[linux-2.6-block.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/module.h>

#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->recv_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->recv_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_bh(&xprt->transport_lock);
	xprt->cwnd = credits << RPC_CWNDSHIFT;
	spin_unlock_bh(&xprt->transport_lock);

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

out_unlock:
	spin_unlock(&xprt->recv_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, &rqst->rq_snd_buf, NULL);
	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 = ctxt->sc_xprt_buf;
	*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;
	svc_rdma_sync_reply_hdr(rdma, ctxt, RPCRDMA_HDRLEN_MIN);

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

	rc = svc_rdma_bc_sendto(rdma, rqst, ctxt);
	if (rc) {
		svc_rdma_send_ctxt_put(rdma, ctxt);
		goto drop_connection;
	}
	return rc;

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

/* Send an RPC call on the passive end of a transport
 * connection.
 */
static int
xprt_rdma_bc_send_request(struct rpc_task *task)
{
	struct rpc_rqst *rqst = task->tk_rqstp;
	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));

	if (!mutex_trylock(&sxprt->xpt_mutex)) {
		rpc_sleep_on(&sxprt->xpt_bc_pending, task, NULL);
		if (!mutex_trylock(&sxprt->xpt_mutex))
			return -EAGAIN;
		rpc_wake_up_queued_task(&sxprt->xpt_bc_pending, task);
	}

	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);

	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);
}

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

	xprt_free(xprt);
	module_put(THIS_MODULE);
}

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,
	.set_retrans_timeout	= xprt_set_retrans_timeout_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->tsh_size = 0;
	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;

	if (!try_module_get(THIS_MODULE))
		goto out_fail;

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

out_fail:
	xprt_rdma_free_addresses(xprt);
	args->bc_xprt->xpt_bc_xprt = NULL;
	args->bc_xprt->xpt_bc_xps = NULL;
	xprt_put(xprt);
	xprt_free(xprt);
	return ERR_PTR(-EINVAL);
}

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
f39b2dde	8	#include <linux/module.h>
bd2abef3	9
5d252f90	10	#include <linux/sunrpc/svc_rdma.h>
bd2abef3	11
5d252f90	12	#include "xprt_rdma.h"
bd2abef3	13	#include <trace/events/rpcrdma.h>
5d252f90 CL	14
	15	#define RPCDBG_FACILITY RPCDBG_SVCXPRT
	16
	17	#undef SVCRDMA_BACKCHANNEL_DEBUG
	18
f5821c76 CL	19	/**
	20	* svc_rdma_handle_bc_reply - Process incoming backchannel reply
	21	* @xprt: controlling backchannel transport
	22	* @rdma_resp: pointer to incoming transport header
	23	* @rcvbuf: XDR buffer into which to decode the reply
	24	*
	25	* Returns:
	26	* %0 if @rcvbuf is filled in, xprt_complete_rqst called,
	27	* %-EAGAIN if server should call ->recvfrom again.
	28	*/
	29	int svc_rdma_handle_bc_reply(struct rpc_xprt xprt, __be32 rdma_resp,
5d252f90 CL	30	struct xdr_buf *rcvbuf)
	31	{
	32	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
	33	struct kvec dst, src = &rcvbuf->head[0];
	34	struct rpc_rqst *req;
5d252f90 CL	35	u32 credits;
	36	size_t len;
	37	__be32 xid;
	38	__be32 *p;
	39	int ret;
	40
	41	p = (__be32 *)src->iov_base;
	42	len = src->iov_len;
f5821c76	43	xid = *rdma_resp;
5d252f90 CL	44
	45	#ifdef SVCRDMA_BACKCHANNEL_DEBUG
	46	pr_info("%s: xid=%08x, length=%zu\n",
	47	__func__, be32_to_cpu(xid), len);
	48	pr_info("%s: RPC/RDMA: %*ph\n",
f5821c76	49	__func__, (int)RPCRDMA_HDRLEN_MIN, rdma_resp);
5d252f90 CL	50	pr_info("%s: RPC: %*ph\n",
	51	__func__, (int)len, p);
	52	#endif
	53
	54	ret = -EAGAIN;
	55	if (src->iov_len < 24)
	56	goto out_shortreply;
	57
ce7c252a	58	spin_lock(&xprt->recv_lock);
5d252f90 CL	59	req = xprt_lookup_rqst(xprt, xid);
	60	if (!req)
	61	goto out_notfound;
	62
	63	dst = &req->rq_private_buf.head[0];
	64	memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(struct xdr_buf));
	65	if (dst->iov_len < len)
	66	goto out_unlock;
	67	memcpy(dst->iov_base, p, len);
596f2a19 CL	68	xprt_pin_rqst(req);
596f2a19 CL	69	spin_unlock(&xprt->recv_lock);
5d252f90	70
f5821c76	71	credits = be32_to_cpup(rdma_resp + 2);
5d252f90 CL	72	if (credits == 0)
	73	credits = 1; /* don't deadlock */
	74	else if (credits > r_xprt->rx_buf.rb_bc_max_requests)
	75	credits = r_xprt->rx_buf.rb_bc_max_requests;
	76
ce7c252a	77	spin_lock_bh(&xprt->transport_lock);
5d252f90	78	xprt->cwnd = credits << RPC_CWNDSHIFT;
ce7c252a TM	79	spin_unlock_bh(&xprt->transport_lock);
ce7c252a TM	80
596f2a19	81	spin_lock(&xprt->recv_lock);
5d252f90 CL	82	ret = 0;
5d252f90 CL	83	xprt_complete_rqst(req->rq_task, rcvbuf->len);
596f2a19	84	xprt_unpin_rqst(req);
5d252f90 CL	85	rcvbuf->len = 0;
	86
	87	out_unlock:
ce7c252a	88	spin_unlock(&xprt->recv_lock);
5d252f90 CL	89	out:
	90	return ret;
	91
	92	out_shortreply:
	93	dprintk("svcrdma: short bc reply: xprt=%p, len=%zu\n",
	94	xprt, src->iov_len);
	95	goto out;
	96
	97	out_notfound:
	98	dprintk("svcrdma: unrecognized bc reply: xprt=%p, xid=%08x\n",
	99	xprt, be32_to_cpu(xid));
5d252f90 CL	100	goto out_unlock;
	101	}
	102
	103	/* Send a backwards direction RPC call.
	104	*
	105	* Caller holds the connection's mutex and has already marshaled
	106	* the RPC/RDMA request.
	107	*
9a6a180b CL	108	* This is similar to svc_rdma_send_reply_msg, but takes a struct
	109	* rpc_rqst instead, does not support chunks, and avoids blocking
	110	* memory allocation.
5d252f90 CL	111	*
	112	* XXX: There is still an opportunity to block in svc_rdma_send()
	113	* if there are no SQ entries to post the Send. This may occur if
	114	* the adapter has a small maximum SQ depth.
	115	*/
	116	static int svc_rdma_bc_sendto(struct svcxprt_rdma *rdma,
99722fe4 CL	117	struct rpc_rqst *rqst,
99722fe4 CL	118	struct svc_rdma_send_ctxt *ctxt)
5d252f90	119	{
5d252f90 CL	120	int ret;
5d252f90 CL	121
99722fe4	122	ret = svc_rdma_map_reply_msg(rdma, ctxt, &rqst->rq_snd_buf, NULL);
6e6092ca	123	if (ret < 0)
99722fe4	124	return -EIO;
5d252f90	125
0bad47ca CL	126	/* Bump page refcnt so Send completion doesn't release
	127	* the rq_buffer before all retransmits are complete.
	128	*/
	129	get_page(virt_to_page(rqst->rq_buffer));
986b7889	130	ctxt->sc_send_wr.opcode = IB_WR_SEND;
99722fe4	131	return svc_rdma_send(rdma, &ctxt->sc_send_wr);
5d252f90 CL	132	}
	133
	134	/* Server-side transport endpoint wants a whole page for its send
	135	* buffer. The client RPC code constructs the RPC header in this
	136	* buffer before it invokes ->send_request.
5d252f90	137	*/
5fe6eaa1 CL	138	static int
5fe6eaa1 CL	139	xprt_rdma_bc_allocate(struct rpc_task *task)
5d252f90 CL	140	{
5d252f90 CL	141	struct rpc_rqst *rqst = task->tk_rqstp;
5fe6eaa1	142	size_t size = rqst->rq_callsize;
5d252f90 CL	143	struct page *page;
5d252f90 CL	144
5fe6eaa1	145	if (size > PAGE_SIZE) {
5d252f90 CL	146	WARN_ONCE(1, "svcrdma: large bc buffer request (size %zu)\n",
5d252f90 CL	147	size);
5fe6eaa1 CL	148	return -EINVAL;
5fe6eaa1 CL	149	}
5d252f90 CL	150
	151	page = alloc_page(RPCRDMA_DEF_GFP);
	152	if (!page)
5fe6eaa1	153	return -ENOMEM;
5fe6eaa1	154	rqst->rq_buffer = page_address(page);
8d42629b CL	155
	156	rqst->rq_rbuffer = kmalloc(rqst->rq_rcvsize, RPCRDMA_DEF_GFP);
	157	if (!rqst->rq_rbuffer) {
	158	put_page(page);
	159	return -ENOMEM;
	160	}
5fe6eaa1	161	return 0;
5d252f90 CL	162	}
	163
	164	static void
3435c74a	165	xprt_rdma_bc_free(struct rpc_task *task)
5d252f90	166	{
8d42629b CL	167	struct rpc_rqst *rqst = task->tk_rqstp;
8d42629b CL	168
0bad47ca	169	put_page(virt_to_page(rqst->rq_buffer));
8d42629b	170	kfree(rqst->rq_rbuffer);
5d252f90 CL	171	}
	172
	173	static int
	174	rpcrdma_bc_send_request(struct svcxprt_rdma rdma, struct rpc_rqst rqst)
	175	{
	176	struct rpc_xprt *xprt = rqst->rq_xprt;
	177	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
99722fe4	178	struct svc_rdma_send_ctxt *ctxt;
c2ccf64a	179	__be32 *p;
5d252f90 CL	180	int rc;
5d252f90 CL	181
99722fe4 CL	182	ctxt = svc_rdma_send_ctxt_get(rdma);
	183	if (!ctxt)
	184	goto drop_connection;
	185
	186	p = ctxt->sc_xprt_buf;
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;
99722fe4	194	svc_rdma_sync_reply_hdr(rdma, ctxt, RPCRDMA_HDRLEN_MIN);
5d252f90 CL	195
	196	#ifdef SVCRDMA_BACKCHANNEL_DEBUG
	197	pr_info("%s: %*ph\n", __func__, 64, rqst->rq_buffer);
	198	#endif
	199
99722fe4 CL	200	rc = svc_rdma_bc_sendto(rdma, rqst, ctxt);
	201	if (rc) {
	202	svc_rdma_send_ctxt_put(rdma, ctxt);
5d252f90	203	goto drop_connection;
99722fe4	204	}
5d252f90 CL	205	return rc;
	206
	207	drop_connection:
	208	dprintk("svcrdma: failed to send bc call\n");
	209	xprt_disconnect_done(xprt);
	210	return -ENOTCONN;
	211	}
	212
	213	/* Send an RPC call on the passive end of a transport
	214	* connection.
	215	*/
	216	static int
	217	xprt_rdma_bc_send_request(struct rpc_task *task)
	218	{
	219	struct rpc_rqst *rqst = task->tk_rqstp;
	220	struct svc_xprt *sxprt = rqst->rq_xprt->bc_xprt;
	221	struct svcxprt_rdma *rdma;
	222	int ret;
	223
	224	dprintk("svcrdma: sending bc call with xid: %08x\n",
	225	be32_to_cpu(rqst->rq_xid));
	226
	227	if (!mutex_trylock(&sxprt->xpt_mutex)) {
	228	rpc_sleep_on(&sxprt->xpt_bc_pending, task, NULL);
	229	if (!mutex_trylock(&sxprt->xpt_mutex))
	230	return -EAGAIN;
	231	rpc_wake_up_queued_task(&sxprt->xpt_bc_pending, task);
	232	}
	233
	234	ret = -ENOTCONN;
	235	rdma = container_of(sxprt, struct svcxprt_rdma, sc_xprt);
	236	if (!test_bit(XPT_DEAD, &sxprt->xpt_flags))
	237	ret = rpcrdma_bc_send_request(rdma, rqst);
	238
	239	mutex_unlock(&sxprt->xpt_mutex);
	240
	241	if (ret < 0)
	242	return ret;
	243	return 0;
	244	}
	245
	246	static void
	247	xprt_rdma_bc_close(struct rpc_xprt *xprt)
	248	{
	249	dprintk("svcrdma: %s: xprt %p\n", __func__, xprt);
	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
	257	xprt_free(xprt);
	258	module_put(THIS_MODULE);
	259	}
	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,
	270	.set_retrans_timeout = xprt_set_retrans_timeout_def,
	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;
99722fe4	313	xprt->tsh_size = 0;
5d252f90 CL	314	xprt->ops = &xprt_rdma_bc_procs;
	315
	316	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
	317	xprt->addrlen = args->addrlen;
	318	xprt_rdma_format_addresses(xprt, (struct sockaddr *)&xprt->addr);
	319	xprt->resvport = 0;
	320
	321	xprt->max_payload = xprt_rdma_max_inline_read;
	322
	323	new_xprt = rpcx_to_rdmax(xprt);
	324	new_xprt->rx_buf.rb_bc_max_requests = xprt->max_reqs;
	325
	326	xprt_get(xprt);
	327	args->bc_xprt->xpt_bc_xprt = xprt;
	328	xprt->bc_xprt = args->bc_xprt;
	329
	330	if (!try_module_get(THIS_MODULE))
	331	goto out_fail;
	332
	333	/* Final put for backchannel xprt is in __svc_rdma_free */
	334	xprt_get(xprt);
	335	return xprt;
	336
	337	out_fail:
	338	xprt_rdma_free_addresses(xprt);
	339	args->bc_xprt->xpt_bc_xprt = NULL;
1b9f700b	340	args->bc_xprt->xpt_bc_xps = NULL;
5d252f90 CL	341	xprt_put(xprt);
	342	xprt_free(xprt);
	343	return ERR_PTR(-EINVAL);
	344	}
	345
	346	struct xprt_class xprt_rdma_bc = {
	347	.list = LIST_HEAD_INIT(xprt_rdma_bc.list),
	348	.name = "rdma backchannel",
	349	.owner = THIS_MODULE,
	350	.ident = XPRT_TRANSPORT_BC_RDMA,
	351	.setup = xprt_setup_rdma_bc,
	352	};