_rdma_set_sg_null(struct nvme_command *c)
> +{
> +	struct nvme_keyed_sgl_desc *sg = &c->common.dptr.ksgl;
> +
> +	sg->addr = 0;
> +	put_unaligned_le24(0, sg->length);
> +	put_unaligned_le32(0, sg->key);
> +	sg->type = NVME_KEY_SGL_FMT_DATA_DESC << 4;
> +	return 0;
> +}
> +
> +static int nvme_rdma_map_sg_inline(struct nvme_rdma_queue *queue,
> +		struct nvme_rdma_request *req, struct nvme_command *c)
> +{
> +	struct nvme_sgl_desc *sg = &c->common.dptr.sgl;
> +
> +	req->sge[1].addr = sg_dma_address(req->sg_table.sgl);
> +	req->sge[1].length = sg_dma_len(req->sg_table.sgl);
> +	req->sge[1].lkey = queue->device->pd->local_dma_lkey;
> +
> +	sg->addr = cpu_to_le64(queue->ctrl->ctrl.icdoff);
> +	sg->length = cpu_to_le32(sg_dma_len(req->sg_table.sgl));
> +	sg->type = (NVME_SGL_FMT_DATA_DESC << 4) | NVME_SGL_FMT_OFFSET;
> +
> +	req->inline_data = true;
> +	req->num_sge++;
> +	return 0;
> +}
> +
> +static int nvme_rdma_map_sg_single(struct nvme_rdma_queue *queue,
> +		struct nvme_rdma_request *req, struct nvme_command *c)
> +{
> +	struct nvme_keyed_sgl_desc *sg = &c->common.dptr.ksgl;
> +
> +	sg->addr = cpu_to_le64(sg_dma_address(req->sg_table.sgl));
> +	put_unaligned_le24(sg_dma_len(req->sg_table.sgl), sg->length);
> +	put_unaligned_le32(queue->device->mr->rkey, sg->key);
> +	sg->type = NVME_KEY_SGL_FMT_DATA_DESC << 4;
> +	return 0;
> +}
> +
> +static int nvme_rdma_map_sg_fr(struct nvme_rdma_queue *queue,
> +		struct nvme_rdma_request *req, struct nvme_command *c,
> +		int count)
> +{
> +	struct nvme_keyed_sgl_desc *sg = &c->common.dptr.ksgl;
> +	int nr;
> +
> +	nr = ib_map_mr_sg(req->mr, req->sg_table.sgl, count, NULL, PAGE_SIZE);
> +	if (nr < count) {
> +		if (nr < 0)
> +			return nr;
> +		return -EINVAL;
> +	}
> +
> +	ib_update_fast_reg_key(req->mr, ib_inc_rkey(req->mr->rkey));
> +
> +	req->reg_cqe.done = nvme_rdma_memreg_done;
> +	memset(&req->reg_wr, 0, sizeof(req->reg_wr));
> +	req->reg_wr.wr.opcode = IB_WR_REG_MR;
> +	req->reg_wr.wr.wr_cqe = &req->reg_cqe;
> +	req->reg_wr.wr.num_sge = 0;
> +	req->reg_wr.mr = req->mr;
> +	req->reg_wr.key = req->mr->rkey;
> +	req->reg_wr.access = IB_ACCESS_LOCAL_WRITE |
> +			     IB_ACCESS_REMOTE_READ |
> +			     IB_ACCESS_REMOTE_WRITE;
> +
> +	req->need_inval = true;
> +
> +	sg->addr = cpu_to_le64(req->mr->iova);
> +	put_unaligned_le24(req->mr->length, sg->length);
> +	put_unaligned_le32(req->mr->rkey, sg->key);
> +	sg->type = (NVME_KEY_SGL_FMT_DATA_DESC << 4) |
> +			NVME_SGL_FMT_INVALIDATE;
> +
> +	return 0;
> +}
> +
> +static int nvme_rdma_map_data(struct nvme_rdma_queue *queue,
> +		struct request *rq, unsigned int map_len,
> +		struct nvme_command *c)
> +{
> +	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
> +	struct nvme_rdma_device *dev = queue->device;
> +	struct ib_device *ibdev = dev->dev;
> +	int nents, count;
> +	int ret;
> +
> +	req->num_sge = 1;
> +	req->inline_data = false;
> +	req->need_inval = false;
> +
> +	c->common.flags |= NVME_CMD_SGL_METABUF;
> +
> +	if (!blk_rq_bytes(rq))
> +		return nvme_rdma_set_sg_null(c);
> +
> +	req->sg_table.sgl = req->first_sgl;
> +	ret = sg_alloc_table_chained(&req->sg_table, rq->nr_phys_segments,
> +				req->sg_table.sgl);
> +	if (ret)
> +		return -ENOMEM;
> +
> +	nents = blk_rq_map_sg(rq->q, rq, req->sg_table.sgl);
> +	BUG_ON(nents > rq->nr_phys_segments);
> +	req->nents = nents;
> +
> +	count = ib_dma_map_sg(ibdev, req->sg_table.sgl, nents,
> +		    rq_data_dir(rq) == WRITE ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
> +	if (unlikely(count <= 0)) {
> +		sg_free_table_chained(&req->sg_table, true);
> +		return -EIO;
> +	}
> +
> +	if (count == 1) {
> +		if (rq_data_dir(rq) == WRITE &&
> +		    map_len <= nvme_rdma_inline_data_size(queue) &&
> +		    nvme_rdma_queue_idx(queue))
> +			return nvme_rdma_map_sg_inline(queue, req, c);
> +
> +		if (!register_always)
> +			return nvme_rdma_map_sg_single(queue, req, c);
> +	}
> +
> +	return nvme_rdma_map_sg_fr(queue, req, c, count);
> +}
> +
> +static void nvme_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc)
> +{
> +	if (unlikely(wc->status != IB_WC_SUCCESS))
> +		nvme_rdma_wr_error(cq, wc, "SEND");
> +}
> +
> +static int nvme_rdma_post_send(struct nvme_rdma_queue *queue,
> +		struct nvme_rdma_qe *qe, struct ib_sge *sge, u32 num_sge,
> +		struct ib_send_wr *first, bool flush)
> +{
> +	struct ib_send_wr wr, *bad_wr;
> +	int ret;
> +
> +	sge->addr   = qe->dma;
> +	sge->length = sizeof(struct nvme_command),
> +	sge->lkey   = queue->device->pd->local_dma_lkey;
> +
> +	qe->cqe.done = nvme_rdma_send_done;
> +
> +	wr.next       = NULL;
> +	wr.wr_cqe     = &qe->cqe;
> +	wr.sg_list    = sge;
> +	wr.num_sge    = num_sge;
> +	wr.opcode     = IB_WR_SEND;
> +	wr.send_flags = 0;
> +
> +	/*
> +	 * Unsignalled send completions are another giant desaster in the
> +	 * IB Verbs spec:  If we don't regularly post signalled sends
> +	 * the send queue will fill up and only a QP reset will rescue us.
> +	 * Would have been way to obvious to handle this in hardware or
> +	 * at least the RDMA stack..
> +	 *
> +	 * This messy and racy code sniplet is copy and pasted from the iSER
> +	 * initiator, and the magic '32' comes from there as well.
> +	 *
> +	 * Always signal the flushes. The magic request used for the flush
> +	 * sequencer is not allocated in our driver's tagset and it's
> +	 * triggered to be freed by blk_cleanup_queue(). So we need to
> +	 * always mark it as signaled to ensure that the "wr_cqe", which is
> +	 * embeded in request's payload, is not freed when __ib_process_cq()
> +	 * calls wr_cqe->done().
> +	 */
> +	if ((++queue->sig_count % 32) == 0 || flush)
> +		wr.send_flags |= IB_SEND_SIGNALED;
> +
> +	if (first)
> +		first->next = &wr;
> +	else
> +		first = &wr;
> +
> +	ret = ib_post_send(queue->qp, first, &bad_wr);
> +	if (ret) {
> +		dev_err(queue->ctrl->ctrl.device,
> +			     "%s failed with error code %d\n", __func__, ret);
> +	}
> +	return ret;
> +}
> +
> +static int nvme_rdma_post_recv(struct nvme_rdma_queue *queue,
> +		struct nvme_rdma_qe *qe)
> +{
> +	struct ib_recv_wr wr, *bad_wr;
> +	struct ib_sge list;
> +	int ret;
> +
> +	list.addr   = qe->dma;
> +	list.length = sizeof(struct nvme_completion);
> +	list.lkey   = queue->device->pd->local_dma_lkey;
> +
> +	qe->cqe.done = nvme_rdma_recv_done;
> +
> +	wr.next     = NULL;
> +	wr.wr_cqe   = &qe->cqe;
> +	wr.sg_list  = &list;
> +	wr.num_sge  = 1;
> +
> +	ret = ib_post_recv(queue->qp, &wr, &bad_wr);
> +	if (ret) {
> +		dev_err(queue->ctrl->ctrl.device,
> +			"%s failed with error code %d\n", __func__, ret);
> +	}
> +	return ret;
> +}
> +
> +static struct blk_mq_tags *nvme_rdma_tagset(struct nvme_rdma_queue *queue)
> +{
> +	u32 queue_idx = nvme_rdma_queue_idx(queue);
> +
> +	if (queue_idx == 0)
> +		return queue->ctrl->admin_tag_set.tags[queue_idx];
> +	return queue->ctrl->tag_set.tags[queue_idx - 1];
> +}
> +
> +static void nvme_rdma_submit_async_event(struct nvme_ctrl *arg, int aer_idx)
> +{
> +	struct nvme_rdma_ctrl *ctrl = to_rdma_ctrl(arg);
> +	struct nvme_rdma_queue *queue = &ctrl->queues[0];
> +	struct ib_device *dev = queue->device->dev;
> +	struct nvme_rdma_qe *sqe = &ctrl->async_event_sqe;
> +	struct nvme_command *cmd = sqe->data;
> +	struct ib_sge sge;
> +	int ret;
> +
> +	if (WARN_ON_ONCE(aer_idx != 0))
> +		return;
> +
> +	ib_dma_sync_single_for_cpu(dev, sqe->dma, sizeof(*cmd), DMA_TO_DEVICE);
> +
> +	memset(cmd, 0, sizeof(*cmd));
> +	cmd->common.opcode = nvme_admin_async_event;
> +	cmd->common.command_id = NVME_RDMA_AQ_BLKMQ_DEPTH;
> +	nvme_rdma_set_sg_null(cmd);
> +
> +	ib_dma_sync_single_for_device(dev, sqe->dma, sizeof(*cmd),
> +			DMA_TO_DEVICE);
> +
> +	ret = nvme_rdma_post_send(queue, sqe, &sge, 1, NULL, false);
> +	WARN_ON_ONCE(ret);
> +}
> +
> +static int nvme_rdma_process_nvme_rsp(struct nvme_rdma_queue *queue,
> +		struct nvme_completion *cqe, struct ib_wc *wc, int tag)
> +{
> +	u16 status = le16_to_cpu(cqe->status);
> +	struct request *rq;
> +	struct nvme_rdma_request *req;
> +	int ret = 0;
> +
> +	status >>= 1;
> +
> +	rq = blk_mq_tag_to_rq(nvme_rdma_tagset(queue), cqe->command_id);
> +	if (!rq) {
> +		dev_err(queue->ctrl->ctrl.device,
> +			"tag 0x%x on QP %#x not found\n",
> +			cqe->command_id, queue->qp->qp_num);
> +		nvme_rdma_error_recovery(queue->ctrl);
> +		return ret;
> +	}
> +	req = blk_mq_rq_to_pdu(rq);
> +
> +	if (rq->cmd_type == REQ_TYPE_DRV_PRIV && rq->special)
> +		memcpy(rq->special, cqe, sizeof(*cqe));
> +
> +	if (rq->tag == tag)
> +		ret = 1;
> +
> +	if ((wc->wc_flags & IB_WC_WITH_INVALIDATE) &&
> +	    wc->ex.invalidate_rkey == req->mr->rkey)
> +		req->need_inval = false;
> +
> +	blk_mq_complete_request(rq, status);
> +
> +	return ret;
> +}
> +
> +static int __nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc, int tag)
> +{
> +	struct nvme_rdma_qe *qe =
> +		container_of(wc->wr_cqe, struct nvme_rdma_qe, cqe);
> +	struct nvme_rdma_queue *queue = cq->cq_context;
> +	struct ib_device *ibdev = queue->device->dev;
> +	struct nvme_completion *cqe = qe->data;
> +	const size_t len = sizeof(struct nvme_completion);
> +	int ret = 0;
> +
> +	if (unlikely(wc->status != IB_WC_SUCCESS)) {
> +		nvme_rdma_wr_error(cq, wc, "RECV");
> +		return 0;
> +	}
> +
> +	ib_dma_sync_single_for_cpu(ibdev, qe->dma, len, DMA_FROM_DEVICE);
> +	/*
> +	 * AEN requests are special as they don't time out and can
> +	 * survive any kind of queue freeze and often don't respond to
> +	 * aborts.  We don't even bother to allocate a struct request
> +	 * for them but rather special case them here.
> +	 */
> +	if (unlikely(nvme_rdma_queue_idx(queue) == 0 &&
> +			cqe->command_id >= NVME_RDMA_AQ_BLKMQ_DEPTH))
> +		nvme_complete_async_event(&queue->ctrl->ctrl, cqe);
> +	else
> +		ret = nvme_rdma_process_nvme_rsp(queue, cqe, wc, tag);
> +	ib_dma_sync_single_for_device(ibdev, qe->dma, len, DMA_FROM_DEVICE);
> +
> +	nvme_rdma_post_recv(queue, qe);
> +	return ret;
> +}
> +
> +static void nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
> +{
> +	__nvme_rdma_recv_done(cq, wc, -1);
> +}
> +
> +static int nvme_rdma_conn_established(struct nvme_rdma_queue *queue)
> +{
> +	int ret, i;
> +
> +	for (i = 0; i < queue->queue_size; i++) {
> +		ret = nvme_rdma_post_recv(queue, &queue->rsp_ring[i]);
> +		if (ret)
> +			goto out_destroy_queue_ib;
> +	}
> +
> +	return 0;
> +
> +out_destroy_queue_ib:
> +	nvme_rdma_destroy_queue_ib(queue);
> +	return ret;
> +}
> +
> +static int nvme_rdma_conn_rejected(struct nvme_rdma_queue *queue,
> +		struct rdma_cm_event *ev)
> +{
> +	if (ev->status == IB_CM_REJ_CONSUMER_DEFINED) {
> +		struct nvme_rdma_cm_rej *rej =
> +			(struct nvme_rdma_cm_rej *)ev->param.conn.private_data;
> +
> +		dev_err(queue->ctrl->ctrl.device,
> +			"Connect rejected, status %d.", le16_to_cpu(rej->sts));
> +		/* XXX: Think of something clever to do here... */
> +	} else {
> +		dev_err(queue->ctrl->ctrl.device,
> +			"Connect rejected, no private data.\n");
> +	}
> +
> +	return -ECONNRESET;
> +}
> +
> +static int nvme_rdma_addr_resolved(struct nvme_rdma_queue *queue)
> +{
> +	struct nvme_rdma_device *dev;
> +	int ret;
> +
> +	dev = nvme_rdma_find_get_device(queue->cm_id);
> +	if (!dev) {
> +		dev_err(queue->cm_id->device->dma_device,
> +			"no client data found!\n");
> +		return -ECONNREFUSED;
> +	}
> +
> +	ret = nvme_rdma_create_queue_ib(queue, dev);
> +	if (ret) {
> +		nvme_rdma_dev_put(dev);
> +		goto out;
> +	}
> +
> +	ret = rdma_resolve_route(queue->cm_id, NVME_RDMA_CONNECT_TIMEOUT_MS);
> +	if (ret) {
> +		dev_err(queue->ctrl->ctrl.device,
> +			"rdma_resolve_route failed (%d).\n",
> +			queue->cm_error);
> +		goto out_destroy_queue;
> +	}
> +
> +	return 0;
> +
> +out_destroy_queue:
> +	nvme_rdma_destroy_queue_ib(queue);
> +out:
> +	return ret;
> +}
> +
> +static int nvme_rdma_route_resolved(struct nvme_rdma_queue *queue)
> +{
> +	struct nvme_rdma_ctrl *ctrl = queue->ctrl;
> +	struct rdma_conn_param param = { };
> +	struct nvme_rdma_cm_req priv;
> +	int ret;
> +
> +	param.qp_num = queue->qp->qp_num;
> +	param.flow_control = 1;
> +
> +	param.responder_resources = queue->device->dev->attrs.max_qp_rd_atom;
> +	/* rdma_cm will clamp down to max QP retry count (7) */
> +	param.retry_count = ctrl->tl_retry_count;
> +	param.rnr_retry_count = 7;
> +	param.private_data = &priv;
> +	param.private_data_len = sizeof(priv);
> +
> +	priv.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
> +	priv.qid = cpu_to_le16(nvme_rdma_queue_idx(queue));
> +	priv.hrqsize = cpu_to_le16(queue->queue_size);
> +	priv.hsqsize = cpu_to_le16(queue->queue_size);
> +
> +	ret = rdma_connect(queue->cm_id, &param);
> +	if (ret) {
> +		dev_err(ctrl->ctrl.device,
> +			"rdma_connect failed (%d).\n", ret);
> +		goto out_destroy_queue_ib;
> +	}
> +
> +	return 0;
> +
> +out_destroy_queue_ib:
> +	nvme_rdma_destroy_queue_ib(queue);
> +	return ret;
> +}
> +
> +/**
> + * nvme_rdma_device_unplug() - Handle RDMA device unplug
> + * @queue:      Queue that owns the cm_id that caught the event
> + *
> + * DEVICE_REMOVAL event notifies us that the RDMA device is about
> + * to unplug so we should take care of destroying our RDMA resources.
> + * This event will be generated for each allocated cm_id.
> + *
> + * In our case, the RDMA resources are managed per controller and not
> + * only per queue. So the way we handle this is we trigger an implicit
> + * controller deletion upon the first DEVICE_REMOVAL event we see, and
> + * hold the event inflight until the controller deletion is completed.
> + *
> + * One exception that we need to handle is the destruction of the cm_id
> + * that caught the event. Since we hold the callout until the controller
> + * deletion is completed, we'll deadlock if the controller deletion will
> + * call rdma_destroy_id on this queue's cm_id. Thus, we claim ownership
> + * of destroying this queue before-hand, destroy the queue resources
> + * after the controller deletion completed with the exception of destroying
> + * the cm_id implicitely by returning a non-zero rc to the callout.
> + */
> +static int nvme_rdma_device_unplug(struct nvme_rdma_queue *queue)
> +{
> +	struct nvme_rdma_ctrl *ctrl = queue->ctrl;
> +	int ret, ctrl_deleted = 0;
> +
> +	/* First disable the queue so ctrl delete won't free it */
> +	if (!test_and_clear_bit(NVME_RDMA_Q_CONNECTED, &queue->flags))
> +		goto out;
> +
> +	/* delete the controller */
> +	ret = __nvme_rdma_del_ctrl(ctrl);
> +	if (!ret) {
> +		dev_warn(ctrl->ctrl.device,
> +			"Got rdma device removal event, deleting ctrl\n");
> +		flush_work(&ctrl->delete_work);
> +
> +		/* Return non-zero so the cm_id will destroy implicitly */
> +		ctrl_deleted = 1;
> +
> +		/* Free this queue ourselves */
> +		rdma_disconnect(queue->cm_id);
> +		ib_drain_qp(queue->qp);
> +		nvme_rdma_destroy_queue_ib(queue);
> +	}
> +
> +out:
> +	return ctrl_deleted;
> +}
> +
> +static int nvme_rdma_cm_handler(struct rdma_cm_id *cm_id,
> +		struct rdma_cm_event *ev)
> +{
> +	struct nvme_rdma_queue *queue = cm_id->context;
> +	int cm_error = 0;
> +
> +	dev_dbg(queue->ctrl->ctrl.device, "%s (%d): status %d id %p\n",
> +		rdma_event_msg(ev->event), ev->event,
> +		ev->status, cm_id);
> +
> +	switch (ev->event) {
> +	case RDMA_CM_EVENT_ADDR_RESOLVED:
> +		cm_error = nvme_rdma_addr_resolved(queue);
> +		break;
> +	case RDMA_CM_EVENT_ROUTE_RESOLVED:
> +		cm_error = nvme_rdma_route_resolved(queue);
> +		break;
> +	case RDMA_CM_EVENT_ESTABLISHED:
> +		queue->cm_error = nvme_rdma_conn_established(queue);
> +		/* complete cm_done regardless of success/failure */
> +		complete(&queue->cm_done);
> +		return 0;
> +	case RDMA_CM_EVENT_REJECTED:
> +		cm_error = nvme_rdma_conn_rejected(queue, ev);
> +		break;
> +	case RDMA_CM_EVENT_ADDR_ERROR:
> +	case RDMA_CM_EVENT_ROUTE_ERROR:
> +	case RDMA_CM_EVENT_CONNECT_ERROR:
> +	case RDMA_CM_EVENT_UNREACHABLE:
> +		dev_dbg(queue->ctrl->ctrl.device,
> +			"CM error event %d\n", ev->event);
> +		cm_error = -ECONNRESET;
> +		break;
> +	case RDMA_CM_EVENT_DISCONNECTED:
> +	case RDMA_CM_EVENT_ADDR_CHANGE:
> +	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
> +		dev_dbg(queue->ctrl->ctrl.device,
> +			"disconnect received - connection closed\n");
> +		nvme_rdma_error_recovery(queue->ctrl);
> +		break;
> +	case RDMA_CM_EVENT_DEVICE_REMOVAL:
> +		/* return 1 means impliciy CM ID destroy */
> +		return nvme_rdma_device_unplug(queue);
> +	default:
> +		dev_err(queue->ctrl->ctrl.device,
> +			"Unexpected RDMA CM event (%d)\n", ev->event);
> +		nvme_rdma_error_recovery(queue->ctrl);
> +		break;
> +	}
> +
> +	if (cm_error) {
> +		queue->cm_error = cm_error;
> +		complete(&queue->cm_done);
> +	}
> +
> +	return 0;
> +}
> +
> +static enum blk_eh_timer_return
> +nvme_rdma_timeout(struct request *rq, bool reserved)
> +{
> +	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
> +
> +	/* queue error recovery */
> +	nvme_rdma_error_recovery(req->queue->ctrl);
> +
> +	/* fail with DNR on cmd timeout */
> +	rq->errors = NVME_SC_ABORT_REQ | NVME_SC_DNR;
> +
> +	return BLK_EH_HANDLED;
> +}
> +
> +static int nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
> +		const struct blk_mq_queue_data *bd)
> +{
> +	struct nvme_ns *ns = hctx->queue->queuedata;
> +	struct nvme_rdma_queue *queue = hctx->driver_data;
> +	struct request *rq = bd->rq;
> +	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
> +	struct nvme_rdma_qe *sqe = &req->sqe;
> +	struct nvme_command *c = sqe->data;
> +	bool flush = false;
> +	struct ib_device *dev;
> +	unsigned int map_len;
> +	int ret;
> +
> +	WARN_ON_ONCE(rq->tag < 0);
> +
> +	dev = queue->device->dev;
> +	ib_dma_sync_single_for_cpu(dev, sqe->dma,
> +			sizeof(struct nvme_command), DMA_TO_DEVICE);
> +
> +	ret = nvme_setup_cmd(ns, rq, c);
> +	if (ret)
> +		return ret;
> +
> +	c->common.command_id = rq->tag;
> +	blk_mq_start_request(rq);
> +
> +	map_len = nvme_map_len(rq);
> +	ret = nvme_rdma_map_data(queue, rq, map_len, c);
> +	if (ret < 0) {
> +		dev_err(queue->ctrl->ctrl.device,
> +			     "Failed to map data (%d)\n", ret);
> +		nvme_cleanup_cmd(rq);
> +		goto err;
> +	}
> +
> +	ib_dma_sync_single_for_device(dev, sqe->dma,
> +			sizeof(struct nvme_command), DMA_TO_DEVICE);
> +
> +	if (rq->cmd_type == REQ_TYPE_FS && (rq->cmd_flags & REQ_FLUSH))
> +		flush = true;
> +	ret = nvme_rdma_post_send(queue, sqe, req->sge, req->num_sge,
> +			req->need_inval ? &req->reg_wr.wr : NULL, flush);
> +	if (ret) {
> +		nvme_rdma_unmap_data(queue, rq);
> +		goto err;
> +	}
> +
> +	return BLK_MQ_RQ_QUEUE_OK;
> +err:
> +	return (ret == -ENOMEM || ret == -EAGAIN) ?
> +		BLK_MQ_RQ_QUEUE_BUSY : BLK_MQ_RQ_QUEUE_ERROR;
> +}
> +
> +static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag)
> +{
> +	struct nvme_rdma_queue *queue = hctx->driver_data;
> +	struct ib_cq *cq = queue->ib_cq;
> +	struct ib_wc wc;
> +	int found = 0;
> +
> +	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
> +	while (ib_poll_cq(cq, 1, &wc) > 0) {
> +		struct ib_cqe *cqe = wc.wr_cqe;
> +
> +		if (cqe) {
> +			if (cqe->done == nvme_rdma_recv_done)
> +				found |= __nvme_rdma_recv_done(cq, &wc, tag);
> +			else
> +				cqe->done(cq, &wc);
> +		}
> +	}
> +
> +	return found;
> +}
> +
> +static void nvme_rdma_complete_rq(struct request *rq)
> +{
> +	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
> +	struct nvme_rdma_queue *queue = req->queue;
> +	int error = 0;
> +
> +	nvme_rdma_unmap_data(queue, rq);
> +
> +	if (unlikely(rq->errors)) {
> +		if (nvme_req_needs_retry(rq, rq->errors)) {
> +			nvme_requeue_req(rq);
> +			return;
> +		}
> +
> +		if (rq->cmd_type == REQ_TYPE_DRV_PRIV)
> +			error = rq->errors;
> +		else
> +			error = nvme_error_status(rq->errors);
> +	}
> +
> +	blk_mq_end_request(rq, error);
> +}
> +
> +static struct blk_mq_ops nvme_rdma_mq_ops = {
> +	.queue_rq	= nvme_rdma_queue_rq,
> +	.complete	= nvme_rdma_complete_rq,
> +	.map_queue	= blk_mq_map_queue,
> +	.init_request	= nvme_rdma_init_request,
> +	.exit_request	= nvme_rdma_exit_request,
> +	.reinit_request	= nvme_rdma_reinit_request,
> +	.init_hctx	= nvme_rdma_init_hctx,
> +	.poll		= nvme_rdma_poll,
> +	.timeout	= nvme_rdma_timeout,
> +};
> +
> +static struct blk_mq_ops nvme_rdma_admin_mq_ops = {
> +	.queue_rq	= nvme_rdma_queue_rq,
> +	.complete	= nvme_rdma_complete_rq,
> +	.map_queue	= blk_mq_map_queue,
> +	.init_request	= nvme_rdma_init_admin_request,
> +	.exit_request	= nvme_rdma_exit_admin_request,
> +	.reinit_request	= nvme_rdma_reinit_request,
> +	.init_hctx	= nvme_rdma_init_admin_hctx,
> +	.timeout	= nvme_rdma_timeout,
> +};
> +
> +static int nvme_rdma_configure_admin_queue(struct nvme_rdma_ctrl *ctrl)
> +{
> +	int error;
> +
> +	error = nvme_rdma_init_queue(ctrl, 0, NVMF_AQ_DEPTH);
> +	if (error)
> +		return error;
> +
> +	ctrl->device = ctrl->queues[0].device;
> +
> +	/*
> +	 * We need a reference on the device as long as the tag_set is alive,
> +	 * as the MRs in the request structures need a valid ib_device.
> +	 */
> +	error = -EINVAL;
> +	if (!nvme_rdma_dev_get(ctrl->device))
> +		goto out_free_queue;
> +
> +	ctrl->max_fr_pages = min_t(u32, NVME_RDMA_MAX_SEGMENTS,
> +		ctrl->device->dev->attrs.max_fast_reg_page_list_len);
> +
> +	memset(&ctrl->admin_tag_set, 0, sizeof(ctrl->admin_tag_set));
> +	ctrl->admin_tag_set.ops = &nvme_rdma_admin_mq_ops;
> +	ctrl->admin_tag_set.queue_depth = NVME_RDMA_AQ_BLKMQ_DEPTH;
> +	ctrl->admin_tag_set.reserved_tags = 2; /* connect + keep-alive */
> +	ctrl->admin_tag_set.numa_node = NUMA_NO_NODE;
> +	ctrl->admin_tag_set.cmd_size = sizeof(struct nvme_rdma_request) +
> +		SG_CHUNK_SIZE * sizeof(struct scatterlist);
> +	ctrl->admin_tag_set.driver_data = ctrl;
> +	ctrl->admin_tag_set.nr_hw_queues = 1;
> +	ctrl->admin_tag_set.timeout = ADMIN_TIMEOUT;
> +
> +	error = blk_mq_alloc_tag_set(&ctrl->admin_tag_set);
> +	if (error)
> +		goto out_put_dev;
> +
> +	ctrl->ctrl.admin_q = blk_mq_init_queue(&ctrl->admin_tag_set);
> +	if (IS_ERR(ctrl->ctrl.admin_q)) {
> +		error = PTR_ERR(ctrl->ctrl.admin_q);
> +		goto out_free_tagset;
> +	}
> +
> +	error = nvmf_connect_admin_queue(&ctrl->ctrl);
> +	if (error)
> +		goto out_cleanup_queue;
> +
> +	error = nvmf_reg_read64(&ctrl->ctrl, NVME_REG_CAP, &ctrl->cap);
> +	if (error) {
> +		dev_err(ctrl->ctrl.device,
> +			"prop_get NVME_REG_CAP failed\n");
> +		goto out_cleanup_queue;
> +	}
> +
> +	ctrl->ctrl.sqsize =
> +		min_t(int, NVME_CAP_MQES(ctrl->cap) + 1, ctrl->ctrl.sqsize);
> +
> +	error = nvme_enable_ctrl(&ctrl->ctrl, ctrl->cap);
> +	if (error)
> +		goto out_cleanup_queue;
> +
> +	ctrl->ctrl.max_hw_sectors =
> +		(ctrl->max_fr_pages - 1) << (PAGE_SHIFT - 9);
> +
> +	error = nvme_init_identify(&ctrl->ctrl);
> +	if (error)
> +		goto out_cleanup_queue;
> +
> +	nvme_start_keep_alive(&ctrl->ctrl);
> +
> +	error = nvme_rdma_alloc_qe(ctrl->queues[0].device->dev,
> +			&ctrl->async_event_sqe, sizeof(struct nvme_command),
> +			DMA_TO_DEVICE);
> +	if (error)
> +		goto out_cleanup_queue;
> +
> +	return 0;
> +
> +out_cleanup_queue:
> +	blk_cleanup_queue(ctrl->ctrl.admin_q);
> +out_free_tagset:
> +	blk_mq_free_tag_set(&ctrl->admin_tag_set);
> +out_put_dev:
> +	nvme_rdma_dev_put(ctrl->device);
> +out_free_queue:
> +	nvme_rdma_free_queue(&ctrl->queues[0]);
> +	return error;
> +}
> +
> +static void nvme_rdma_shutdown_ctrl(struct nvme_rdma_ctrl *ctrl)
> +{
> +	nvme_stop_keep_alive(&ctrl->ctrl);
> +	cancel_work_sync(&ctrl->err_work);
> +	cancel_delayed_work_sync(&ctrl->reconnect_work);
> +
> +	if (ctrl->queue_count > 1) {
> +		nvme_stop_queues(&ctrl->ctrl);
> +		blk_mq_tagset_busy_iter(&ctrl->tag_set,
> +					nvme_cancel_request, &ctrl->ctrl);
> +		nvme_rdma_free_io_queues(ctrl);
> +	}
> +
> +	if (ctrl->ctrl.state == NVME_CTRL_LIVE)
> +		nvme_shutdown_ctrl(&ctrl->ctrl);
> +
> +	blk_mq_stop_hw_queues(ctrl->ctrl.admin_q);
> +	blk_mq_tagset_busy_iter(&ctrl->admin_tag_set,
> +				nvme_cancel_request, &ctrl->ctrl);
> +	nvme_rdma_destroy_admin_queue(ctrl);
> +}
> +
> +static void nvme_rdma_del_ctrl_work(struct work_struct *work)
> +{
> +	struct nvme_rdma_ctrl *ctrl = container_of(work,
> +				struct nvme_rdma_ctrl, delete_work);
> +
> +	nvme_remove_namespaces(&ctrl->ctrl);
> +	nvme_rdma_shutdown_ctrl(ctrl);
> +	nvme_uninit_ctrl(&ctrl->ctrl);
> +	nvme_put_ctrl(&ctrl->ctrl);
> +}
> +
> +static int __nvme_rdma_del_ctrl(struct nvme_rdma_ctrl *ctrl)
> +{
> +	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_DELETING))
> +		return -EBUSY;
> +
> +	if (!queue_work(nvme_rdma_wq, &ctrl->delete_work))
> +		return -EBUSY;
> +
> +	return 0;
> +}
> +
> +static int nvme_rdma_del_ctrl(struct nvme_ctrl *nctrl)
> +{
> +	struct nvme_rdma_ctrl *ctrl = to_rdma_ctrl(nctrl);
> +	int ret;
> +
> +	ret = __nvme_rdma_del_ctrl(ctrl);
> +	if (ret)
> +		return ret;
> +
> +	flush_work(&ctrl->delete_work);
> +
> +	return 0;
> +}
> +
> +static void nvme_rdma_remove_ctrl_work(struct work_struct *work)
> +{
> +	struct nvme_rdma_ctrl *ctrl = container_of(work,
> +				struct nvme_rdma_ctrl, delete_work);
> +
> +	nvme_remove_namespaces(&ctrl->ctrl);
> +	nvme_uninit_ctrl(&ctrl->ctrl);
> +	nvme_put_ctrl(&ctrl->ctrl);
> +}
> +
> +static void nvme_rdma_reset_ctrl_work(struct work_struct *work)
> +{
> +	struct nvme_rdma_ctrl *ctrl = container_of(work,
> +					struct nvme_rdma_ctrl, reset_work);
> +	int ret;
> +	bool changed;
> +
> +	nvme_rdma_shutdown_ctrl(ctrl);
> +
> +	ret = nvme_rdma_configure_admin_queue(ctrl);
> +	if (ret) {
> +		/* ctrl is already shutdown, just remove the ctrl */
> +		INIT_WORK(&ctrl->delete_work, nvme_rdma_remove_ctrl_work);
> +		goto del_dead_ctrl;
> +	}
> +
> +	if (ctrl->queue_count > 1) {
> +		ret = blk_mq_reinit_tagset(&ctrl->tag_set);
> +		if (ret)
> +			goto del_dead_ctrl;
> +
> +		ret = nvme_rdma_init_io_queues(ctrl);
> +		if (ret)
> +			goto del_dead_ctrl;
> +
> +		ret = nvme_rdma_connect_io_queues(ctrl);
> +		if (ret)
> +			goto del_dead_ctrl;
> +	}
> +
> +	changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
> +	WARN_ON_ONCE(!changed);
> +
> +	if (ctrl->queue_count > 1) {
> +		nvme_start_queues(&ctrl->ctrl);
> +		nvme_queue_scan(&ctrl->ctrl);
> +	}
> +
> +	return;
> +
> +del_dead_ctrl:
> +	/* Deleting this dead controller... */
> +	dev_warn(ctrl->ctrl.device, "Removing after reset failure\n");
> +	WARN_ON(!queue_work(nvme_rdma_wq, &ctrl->delete_work));
> +}
> +
> +static int nvme_rdma_reset_ctrl(struct nvme_ctrl *nctrl)
> +{
> +	struct nvme_rdma_ctrl *ctrl = to_rdma_ctrl(nctrl);
> +
> +	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_RESETTING))
> +		return -EBUSY;
> +
> +	if (!queue_work(nvme_rdma_wq, &ctrl->reset_work))
> +		return -EBUSY;
> +
> +	flush_work(&ctrl->reset_work);
> +
> +	return 0;
> +}
> +
> +static const struct nvme_ctrl_ops nvme_rdma_ctrl_ops = {
> +	.name			= "rdma",
> +	.module			= THIS_MODULE,
> +	.is_fabrics		= true,
> +	.reg_read32		= nvmf_reg_read32,
> +	.reg_read64		= nvmf_reg_read64,
> +	.reg_write32		= nvmf_reg_write32,
> +	.reset_ctrl		= nvme_rdma_reset_ctrl,
> +	.free_ctrl		= nvme_rdma_free_ctrl,
> +	.submit_async_event	= nvme_rdma_submit_async_event,
> +	.delete_ctrl		= nvme_rdma_del_ctrl,
> +	.get_subsysnqn		= nvmf_get_subsysnqn,
> +	.get_address		= nvmf_get_address,
> +};
> +
> +static int nvme_rdma_create_io_queues(struct nvme_rdma_ctrl *ctrl)
> +{
> +	struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;
> +	int ret;
> +
> +	ret = nvme_set_queue_count(&ctrl->ctrl, &opts->nr_io_queues);
> +	if (ret)
> +		return ret;
> +
> +	ctrl->queue_count = opts->nr_io_queues + 1;
> +	if (ctrl->queue_count < 2)
> +		return 0;
> +
> +	dev_info(ctrl->ctrl.device,
> +		"creating %d I/O queues.\n", opts->nr_io_queues);
> +
> +	ret = nvme_rdma_init_io_queues(ctrl);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * We need a reference on the device as long as the tag_set is alive,
> +	 * as the MRs in the request structures need a valid ib_device.
> +	 */
> +	ret = -EINVAL;
> +	if (!nvme_rdma_dev_get(ctrl->device))
> +		goto out_free_io_queues;
> +
> +	memset(&ctrl->tag_set, 0, sizeof(ctrl->tag_set));
> +	ctrl->tag_set.ops = &nvme_rdma_mq_ops;
> +	ctrl->tag_set.queue_depth = ctrl->ctrl.sqsize;
> +	ctrl->tag_set.reserved_tags = 1; /* fabric connect */
> +	ctrl->tag_set.numa_node = NUMA_NO_NODE;
> +	ctrl->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
> +	ctrl->tag_set.cmd_size = sizeof(struct nvme_rdma_request) +
> +		SG_CHUNK_SIZE * sizeof(struct scatterlist);
> +	ctrl->tag_set.driver_data = ctrl;
> +	ctrl->tag_set.nr_hw_queues = ctrl->queue_count - 1;
> +	ctrl->tag_set.timeout = NVME_IO_TIMEOUT;
> +
> +	ret = blk_mq_alloc_tag_set(&ctrl->tag_set);
> +	if (ret)
> +		goto out_put_dev;
> +	ctrl->ctrl.tagset = &ctrl->tag_set;
> +
> +	ctrl->ctrl.connect_q = blk_mq_init_queue(&ctrl->tag_set);
> +	if (IS_ERR(ctrl->ctrl.connect_q)) {
> +		ret = PTR_ERR(ctrl->ctrl.connect_q);
> +		goto out_free_tag_set;
> +	}
> +
> +	ret = nvme_rdma_connect_io_queues(ctrl);
> +	if (ret)
> +		goto out_cleanup_connect_q;
> +
> +	return 0;
> +
> +out_cleanup_connect_q:
> +	nvme_stop_keep_alive(&ctrl->ctrl);
> +	blk_cleanup_queue(ctrl->ctrl.connect_q);
> +out_free_tag_set:
> +	blk_mq_free_tag_set(&ctrl->tag_set);
> +out_put_dev:
> +	nvme_rdma_dev_put(ctrl->device);
> +out_free_io_queues:
> +	nvme_rdma_free_io_queues(ctrl);
> +	return ret;
> +}
> +
> +static int nvme_rdma_parse_ipaddr(struct sockaddr_in *in_addr, char *p)
> +{
> +	u8 *addr = (u8 *)&in_addr->sin_addr.s_addr;
> +	size_t buflen = strlen(p);
> +
> +	/* XXX: handle IPv6 addresses */
> +
> +	if (buflen > INET_ADDRSTRLEN)
> +		return -EINVAL;
> +	if (in4_pton(p, buflen, addr, '\0', NULL) == 0)
> +		return -EINVAL;
> +	in_addr->sin_family = AF_INET;
> +	return 0;
> +}
> +
> +static struct nvme_ctrl *nvme_rdma_create_ctrl(struct device *dev,
> +		struct nvmf_ctrl_options *opts)
> +{
> +	struct nvme_rdma_ctrl *ctrl;
> +	int ret;
> +	bool changed;
> +
> +	ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
> +	if (!ctrl)
> +		return ERR_PTR(-ENOMEM);
> +	ctrl->ctrl.opts = opts;
> +	INIT_LIST_HEAD(&ctrl->list);
> +
> +	ret = nvme_rdma_parse_ipaddr(&ctrl->addr_in, opts->traddr);
> +	if (ret) {
> +		pr_err("malformed IP address passed: %s\n", opts->traddr);
> +		goto out_free_ctrl;
> +	}
> +
> +	if (opts->mask & NVMF_OPT_TRSVCID) {
> +		u16 port;
> +
> +		ret = kstrtou16(opts->trsvcid, 0, &port);
> +		if (ret)
> +			goto out_free_ctrl;
> +
> +		ctrl->addr_in.sin_port = cpu_to_be16(port);
> +	} else {
> +		ctrl->addr_in.sin_port = cpu_to_be16(NVME_RDMA_IP_PORT);
> +	}
> +
> +	ret = nvme_init_ctrl(&ctrl->ctrl, dev, &nvme_rdma_ctrl_ops,
> +				0 /* no quirks, we're perfect! */);
> +	if (ret)
> +		goto out_free_ctrl;
> +
> +	ctrl->reconnect_delay = opts->reconnect_delay;
> +	INIT_DELAYED_WORK(&ctrl->reconnect_work,
> +			nvme_rdma_reconnect_ctrl_work);
> +	INIT_WORK(&ctrl->err_work, nvme_rdma_error_recovery_work);
> +	INIT_WORK(&ctrl->delete_work, nvme_rdma_del_ctrl_work);
> +	INIT_WORK(&ctrl->reset_work, nvme_rdma_reset_ctrl_work);
> +	spin_lock_init(&ctrl->lock);
> +
> +	ctrl->queue_count = opts->nr_io_queues + 1; /* +1 for admin queue */
> +	ctrl->ctrl.sqsize = opts->queue_size;
> +	ctrl->tl_retry_count = opts->tl_retry_count;
> +	ctrl->ctrl.kato = opts->kato;
> +
> +	ret = -ENOMEM;
> +	ctrl->queues = kcalloc(ctrl->queue_count, sizeof(*ctrl->queues),
> +				GFP_KERNEL);
> +	if (!ctrl->queues)
> +		goto out_uninit_ctrl;
> +
> +	ret = nvme_rdma_configure_admin_queue(ctrl);
> +	if (ret)
> +		goto out_kfree_queues;
> +
> +	/* sanity check icdoff */
> +	if (ctrl->ctrl.icdoff) {
> +		dev_err(ctrl->ctrl.device, "icdoff is not supported!\n");
> +		goto out_remove_admin_queue;
> +	}
> +
> +	/* sanity check keyed sgls */
> +	if (!(ctrl->ctrl.sgls & (1 << 20))) {
> +		dev_err(ctrl->ctrl.device, "Mandatory keyed sgls are not support\n");
> +		goto out_remove_admin_queue;
> +	}
> +
> +	if (opts->queue_size > ctrl->ctrl.maxcmd) {
> +		/* warn if maxcmd is lower than queue_size */
> +		dev_warn(ctrl->ctrl.device,
> +			"queue_size %zu > ctrl maxcmd %u, clamping down\n",
> +			opts->queue_size, ctrl->ctrl.maxcmd);
> +		opts->queue_size = ctrl->ctrl.maxcmd;
> +	}
> +
> +	if (opts->nr_io_queues) {
> +		ret = nvme_rdma_create_io_queues(ctrl);
> +		if (ret)
> +			goto out_remove_admin_queue;
> +	}
> +
> +	changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
> +	WARN_ON_ONCE(!changed);
> +
> +	dev_info(ctrl->ctrl.device, "new ctrl: NQN \"%s\", addr %pISp\n",
> +		ctrl->ctrl.opts->subsysnqn, &ctrl->addr);
> +
> +	kref_get(&ctrl->ctrl.kref);
> +
> +	mutex_lock(&nvme_rdma_ctrl_mutex);
> +	list_add_tail(&ctrl->list, &nvme_rdma_ctrl_list);
> +	mutex_unlock(&nvme_rdma_ctrl_mutex);
> +
> +	if (opts->nr_io_queues) {
> +		nvme_queue_scan(&ctrl->ctrl);
> +		nvme_queue_async_events(&ctrl->ctrl);
> +	}
> +
> +	return &ctrl->ctrl;
> +
> +out_remove_admin_queue:
> +	nvme_rdma_destroy_admin_queue(ctrl);
> +out_kfree_queues:
> +	kfree(ctrl->queues);
> +out_uninit_ctrl:
> +	nvme_uninit_ctrl(&ctrl->ctrl);
> +	nvme_put_ctrl(&ctrl->ctrl);
> +	if (ret > 0)
> +		ret = -EIO;
> +	return ERR_PTR(ret);
> +out_free_ctrl:
> +	kfree(ctrl);
> +	return ERR_PTR(ret);
> +}
> +
> +static struct nvmf_transport_ops nvme_rdma_transport = {
> +	.name		= "rdma",
> +	.required_opts	= NVMF_OPT_TRADDR,
> +	.allowed_opts	= NVMF_OPT_TRSVCID | NVMF_OPT_TL_RETRY_COUNT |
> +			  NVMF_OPT_RECONNECT_DELAY,
> +	.create_ctrl	= nvme_rdma_create_ctrl,
> +};
> +
> +static int __init nvme_rdma_init_module(void)
> +{
> +	nvme_rdma_wq = create_workqueue("nvme_rdma_wq");
> +	if (!nvme_rdma_wq)
> +		return -ENOMEM;
> +
> +	nvmf_register_transport(&nvme_rdma_transport);
> +	return 0;
> +}
> +
> +static void __exit nvme_rdma_cleanup_module(void)
> +{
> +	struct nvme_rdma_ctrl *ctrl;
> +
> +	nvmf_unregister_transport(&nvme_rdma_transport);
> +
> +	mutex_lock(&nvme_rdma_ctrl_mutex);
> +	list_for_each_entry(ctrl, &nvme_rdma_ctrl_list, list)
> +		__nvme_rdma_del_ctrl(ctrl);
> +	mutex_unlock(&nvme_rdma_ctrl_mutex);
> +
> +	destroy_workqueue(nvme_rdma_wq);
> +}
> +
> +module_init(nvme_rdma_init_module);
> +module_exit(nvme_rdma_cleanup_module);
> +
> +MODULE_LICENSE("GPL v2");
>
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Re: NVMe over Fabrics RDMA transport drivers

[Christoph Hellwig]

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

D'oh - thanks for catching this.
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RE: NVMe over Fabrics RDMA transport drivers

[Woodruff, Robert J]

Sagi Grimberg wrote,

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

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

Re: NVMe over Fabrics RDMA transport drivers

[Steve Wise]

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

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

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

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

Re: NVMe over Fabrics RDMA transport drivers

[Christoph Hellwig]

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

Just go for the git tree at

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

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

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

[Steve Wise]

<snip>

> > +
> > +static struct nvmet_rdma_queue *
> > +nvmet_rdma_alloc_queue(struct nvmet_rdma_device *ndev,
> > +		struct rdma_cm_id *cm_id,
> > +		struct rdma_cm_event *event)
> > +{
> > +	struct nvmet_rdma_queue *queue;
> > +	int ret;
> > +
> > +	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
> > +	if (!queue) {
> > +		ret = NVME_RDMA_CM_NO_RSC;
> > +		goto out_reject;
> > +	}
> > +
> > +	ret = nvmet_sq_init(&queue->nvme_sq);
> > +	if (ret)
> > +		goto out_free_queue;
> > +
> > +	ret = nvmet_rdma_parse_cm_connect_req(&event->param.conn,
> queue);
> > +	if (ret)
> > +		goto out_destroy_sq;
> > +
> > +	/*
> > +	 * Schedules the actual release because calling rdma_destroy_id from
> > +	 * inside a CM callback would trigger a deadlock. (great API
design..)
> > +	 */
> > +	INIT_WORK(&queue->release_work,
> nvmet_rdma_release_queue_work);
> > +	queue->dev = ndev;
> > +	queue->cm_id = cm_id;
> > +
> > +	spin_lock_init(&queue->state_lock);
> > +	queue->state = NVMET_RDMA_Q_CONNECTING;
> > +	INIT_LIST_HEAD(&queue->rsp_wait_list);
> > +	INIT_LIST_HEAD(&queue->rsp_wr_wait_list);
> > +	spin_lock_init(&queue->rsp_wr_wait_lock);
> > +	INIT_LIST_HEAD(&queue->free_rsps);
> > +	spin_lock_init(&queue->rsps_lock);
> > +
> > +	queue->idx = ida_simple_get(&nvmet_rdma_queue_ida, 0, 0,
> GFP_KERNEL);
> > +	if (queue->idx < 0) {
> > +		ret = NVME_RDMA_CM_NO_RSC;
> > +		goto out_free_queue;
> > +	}
> > +
> > +	ret = nvmet_rdma_alloc_rsps(queue);
> > +	if (ret) {
> > +		ret = NVME_RDMA_CM_NO_RSC;
> > +		goto out_ida_remove;
> > +	}
> > +
> > +	if (!ndev->srq) {
> > +		queue->cmds = nvmet_rdma_alloc_cmds(ndev,
> > +				queue->recv_queue_size,
> > +				!queue->host_qid);
> > +		if (IS_ERR(queue->cmds)) {
> > +			ret = NVME_RDMA_CM_NO_RSC;
> > +			goto out_free_cmds;
> > +		}
> > +	}
> > +

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

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

@@ -1073,6 +1073,8 @@ out_free_cmds:
                                queue->recv_queue_size,
                                !queue->host_qid);
        }
+out_free_responses:
+        nvmet_rdma_free_rsps(queue);
 out_ida_remove:
        ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
 out_destroy_sq:


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

[Ming Lin]

On Thu, Jun 9, 2016 at 2:42 PM, Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org> wrote:

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

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

[Steve Wise]

<snip>

> > +
> > +static int nvmet_rdma_cm_handler(struct rdma_cm_id *cm_id,
> > +		struct rdma_cm_event *event)
> > +{
> > +	struct nvmet_rdma_queue *queue = NULL;
> > +	int ret = 0;
> > +
> > +	if (cm_id->qp)
> > +		queue = cm_id->qp->qp_context;
> > +
> > +	pr_debug("%s (%d): status %d id %p\n",
> > +		rdma_event_msg(event->event), event->event,
> > +		event->status, cm_id);
> > +
> > +	switch (event->event) {
> > +	case RDMA_CM_EVENT_CONNECT_REQUEST:
> > +		ret = nvmet_rdma_queue_connect(cm_id, event);

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

Steve.



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

[Christoph Hellwig]

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

Can you just send a patch?
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Re: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Christoph Hellwig]

On Thu, Jun 09, 2016 at 04:42:11PM -0500, Steve Wise wrote:
> 
> <snip>
> 
> > > +
> > > +static struct nvmet_rdma_queue *
> > > +nvmet_rdma_alloc_queue(struct nvmet_rdma_device *ndev,
> > > +		struct rdma_cm_id *cm_id,
> > > +		struct rdma_cm_event *event)
> > > +{
> > > +	struct nvmet_rdma_queue *queue;
> > > +	int ret;
> > > +
> > > +	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
> > > +	if (!queue) {
> > > +		ret = NVME_RDMA_CM_NO_RSC;
> > > +		goto out_reject;
> > > +	}
> > > +
> > > +	ret = nvmet_sq_init(&queue->nvme_sq);
> > > +	if (ret)
> > > +		goto out_free_queue;
> > > +
> > > +	ret = nvmet_rdma_parse_cm_connect_req(&event->param.conn,
> > queue);
> > > +	if (ret)
> > > +		goto out_destroy_sq;
> > > +
> > > +	/*
> > > +	 * Schedules the actual release because calling rdma_destroy_id from
> > > +	 * inside a CM callback would trigger a deadlock. (great API
> design..)
> > > +	 */
> > > +	INIT_WORK(&queue->release_work,
> > nvmet_rdma_release_queue_work);
> > > +	queue->dev = ndev;
> > > +	queue->cm_id = cm_id;
> > > +
> > > +	spin_lock_init(&queue->state_lock);
> > > +	queue->state = NVMET_RDMA_Q_CONNECTING;
> > > +	INIT_LIST_HEAD(&queue->rsp_wait_list);
> > > +	INIT_LIST_HEAD(&queue->rsp_wr_wait_list);
> > > +	spin_lock_init(&queue->rsp_wr_wait_lock);
> > > +	INIT_LIST_HEAD(&queue->free_rsps);
> > > +	spin_lock_init(&queue->rsps_lock);
> > > +
> > > +	queue->idx = ida_simple_get(&nvmet_rdma_queue_ida, 0, 0,
> > GFP_KERNEL);
> > > +	if (queue->idx < 0) {
> > > +		ret = NVME_RDMA_CM_NO_RSC;
> > > +		goto out_free_queue;
> > > +	}
> > > +
> > > +	ret = nvmet_rdma_alloc_rsps(queue);
> > > +	if (ret) {
> > > +		ret = NVME_RDMA_CM_NO_RSC;
> > > +		goto out_ida_remove;
> > > +	}
> > > +
> > > +	if (!ndev->srq) {
> > > +		queue->cmds = nvmet_rdma_alloc_cmds(ndev,
> > > +				queue->recv_queue_size,
> > > +				!queue->host_qid);
> > > +		if (IS_ERR(queue->cmds)) {
> > > +			ret = NVME_RDMA_CM_NO_RSC;
> > > +			goto out_free_cmds;
> > > +		}
> > > +	}
> > > +
> 
> Should the above error path actually goto a block that frees the rsps?  Like
> this?

Yes, this looks good.  Thanks a lot, I'll include it in when reposting.
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RE: [PATCH 4/5] nvmet-rdma: add a NVMe over Fabrics RDMA target driver

[Steve Wise]

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

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

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

[Steve Wise]

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

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

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

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

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

[Steve Wise]

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

Hey Sean, 

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

Thanks,

Steve.

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

[Steve Wise]

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


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

void rdma_destroy_id(struct rdma_cm_id *id)
{

<snip>

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

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

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

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

Steve. 

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

[Hefty, Sean]

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

yes

> rmda_destroy_id() the CONNECT_REQUEST cm_id _inside_ its event handler

no

> as long
> as it returns 0?

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

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

[Sagi Grimberg]

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

...

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

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