[thirdparty/linux.git] / net / sunrpc / xprtrdma / svc_rdma_backchannel.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2015-2018 Oracle.  All rights reserved.
 *
 * Support for backward direction RPCs on RPC/RDMA (server-side).
 */

#include <linux/sunrpc/svc_rdma.h>

#include "xprt_rdma.h"
#include <trace/events/rpcrdma.h>

#define RPCDBG_FACILITY	RPCDBG_SVCXPRT

#undef SVCRDMA_BACKCHANNEL_DEBUG

/**
 * svc_rdma_handle_bc_reply - Process incoming backchannel reply
 * @xprt: controlling backchannel transport
 * @rdma_resp: pointer to incoming transport header
 * @rcvbuf: XDR buffer into which to decode the reply
 *
 * Returns:
 *	%0 if @rcvbuf is filled in, xprt_complete_rqst called,
 *	%-EAGAIN if server should call ->recvfrom again.
 */
int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt, __be32 *rdma_resp,
			     struct xdr_buf *rcvbuf)
{
	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
	struct kvec *dst, *src = &rcvbuf->head[0];
	struct rpc_rqst *req;
	u32 credits;
	size_t len;
	__be32 xid;
	__be32 *p;
	int ret;

	p = (__be32 *)src->iov_base;
	len = src->iov_len;
	xid = *rdma_resp;

#ifdef SVCRDMA_BACKCHANNEL_DEBUG
	pr_info("%s: xid=%08x, length=%zu\n",
		__func__, be32_to_cpu(xid), len);
	pr_info("%s: RPC/RDMA: %*ph\n",
		__func__, (int)RPCRDMA_HDRLEN_MIN, rdma_resp);
	pr_info("%s:      RPC: %*ph\n",
		__func__, (int)len, p);
#endif

	ret = -EAGAIN;
	if (src->iov_len < 24)
		goto out_shortreply;

	spin_lock(&xprt->queue_lock);
	req = xprt_lookup_rqst(xprt, xid);
	if (!req)
		goto out_notfound;

	dst = &req->rq_private_buf.head[0];
	memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(struct xdr_buf));
	if (dst->iov_len < len)
		goto out_unlock;
	memcpy(dst->iov_base, p, len);
	xprt_pin_rqst(req);
	spin_unlock(&xprt->queue_lock);

	credits = be32_to_cpup(rdma_resp + 2);
	if (credits == 0)
		credits = 1;	/* don't deadlock */
	else if (credits > r_xprt->rx_buf.rb_bc_max_requests)
		credits = r_xprt->rx_buf.rb_bc_max_requests;

	spin_lock(&xprt->transport_lock);
	xprt->cwnd = credits << RPC_CWNDSHIFT;
	spin_unlock(&xprt->transport_lock);

	spin_lock(&xprt->queue_lock);
	ret = 0;
	xprt_complete_rqst(req->rq_task, rcvbuf->len);
	xprt_unpin_rqst(req);
	rcvbuf->len = 0;

out_unlock:
	spin_unlock(&xprt->queue_lock);
out:
	return ret;

out_shortreply:
	dprintk("svcrdma: short bc reply: xprt=%p, len=%zu\n",
		xprt, src->iov_len);
	goto out;

out_notfound:
	dprintk("svcrdma: unrecognized bc reply: xprt=%p, xid=%08x\n",
		xprt, be32_to_cpu(xid));
	goto out_unlock;
}

/* Send a backwards direction RPC call.
 *
 * Caller holds the connection's mutex and has already marshaled
 * the RPC/RDMA request.
 *
 * This is similar to svc_rdma_send_reply_msg, but takes a struct
 * rpc_rqst instead, does not support chunks, and avoids blocking
 * memory allocation.
 *
 * XXX: There is still an opportunity to block in svc_rdma_send()
 * if there are no SQ entries to post the Send. This may occur if
 * the adapter has a small maximum SQ depth.
 */
static int svc_rdma_bc_sendto(struct svcxprt_rdma *rdma,
			      struct rpc_rqst *rqst,
			      struct svc_rdma_send_ctxt *ctxt)
{
	int ret;

	ret = svc_rdma_map_reply_msg(rdma, ctxt, NULL, &rqst->rq_snd_buf);
	if (ret < 0)
		return -EIO;

	/* Bump page refcnt so Send completion doesn't release
	 * the rq_buffer before all retransmits are complete.
	 */
	get_page(virt_to_page(rqst->rq_buffer));
	ctxt->sc_send_wr.opcode = IB_WR_SEND;
	return svc_rdma_send(rdma, &ctxt->sc_send_wr);
}

/* Server-side transport endpoint wants a whole page for its send
 * buffer. The client RPC code constructs the RPC header in this
 * buffer before it invokes ->send_request.
 */
static int
xprt_rdma_bc_allocate(struct rpc_task *task)
{
	struct rpc_rqst *rqst = task->tk_rqstp;
	size_t size = rqst->rq_callsize;
	struct page *page;

	if (size > PAGE_SIZE) {
		WARN_ONCE(1, "svcrdma: large bc buffer request (size %zu)\n",
			  size);
		return -EINVAL;
	}

	page = alloc_page(RPCRDMA_DEF_GFP);
	if (!page)
		return -ENOMEM;
	rqst->rq_buffer = page_address(page);

	rqst->rq_rbuffer = kmalloc(rqst->rq_rcvsize, RPCRDMA_DEF_GFP);
	if (!rqst->rq_rbuffer) {
		put_page(page);
		return -ENOMEM;
	}
	return 0;
}

static void
xprt_rdma_bc_free(struct rpc_task *task)
{
	struct rpc_rqst *rqst = task->tk_rqstp;

	put_page(virt_to_page(rqst->rq_buffer));
	kfree(rqst->rq_rbuffer);
}

static int
rpcrdma_bc_send_request(struct svcxprt_rdma *rdma, struct rpc_rqst *rqst)
{
	struct rpc_xprt *xprt = rqst->rq_xprt;
	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
	struct svc_rdma_send_ctxt *ctxt;
	__be32 *p;
	int rc;

	ctxt = svc_rdma_send_ctxt_get(rdma);
	if (!ctxt)
		goto drop_connection;

	p = xdr_reserve_space(&ctxt->sc_stream, RPCRDMA_HDRLEN_MIN);
	if (!p)
		goto put_ctxt;
	*p++ = rqst->rq_xid;
	*p++ = rpcrdma_version;
	*p++ = cpu_to_be32(r_xprt->rx_buf.rb_bc_max_requests);
	*p++ = rdma_msg;
	*p++ = xdr_zero;
	*p++ = xdr_zero;
	*p   = xdr_zero;

#ifdef SVCRDMA_BACKCHANNEL_DEBUG
	pr_info("%s: %*ph\n", __func__, 64, rqst->rq_buffer);
#endif

	rqst->rq_xtime = ktime_get();
	rc = svc_rdma_bc_sendto(rdma, rqst, ctxt);
	if (rc)
		goto put_ctxt;
	return 0;

put_ctxt:
	svc_rdma_send_ctxt_put(rdma, ctxt);

drop_connection:
	dprintk("svcrdma: failed to send bc call\n");
	return -ENOTCONN;
}

/* Send an RPC call on the passive end of a transport
 * connection.
 */
static int
xprt_rdma_bc_send_request(struct rpc_rqst *rqst)
{
	struct svc_xprt *sxprt = rqst->rq_xprt->bc_xprt;
	struct svcxprt_rdma *rdma;
	int ret;

	dprintk("svcrdma: sending bc call with xid: %08x\n",
		be32_to_cpu(rqst->rq_xid));

	mutex_lock(&sxprt->xpt_mutex);

	ret = -ENOTCONN;
	rdma = container_of(sxprt, struct svcxprt_rdma, sc_xprt);
	if (!test_bit(XPT_DEAD, &sxprt->xpt_flags)) {
		ret = rpcrdma_bc_send_request(rdma, rqst);
		if (ret == -ENOTCONN)
			svc_close_xprt(sxprt);
	}

	mutex_unlock(&sxprt->xpt_mutex);

	if (ret < 0)
		return ret;
	return 0;
}

static void
xprt_rdma_bc_close(struct rpc_xprt *xprt)
{
	dprintk("svcrdma: %s: xprt %p\n", __func__, xprt);

	xprt_disconnect_done(xprt);
	xprt->cwnd = RPC_CWNDSHIFT;
}

static void
xprt_rdma_bc_put(struct rpc_xprt *xprt)
{
	dprintk("svcrdma: %s: xprt %p\n", __func__, xprt);

	xprt_rdma_free_addresses(xprt);
	xprt_free(xprt);
}

static const struct rpc_xprt_ops xprt_rdma_bc_procs = {
	.reserve_xprt		= xprt_reserve_xprt_cong,
	.release_xprt		= xprt_release_xprt_cong,
	.alloc_slot		= xprt_alloc_slot,
	.free_slot		= xprt_free_slot,
	.release_request	= xprt_release_rqst_cong,
	.buf_alloc		= xprt_rdma_bc_allocate,
	.buf_free		= xprt_rdma_bc_free,
	.send_request		= xprt_rdma_bc_send_request,
	.wait_for_reply_request	= xprt_wait_for_reply_request_def,
	.close			= xprt_rdma_bc_close,
	.destroy		= xprt_rdma_bc_put,
	.print_stats		= xprt_rdma_print_stats
};

static const struct rpc_timeout xprt_rdma_bc_timeout = {
	.to_initval = 60 * HZ,
	.to_maxval = 60 * HZ,
};

/* It shouldn't matter if the number of backchannel session slots
 * doesn't match the number of RPC/RDMA credits. That just means
 * one or the other will have extra slots that aren't used.
 */
static struct rpc_xprt *
xprt_setup_rdma_bc(struct xprt_create *args)
{
	struct rpc_xprt *xprt;
	struct rpcrdma_xprt *new_xprt;

	if (args->addrlen > sizeof(xprt->addr)) {
		dprintk("RPC:       %s: address too large\n", __func__);
		return ERR_PTR(-EBADF);
	}

	xprt = xprt_alloc(args->net, sizeof(*new_xprt),
			  RPCRDMA_MAX_BC_REQUESTS,
			  RPCRDMA_MAX_BC_REQUESTS);
	if (!xprt) {
		dprintk("RPC:       %s: couldn't allocate rpc_xprt\n",
			__func__);
		return ERR_PTR(-ENOMEM);
	}

	xprt->timeout = &xprt_rdma_bc_timeout;
	xprt_set_bound(xprt);
	xprt_set_connected(xprt);
	xprt->bind_timeout = RPCRDMA_BIND_TO;
	xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
	xprt->idle_timeout = RPCRDMA_IDLE_DISC_TO;

	xprt->prot = XPRT_TRANSPORT_BC_RDMA;
	xprt->ops = &xprt_rdma_bc_procs;

	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
	xprt->addrlen = args->addrlen;
	xprt_rdma_format_addresses(xprt, (struct sockaddr *)&xprt->addr);
	xprt->resvport = 0;

	xprt->max_payload = xprt_rdma_max_inline_read;

	new_xprt = rpcx_to_rdmax(xprt);
	new_xprt->rx_buf.rb_bc_max_requests = xprt->max_reqs;

	xprt_get(xprt);
	args->bc_xprt->xpt_bc_xprt = xprt;
	xprt->bc_xprt = args->bc_xprt;

	/* Final put for backchannel xprt is in __svc_rdma_free */
	xprt_get(xprt);
	return xprt;
}

struct xprt_class xprt_rdma_bc = {
	.list			= LIST_HEAD_INIT(xprt_rdma_bc.list),
	.name			= "rdma backchannel",
	.owner			= THIS_MODULE,
	.ident			= XPRT_TRANSPORT_BC_RDMA,
	.setup			= xprt_setup_rdma_bc,
};
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
5d252f90	2	/*
4201c746	3	* Copyright (c) 2015-2018 Oracle. All rights reserved.
5d252f90 CL	4	*
	5	* Support for backward direction RPCs on RPC/RDMA (server-side).
	6	*/
	7
	8	#include <linux/sunrpc/svc_rdma.h>
bd2abef3	9
5d252f90	10	#include "xprt_rdma.h"
bd2abef3	11	#include <trace/events/rpcrdma.h>
5d252f90 CL	12
	13	#define RPCDBG_FACILITY RPCDBG_SVCXPRT
	14
	15	#undef SVCRDMA_BACKCHANNEL_DEBUG
	16
f5821c76 CL	17	/**
	18	* svc_rdma_handle_bc_reply - Process incoming backchannel reply
	19	* @xprt: controlling backchannel transport
	20	* @rdma_resp: pointer to incoming transport header
	21	* @rcvbuf: XDR buffer into which to decode the reply
	22	*
	23	* Returns:
	24	* %0 if @rcvbuf is filled in, xprt_complete_rqst called,
	25	* %-EAGAIN if server should call ->recvfrom again.
	26	*/
	27	int svc_rdma_handle_bc_reply(struct rpc_xprt xprt, __be32 rdma_resp,
5d252f90 CL	28	struct xdr_buf *rcvbuf)
	29	{
	30	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
	31	struct kvec dst, src = &rcvbuf->head[0];
	32	struct rpc_rqst *req;
5d252f90 CL	33	u32 credits;
	34	size_t len;
	35	__be32 xid;
	36	__be32 *p;
	37	int ret;
	38
	39	p = (__be32 *)src->iov_base;
	40	len = src->iov_len;
f5821c76	41	xid = *rdma_resp;
5d252f90 CL	42
	43	#ifdef SVCRDMA_BACKCHANNEL_DEBUG
	44	pr_info("%s: xid=%08x, length=%zu\n",
	45	__func__, be32_to_cpu(xid), len);
	46	pr_info("%s: RPC/RDMA: %*ph\n",
f5821c76	47	__func__, (int)RPCRDMA_HDRLEN_MIN, rdma_resp);
5d252f90 CL	48	pr_info("%s: RPC: %*ph\n",
	49	__func__, (int)len, p);
	50	#endif
	51
	52	ret = -EAGAIN;
	53	if (src->iov_len < 24)
	54	goto out_shortreply;
	55
75c84151	56	spin_lock(&xprt->queue_lock);
5d252f90 CL	57	req = xprt_lookup_rqst(xprt, xid);
	58	if (!req)
	59	goto out_notfound;
	60
	61	dst = &req->rq_private_buf.head[0];
	62	memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(struct xdr_buf));
	63	if (dst->iov_len < len)
	64	goto out_unlock;
	65	memcpy(dst->iov_base, p, len);
596f2a19	66	xprt_pin_rqst(req);
310c7585	67	spin_unlock(&xprt->queue_lock);
5d252f90	68
f5821c76	69	credits = be32_to_cpup(rdma_resp + 2);
5d252f90 CL	70	if (credits == 0)
	71	credits = 1; /* don't deadlock */
	72	else if (credits > r_xprt->rx_buf.rb_bc_max_requests)
	73	credits = r_xprt->rx_buf.rb_bc_max_requests;
	74
b5e92419	75	spin_lock(&xprt->transport_lock);
5d252f90	76	xprt->cwnd = credits << RPC_CWNDSHIFT;
b5e92419	77	spin_unlock(&xprt->transport_lock);
ce7c252a	78
310c7585	79	spin_lock(&xprt->queue_lock);
5d252f90 CL	80	ret = 0;
5d252f90 CL	81	xprt_complete_rqst(req->rq_task, rcvbuf->len);
596f2a19	82	xprt_unpin_rqst(req);
5d252f90 CL	83	rcvbuf->len = 0;
	84
	85	out_unlock:
75c84151	86	spin_unlock(&xprt->queue_lock);
5d252f90 CL	87	out:
	88	return ret;
	89
	90	out_shortreply:
	91	dprintk("svcrdma: short bc reply: xprt=%p, len=%zu\n",
	92	xprt, src->iov_len);
	93	goto out;
	94
	95	out_notfound:
	96	dprintk("svcrdma: unrecognized bc reply: xprt=%p, xid=%08x\n",
	97	xprt, be32_to_cpu(xid));
5d252f90 CL	98	goto out_unlock;
	99	}
	100
	101	/* Send a backwards direction RPC call.
	102	*
	103	* Caller holds the connection's mutex and has already marshaled
	104	* the RPC/RDMA request.
	105	*
9a6a180b CL	106	* This is similar to svc_rdma_send_reply_msg, but takes a struct
	107	* rpc_rqst instead, does not support chunks, and avoids blocking
	108	* memory allocation.
5d252f90 CL	109	*
	110	* XXX: There is still an opportunity to block in svc_rdma_send()
	111	* if there are no SQ entries to post the Send. This may occur if
	112	* the adapter has a small maximum SQ depth.
	113	*/
	114	static int svc_rdma_bc_sendto(struct svcxprt_rdma *rdma,
99722fe4 CL	115	struct rpc_rqst *rqst,
99722fe4 CL	116	struct svc_rdma_send_ctxt *ctxt)
5d252f90	117	{
5d252f90 CL	118	int ret;
5d252f90 CL	119
4554755e	120	ret = svc_rdma_map_reply_msg(rdma, ctxt, NULL, &rqst->rq_snd_buf);
6e6092ca	121	if (ret < 0)
99722fe4	122	return -EIO;
5d252f90	123
0bad47ca CL	124	/* Bump page refcnt so Send completion doesn't release
	125	* the rq_buffer before all retransmits are complete.
	126	*/
	127	get_page(virt_to_page(rqst->rq_buffer));
986b7889	128	ctxt->sc_send_wr.opcode = IB_WR_SEND;
99722fe4	129	return svc_rdma_send(rdma, &ctxt->sc_send_wr);
5d252f90 CL	130	}
	131
	132	/* Server-side transport endpoint wants a whole page for its send
	133	* buffer. The client RPC code constructs the RPC header in this
	134	* buffer before it invokes ->send_request.
5d252f90	135	*/
5fe6eaa1 CL	136	static int
5fe6eaa1 CL	137	xprt_rdma_bc_allocate(struct rpc_task *task)
5d252f90 CL	138	{
5d252f90 CL	139	struct rpc_rqst *rqst = task->tk_rqstp;
5fe6eaa1	140	size_t size = rqst->rq_callsize;
5d252f90 CL	141	struct page *page;
5d252f90 CL	142
5fe6eaa1	143	if (size > PAGE_SIZE) {
5d252f90 CL	144	WARN_ONCE(1, "svcrdma: large bc buffer request (size %zu)\n",
5d252f90 CL	145	size);
5fe6eaa1 CL	146	return -EINVAL;
5fe6eaa1 CL	147	}
5d252f90 CL	148
	149	page = alloc_page(RPCRDMA_DEF_GFP);
	150	if (!page)
5fe6eaa1	151	return -ENOMEM;
5fe6eaa1	152	rqst->rq_buffer = page_address(page);
8d42629b CL	153
	154	rqst->rq_rbuffer = kmalloc(rqst->rq_rcvsize, RPCRDMA_DEF_GFP);
	155	if (!rqst->rq_rbuffer) {
	156	put_page(page);
	157	return -ENOMEM;
	158	}
5fe6eaa1	159	return 0;
5d252f90 CL	160	}
	161
	162	static void
3435c74a	163	xprt_rdma_bc_free(struct rpc_task *task)
5d252f90	164	{
8d42629b CL	165	struct rpc_rqst *rqst = task->tk_rqstp;
8d42629b CL	166
0bad47ca	167	put_page(virt_to_page(rqst->rq_buffer));
8d42629b	168	kfree(rqst->rq_rbuffer);
5d252f90 CL	169	}
	170
	171	static int
	172	rpcrdma_bc_send_request(struct svcxprt_rdma rdma, struct rpc_rqst rqst)
	173	{
	174	struct rpc_xprt *xprt = rqst->rq_xprt;
	175	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
99722fe4	176	struct svc_rdma_send_ctxt *ctxt;
c2ccf64a	177	__be32 *p;
5d252f90 CL	178	int rc;
5d252f90 CL	179
99722fe4 CL	180	ctxt = svc_rdma_send_ctxt_get(rdma);
	181	if (!ctxt)
	182	goto drop_connection;
	183
6fd5034d CL	184	p = xdr_reserve_space(&ctxt->sc_stream, RPCRDMA_HDRLEN_MIN);
	185	if (!p)
	186	goto put_ctxt;
c2ccf64a CL	187	*p++ = rqst->rq_xid;
	188	*p++ = rpcrdma_version;
	189	*p++ = cpu_to_be32(r_xprt->rx_buf.rb_bc_max_requests);
	190	*p++ = rdma_msg;
	191	*p++ = xdr_zero;
	192	*p++ = xdr_zero;
	193	*p = xdr_zero;
5d252f90 CL	194
	195	#ifdef SVCRDMA_BACKCHANNEL_DEBUG
	196	pr_info("%s: %*ph\n", __func__, 64, rqst->rq_buffer);
	197	#endif
	198
8729aaba	199	rqst->rq_xtime = ktime_get();
99722fe4	200	rc = svc_rdma_bc_sendto(rdma, rqst, ctxt);
6fd5034d CL	201	if (rc)
6fd5034d CL	202	goto put_ctxt;
0c0829bc	203	return 0;
5d252f90	204
6fd5034d CL	205	put_ctxt:
	206	svc_rdma_send_ctxt_put(rdma, ctxt);
	207
5d252f90 CL	208	drop_connection:
5d252f90 CL	209	dprintk("svcrdma: failed to send bc call\n");
5d252f90 CL	210	return -ENOTCONN;
	211	}
	212
	213	/* Send an RPC call on the passive end of a transport
	214	* connection.
	215	*/
	216	static int
adfa7144	217	xprt_rdma_bc_send_request(struct rpc_rqst *rqst)
5d252f90	218	{
5d252f90 CL	219	struct svc_xprt *sxprt = rqst->rq_xprt->bc_xprt;
	220	struct svcxprt_rdma *rdma;
	221	int ret;
	222
	223	dprintk("svcrdma: sending bc call with xid: %08x\n",
	224	be32_to_cpu(rqst->rq_xid));
	225
c544577d	226	mutex_lock(&sxprt->xpt_mutex);
5d252f90 CL	227
	228	ret = -ENOTCONN;
	229	rdma = container_of(sxprt, struct svcxprt_rdma, sc_xprt);
0c0829bc	230	if (!test_bit(XPT_DEAD, &sxprt->xpt_flags)) {
5d252f90	231	ret = rpcrdma_bc_send_request(rdma, rqst);
0c0829bc CL	232	if (ret == -ENOTCONN)
	233	svc_close_xprt(sxprt);
	234	}
5d252f90 CL	235
	236	mutex_unlock(&sxprt->xpt_mutex);
	237
	238	if (ret < 0)
	239	return ret;
	240	return 0;
	241	}
	242
	243	static void
	244	xprt_rdma_bc_close(struct rpc_xprt *xprt)
	245	{
	246	dprintk("svcrdma: %s: xprt %p\n", __func__, xprt);
6221f1d9 CL	247
6221f1d9 CL	248	xprt_disconnect_done(xprt);
ef739b21	249	xprt->cwnd = RPC_CWNDSHIFT;
5d252f90 CL	250	}
	251
	252	static void
	253	xprt_rdma_bc_put(struct rpc_xprt *xprt)
	254	{
	255	dprintk("svcrdma: %s: xprt %p\n", __func__, xprt);
	256
1a33d8a2	257	xprt_rdma_free_addresses(xprt);
5d252f90	258	xprt_free(xprt);
5d252f90 CL	259	}
5d252f90 CL	260
d31ae254	261	static const struct rpc_xprt_ops xprt_rdma_bc_procs = {
5d252f90 CL	262	.reserve_xprt = xprt_reserve_xprt_cong,
	263	.release_xprt = xprt_release_xprt_cong,
	264	.alloc_slot = xprt_alloc_slot,
a9cde23a	265	.free_slot = xprt_free_slot,
5d252f90 CL	266	.release_request = xprt_release_rqst_cong,
	267	.buf_alloc = xprt_rdma_bc_allocate,
	268	.buf_free = xprt_rdma_bc_free,
	269	.send_request = xprt_rdma_bc_send_request,
8ba6a92d	270	.wait_for_reply_request = xprt_wait_for_reply_request_def,
5d252f90 CL	271	.close = xprt_rdma_bc_close,
	272	.destroy = xprt_rdma_bc_put,
	273	.print_stats = xprt_rdma_print_stats
	274	};
	275
	276	static const struct rpc_timeout xprt_rdma_bc_timeout = {
	277	.to_initval = 60 * HZ,
	278	.to_maxval = 60 * HZ,
	279	};
	280
	281	/* It shouldn't matter if the number of backchannel session slots
	282	* doesn't match the number of RPC/RDMA credits. That just means
	283	* one or the other will have extra slots that aren't used.
	284	*/
	285	static struct rpc_xprt *
	286	xprt_setup_rdma_bc(struct xprt_create *args)
	287	{
	288	struct rpc_xprt *xprt;
	289	struct rpcrdma_xprt *new_xprt;
	290
	291	if (args->addrlen > sizeof(xprt->addr)) {
	292	dprintk("RPC: %s: address too large\n", __func__);
	293	return ERR_PTR(-EBADF);
	294	}
	295
	296	xprt = xprt_alloc(args->net, sizeof(*new_xprt),
	297	RPCRDMA_MAX_BC_REQUESTS,
	298	RPCRDMA_MAX_BC_REQUESTS);
	299	if (!xprt) {
	300	dprintk("RPC: %s: couldn't allocate rpc_xprt\n",
	301	__func__);
	302	return ERR_PTR(-ENOMEM);
	303	}
	304
	305	xprt->timeout = &xprt_rdma_bc_timeout;
	306	xprt_set_bound(xprt);
	307	xprt_set_connected(xprt);
	308	xprt->bind_timeout = RPCRDMA_BIND_TO;
	309	xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
	310	xprt->idle_timeout = RPCRDMA_IDLE_DISC_TO;
	311
	312	xprt->prot = XPRT_TRANSPORT_BC_RDMA;
5d252f90 CL	313	xprt->ops = &xprt_rdma_bc_procs;
	314
	315	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
	316	xprt->addrlen = args->addrlen;
	317	xprt_rdma_format_addresses(xprt, (struct sockaddr *)&xprt->addr);
	318	xprt->resvport = 0;
	319
	320	xprt->max_payload = xprt_rdma_max_inline_read;
	321
	322	new_xprt = rpcx_to_rdmax(xprt);
	323	new_xprt->rx_buf.rb_bc_max_requests = xprt->max_reqs;
	324
	325	xprt_get(xprt);
	326	args->bc_xprt->xpt_bc_xprt = xprt;
	327	xprt->bc_xprt = args->bc_xprt;
	328
5d252f90 CL	329	/* Final put for backchannel xprt is in __svc_rdma_free */
	330	xprt_get(xprt);
	331	return xprt;
5d252f90 CL	332	}
	333
	334	struct xprt_class xprt_rdma_bc = {
	335	.list = LIST_HEAD_INIT(xprt_rdma_bc.list),
	336	.name = "rdma backchannel",
	337	.owner = THIS_MODULE,
	338	.ident = XPRT_TRANSPORT_BC_RDMA,
	339	.setup = xprt_setup_rdma_bc,
	340	};