[linux.git] / net / 9p / trans_rdma.c

/*
 * linux/fs/9p/trans_rdma.c
 *
 * RDMA transport layer based on the trans_fd.c implementation.
 *
 *  Copyright (C) 2008 by Tom Tucker <[email protected]>
 *  Copyright (C) 2006 by Russ Cox <[email protected]>
 *  Copyright (C) 2004-2005 by Latchesar Ionkov <[email protected]>
 *  Copyright (C) 2004-2008 by Eric Van Hensbergen <[email protected]>
 *  Copyright (C) 1997-2002 by Ron Minnich <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that 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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/in.h>
#include <linux/module.h>
#include <linux/net.h>
#include <linux/ipv6.h>
#include <linux/kthread.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/un.h>
#include <linux/uaccess.h>
#include <linux/inet.h>
#include <linux/idr.h>
#include <linux/file.h>
#include <linux/parser.h>
#include <linux/semaphore.h>
#include <linux/slab.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>

#define P9_PORT			5640
#define P9_RDMA_SQ_DEPTH	32
#define P9_RDMA_RQ_DEPTH	32
#define P9_RDMA_SEND_SGE	4
#define P9_RDMA_RECV_SGE	4
#define P9_RDMA_IRD		0
#define P9_RDMA_ORD		0
#define P9_RDMA_TIMEOUT		30000		/* 30 seconds */
#define P9_RDMA_MAXSIZE		(4*4096)	/* Min SGE is 4, so we can
						 * safely advertise a maxsize
						 * of 64k */

/**
 * struct p9_trans_rdma - RDMA transport instance
 *
 * @state: tracks the transport state machine for connection setup and tear down
 * @cm_id: The RDMA CM ID
 * @pd: Protection Domain pointer
 * @qp: Queue Pair pointer
 * @cq: Completion Queue pointer
 * @dm_mr: DMA Memory Region pointer
 * @lkey: The local access only memory region key
 * @timeout: Number of uSecs to wait for connection management events
 * @sq_depth: The depth of the Send Queue
 * @sq_sem: Semaphore for the SQ
 * @rq_depth: The depth of the Receive Queue.
 * @rq_count: Count of requests in the Receive Queue.
 * @addr: The remote peer's address
 * @req_lock: Protects the active request list
 * @cm_done: Completion event for connection management tracking
 */
struct p9_trans_rdma {
	enum {
		P9_RDMA_INIT,
		P9_RDMA_ADDR_RESOLVED,
		P9_RDMA_ROUTE_RESOLVED,
		P9_RDMA_CONNECTED,
		P9_RDMA_FLUSHING,
		P9_RDMA_CLOSING,
		P9_RDMA_CLOSED,
	} state;
	struct rdma_cm_id *cm_id;
	struct ib_pd *pd;
	struct ib_qp *qp;
	struct ib_cq *cq;
	struct ib_mr *dma_mr;
	u32 lkey;
	long timeout;
	int sq_depth;
	struct semaphore sq_sem;
	int rq_depth;
	atomic_t rq_count;
	struct sockaddr_in addr;
	spinlock_t req_lock;

	struct completion cm_done;
};

/**
 * p9_rdma_context - Keeps track of in-process WR
 *
 * @wc_op: The original WR op for when the CQE completes in error.
 * @busa: Bus address to unmap when the WR completes
 * @req: Keeps track of requests (send)
 * @rc: Keepts track of replies (receive)
 */
struct p9_rdma_req;
struct p9_rdma_context {
	enum ib_wc_opcode wc_op;
	dma_addr_t busa;
	union {
		struct p9_req_t *req;
		struct p9_fcall *rc;
	};
};

/**
 * p9_rdma_opts - Collection of mount options
 * @port: port of connection
 * @sq_depth: The requested depth of the SQ. This really doesn't need
 * to be any deeper than the number of threads used in the client
 * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
 * @timeout: Time to wait in msecs for CM events
 */
struct p9_rdma_opts {
	short port;
	int sq_depth;
	int rq_depth;
	long timeout;
};

/*
 * Option Parsing (code inspired by NFS code)
 */
enum {
	/* Options that take integer arguments */
	Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout, Opt_err,
};

static match_table_t tokens = {
	{Opt_port, "port=%u"},
	{Opt_sq_depth, "sq=%u"},
	{Opt_rq_depth, "rq=%u"},
	{Opt_timeout, "timeout=%u"},
	{Opt_err, NULL},
};

/**
 * parse_opts - parse mount options into rdma options structure
 * @params: options string passed from mount
 * @opts: rdma transport-specific structure to parse options into
 *
 * Returns 0 upon success, -ERRNO upon failure
 */
static int parse_opts(char *params, struct p9_rdma_opts *opts)
{
	char *p;
	substring_t args[MAX_OPT_ARGS];
	int option;
	char *options, *tmp_options;
	int ret;

	opts->port = P9_PORT;
	opts->sq_depth = P9_RDMA_SQ_DEPTH;
	opts->rq_depth = P9_RDMA_RQ_DEPTH;
	opts->timeout = P9_RDMA_TIMEOUT;

	if (!params)
		return 0;

	tmp_options = kstrdup(params, GFP_KERNEL);
	if (!tmp_options) {
		P9_DPRINTK(P9_DEBUG_ERROR,
			   "failed to allocate copy of option string\n");
		return -ENOMEM;
	}
	options = tmp_options;

	while ((p = strsep(&options, ",")) != NULL) {
		int token;
		int r;
		if (!*p)
			continue;
		token = match_token(p, tokens, args);
		r = match_int(&args[0], &option);
		if (r < 0) {
			P9_DPRINTK(P9_DEBUG_ERROR,
				   "integer field, but no integer?\n");
			ret = r;
			continue;
		}
		switch (token) {
		case Opt_port:
			opts->port = option;
			break;
		case Opt_sq_depth:
			opts->sq_depth = option;
			break;
		case Opt_rq_depth:
			opts->rq_depth = option;
			break;
		case Opt_timeout:
			opts->timeout = option;
			break;
		default:
			continue;
		}
	}
	/* RQ must be at least as large as the SQ */
	opts->rq_depth = max(opts->rq_depth, opts->sq_depth);
	kfree(tmp_options);
	return 0;
}

static int
p9_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
{
	struct p9_client *c = id->context;
	struct p9_trans_rdma *rdma = c->trans;
	switch (event->event) {
	case RDMA_CM_EVENT_ADDR_RESOLVED:
		BUG_ON(rdma->state != P9_RDMA_INIT);
		rdma->state = P9_RDMA_ADDR_RESOLVED;
		break;

	case RDMA_CM_EVENT_ROUTE_RESOLVED:
		BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED);
		rdma->state = P9_RDMA_ROUTE_RESOLVED;
		break;

	case RDMA_CM_EVENT_ESTABLISHED:
		BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED);
		rdma->state = P9_RDMA_CONNECTED;
		break;

	case RDMA_CM_EVENT_DISCONNECTED:
		if (rdma)
			rdma->state = P9_RDMA_CLOSED;
		if (c)
			c->status = Disconnected;
		break;

	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
		break;

	case RDMA_CM_EVENT_ADDR_CHANGE:
	case RDMA_CM_EVENT_ROUTE_ERROR:
	case RDMA_CM_EVENT_DEVICE_REMOVAL:
	case RDMA_CM_EVENT_MULTICAST_JOIN:
	case RDMA_CM_EVENT_MULTICAST_ERROR:
	case RDMA_CM_EVENT_REJECTED:
	case RDMA_CM_EVENT_CONNECT_REQUEST:
	case RDMA_CM_EVENT_CONNECT_RESPONSE:
	case RDMA_CM_EVENT_CONNECT_ERROR:
	case RDMA_CM_EVENT_ADDR_ERROR:
	case RDMA_CM_EVENT_UNREACHABLE:
		c->status = Disconnected;
		rdma_disconnect(rdma->cm_id);
		break;
	default:
		BUG();
	}
	complete(&rdma->cm_done);
	return 0;
}

static void
handle_recv(struct p9_client *client, struct p9_trans_rdma *rdma,
	    struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
{
	struct p9_req_t *req;
	int err = 0;
	int16_t tag;

	req = NULL;
	ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize,
							 DMA_FROM_DEVICE);

	if (status != IB_WC_SUCCESS)
		goto err_out;

	err = p9_parse_header(c->rc, NULL, NULL, &tag, 1);
	if (err)
		goto err_out;

	req = p9_tag_lookup(client, tag);
	if (!req)
		goto err_out;

	req->rc = c->rc;
	req->status = REQ_STATUS_RCVD;
	p9_client_cb(client, req);

	return;

 err_out:
	P9_DPRINTK(P9_DEBUG_ERROR, "req %p err %d status %d\n",
		   req, err, status);
	rdma->state = P9_RDMA_FLUSHING;
	client->status = Disconnected;
}

static void
handle_send(struct p9_client *client, struct p9_trans_rdma *rdma,
	    struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
{
	ib_dma_unmap_single(rdma->cm_id->device,
			    c->busa, c->req->tc->size,
			    DMA_TO_DEVICE);
}

static void qp_event_handler(struct ib_event *event, void *context)
{
	P9_DPRINTK(P9_DEBUG_ERROR, "QP event %d context %p\n", event->event,
								context);
}

static void cq_comp_handler(struct ib_cq *cq, void *cq_context)
{
	struct p9_client *client = cq_context;
	struct p9_trans_rdma *rdma = client->trans;
	int ret;
	struct ib_wc wc;

	ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
	while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
		struct p9_rdma_context *c = (void *) (unsigned long) wc.wr_id;

		switch (c->wc_op) {
		case IB_WC_RECV:
			atomic_dec(&rdma->rq_count);
			handle_recv(client, rdma, c, wc.status, wc.byte_len);
			break;

		case IB_WC_SEND:
			handle_send(client, rdma, c, wc.status, wc.byte_len);
			up(&rdma->sq_sem);
			break;

		default:
			printk(KERN_ERR "9prdma: unexpected completion type, "
			       "c->wc_op=%d, wc.opcode=%d, status=%d\n",
			       c->wc_op, wc.opcode, wc.status);
			break;
		}
		kfree(c);
	}
}

static void cq_event_handler(struct ib_event *e, void *v)
{
	P9_DPRINTK(P9_DEBUG_ERROR, "CQ event %d context %p\n", e->event, v);
}

static void rdma_destroy_trans(struct p9_trans_rdma *rdma)
{
	if (!rdma)
		return;

	if (rdma->dma_mr && !IS_ERR(rdma->dma_mr))
		ib_dereg_mr(rdma->dma_mr);

	if (rdma->qp && !IS_ERR(rdma->qp))
		ib_destroy_qp(rdma->qp);

	if (rdma->pd && !IS_ERR(rdma->pd))
		ib_dealloc_pd(rdma->pd);

	if (rdma->cq && !IS_ERR(rdma->cq))
		ib_destroy_cq(rdma->cq);

	if (rdma->cm_id && !IS_ERR(rdma->cm_id))
		rdma_destroy_id(rdma->cm_id);

	kfree(rdma);
}

static int
post_recv(struct p9_client *client, struct p9_rdma_context *c)
{
	struct p9_trans_rdma *rdma = client->trans;
	struct ib_recv_wr wr, *bad_wr;
	struct ib_sge sge;

	c->busa = ib_dma_map_single(rdma->cm_id->device,
				    c->rc->sdata, client->msize,
				    DMA_FROM_DEVICE);
	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
		goto error;

	sge.addr = c->busa;
	sge.length = client->msize;
	sge.lkey = rdma->lkey;

	wr.next = NULL;
	c->wc_op = IB_WC_RECV;
	wr.wr_id = (unsigned long) c;
	wr.sg_list = &sge;
	wr.num_sge = 1;
	return ib_post_recv(rdma->qp, &wr, &bad_wr);

 error:
	P9_DPRINTK(P9_DEBUG_ERROR, "EIO\n");
	return -EIO;
}

static int rdma_request(struct p9_client *client, struct p9_req_t *req)
{
	struct p9_trans_rdma *rdma = client->trans;
	struct ib_send_wr wr, *bad_wr;
	struct ib_sge sge;
	int err = 0;
	unsigned long flags;
	struct p9_rdma_context *c = NULL;
	struct p9_rdma_context *rpl_context = NULL;

	/* Allocate an fcall for the reply */
	rpl_context = kmalloc(sizeof *rpl_context, GFP_KERNEL);
	if (!rpl_context) {
		err = -ENOMEM;
		goto err_close;
	}

	/*
	 * If the request has a buffer, steal it, otherwise
	 * allocate a new one.  Typically, requests should already
	 * have receive buffers allocated and just swap them around
	 */
	if (!req->rc) {
		req->rc = kmalloc(sizeof(struct p9_fcall)+client->msize,
								GFP_KERNEL);
		if (req->rc) {
			req->rc->sdata = (char *) req->rc +
						sizeof(struct p9_fcall);
			req->rc->capacity = client->msize;
		}
	}
	rpl_context->rc = req->rc;
	if (!rpl_context->rc) {
		err = -ENOMEM;
		goto err_free2;
	}

	/*
	 * Post a receive buffer for this request. We need to ensure
	 * there is a reply buffer available for every outstanding
	 * request. A flushed request can result in no reply for an
	 * outstanding request, so we must keep a count to avoid
	 * overflowing the RQ.
	 */
	if (atomic_inc_return(&rdma->rq_count) <= rdma->rq_depth) {
		err = post_recv(client, rpl_context);
		if (err)
			goto err_free1;
	} else
		atomic_dec(&rdma->rq_count);

	/* remove posted receive buffer from request structure */
	req->rc = NULL;

	/* Post the request */
	c = kmalloc(sizeof *c, GFP_KERNEL);
	if (!c) {
		err = -ENOMEM;
		goto err_free1;
	}
	c->req = req;

	c->busa = ib_dma_map_single(rdma->cm_id->device,
				    c->req->tc->sdata, c->req->tc->size,
				    DMA_TO_DEVICE);
	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
		goto error;

	sge.addr = c->busa;
	sge.length = c->req->tc->size;
	sge.lkey = rdma->lkey;

	wr.next = NULL;
	c->wc_op = IB_WC_SEND;
	wr.wr_id = (unsigned long) c;
	wr.opcode = IB_WR_SEND;
	wr.send_flags = IB_SEND_SIGNALED;
	wr.sg_list = &sge;
	wr.num_sge = 1;

	if (down_interruptible(&rdma->sq_sem))
		goto error;

	return ib_post_send(rdma->qp, &wr, &bad_wr);

 error:
	kfree(c);
	kfree(rpl_context->rc);
	kfree(rpl_context);
	P9_DPRINTK(P9_DEBUG_ERROR, "EIO\n");
	return -EIO;
 err_free1:
	kfree(rpl_context->rc);
 err_free2:
	kfree(rpl_context);
 err_close:
	spin_lock_irqsave(&rdma->req_lock, flags);
	if (rdma->state < P9_RDMA_CLOSING) {
		rdma->state = P9_RDMA_CLOSING;
		spin_unlock_irqrestore(&rdma->req_lock, flags);
		rdma_disconnect(rdma->cm_id);
	} else
		spin_unlock_irqrestore(&rdma->req_lock, flags);
	return err;
}

static void rdma_close(struct p9_client *client)
{
	struct p9_trans_rdma *rdma;

	if (!client)
		return;

	rdma = client->trans;
	if (!rdma)
		return;

	client->status = Disconnected;
	rdma_disconnect(rdma->cm_id);
	rdma_destroy_trans(rdma);
}

/**
 * alloc_rdma - Allocate and initialize the rdma transport structure
 * @opts: Mount options structure
 */
static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
{
	struct p9_trans_rdma *rdma;

	rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
	if (!rdma)
		return NULL;

	rdma->sq_depth = opts->sq_depth;
	rdma->rq_depth = opts->rq_depth;
	rdma->timeout = opts->timeout;
	spin_lock_init(&rdma->req_lock);
	init_completion(&rdma->cm_done);
	sema_init(&rdma->sq_sem, rdma->sq_depth);
	atomic_set(&rdma->rq_count, 0);

	return rdma;
}

/* its not clear to me we can do anything after send has been posted */
static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
{
	return 1;
}

/**
 * trans_create_rdma - Transport method for creating atransport instance
 * @client: client instance
 * @addr: IP address string
 * @args: Mount options string
 */
static int
rdma_create_trans(struct p9_client *client, const char *addr, char *args)
{
	int err;
	struct p9_rdma_opts opts;
	struct p9_trans_rdma *rdma;
	struct rdma_conn_param conn_param;
	struct ib_qp_init_attr qp_attr;
	struct ib_device_attr devattr;

	/* Parse the transport specific mount options */
	err = parse_opts(args, &opts);
	if (err < 0)
		return err;

	/* Create and initialize the RDMA transport structure */
	rdma = alloc_rdma(&opts);
	if (!rdma)
		return -ENOMEM;

	/* Create the RDMA CM ID */
	rdma->cm_id = rdma_create_id(p9_cm_event_handler, client, RDMA_PS_TCP);
	if (IS_ERR(rdma->cm_id))
		goto error;

	/* Associate the client with the transport */
	client->trans = rdma;

	/* Resolve the server's address */
	rdma->addr.sin_family = AF_INET;
	rdma->addr.sin_addr.s_addr = in_aton(addr);
	rdma->addr.sin_port = htons(opts.port);
	err = rdma_resolve_addr(rdma->cm_id, NULL,
				(struct sockaddr *)&rdma->addr,
				rdma->timeout);
	if (err)
		goto error;
	err = wait_for_completion_interruptible(&rdma->cm_done);
	if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED))
		goto error;

	/* Resolve the route to the server */
	err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
	if (err)
		goto error;
	err = wait_for_completion_interruptible(&rdma->cm_done);
	if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED))
		goto error;

	/* Query the device attributes */
	err = ib_query_device(rdma->cm_id->device, &devattr);
	if (err)
		goto error;

	/* Create the Completion Queue */
	rdma->cq = ib_create_cq(rdma->cm_id->device, cq_comp_handler,
				cq_event_handler, client,
				opts.sq_depth + opts.rq_depth + 1, 0);
	if (IS_ERR(rdma->cq))
		goto error;
	ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);

	/* Create the Protection Domain */
	rdma->pd = ib_alloc_pd(rdma->cm_id->device);
	if (IS_ERR(rdma->pd))
		goto error;

	/* Cache the DMA lkey in the transport */
	rdma->dma_mr = NULL;
	if (devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)
		rdma->lkey = rdma->cm_id->device->local_dma_lkey;
	else {
		rdma->dma_mr = ib_get_dma_mr(rdma->pd, IB_ACCESS_LOCAL_WRITE);
		if (IS_ERR(rdma->dma_mr))
			goto error;
		rdma->lkey = rdma->dma_mr->lkey;
	}

	/* Create the Queue Pair */
	memset(&qp_attr, 0, sizeof qp_attr);
	qp_attr.event_handler = qp_event_handler;
	qp_attr.qp_context = client;
	qp_attr.cap.max_send_wr = opts.sq_depth;
	qp_attr.cap.max_recv_wr = opts.rq_depth;
	qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
	qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
	qp_attr.qp_type = IB_QPT_RC;
	qp_attr.send_cq = rdma->cq;
	qp_attr.recv_cq = rdma->cq;
	err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
	if (err)
		goto error;
	rdma->qp = rdma->cm_id->qp;

	/* Request a connection */
	memset(&conn_param, 0, sizeof(conn_param));
	conn_param.private_data = NULL;
	conn_param.private_data_len = 0;
	conn_param.responder_resources = P9_RDMA_IRD;
	conn_param.initiator_depth = P9_RDMA_ORD;
	err = rdma_connect(rdma->cm_id, &conn_param);
	if (err)
		goto error;
	err = wait_for_completion_interruptible(&rdma->cm_done);
	if (err || (rdma->state != P9_RDMA_CONNECTED))
		goto error;

	client->status = Connected;

	return 0;

error:
	rdma_destroy_trans(rdma);
	return -ENOTCONN;
}

static struct p9_trans_module p9_rdma_trans = {
	.name = "rdma",
	.maxsize = P9_RDMA_MAXSIZE,
	.def = 0,
	.owner = THIS_MODULE,
	.create = rdma_create_trans,
	.close = rdma_close,
	.request = rdma_request,
	.cancel = rdma_cancel,
};

/**
 * p9_trans_rdma_init - Register the 9P RDMA transport driver
 */
static int __init p9_trans_rdma_init(void)
{
	v9fs_register_trans(&p9_rdma_trans);
	return 0;
}

static void __exit p9_trans_rdma_exit(void)
{
	v9fs_unregister_trans(&p9_rdma_trans);
}

module_init(p9_trans_rdma_init);
module_exit(p9_trans_rdma_exit);

MODULE_AUTHOR("Tom Tucker <[email protected]>");
MODULE_DESCRIPTION("RDMA Transport for 9P");
MODULE_LICENSE("Dual BSD/GPL");
Commit	Line	Data
fc79d4b1 TT	1	/*
	2	* linux/fs/9p/trans_rdma.c
	3	*
	4	* RDMA transport layer based on the trans_fd.c implementation.
	5	*
	6	* Copyright (C) 2008 by Tom Tucker <[email protected]>
	7	* Copyright (C) 2006 by Russ Cox <[email protected]>
	8	* Copyright (C) 2004-2005 by Latchesar Ionkov <[email protected]>
	9	* Copyright (C) 2004-2008 by Eric Van Hensbergen <[email protected]>
	10	* Copyright (C) 1997-2002 by Ron Minnich <[email protected]>
	11	*
	12	* This program is free software; you can redistribute it and/or modify
	13	* it under the terms of the GNU General Public License version 2
	14	* as published by the Free Software Foundation.
	15	*
	16	* This program is distributed in the hope that it will be useful,
	17	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	* GNU General Public License for more details.
	20	*
	21	* You should have received a copy of the GNU General Public License
	22	* along with this program; if not, write to:
	23	* Free Software Foundation
	24	* 51 Franklin Street, Fifth Floor
	25	* Boston, MA 02111-1301 USA
	26	*
	27	*/
	28
	29	#include <linux/in.h>
	30	#include <linux/module.h>
	31	#include <linux/net.h>
	32	#include <linux/ipv6.h>
	33	#include <linux/kthread.h>
	34	#include <linux/errno.h>
	35	#include <linux/kernel.h>
	36	#include <linux/un.h>
	37	#include <linux/uaccess.h>
	38	#include <linux/inet.h>
	39	#include <linux/idr.h>
	40	#include <linux/file.h>
	41	#include <linux/parser.h>
	42	#include <linux/semaphore.h>
5a0e3ad6	43	#include <linux/slab.h>
fc79d4b1 TT	44	#include <net/9p/9p.h>
	45	#include <net/9p/client.h>
	46	#include <net/9p/transport.h>
	47	#include <rdma/ib_verbs.h>
	48	#include <rdma/rdma_cm.h>
fc79d4b1 TT	49
	50	#define P9_PORT 5640
	51	#define P9_RDMA_SQ_DEPTH 32
	52	#define P9_RDMA_RQ_DEPTH 32
	53	#define P9_RDMA_SEND_SGE 4
	54	#define P9_RDMA_RECV_SGE 4
	55	#define P9_RDMA_IRD 0
	56	#define P9_RDMA_ORD 0
	57	#define P9_RDMA_TIMEOUT 30000 /* 30 seconds */
	58	#define P9_RDMA_MAXSIZE (44096) / Min SGE is 4, so we can
	59	* safely advertise a maxsize
	60	* of 64k */
	61
fc79d4b1 TT	62	/**
	63	* struct p9_trans_rdma - RDMA transport instance
	64	*
	65	* @state: tracks the transport state machine for connection setup and tear down
	66	* @cm_id: The RDMA CM ID
	67	* @pd: Protection Domain pointer
	68	* @qp: Queue Pair pointer
	69	* @cq: Completion Queue pointer
0e15597e	70	* @dm_mr: DMA Memory Region pointer
fc79d4b1 TT	71	* @lkey: The local access only memory region key
	72	* @timeout: Number of uSecs to wait for connection management events
	73	* @sq_depth: The depth of the Send Queue
	74	* @sq_sem: Semaphore for the SQ
	75	* @rq_depth: The depth of the Receive Queue.
0e15597e	76	* @rq_count: Count of requests in the Receive Queue.
fc79d4b1 TT	77	* @addr: The remote peer's address
fc79d4b1 TT	78	* @req_lock: Protects the active request list
fc79d4b1 TT	79	* @cm_done: Completion event for connection management tracking
	80	*/
	81	struct p9_trans_rdma {
	82	enum {
	83	P9_RDMA_INIT,
	84	P9_RDMA_ADDR_RESOLVED,
	85	P9_RDMA_ROUTE_RESOLVED,
	86	P9_RDMA_CONNECTED,
	87	P9_RDMA_FLUSHING,
	88	P9_RDMA_CLOSING,
	89	P9_RDMA_CLOSED,
	90	} state;
	91	struct rdma_cm_id *cm_id;
	92	struct ib_pd *pd;
	93	struct ib_qp *qp;
	94	struct ib_cq *cq;
	95	struct ib_mr *dma_mr;
	96	u32 lkey;
	97	long timeout;
	98	int sq_depth;
	99	struct semaphore sq_sem;
	100	int rq_depth;
	101	atomic_t rq_count;
	102	struct sockaddr_in addr;
	103	spinlock_t req_lock;
	104
	105	struct completion cm_done;
	106	};
	107
	108	/**
	109	* p9_rdma_context - Keeps track of in-process WR
	110	*
	111	* @wc_op: The original WR op for when the CQE completes in error.
	112	* @busa: Bus address to unmap when the WR completes
	113	* @req: Keeps track of requests (send)
	114	* @rc: Keepts track of replies (receive)
	115	*/
	116	struct p9_rdma_req;
	117	struct p9_rdma_context {
	118	enum ib_wc_opcode wc_op;
	119	dma_addr_t busa;
	120	union {
	121	struct p9_req_t *req;
	122	struct p9_fcall *rc;
	123	};
	124	};
	125
	126	/**
	127	* p9_rdma_opts - Collection of mount options
	128	* @port: port of connection
	129	* @sq_depth: The requested depth of the SQ. This really doesn't need
	130	* to be any deeper than the number of threads used in the client
	131	* @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
	132	* @timeout: Time to wait in msecs for CM events
	133	*/
	134	struct p9_rdma_opts {
	135	short port;
	136	int sq_depth;
	137	int rq_depth;
	138	long timeout;
	139	};
	140
	141	/*
	142	* Option Parsing (code inspired by NFS code)
143	*/
144	enum {
145	/* Options that take integer arguments */
146	Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout, Opt_err,
147	};
148
149	static match_table_t tokens = {
150	{Opt_port, "port=%u"},
151	{Opt_sq_depth, "sq=%u"},
152	{Opt_rq_depth, "rq=%u"},
153	{Opt_timeout, "timeout=%u"},
154	{Opt_err, NULL},
155	};
156
157	/**
0e15597e AK	158	* parse_opts - parse mount options into rdma options structure
	159	* @params: options string passed from mount
	160	* @opts: rdma transport-specific structure to parse options into
fc79d4b1 TT	161	*
	162	* Returns 0 upon success, -ERRNO upon failure
	163	*/
	164	static int parse_opts(char params, struct p9_rdma_opts opts)
	165	{
	166	char *p;
	167	substring_t args[MAX_OPT_ARGS];
	168	int option;
d8c8a9e3	169	char options, tmp_options;
fc79d4b1 TT	170	int ret;
	171
	172	opts->port = P9_PORT;
	173	opts->sq_depth = P9_RDMA_SQ_DEPTH;
	174	opts->rq_depth = P9_RDMA_RQ_DEPTH;
	175	opts->timeout = P9_RDMA_TIMEOUT;
	176
	177	if (!params)
	178	return 0;
	179
d8c8a9e3 EVH	180	tmp_options = kstrdup(params, GFP_KERNEL);
d8c8a9e3 EVH	181	if (!tmp_options) {
fc79d4b1 TT	182	P9_DPRINTK(P9_DEBUG_ERROR,
	183	"failed to allocate copy of option string\n");
	184	return -ENOMEM;
	185	}
d8c8a9e3	186	options = tmp_options;
fc79d4b1 TT	187
	188	while ((p = strsep(&options, ",")) != NULL) {
	189	int token;
	190	int r;
	191	if (!*p)
	192	continue;
	193	token = match_token(p, tokens, args);
	194	r = match_int(&args[0], &option);
	195	if (r < 0) {
	196	P9_DPRINTK(P9_DEBUG_ERROR,
	197	"integer field, but no integer?\n");
	198	ret = r;
	199	continue;
	200	}
	201	switch (token) {
	202	case Opt_port:
	203	opts->port = option;
	204	break;
	205	case Opt_sq_depth:
	206	opts->sq_depth = option;
	207	break;
	208	case Opt_rq_depth:
	209	opts->rq_depth = option;
	210	break;
	211	case Opt_timeout:
	212	opts->timeout = option;
	213	break;
	214	default:
	215	continue;
	216	}
	217	}
	218	/* RQ must be at least as large as the SQ */
	219	opts->rq_depth = max(opts->rq_depth, opts->sq_depth);
d8c8a9e3	220	kfree(tmp_options);
fc79d4b1 TT	221	return 0;
	222	}
	223
	224	static int
	225	p9_cm_event_handler(struct rdma_cm_id id, struct rdma_cm_event event)
	226	{
	227	struct p9_client *c = id->context;
	228	struct p9_trans_rdma *rdma = c->trans;
	229	switch (event->event) {
	230	case RDMA_CM_EVENT_ADDR_RESOLVED:
	231	BUG_ON(rdma->state != P9_RDMA_INIT);
	232	rdma->state = P9_RDMA_ADDR_RESOLVED;
	233	break;
	234
	235	case RDMA_CM_EVENT_ROUTE_RESOLVED:
	236	BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED);
	237	rdma->state = P9_RDMA_ROUTE_RESOLVED;
	238	break;
	239
	240	case RDMA_CM_EVENT_ESTABLISHED:
	241	BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED);
	242	rdma->state = P9_RDMA_CONNECTED;
	243	break;
	244
	245	case RDMA_CM_EVENT_DISCONNECTED:
	246	if (rdma)
	247	rdma->state = P9_RDMA_CLOSED;
	248	if (c)
	249	c->status = Disconnected;
	250	break;
	251
	252	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
	253	break;
	254
	255	case RDMA_CM_EVENT_ADDR_CHANGE:
	256	case RDMA_CM_EVENT_ROUTE_ERROR:
	257	case RDMA_CM_EVENT_DEVICE_REMOVAL:
	258	case RDMA_CM_EVENT_MULTICAST_JOIN:
	259	case RDMA_CM_EVENT_MULTICAST_ERROR:
	260	case RDMA_CM_EVENT_REJECTED:
	261	case RDMA_CM_EVENT_CONNECT_REQUEST:
	262	case RDMA_CM_EVENT_CONNECT_RESPONSE:
	263	case RDMA_CM_EVENT_CONNECT_ERROR:
	264	case RDMA_CM_EVENT_ADDR_ERROR:
	265	case RDMA_CM_EVENT_UNREACHABLE:
	266	c->status = Disconnected;
	267	rdma_disconnect(rdma->cm_id);
	268	break;
	269	default:
	270	BUG();
	271	}
	272	complete(&rdma->cm_done);
	273	return 0;
	274	}
	275
	276	static void
	277	handle_recv(struct p9_client client, struct p9_trans_rdma rdma,
	278	struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
	279	{
	280	struct p9_req_t *req;
	281	int err = 0;
	282	int16_t tag;
	283
	284	req = NULL;
285	ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize,
286	DMA_FROM_DEVICE);
287
288	if (status != IB_WC_SUCCESS)
289	goto err_out;
290
291	err = p9_parse_header(c->rc, NULL, NULL, &tag, 1);
292	if (err)
293	goto err_out;
294
295	req = p9_tag_lookup(client, tag);
296	if (!req)
297	goto err_out;
298
299	req->rc = c->rc;
1bab88b2	300	req->status = REQ_STATUS_RCVD;
fc79d4b1 TT	301	p9_client_cb(client, req);
	302
	303	return;
	304
	305	err_out:
	306	P9_DPRINTK(P9_DEBUG_ERROR, "req %p err %d status %d\n",
	307	req, err, status);
	308	rdma->state = P9_RDMA_FLUSHING;
	309	client->status = Disconnected;
fc79d4b1 TT	310	}
	311
	312	static void
	313	handle_send(struct p9_client client, struct p9_trans_rdma rdma,
	314	struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
	315	{
	316	ib_dma_unmap_single(rdma->cm_id->device,
	317	c->busa, c->req->tc->size,
	318	DMA_TO_DEVICE);
	319	}
	320
	321	static void qp_event_handler(struct ib_event event, void context)
	322	{
	323	P9_DPRINTK(P9_DEBUG_ERROR, "QP event %d context %p\n", event->event,
	324	context);
	325	}
	326
	327	static void cq_comp_handler(struct ib_cq cq, void cq_context)
	328	{
	329	struct p9_client *client = cq_context;
	330	struct p9_trans_rdma *rdma = client->trans;
	331	int ret;
	332	struct ib_wc wc;
	333
	334	ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
	335	while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
	336	struct p9_rdma_context c = (void ) (unsigned long) wc.wr_id;
	337
	338	switch (c->wc_op) {
	339	case IB_WC_RECV:
	340	atomic_dec(&rdma->rq_count);
	341	handle_recv(client, rdma, c, wc.status, wc.byte_len);
	342	break;
	343
	344	case IB_WC_SEND:
	345	handle_send(client, rdma, c, wc.status, wc.byte_len);
	346	up(&rdma->sq_sem);
	347	break;
	348
	349	default:
	350	printk(KERN_ERR "9prdma: unexpected completion type, "
	351	"c->wc_op=%d, wc.opcode=%d, status=%d\n",
	352	c->wc_op, wc.opcode, wc.status);
	353	break;
	354	}
	355	kfree(c);
	356	}
	357	}
	358
	359	static void cq_event_handler(struct ib_event e, void v)
	360	{
	361	P9_DPRINTK(P9_DEBUG_ERROR, "CQ event %d context %p\n", e->event, v);
	362	}
	363
	364	static void rdma_destroy_trans(struct p9_trans_rdma *rdma)
	365	{
	366	if (!rdma)
	367	return;
	368
	369	if (rdma->dma_mr && !IS_ERR(rdma->dma_mr))
	370	ib_dereg_mr(rdma->dma_mr);
	371
	372	if (rdma->qp && !IS_ERR(rdma->qp))
	373	ib_destroy_qp(rdma->qp);
374
375	if (rdma->pd && !IS_ERR(rdma->pd))
376	ib_dealloc_pd(rdma->pd);
377
378	if (rdma->cq && !IS_ERR(rdma->cq))
379	ib_destroy_cq(rdma->cq);
380
381	if (rdma->cm_id && !IS_ERR(rdma->cm_id))
382	rdma_destroy_id(rdma->cm_id);
383
384	kfree(rdma);
385	}
386
387	static int
388	post_recv(struct p9_client client, struct p9_rdma_context c)
389	{
390	struct p9_trans_rdma *rdma = client->trans;
391	struct ib_recv_wr wr, *bad_wr;
392	struct ib_sge sge;
393
394	c->busa = ib_dma_map_single(rdma->cm_id->device,
395	c->rc->sdata, client->msize,
396	DMA_FROM_DEVICE);
397	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
398	goto error;
399
400	sge.addr = c->busa;
401	sge.length = client->msize;
402	sge.lkey = rdma->lkey;
403
404	wr.next = NULL;
405	c->wc_op = IB_WC_RECV;
406	wr.wr_id = (unsigned long) c;
407	wr.sg_list = &sge;
408	wr.num_sge = 1;
409	return ib_post_recv(rdma->qp, &wr, &bad_wr);
410
411	error:
412	P9_DPRINTK(P9_DEBUG_ERROR, "EIO\n");
413	return -EIO;
414	}
415
416	static int rdma_request(struct p9_client client, struct p9_req_t req)
417	{
418	struct p9_trans_rdma *rdma = client->trans;
419	struct ib_send_wr wr, *bad_wr;
420	struct ib_sge sge;
421	int err = 0;
422	unsigned long flags;
423	struct p9_rdma_context *c = NULL;
424	struct p9_rdma_context *rpl_context = NULL;
425
426	/* Allocate an fcall for the reply */
427	rpl_context = kmalloc(sizeof *rpl_context, GFP_KERNEL);
1d6400c7 DB	428	if (!rpl_context) {
1d6400c7 DB	429	err = -ENOMEM;
fc79d4b1	430	goto err_close;
1d6400c7	431	}
fc79d4b1 TT	432
	433	/*
	434	* If the request has a buffer, steal it, otherwise
	435	* allocate a new one. Typically, requests should already
	436	* have receive buffers allocated and just swap them around
	437	*/
	438	if (!req->rc) {
	439	req->rc = kmalloc(sizeof(struct p9_fcall)+client->msize,
	440	GFP_KERNEL);
	441	if (req->rc) {
	442	req->rc->sdata = (char *) req->rc +
	443	sizeof(struct p9_fcall);
	444	req->rc->capacity = client->msize;
	445	}
	446	}
	447	rpl_context->rc = req->rc;
	448	if (!rpl_context->rc) {
1d6400c7 DB	449	err = -ENOMEM;
1d6400c7 DB	450	goto err_free2;
fc79d4b1 TT	451	}
	452
	453	/*
	454	* Post a receive buffer for this request. We need to ensure
	455	* there is a reply buffer available for every outstanding
	456	* request. A flushed request can result in no reply for an
	457	* outstanding request, so we must keep a count to avoid
	458	* overflowing the RQ.
	459	*/
	460	if (atomic_inc_return(&rdma->rq_count) <= rdma->rq_depth) {
	461	err = post_recv(client, rpl_context);
1d6400c7 DB	462	if (err)
1d6400c7 DB	463	goto err_free1;
fc79d4b1 TT	464	} else
	465	atomic_dec(&rdma->rq_count);
	466
	467	/* remove posted receive buffer from request structure */
	468	req->rc = NULL;
	469
	470	/* Post the request */
	471	c = kmalloc(sizeof *c, GFP_KERNEL);
1d6400c7 DB	472	if (!c) {
	473	err = -ENOMEM;
	474	goto err_free1;
	475	}
fc79d4b1 TT	476	c->req = req;
	477
	478	c->busa = ib_dma_map_single(rdma->cm_id->device,
	479	c->req->tc->sdata, c->req->tc->size,
	480	DMA_TO_DEVICE);
	481	if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
	482	goto error;
	483
	484	sge.addr = c->busa;
	485	sge.length = c->req->tc->size;
	486	sge.lkey = rdma->lkey;
	487
	488	wr.next = NULL;
	489	c->wc_op = IB_WC_SEND;
	490	wr.wr_id = (unsigned long) c;
	491	wr.opcode = IB_WR_SEND;
	492	wr.send_flags = IB_SEND_SIGNALED;
	493	wr.sg_list = &sge;
	494	wr.num_sge = 1;
	495
	496	if (down_interruptible(&rdma->sq_sem))
	497	goto error;
	498
	499	return ib_post_send(rdma->qp, &wr, &bad_wr);
	500
	501	error:
1d6400c7 DB	502	kfree(c);
	503	kfree(rpl_context->rc);
	504	kfree(rpl_context);
fc79d4b1 TT	505	P9_DPRINTK(P9_DEBUG_ERROR, "EIO\n");
fc79d4b1 TT	506	return -EIO;
1d6400c7 DB	507	err_free1:
	508	kfree(rpl_context->rc);
	509	err_free2:
	510	kfree(rpl_context);
fc79d4b1 TT	511	err_close:
	512	spin_lock_irqsave(&rdma->req_lock, flags);
	513	if (rdma->state < P9_RDMA_CLOSING) {
	514	rdma->state = P9_RDMA_CLOSING;
	515	spin_unlock_irqrestore(&rdma->req_lock, flags);
	516	rdma_disconnect(rdma->cm_id);
	517	} else
	518	spin_unlock_irqrestore(&rdma->req_lock, flags);
	519	return err;
	520	}
	521
	522	static void rdma_close(struct p9_client *client)
	523	{
	524	struct p9_trans_rdma *rdma;
	525
	526	if (!client)
	527	return;
	528
	529	rdma = client->trans;
	530	if (!rdma)
	531	return;
	532
	533	client->status = Disconnected;
	534	rdma_disconnect(rdma->cm_id);
	535	rdma_destroy_trans(rdma);
	536	}
	537
	538	/**
	539	* alloc_rdma - Allocate and initialize the rdma transport structure
fc79d4b1 TT	540	* @opts: Mount options structure
	541	*/
	542	static struct p9_trans_rdma alloc_rdma(struct p9_rdma_opts opts)
	543	{
	544	struct p9_trans_rdma *rdma;
	545
	546	rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
	547	if (!rdma)
	548	return NULL;
	549
	550	rdma->sq_depth = opts->sq_depth;
	551	rdma->rq_depth = opts->rq_depth;
	552	rdma->timeout = opts->timeout;
	553	spin_lock_init(&rdma->req_lock);
	554	init_completion(&rdma->cm_done);
	555	sema_init(&rdma->sq_sem, rdma->sq_depth);
	556	atomic_set(&rdma->rq_count, 0);
	557
	558	return rdma;
	559	}
	560
	561	/* its not clear to me we can do anything after send has been posted */
	562	static int rdma_cancel(struct p9_client client, struct p9_req_t req)
	563	{
	564	return 1;
	565	}
	566
	567	/**
	568	* trans_create_rdma - Transport method for creating atransport instance
	569	* @client: client instance
	570	* @addr: IP address string
	571	* @args: Mount options string
	572	*/
	573	static int
	574	rdma_create_trans(struct p9_client client, const char addr, char *args)
	575	{
	576	int err;
	577	struct p9_rdma_opts opts;
	578	struct p9_trans_rdma *rdma;
	579	struct rdma_conn_param conn_param;
	580	struct ib_qp_init_attr qp_attr;
	581	struct ib_device_attr devattr;
	582
	583	/* Parse the transport specific mount options */
	584	err = parse_opts(args, &opts);
	585	if (err < 0)
	586	return err;
	587
	588	/* Create and initialize the RDMA transport structure */
	589	rdma = alloc_rdma(&opts);
	590	if (!rdma)
	591	return -ENOMEM;
	592
	593	/* Create the RDMA CM ID */
	594	rdma->cm_id = rdma_create_id(p9_cm_event_handler, client, RDMA_PS_TCP);
	595	if (IS_ERR(rdma->cm_id))
	596	goto error;
	597
517ac45a TT	598	/* Associate the client with the transport */
	599	client->trans = rdma;
	600
fc79d4b1 TT	601	/* Resolve the server's address */
	602	rdma->addr.sin_family = AF_INET;
	603	rdma->addr.sin_addr.s_addr = in_aton(addr);
	604	rdma->addr.sin_port = htons(opts.port);
	605	err = rdma_resolve_addr(rdma->cm_id, NULL,
	606	(struct sockaddr *)&rdma->addr,
	607	rdma->timeout);
	608	if (err)
	609	goto error;
	610	err = wait_for_completion_interruptible(&rdma->cm_done);
	611	if (err \|\| (rdma->state != P9_RDMA_ADDR_RESOLVED))
	612	goto error;
	613
	614	/* Resolve the route to the server */
	615	err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
	616	if (err)
	617	goto error;
	618	err = wait_for_completion_interruptible(&rdma->cm_done);
	619	if (err \|\| (rdma->state != P9_RDMA_ROUTE_RESOLVED))
	620	goto error;
	621
	622	/* Query the device attributes */
	623	err = ib_query_device(rdma->cm_id->device, &devattr);
	624	if (err)
	625	goto error;
	626
	627	/* Create the Completion Queue */
	628	rdma->cq = ib_create_cq(rdma->cm_id->device, cq_comp_handler,
	629	cq_event_handler, client,
	630	opts.sq_depth + opts.rq_depth + 1, 0);
	631	if (IS_ERR(rdma->cq))
	632	goto error;
	633	ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
	634
	635	/* Create the Protection Domain */
	636	rdma->pd = ib_alloc_pd(rdma->cm_id->device);
	637	if (IS_ERR(rdma->pd))
	638	goto error;
	639
	640	/* Cache the DMA lkey in the transport */
	641	rdma->dma_mr = NULL;
	642	if (devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)
	643	rdma->lkey = rdma->cm_id->device->local_dma_lkey;
	644	else {
	645	rdma->dma_mr = ib_get_dma_mr(rdma->pd, IB_ACCESS_LOCAL_WRITE);
	646	if (IS_ERR(rdma->dma_mr))
	647	goto error;
	648	rdma->lkey = rdma->dma_mr->lkey;
	649	}
	650
	651	/* Create the Queue Pair */
	652	memset(&qp_attr, 0, sizeof qp_attr);
	653	qp_attr.event_handler = qp_event_handler;
	654	qp_attr.qp_context = client;
	655	qp_attr.cap.max_send_wr = opts.sq_depth;
	656	qp_attr.cap.max_recv_wr = opts.rq_depth;
	657	qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
	658	qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
	659	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
	660	qp_attr.qp_type = IB_QPT_RC;
	661	qp_attr.send_cq = rdma->cq;
	662	qp_attr.recv_cq = rdma->cq;
	663	err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
	664	if (err)
665	goto error;
666	rdma->qp = rdma->cm_id->qp;
667
668	/* Request a connection */
669	memset(&conn_param, 0, sizeof(conn_param));
670	conn_param.private_data = NULL;
671	conn_param.private_data_len = 0;
672	conn_param.responder_resources = P9_RDMA_IRD;
673	conn_param.initiator_depth = P9_RDMA_ORD;
674	err = rdma_connect(rdma->cm_id, &conn_param);
675	if (err)
676	goto error;
677	err = wait_for_completion_interruptible(&rdma->cm_done);
678	if (err \|\| (rdma->state != P9_RDMA_CONNECTED))
679	goto error;
680
fc79d4b1 TT	681	client->status = Connected;
	682
	683	return 0;
	684
	685	error:
	686	rdma_destroy_trans(rdma);
	687	return -ENOTCONN;
	688	}
	689
	690	static struct p9_trans_module p9_rdma_trans = {
	691	.name = "rdma",
	692	.maxsize = P9_RDMA_MAXSIZE,
	693	.def = 0,
	694	.owner = THIS_MODULE,
	695	.create = rdma_create_trans,
	696	.close = rdma_close,
	697	.request = rdma_request,
	698	.cancel = rdma_cancel,
	699	};
	700
	701	/**
	702	* p9_trans_rdma_init - Register the 9P RDMA transport driver
	703	*/
	704	static int __init p9_trans_rdma_init(void)
	705	{
	706	v9fs_register_trans(&p9_rdma_trans);
	707	return 0;
	708	}
	709
	710	static void __exit p9_trans_rdma_exit(void)
	711	{
	712	v9fs_unregister_trans(&p9_rdma_trans);
	713	}
	714
	715	module_init(p9_trans_rdma_init);
	716	module_exit(p9_trans_rdma_exit);
	717
	718	MODULE_AUTHOR("Tom Tucker <[email protected]>");
	719	MODULE_DESCRIPTION("RDMA Transport for 9P");
	720	MODULE_LICENSE("Dual BSD/GPL");