SUNRPC/xprt: async tasks mustn't block waiting for memory

[mirror_ubuntu-jammy-kernel.git] / net / sunrpc / xprtrdma / transport.c

// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
 * Copyright (c) 2014-2017 Oracle.  All rights reserved.
 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the BSD-type
 * license below:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *      Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *      Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer in the documentation and/or other materials provided
 *      with the distribution.
 *
 *      Neither the name of the Network Appliance, Inc. nor the names of
 *      its contributors may be used to endorse or promote products
 *      derived from this software without specific prior written
 *      permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * transport.c
 *
 * This file contains the top-level implementation of an RPC RDMA
 * transport.
 *
 * Naming convention: functions beginning with xprt_ are part of the
 * transport switch. All others are RPC RDMA internal.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/smp.h>

#include <linux/sunrpc/addr.h>
#include <linux/sunrpc/svc_rdma.h>

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

#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY        RPCDBG_TRANS
#endif

/*
 * tunables
 */

static unsigned int xprt_rdma_slot_table_entries = RPCRDMA_DEF_SLOT_TABLE;
unsigned int xprt_rdma_max_inline_read = RPCRDMA_DEF_INLINE;
unsigned int xprt_rdma_max_inline_write = RPCRDMA_DEF_INLINE;
unsigned int xprt_rdma_memreg_strategy          = RPCRDMA_FRWR;
int xprt_rdma_pad_optimize;
static struct xprt_class xprt_rdma;

#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)

static unsigned int min_slot_table_size = RPCRDMA_MIN_SLOT_TABLE;
static unsigned int max_slot_table_size = RPCRDMA_MAX_SLOT_TABLE;
static unsigned int min_inline_size = RPCRDMA_MIN_INLINE;
static unsigned int max_inline_size = RPCRDMA_MAX_INLINE;
static unsigned int max_padding = PAGE_SIZE;
static unsigned int min_memreg = RPCRDMA_BOUNCEBUFFERS;
static unsigned int max_memreg = RPCRDMA_LAST - 1;
static unsigned int dummy;

static struct ctl_table_header *sunrpc_table_header;

static struct ctl_table xr_tunables_table[] = {
        {
                .procname       = "rdma_slot_table_entries",
                .data           = &xprt_rdma_slot_table_entries,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &min_slot_table_size,
                .extra2         = &max_slot_table_size
        },
        {
                .procname       = "rdma_max_inline_read",
                .data           = &xprt_rdma_max_inline_read,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &min_inline_size,
                .extra2         = &max_inline_size,
        },
        {
                .procname       = "rdma_max_inline_write",
                .data           = &xprt_rdma_max_inline_write,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &min_inline_size,
                .extra2         = &max_inline_size,
        },
        {
                .procname       = "rdma_inline_write_padding",
                .data           = &dummy,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = SYSCTL_ZERO,
                .extra2         = &max_padding,
        },
        {
                .procname       = "rdma_memreg_strategy",
                .data           = &xprt_rdma_memreg_strategy,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &min_memreg,
                .extra2         = &max_memreg,
        },
        {
                .procname       = "rdma_pad_optimize",
                .data           = &xprt_rdma_pad_optimize,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        { },
};

static struct ctl_table sunrpc_table[] = {
        {
                .procname       = "sunrpc",
                .mode           = 0555,
                .child          = xr_tunables_table
        },
        { },
};

#endif

static const struct rpc_xprt_ops xprt_rdma_procs;

static void
xprt_rdma_format_addresses4(struct rpc_xprt *xprt, struct sockaddr *sap)
{
        struct sockaddr_in *sin = (struct sockaddr_in *)sap;
        char buf[20];

        snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
        xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);

        xprt->address_strings[RPC_DISPLAY_NETID] = RPCBIND_NETID_RDMA;
}

static void
xprt_rdma_format_addresses6(struct rpc_xprt *xprt, struct sockaddr *sap)
{
        struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
        char buf[40];

        snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
        xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);

        xprt->address_strings[RPC_DISPLAY_NETID] = RPCBIND_NETID_RDMA6;
}

void
xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap)
{
        char buf[128];

        switch (sap->sa_family) {
        case AF_INET:
                xprt_rdma_format_addresses4(xprt, sap);
                break;
        case AF_INET6:
                xprt_rdma_format_addresses6(xprt, sap);
                break;
        default:
                pr_err("rpcrdma: Unrecognized address family\n");
                return;
        }

        (void)rpc_ntop(sap, buf, sizeof(buf));
        xprt->address_strings[RPC_DISPLAY_ADDR] = kstrdup(buf, GFP_KERNEL);

        snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
        xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);

        snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
        xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);

        xprt->address_strings[RPC_DISPLAY_PROTO] = "rdma";
}

void
xprt_rdma_free_addresses(struct rpc_xprt *xprt)
{
        unsigned int i;

        for (i = 0; i < RPC_DISPLAY_MAX; i++)
                switch (i) {
                case RPC_DISPLAY_PROTO:
                case RPC_DISPLAY_NETID:
                        continue;
                default:
                        kfree(xprt->address_strings[i]);
                }
}

/**
 * xprt_rdma_connect_worker - establish connection in the background
 * @work: worker thread context
 *
 * Requester holds the xprt's send lock to prevent activity on this
 * transport while a fresh connection is being established. RPC tasks
 * sleep on the xprt's pending queue waiting for connect to complete.
 */
static void
xprt_rdma_connect_worker(struct work_struct *work)
{
        struct rpcrdma_xprt *r_xprt = container_of(work, struct rpcrdma_xprt,
                                                   rx_connect_worker.work);
        struct rpc_xprt *xprt = &r_xprt->rx_xprt;
        int rc;

        rc = rpcrdma_xprt_connect(r_xprt);
        xprt_clear_connecting(xprt);
        if (!rc) {
                xprt->connect_cookie++;
                xprt->stat.connect_count++;
                xprt->stat.connect_time += (long)jiffies -
                                           xprt->stat.connect_start;
                xprt_set_connected(xprt);
                rc = -EAGAIN;
        } else
                rpcrdma_xprt_disconnect(r_xprt);
        xprt_unlock_connect(xprt, r_xprt);
        xprt_wake_pending_tasks(xprt, rc);
}

/**
 * xprt_rdma_inject_disconnect - inject a connection fault
 * @xprt: transport context
 *
 * If @xprt is connected, disconnect it to simulate spurious
 * connection loss. Caller must hold @xprt's send lock to
 * ensure that data structures and hardware resources are
 * stable during the rdma_disconnect() call.
 */
static void
xprt_rdma_inject_disconnect(struct rpc_xprt *xprt)
{
        struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);

        trace_xprtrdma_op_inject_dsc(r_xprt);
        rdma_disconnect(r_xprt->rx_ep->re_id);
}

/**
 * xprt_rdma_destroy - Full tear down of transport
 * @xprt: doomed transport context
 *
 * Caller guarantees there will be no more calls to us with
 * this @xprt.
 */
static void
xprt_rdma_destroy(struct rpc_xprt *xprt)
{
        struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);

        cancel_delayed_work_sync(&r_xprt->rx_connect_worker);

        rpcrdma_xprt_disconnect(r_xprt);
        rpcrdma_buffer_destroy(&r_xprt->rx_buf);

        xprt_rdma_free_addresses(xprt);
        xprt_free(xprt);

        module_put(THIS_MODULE);
}

/* 60 second timeout, no retries */
static const struct rpc_timeout xprt_rdma_default_timeout = {
        .to_initval = 60 * HZ,
        .to_maxval = 60 * HZ,
};

/**
 * xprt_setup_rdma - Set up transport to use RDMA
 *
 * @args: rpc transport arguments
 */
static struct rpc_xprt *
xprt_setup_rdma(struct xprt_create *args)
{
        struct rpc_xprt *xprt;
        struct rpcrdma_xprt *new_xprt;
        struct sockaddr *sap;
        int rc;

        if (args->addrlen > sizeof(xprt->addr))
                return ERR_PTR(-EBADF);

        if (!try_module_get(THIS_MODULE))
                return ERR_PTR(-EIO);

        xprt = xprt_alloc(args->net, sizeof(struct rpcrdma_xprt), 0,
                          xprt_rdma_slot_table_entries);
        if (!xprt) {
                module_put(THIS_MODULE);
                return ERR_PTR(-ENOMEM);
        }

        xprt->timeout = &xprt_rdma_default_timeout;
        xprt->connect_timeout = xprt->timeout->to_initval;
        xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
        xprt->bind_timeout = RPCRDMA_BIND_TO;
        xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
        xprt->idle_timeout = RPCRDMA_IDLE_DISC_TO;

        xprt->resvport = 0;             /* privileged port not needed */
        xprt->ops = &xprt_rdma_procs;

        /*
         * Set up RDMA-specific connect data.
         */
        sap = args->dstaddr;

        /* Ensure xprt->addr holds valid server TCP (not RDMA)
         * address, for any side protocols which peek at it */
        xprt->prot = IPPROTO_TCP;
        xprt->xprt_class = &xprt_rdma;
        xprt->addrlen = args->addrlen;
        memcpy(&xprt->addr, sap, xprt->addrlen);

        if (rpc_get_port(sap))
                xprt_set_bound(xprt);
        xprt_rdma_format_addresses(xprt, sap);

        new_xprt = rpcx_to_rdmax(xprt);
        rc = rpcrdma_buffer_create(new_xprt);
        if (rc) {
                xprt_rdma_free_addresses(xprt);
                xprt_free(xprt);
                module_put(THIS_MODULE);
                return ERR_PTR(rc);
        }

        INIT_DELAYED_WORK(&new_xprt->rx_connect_worker,
                          xprt_rdma_connect_worker);

        xprt->max_payload = RPCRDMA_MAX_DATA_SEGS << PAGE_SHIFT;

        return xprt;
}

/**
 * xprt_rdma_close - close a transport connection
 * @xprt: transport context
 *
 * Called during autoclose or device removal.
 *
 * Caller holds @xprt's send lock to prevent activity on this
 * transport while the connection is torn down.
 */
void xprt_rdma_close(struct rpc_xprt *xprt)
{
        struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);

        rpcrdma_xprt_disconnect(r_xprt);

        xprt->reestablish_timeout = 0;
        ++xprt->connect_cookie;
        xprt_disconnect_done(xprt);
}

/**
 * xprt_rdma_set_port - update server port with rpcbind result
 * @xprt: controlling RPC transport
 * @port: new port value
 *
 * Transport connect status is unchanged.
 */
static void
xprt_rdma_set_port(struct rpc_xprt *xprt, u16 port)
{
        struct sockaddr *sap = (struct sockaddr *)&xprt->addr;
        char buf[8];

        rpc_set_port(sap, port);

        kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
        snprintf(buf, sizeof(buf), "%u", port);
        xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);

        kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
        snprintf(buf, sizeof(buf), "%4hx", port);
        xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
}

/**
 * xprt_rdma_timer - invoked when an RPC times out
 * @xprt: controlling RPC transport
 * @task: RPC task that timed out
 *
 * Invoked when the transport is still connected, but an RPC
 * retransmit timeout occurs.
 *
 * Since RDMA connections don't have a keep-alive, forcibly
 * disconnect and retry to connect. This drives full
 * detection of the network path, and retransmissions of
 * all pending RPCs.
 */
static void
xprt_rdma_timer(struct rpc_xprt *xprt, struct rpc_task *task)
{
        xprt_force_disconnect(xprt);
}

/**
 * xprt_rdma_set_connect_timeout - set timeouts for establishing a connection
 * @xprt: controlling transport instance
 * @connect_timeout: reconnect timeout after client disconnects
 * @reconnect_timeout: reconnect timeout after server disconnects
 *
 */
static void xprt_rdma_set_connect_timeout(struct rpc_xprt *xprt,
                                          unsigned long connect_timeout,
                                          unsigned long reconnect_timeout)
{
        struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);

        trace_xprtrdma_op_set_cto(r_xprt, connect_timeout, reconnect_timeout);

        spin_lock(&xprt->transport_lock);

        if (connect_timeout < xprt->connect_timeout) {
                struct rpc_timeout to;
                unsigned long initval;

                to = *xprt->timeout;
                initval = connect_timeout;
                if (initval < RPCRDMA_INIT_REEST_TO << 1)
                        initval = RPCRDMA_INIT_REEST_TO << 1;
                to.to_initval = initval;
                to.to_maxval = initval;
                r_xprt->rx_timeout = to;
                xprt->timeout = &r_xprt->rx_timeout;
                xprt->connect_timeout = connect_timeout;
        }

        if (reconnect_timeout < xprt->max_reconnect_timeout)
                xprt->max_reconnect_timeout = reconnect_timeout;

        spin_unlock(&xprt->transport_lock);
}

/**
 * xprt_rdma_connect - schedule an attempt to reconnect
 * @xprt: transport state
 * @task: RPC scheduler context (unused)
 *
 */
static void
xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
{
        struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
        struct rpcrdma_ep *ep = r_xprt->rx_ep;
        unsigned long delay;

        WARN_ON_ONCE(!xprt_lock_connect(xprt, task, r_xprt));

        delay = 0;
        if (ep && ep->re_connect_status != 0) {
                delay = xprt_reconnect_delay(xprt);
                xprt_reconnect_backoff(xprt, RPCRDMA_INIT_REEST_TO);
        }
        trace_xprtrdma_op_connect(r_xprt, delay);
        queue_delayed_work(xprtiod_workqueue, &r_xprt->rx_connect_worker,
                           delay);
}

/**
 * xprt_rdma_alloc_slot - allocate an rpc_rqst
 * @xprt: controlling RPC transport
 * @task: RPC task requesting a fresh rpc_rqst
 *
 * tk_status values:
 *      %0 if task->tk_rqstp points to a fresh rpc_rqst
 *      %-EAGAIN if no rpc_rqst is available; queued on backlog
 */
static void
xprt_rdma_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task)
{
        struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
        struct rpcrdma_req *req;

        req = rpcrdma_buffer_get(&r_xprt->rx_buf);
        if (!req)
                goto out_sleep;
        task->tk_rqstp = &req->rl_slot;
        task->tk_status = 0;
        return;

out_sleep:
        task->tk_status = -ENOMEM;
        xprt_add_backlog(xprt, task);
}

/**
 * xprt_rdma_free_slot - release an rpc_rqst
 * @xprt: controlling RPC transport
 * @rqst: rpc_rqst to release
 *
 */
static void
xprt_rdma_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *rqst)
{
        struct rpcrdma_xprt *r_xprt =
                container_of(xprt, struct rpcrdma_xprt, rx_xprt);

        rpcrdma_reply_put(&r_xprt->rx_buf, rpcr_to_rdmar(rqst));
        if (!xprt_wake_up_backlog(xprt, rqst)) {
                memset(rqst, 0, sizeof(*rqst));
                rpcrdma_buffer_put(&r_xprt->rx_buf, rpcr_to_rdmar(rqst));
        }
}

static bool rpcrdma_check_regbuf(struct rpcrdma_xprt *r_xprt,
                                 struct rpcrdma_regbuf *rb, size_t size,
                                 gfp_t flags)
{
        if (unlikely(rdmab_length(rb) < size)) {
                if (!rpcrdma_regbuf_realloc(rb, size, flags))
                        return false;
                r_xprt->rx_stats.hardway_register_count += size;
        }
        return true;
}

/**
 * xprt_rdma_allocate - allocate transport resources for an RPC
 * @task: RPC task
 *
 * Return values:
 *        0:    Success; rq_buffer points to RPC buffer to use
 *   ENOMEM:    Out of memory, call again later
 *      EIO:    A permanent error occurred, do not retry
 */
static int
xprt_rdma_allocate(struct rpc_task *task)
{
        struct rpc_rqst *rqst = task->tk_rqstp;
        struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
        struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
        gfp_t flags;

        flags = RPCRDMA_DEF_GFP;
        if (RPC_IS_ASYNC(task))
                flags = GFP_NOWAIT | __GFP_NOWARN;
        if (RPC_IS_SWAPPER(task))
                flags |= __GFP_MEMALLOC;

        if (!rpcrdma_check_regbuf(r_xprt, req->rl_sendbuf, rqst->rq_callsize,
                                  flags))
                goto out_fail;
        if (!rpcrdma_check_regbuf(r_xprt, req->rl_recvbuf, rqst->rq_rcvsize,
                                  flags))
                goto out_fail;

        rqst->rq_buffer = rdmab_data(req->rl_sendbuf);
        rqst->rq_rbuffer = rdmab_data(req->rl_recvbuf);
        return 0;

out_fail:
        return -ENOMEM;
}

/**
 * xprt_rdma_free - release resources allocated by xprt_rdma_allocate
 * @task: RPC task
 *
 * Caller guarantees rqst->rq_buffer is non-NULL.
 */
static void
xprt_rdma_free(struct rpc_task *task)
{
        struct rpc_rqst *rqst = task->tk_rqstp;
        struct rpcrdma_req *req = rpcr_to_rdmar(rqst);

        if (unlikely(!list_empty(&req->rl_registered))) {
                trace_xprtrdma_mrs_zap(task);
                frwr_unmap_sync(rpcx_to_rdmax(rqst->rq_xprt), req);
        }

        /* XXX: If the RPC is completing because of a signal and
         * not because a reply was received, we ought to ensure
         * that the Send completion has fired, so that memory
         * involved with the Send is not still visible to the NIC.
         */
}

/**
 * xprt_rdma_send_request - marshal and send an RPC request
 * @rqst: RPC message in rq_snd_buf
 *
 * Caller holds the transport's write lock.
 *
 * Returns:
 *      %0 if the RPC message has been sent
 *      %-ENOTCONN if the caller should reconnect and call again
 *      %-EAGAIN if the caller should call again
 *      %-ENOBUFS if the caller should call again after a delay
 *      %-EMSGSIZE if encoding ran out of buffer space. The request
 *              was not sent. Do not try to send this message again.
 *      %-EIO if an I/O error occurred. The request was not sent.
 *              Do not try to send this message again.
 */
static int
xprt_rdma_send_request(struct rpc_rqst *rqst)
{
        struct rpc_xprt *xprt = rqst->rq_xprt;
        struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
        struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
        int rc = 0;

#if defined(CONFIG_SUNRPC_BACKCHANNEL)
        if (unlikely(!rqst->rq_buffer))
                return xprt_rdma_bc_send_reply(rqst);
#endif  /* CONFIG_SUNRPC_BACKCHANNEL */

        if (!xprt_connected(xprt))
                return -ENOTCONN;

        if (!xprt_request_get_cong(xprt, rqst))
                return -EBADSLT;

        rc = rpcrdma_marshal_req(r_xprt, rqst);
        if (rc < 0)
                goto failed_marshal;

        /* Must suppress retransmit to maintain credits */
        if (rqst->rq_connect_cookie == xprt->connect_cookie)
                goto drop_connection;
        rqst->rq_xtime = ktime_get();

        if (frwr_send(r_xprt, req))
                goto drop_connection;

        rqst->rq_xmit_bytes_sent += rqst->rq_snd_buf.len;

        /* An RPC with no reply will throw off credit accounting,
         * so drop the connection to reset the credit grant.
         */
        if (!rpc_reply_expected(rqst->rq_task))
                goto drop_connection;
        return 0;

failed_marshal:
        if (rc != -ENOTCONN)
                return rc;
drop_connection:
        xprt_rdma_close(xprt);
        return -ENOTCONN;
}

void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
{
        struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
        long idle_time = 0;

        if (xprt_connected(xprt))
                idle_time = (long)(jiffies - xprt->last_used) / HZ;

        seq_puts(seq, "\txprt:\trdma ");
        seq_printf(seq, "%u %lu %lu %lu %ld %lu %lu %lu %llu %llu ",
                   0,   /* need a local port? */
                   xprt->stat.bind_count,
                   xprt->stat.connect_count,
                   xprt->stat.connect_time / HZ,
                   idle_time,
                   xprt->stat.sends,
                   xprt->stat.recvs,
                   xprt->stat.bad_xids,
                   xprt->stat.req_u,
                   xprt->stat.bklog_u);
        seq_printf(seq, "%lu %lu %lu %llu %llu %llu %llu %lu %lu %lu %lu ",
                   r_xprt->rx_stats.read_chunk_count,
                   r_xprt->rx_stats.write_chunk_count,
                   r_xprt->rx_stats.reply_chunk_count,
                   r_xprt->rx_stats.total_rdma_request,
                   r_xprt->rx_stats.total_rdma_reply,
                   r_xprt->rx_stats.pullup_copy_count,
                   r_xprt->rx_stats.fixup_copy_count,
                   r_xprt->rx_stats.hardway_register_count,
                   r_xprt->rx_stats.failed_marshal_count,
                   r_xprt->rx_stats.bad_reply_count,
                   r_xprt->rx_stats.nomsg_call_count);
        seq_printf(seq, "%lu %lu %lu %lu %lu %lu\n",
                   r_xprt->rx_stats.mrs_recycled,
                   r_xprt->rx_stats.mrs_orphaned,
                   r_xprt->rx_stats.mrs_allocated,
                   r_xprt->rx_stats.local_inv_needed,
                   r_xprt->rx_stats.empty_sendctx_q,
                   r_xprt->rx_stats.reply_waits_for_send);
}

static int
xprt_rdma_enable_swap(struct rpc_xprt *xprt)
{
        return 0;
}

static void
xprt_rdma_disable_swap(struct rpc_xprt *xprt)
{
}

/*
 * Plumbing for rpc transport switch and kernel module
 */

static const struct rpc_xprt_ops xprt_rdma_procs = {
        .reserve_xprt           = xprt_reserve_xprt_cong,
        .release_xprt           = xprt_release_xprt_cong, /* sunrpc/xprt.c */
        .alloc_slot             = xprt_rdma_alloc_slot,
        .free_slot              = xprt_rdma_free_slot,
        .release_request        = xprt_release_rqst_cong,       /* ditto */
        .wait_for_reply_request = xprt_wait_for_reply_request_def, /* ditto */
        .timer                  = xprt_rdma_timer,
        .rpcbind                = rpcb_getport_async,   /* sunrpc/rpcb_clnt.c */
        .set_port               = xprt_rdma_set_port,
        .connect                = xprt_rdma_connect,
        .buf_alloc              = xprt_rdma_allocate,
        .buf_free               = xprt_rdma_free,
        .send_request           = xprt_rdma_send_request,
        .close                  = xprt_rdma_close,
        .destroy                = xprt_rdma_destroy,
        .set_connect_timeout    = xprt_rdma_set_connect_timeout,
        .print_stats            = xprt_rdma_print_stats,
        .enable_swap            = xprt_rdma_enable_swap,
        .disable_swap           = xprt_rdma_disable_swap,
        .inject_disconnect      = xprt_rdma_inject_disconnect,
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
        .bc_setup               = xprt_rdma_bc_setup,
        .bc_maxpayload          = xprt_rdma_bc_maxpayload,
        .bc_num_slots           = xprt_rdma_bc_max_slots,
        .bc_free_rqst           = xprt_rdma_bc_free_rqst,
        .bc_destroy             = xprt_rdma_bc_destroy,
#endif
};

static struct xprt_class xprt_rdma = {
        .list                   = LIST_HEAD_INIT(xprt_rdma.list),
        .name                   = "rdma",
        .owner                  = THIS_MODULE,
        .ident                  = XPRT_TRANSPORT_RDMA,
        .setup                  = xprt_setup_rdma,
        .netid                  = { "rdma", "rdma6", "" },
};

void xprt_rdma_cleanup(void)
{
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
        if (sunrpc_table_header) {
                unregister_sysctl_table(sunrpc_table_header);
                sunrpc_table_header = NULL;
        }
#endif

        xprt_unregister_transport(&xprt_rdma);
        xprt_unregister_transport(&xprt_rdma_bc);
}

int xprt_rdma_init(void)
{
        int rc;

        rc = xprt_register_transport(&xprt_rdma);
        if (rc)
                return rc;

        rc = xprt_register_transport(&xprt_rdma_bc);
        if (rc) {
                xprt_unregister_transport(&xprt_rdma);
                return rc;
        }

#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
        if (!sunrpc_table_header)
                sunrpc_table_header = register_sysctl_table(sunrpc_table);
#endif
        return 0;
}