// SPDX-License-Identifier: GPL-2.0
/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * 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 version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, 2015, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lnet/selftest/rpc.c
 *
 * Author: Isaac Huang <isaac@clusterfs.com>
 *
 * 2012-05-13: Liang Zhen <liang@whamcloud.com>
 * - percpt data for service to improve smp performance
 * - code cleanup
 */

#define DEBUG_SUBSYSTEM S_LNET

#include "selftest.h"

enum srpc_state {
        SRPC_STATE_NONE,
        SRPC_STATE_NI_INIT,
        SRPC_STATE_EQ_INIT,
        SRPC_STATE_RUNNING,
        SRPC_STATE_STOPPING,
};

static struct smoketest_rpc {
        spinlock_t       rpc_glock;     /* global lock */
        struct srpc_service     *rpc_services[SRPC_SERVICE_MAX_ID + 1];
        struct lnet_handle_eq    rpc_lnet_eq;   /* _the_ LNet event queue */
        enum srpc_state  rpc_state;
        struct srpc_counters     rpc_counters;
        __u64            rpc_matchbits; /* matchbits counter */
} srpc_data;

static inline int
srpc_serv_portal(int svc_id)
{
        return svc_id < SRPC_FRAMEWORK_SERVICE_MAX_ID ?
               SRPC_FRAMEWORK_REQUEST_PORTAL : SRPC_REQUEST_PORTAL;
}

/* forward ref's */
void srpc_handle_rpc(struct swi_workitem *wi);

void srpc_get_counters(struct srpc_counters *cnt)
{
        spin_lock(&srpc_data.rpc_glock);
        *cnt = srpc_data.rpc_counters;
        spin_unlock(&srpc_data.rpc_glock);
}

void srpc_set_counters(const struct srpc_counters *cnt)
{
        spin_lock(&srpc_data.rpc_glock);
        srpc_data.rpc_counters = *cnt;
        spin_unlock(&srpc_data.rpc_glock);
}

static int
srpc_add_bulk_page(struct srpc_bulk *bk, struct page *pg, int i, int off,
                   int nob)
{
        LASSERT(off < PAGE_SIZE);
        LASSERT(nob > 0 && nob <= PAGE_SIZE);

        bk->bk_iovs[i].bv_offset = off;
        bk->bk_iovs[i].bv_page = pg;
        bk->bk_iovs[i].bv_len = nob;
        return nob;
}

void
srpc_free_bulk(struct srpc_bulk *bk)
{
        int i;
        struct page *pg;

        LASSERT(bk);

        for (i = 0; i < bk->bk_niov; i++) {
                pg = bk->bk_iovs[i].bv_page;
                if (!pg)
                        break;

                __free_page(pg);
        }

        kfree(bk);
}

struct srpc_bulk *
srpc_alloc_bulk(int cpt, unsigned int bulk_off, unsigned int bulk_npg,
                unsigned int bulk_len, int sink)
{
        struct srpc_bulk *bk;
        int i;

        LASSERT(bulk_npg > 0 && bulk_npg <= LNET_MAX_IOV);

        bk = kzalloc_cpt(offsetof(struct srpc_bulk, bk_iovs[bulk_npg]),
                         GFP_KERNEL, cpt);
        if (!bk) {
                CERROR("Can't allocate descriptor for %d pages\n", bulk_npg);
                return NULL;
        }

        memset(bk, 0, offsetof(struct srpc_bulk, bk_iovs[bulk_npg]));
        bk->bk_sink = sink;
        bk->bk_len = bulk_len;
        bk->bk_niov = bulk_npg;

        for (i = 0; i < bulk_npg; i++) {
                struct page *pg;
                int nob;

                pg = alloc_pages_node(cfs_cpt_spread_node(lnet_cpt_table(), cpt),
                                      GFP_KERNEL, 0);
                if (!pg) {
                        CERROR("Can't allocate page %d of %d\n", i, bulk_npg);
                        srpc_free_bulk(bk);
                        return NULL;
                }

                nob = min_t(unsigned int, bulk_off + bulk_len, PAGE_SIZE) -
                      bulk_off;
                srpc_add_bulk_page(bk, pg, i, bulk_off, nob);
                bulk_len -= nob;
                bulk_off = 0;
        }

        return bk;
}

static inline __u64
srpc_next_id(void)
{
        __u64 id;

        spin_lock(&srpc_data.rpc_glock);
        id = srpc_data.rpc_matchbits++;
        spin_unlock(&srpc_data.rpc_glock);
        return id;
}

static void
srpc_init_server_rpc(struct srpc_server_rpc *rpc,
                     struct srpc_service_cd *scd,
                     struct srpc_buffer *buffer)
{
        memset(rpc, 0, sizeof(*rpc));
        swi_init_workitem(&rpc->srpc_wi, srpc_handle_rpc,
                          srpc_serv_is_framework(scd->scd_svc) ?
                          lst_serial_wq : lst_test_wq[scd->scd_cpt]);

        rpc->srpc_ev.ev_fired = 1; /* no event expected now */

        rpc->srpc_scd = scd;
        rpc->srpc_reqstbuf = buffer;
        rpc->srpc_peer = buffer->buf_peer;
        rpc->srpc_self = buffer->buf_self;
        LNetInvalidateMDHandle(&rpc->srpc_replymdh);
}

static void
srpc_service_fini(struct srpc_service *svc)
{
        struct srpc_service_cd *scd;
        struct srpc_server_rpc *rpc;
        struct srpc_buffer *buf;
        struct list_head *q;
        int i;

        if (!svc->sv_cpt_data)
                return;

        cfs_percpt_for_each(scd, i, svc->sv_cpt_data) {
                while (1) {
                        if (!list_empty(&scd->scd_buf_posted))
                                q = &scd->scd_buf_posted;
                        else if (!list_empty(&scd->scd_buf_blocked))
                                q = &scd->scd_buf_blocked;
                        else
                                break;

                        while (!list_empty(q)) {
                                buf = list_entry(q->next, struct srpc_buffer,
                                                 buf_list);
                                list_del(&buf->buf_list);
                                kfree(buf);
                        }
                }

                LASSERT(list_empty(&scd->scd_rpc_active));

                while (!list_empty(&scd->scd_rpc_free)) {
                        rpc = list_entry(scd->scd_rpc_free.next,
                                         struct srpc_server_rpc,
                                         srpc_list);
                        list_del(&rpc->srpc_list);
                        kfree(rpc);
                }
        }

        cfs_percpt_free(svc->sv_cpt_data);
        svc->sv_cpt_data = NULL;
}

static int
srpc_service_nrpcs(struct srpc_service *svc)
{
        int nrpcs = svc->sv_wi_total / svc->sv_ncpts;

        return srpc_serv_is_framework(svc) ?
               max(nrpcs, SFW_FRWK_WI_MIN) : max(nrpcs, SFW_TEST_WI_MIN);
}

void srpc_add_buffer(struct swi_workitem *wi);

static int
srpc_service_init(struct srpc_service *svc)
{
        struct srpc_service_cd *scd;
        struct srpc_server_rpc *rpc;
        int nrpcs;
        int i;
        int j;

        svc->sv_shuttingdown = 0;

        svc->sv_cpt_data = cfs_percpt_alloc(lnet_cpt_table(),
                                            sizeof(**svc->sv_cpt_data));
        if (!svc->sv_cpt_data)
                return -ENOMEM;

        svc->sv_ncpts = srpc_serv_is_framework(svc) ?
                        1 : cfs_cpt_number(lnet_cpt_table());
        nrpcs = srpc_service_nrpcs(svc);

        cfs_percpt_for_each(scd, i, svc->sv_cpt_data) {
                scd->scd_cpt = i;
                scd->scd_svc = svc;
                spin_lock_init(&scd->scd_lock);
                INIT_LIST_HEAD(&scd->scd_rpc_free);
                INIT_LIST_HEAD(&scd->scd_rpc_active);
                INIT_LIST_HEAD(&scd->scd_buf_posted);
                INIT_LIST_HEAD(&scd->scd_buf_blocked);

                scd->scd_ev.ev_data = scd;
                scd->scd_ev.ev_type = SRPC_REQUEST_RCVD;

                /*
                 * NB: don't use lst_serial_wq for adding buffer,
                 * see details in srpc_service_add_buffers()
                 */
                swi_init_workitem(&scd->scd_buf_wi,
                                  srpc_add_buffer, lst_test_wq[i]);

                if (i && srpc_serv_is_framework(svc)) {
                        /*
                         * NB: framework service only needs srpc_service_cd for
                         * one partition, but we allocate for all to make
                         * it easier to implement, it will waste a little
                         * memory but nobody should care about this
                         */
                        continue;
                }

                for (j = 0; j < nrpcs; j++) {
                        rpc = kzalloc_cpt(sizeof(*rpc), GFP_NOFS, i);
                        if (!rpc) {
                                srpc_service_fini(svc);
                                return -ENOMEM;
                        }
                        list_add(&rpc->srpc_list, &scd->scd_rpc_free);
                }
        }

        return 0;
}

int
srpc_add_service(struct srpc_service *sv)
{
        int id = sv->sv_id;

        LASSERT(0 <= id && id <= SRPC_SERVICE_MAX_ID);

        if (srpc_service_init(sv))
                return -ENOMEM;

        spin_lock(&srpc_data.rpc_glock);

        LASSERT(srpc_data.rpc_state == SRPC_STATE_RUNNING);

        if (srpc_data.rpc_services[id]) {
                spin_unlock(&srpc_data.rpc_glock);
                goto failed;
        }

        srpc_data.rpc_services[id] = sv;
        spin_unlock(&srpc_data.rpc_glock);

        CDEBUG(D_NET, "Adding service: id %d, name %s\n", id, sv->sv_name);
        return 0;

 failed:
        srpc_service_fini(sv);
        return -EBUSY;
}

int
srpc_remove_service(struct srpc_service *sv)
{
        int id = sv->sv_id;

        spin_lock(&srpc_data.rpc_glock);

        if (srpc_data.rpc_services[id] != sv) {
                spin_unlock(&srpc_data.rpc_glock);
                return -ENOENT;
        }

        srpc_data.rpc_services[id] = NULL;
        spin_unlock(&srpc_data.rpc_glock);
        return 0;
}

static int
srpc_post_passive_rdma(int portal, int local, __u64 matchbits, void *buf,
                       int len, int options, struct lnet_process_id peer,
                       struct lnet_handle_md *mdh, struct srpc_event *ev)
{
        int rc;
        struct lnet_md md;
        struct lnet_handle_me meh;

        rc = LNetMEAttach(portal, peer, matchbits, 0, LNET_UNLINK,
                          local ? LNET_INS_LOCAL : LNET_INS_AFTER, &meh);
        if (rc) {
                CERROR("LNetMEAttach failed: %d\n", rc);
                LASSERT(rc == -ENOMEM);
                return -ENOMEM;
        }

        md.threshold = 1;
        md.user_ptr = ev;
        md.start = buf;
        md.length = len;
        md.options = options;
        md.eq_handle = srpc_data.rpc_lnet_eq;

        rc = LNetMDAttach(meh, md, LNET_UNLINK, mdh);
        if (rc) {
                CERROR("LNetMDAttach failed: %d\n", rc);
                LASSERT(rc == -ENOMEM);

                rc = LNetMEUnlink(meh);
                LASSERT(!rc);
                return -ENOMEM;
        }

        CDEBUG(D_NET, "Posted passive RDMA: peer %s, portal %d, matchbits %#llx\n",
               libcfs_id2str(peer), portal, matchbits);
        return 0;
}

static int
srpc_post_active_rdma(int portal, __u64 matchbits, void *buf, int len,
                      int options, struct lnet_process_id peer,
                      lnet_nid_t self, struct lnet_handle_md *mdh,
                      struct srpc_event *ev)
{
        int rc;
        struct lnet_md md;

        md.user_ptr = ev;
        md.start = buf;
        md.length = len;
        md.eq_handle = srpc_data.rpc_lnet_eq;
        md.threshold = options & LNET_MD_OP_GET ? 2 : 1;
        md.options = options & ~(LNET_MD_OP_PUT | LNET_MD_OP_GET);

        rc = LNetMDBind(md, LNET_UNLINK, mdh);
        if (rc) {
                CERROR("LNetMDBind failed: %d\n", rc);
                LASSERT(rc == -ENOMEM);
                return -ENOMEM;
        }

        /*
         * this is kind of an abuse of the LNET_MD_OP_{PUT,GET} options.
         * they're only meaningful for MDs attached to an ME (i.e. passive
         * buffers...
         */
        if (options & LNET_MD_OP_PUT) {
                rc = LNetPut(self, *mdh, LNET_NOACK_REQ, peer,
                             portal, matchbits, 0, 0);
        } else {
                LASSERT(options & LNET_MD_OP_GET);

                rc = LNetGet(self, *mdh, peer, portal, matchbits, 0);
        }

        if (rc) {
                CERROR("LNet%s(%s, %d, %lld) failed: %d\n",
                       options & LNET_MD_OP_PUT ? "Put" : "Get",
                       libcfs_id2str(peer), portal, matchbits, rc);

                /*
                 * The forthcoming unlink event will complete this operation
                 * with failure, so fall through and return success here.
                 */
                rc = LNetMDUnlink(*mdh);
                LASSERT(!rc);
        } else {
                CDEBUG(D_NET, "Posted active RDMA: peer %s, portal %u, matchbits %#llx\n",
                       libcfs_id2str(peer), portal, matchbits);
        }
        return 0;
}

static int
srpc_post_passive_rqtbuf(int service, int local, void *buf, int len,
                         struct lnet_handle_md *mdh, struct srpc_event *ev)
{
        struct lnet_process_id any = { 0 };

        any.nid = LNET_NID_ANY;
        any.pid = LNET_PID_ANY;

        return srpc_post_passive_rdma(srpc_serv_portal(service),
                                      local, service, buf, len,
                                      LNET_MD_OP_PUT, any, mdh, ev);
}

static int
srpc_service_post_buffer(struct srpc_service_cd *scd, struct srpc_buffer *buf)
__must_hold(&scd->scd_lock)
{
        struct srpc_service *sv = scd->scd_svc;
        struct srpc_msg *msg = &buf->buf_msg;
        int rc;

        LNetInvalidateMDHandle(&buf->buf_mdh);
        list_add(&buf->buf_list, &scd->scd_buf_posted);
        scd->scd_buf_nposted++;
        spin_unlock(&scd->scd_lock);

        rc = srpc_post_passive_rqtbuf(sv->sv_id,
                                      !srpc_serv_is_framework(sv),
                                      msg, sizeof(*msg), &buf->buf_mdh,
                                      &scd->scd_ev);

        /*
         * At this point, a RPC (new or delayed) may have arrived in
         * msg and its event handler has been called. So we must add
         * buf to scd_buf_posted _before_ dropping scd_lock
         */
        spin_lock(&scd->scd_lock);

        if (!rc) {
                if (!sv->sv_shuttingdown)
                        return 0;

                spin_unlock(&scd->scd_lock);
                /*
                 * srpc_shutdown_service might have tried to unlink me
                 * when my buf_mdh was still invalid
                 */
                LNetMDUnlink(buf->buf_mdh);
                spin_lock(&scd->scd_lock);
                return 0;
        }

        scd->scd_buf_nposted--;
        if (sv->sv_shuttingdown)
                return rc; /* don't allow to change scd_buf_posted */

        list_del(&buf->buf_list);
        spin_unlock(&scd->scd_lock);

        kfree(buf);

        spin_lock(&scd->scd_lock);
        return rc;
}

void
srpc_add_buffer(struct swi_workitem *wi)
{
        struct srpc_service_cd *scd = container_of(wi, struct srpc_service_cd, scd_buf_wi);
        struct srpc_buffer *buf;
        int rc = 0;

        /*
         * it's called by workitem scheduler threads, these threads
         * should have been set CPT affinity, so buffers will be posted
         * on CPT local list of Portal
         */
        spin_lock(&scd->scd_lock);

        while (scd->scd_buf_adjust > 0 &&
               !scd->scd_svc->sv_shuttingdown) {
                scd->scd_buf_adjust--; /* consume it */
                scd->scd_buf_posting++;

                spin_unlock(&scd->scd_lock);

                buf = kzalloc(sizeof(*buf), GFP_NOFS);
                if (!buf) {
                        CERROR("Failed to add new buf to service: %s\n",
                               scd->scd_svc->sv_name);
                        spin_lock(&scd->scd_lock);
                        rc = -ENOMEM;
                        break;
                }

                spin_lock(&scd->scd_lock);
                if (scd->scd_svc->sv_shuttingdown) {
                        spin_unlock(&scd->scd_lock);
                        kfree(buf);

                        spin_lock(&scd->scd_lock);
                        rc = -ESHUTDOWN;
                        break;
                }

                rc = srpc_service_post_buffer(scd, buf);
                if (rc)
                        break; /* buf has been freed inside */

                LASSERT(scd->scd_buf_posting > 0);
                scd->scd_buf_posting--;
                scd->scd_buf_total++;
                scd->scd_buf_low = max(2, scd->scd_buf_total / 4);
        }

        if (rc) {
                scd->scd_buf_err_stamp = ktime_get_real_seconds();
                scd->scd_buf_err = rc;

                LASSERT(scd->scd_buf_posting > 0);
                scd->scd_buf_posting--;
        }

        spin_unlock(&scd->scd_lock);
}

int
srpc_service_add_buffers(struct srpc_service *sv, int nbuffer)
{
        struct srpc_service_cd *scd;
        int rc = 0;
        int i;

        LASSERTF(nbuffer > 0, "nbuffer must be positive: %d\n", nbuffer);

        cfs_percpt_for_each(scd, i, sv->sv_cpt_data) {
                spin_lock(&scd->scd_lock);

                scd->scd_buf_err = 0;
                scd->scd_buf_err_stamp = 0;
                scd->scd_buf_posting = 0;
                scd->scd_buf_adjust = nbuffer;
                /* start to post buffers */
                swi_schedule_workitem(&scd->scd_buf_wi);
                spin_unlock(&scd->scd_lock);

                /* framework service only post buffer for one partition  */
                if (srpc_serv_is_framework(sv))
                        break;
        }

        cfs_percpt_for_each(scd, i, sv->sv_cpt_data) {
                spin_lock(&scd->scd_lock);
                /*
                 * NB: srpc_service_add_buffers() can be called inside
                 * thread context of lst_serial_wq, and we don't normally
                 * allow to sleep inside thread context of WI scheduler
                 * because it will block current scheduler thread from doing
                 * anything else, even worse, it could deadlock if it's
                 * waiting on result from another WI of the same scheduler.
                 * However, it's safe at here because scd_buf_wi is scheduled
                 * by thread in a different WI scheduler (lst_test_wq),
                 * so we don't have any risk of deadlock, though this could
                 * block all WIs pending on lst_serial_wq for a moment
                 * which is not good but not fatal.
                 */
                lst_wait_until(scd->scd_buf_err ||
                               (!scd->scd_buf_adjust &&
                                !scd->scd_buf_posting),
                               scd->scd_lock, "waiting for adding buffer\n");

                if (scd->scd_buf_err && !rc)
                        rc = scd->scd_buf_err;

                spin_unlock(&scd->scd_lock);
        }

        return rc;
}

void
srpc_service_remove_buffers(struct srpc_service *sv, int nbuffer)
{
        struct srpc_service_cd *scd;
        int num;
        int i;

        LASSERT(!sv->sv_shuttingdown);

        cfs_percpt_for_each(scd, i, sv->sv_cpt_data) {
                spin_lock(&scd->scd_lock);

                num = scd->scd_buf_total + scd->scd_buf_posting;
                scd->scd_buf_adjust -= min(nbuffer, num);

                spin_unlock(&scd->scd_lock);
        }
}

/* returns 1 if sv has finished, otherwise 0 */
int
srpc_finish_service(struct srpc_service *sv)
{
        struct srpc_service_cd *scd;
        struct srpc_server_rpc *rpc;
        int i;

        LASSERT(sv->sv_shuttingdown); /* srpc_shutdown_service called */

        cfs_percpt_for_each(scd, i, sv->sv_cpt_data) {
                swi_cancel_workitem(&scd->scd_buf_wi);

                spin_lock(&scd->scd_lock);

                if (scd->scd_buf_nposted > 0) {
                        CDEBUG(D_NET, "waiting for %d posted buffers to unlink\n",
                               scd->scd_buf_nposted);
                        spin_unlock(&scd->scd_lock);
                        return 0;
                }

                if (list_empty(&scd->scd_rpc_active)) {
                        spin_unlock(&scd->scd_lock);
                        continue;
                }

                rpc = list_entry(scd->scd_rpc_active.next,
                                 struct srpc_server_rpc, srpc_list);
                CNETERR("Active RPC %p on shutdown: sv %s, peer %s, wi %s, ev fired %d type %d status %d lnet %d\n",
                        rpc, sv->sv_name, libcfs_id2str(rpc->srpc_peer),
                        swi_state2str(rpc->srpc_wi.swi_state),
                        rpc->srpc_ev.ev_fired, rpc->srpc_ev.ev_type,
                        rpc->srpc_ev.ev_status, rpc->srpc_ev.ev_lnet);
                spin_unlock(&scd->scd_lock);
                return 0;
        }

        /* no lock needed from now on */
        srpc_service_fini(sv);
        return 1;
}

/* called with sv->sv_lock held */
static void
srpc_service_recycle_buffer(struct srpc_service_cd *scd,
                            struct srpc_buffer *buf)
__must_hold(&scd->scd_lock)
{
        if (!scd->scd_svc->sv_shuttingdown && scd->scd_buf_adjust >= 0) {
                if (srpc_service_post_buffer(scd, buf)) {
                        CWARN("Failed to post %s buffer\n",
                              scd->scd_svc->sv_name);
                }
                return;
        }

        /* service is shutting down, or we want to recycle some buffers */
        scd->scd_buf_total--;

        if (scd->scd_buf_adjust < 0) {
                scd->scd_buf_adjust++;
                if (scd->scd_buf_adjust < 0 &&
                    !scd->scd_buf_total && !scd->scd_buf_posting) {
                        CDEBUG(D_INFO,
                               "Try to recycle %d buffers but nothing left\n",
                               scd->scd_buf_adjust);
                        scd->scd_buf_adjust = 0;
                }
        }

        spin_unlock(&scd->scd_lock);
        kfree(buf);
        spin_lock(&scd->scd_lock);
}

void
srpc_abort_service(struct srpc_service *sv)
{
        struct srpc_service_cd *scd;
        struct srpc_server_rpc *rpc;
        int i;

        CDEBUG(D_NET, "Aborting service: id %d, name %s\n",
               sv->sv_id, sv->sv_name);

        cfs_percpt_for_each(scd, i, sv->sv_cpt_data) {
                spin_lock(&scd->scd_lock);

                /*
                 * schedule in-flight RPCs to notice the abort, NB:
                 * racing with incoming RPCs; complete fix should make test
                 * RPCs carry session ID in its headers
                 */
                list_for_each_entry(rpc, &scd->scd_rpc_active, srpc_list) {
                        rpc->srpc_aborted = 1;
                        swi_schedule_workitem(&rpc->srpc_wi);
                }

                spin_unlock(&scd->scd_lock);
        }
}

void
srpc_shutdown_service(struct srpc_service *sv)
{
        struct srpc_service_cd *scd;
        struct srpc_server_rpc *rpc;
        struct srpc_buffer *buf;
        int i;

        CDEBUG(D_NET, "Shutting down service: id %d, name %s\n",
               sv->sv_id, sv->sv_name);

        cfs_percpt_for_each(scd, i, sv->sv_cpt_data)
                spin_lock(&scd->scd_lock);

        sv->sv_shuttingdown = 1; /* i.e. no new active RPC */

        cfs_percpt_for_each(scd, i, sv->sv_cpt_data)
                spin_unlock(&scd->scd_lock);

        cfs_percpt_for_each(scd, i, sv->sv_cpt_data) {
                spin_lock(&scd->scd_lock);

                /* schedule in-flight RPCs to notice the shutdown */
                list_for_each_entry(rpc, &scd->scd_rpc_active, srpc_list)
                        swi_schedule_workitem(&rpc->srpc_wi);

                spin_unlock(&scd->scd_lock);

                /*
                 * OK to traverse scd_buf_posted without lock, since no one
                 * touches scd_buf_posted now
                 */
                list_for_each_entry(buf, &scd->scd_buf_posted, buf_list)
                        LNetMDUnlink(buf->buf_mdh);
        }
}

static int
srpc_send_request(struct srpc_client_rpc *rpc)
{
        struct srpc_event *ev = &rpc->crpc_reqstev;
        int rc;

        ev->ev_fired = 0;
        ev->ev_data = rpc;
        ev->ev_type = SRPC_REQUEST_SENT;

         rc = srpc_post_active_rdma(srpc_serv_portal(rpc->crpc_service),
                                    rpc->crpc_service, &rpc->crpc_reqstmsg,
                                    sizeof(struct srpc_msg), LNET_MD_OP_PUT,
                                    rpc->crpc_dest, LNET_NID_ANY,
                                    &rpc->crpc_reqstmdh, ev);
        if (rc) {
                LASSERT(rc == -ENOMEM);
                ev->ev_fired = 1;  /* no more event expected */
        }
        return rc;
}

static int
srpc_prepare_reply(struct srpc_client_rpc *rpc)
{
        struct srpc_event *ev = &rpc->crpc_replyev;
        __u64 *id = &rpc->crpc_reqstmsg.msg_body.reqst.rpyid;
        int rc;

        ev->ev_fired = 0;
        ev->ev_data = rpc;
        ev->ev_type = SRPC_REPLY_RCVD;

        *id = srpc_next_id();

        rc = srpc_post_passive_rdma(SRPC_RDMA_PORTAL, 0, *id,
                                    &rpc->crpc_replymsg,
                                    sizeof(struct srpc_msg),
                                    LNET_MD_OP_PUT, rpc->crpc_dest,
                                    &rpc->crpc_replymdh, ev);
        if (rc) {
                LASSERT(rc == -ENOMEM);
                ev->ev_fired = 1;  /* no more event expected */
        }
        return rc;
}

static int
srpc_prepare_bulk(struct srpc_client_rpc *rpc)
{
        struct srpc_bulk *bk = &rpc->crpc_bulk;
        struct srpc_event *ev = &rpc->crpc_bulkev;
        __u64 *id = &rpc->crpc_reqstmsg.msg_body.reqst.bulkid;
        int rc;
        int opt;

        LASSERT(bk->bk_niov <= LNET_MAX_IOV);

        if (!bk->bk_niov)
                return 0; /* nothing to do */

        opt = bk->bk_sink ? LNET_MD_OP_PUT : LNET_MD_OP_GET;
        opt |= LNET_MD_KIOV;

        ev->ev_fired = 0;
        ev->ev_data = rpc;
        ev->ev_type = SRPC_BULK_REQ_RCVD;

        *id = srpc_next_id();

        rc = srpc_post_passive_rdma(SRPC_RDMA_PORTAL, 0, *id,
                                    &bk->bk_iovs[0], bk->bk_niov, opt,
                                    rpc->crpc_dest, &bk->bk_mdh, ev);
        if (rc) {
                LASSERT(rc == -ENOMEM);
                ev->ev_fired = 1;  /* no more event expected */
        }
        return rc;
}

static int
srpc_do_bulk(struct srpc_server_rpc *rpc)
{
        struct srpc_event *ev = &rpc->srpc_ev;
        struct srpc_bulk *bk = rpc->srpc_bulk;
        __u64 id = rpc->srpc_reqstbuf->buf_msg.msg_body.reqst.bulkid;
        int rc;
        int opt;

        LASSERT(bk);

        opt = bk->bk_sink ? LNET_MD_OP_GET : LNET_MD_OP_PUT;
        opt |= LNET_MD_KIOV;

        ev->ev_fired = 0;
        ev->ev_data = rpc;
        ev->ev_type = bk->bk_sink ? SRPC_BULK_GET_RPLD : SRPC_BULK_PUT_SENT;

        rc = srpc_post_active_rdma(SRPC_RDMA_PORTAL, id,
                                   &bk->bk_iovs[0], bk->bk_niov, opt,
                                   rpc->srpc_peer, rpc->srpc_self,
                                   &bk->bk_mdh, ev);
        if (rc)
                ev->ev_fired = 1;  /* no more event expected */
        return rc;
}

/* only called from srpc_handle_rpc */
static void
srpc_server_rpc_done(struct srpc_server_rpc *rpc, int status)
{
        struct srpc_service_cd *scd = rpc->srpc_scd;
        struct srpc_service *sv = scd->scd_svc;
        struct srpc_buffer *buffer;

        LASSERT(status || rpc->srpc_wi.swi_state == SWI_STATE_DONE);

        rpc->srpc_status = status;

        CDEBUG_LIMIT(!status ? D_NET : D_NETERROR,
                     "Server RPC %p done: service %s, peer %s, status %s:%d\n",
                     rpc, sv->sv_name, libcfs_id2str(rpc->srpc_peer),
                     swi_state2str(rpc->srpc_wi.swi_state), status);

        if (status) {
                spin_lock(&srpc_data.rpc_glock);
                srpc_data.rpc_counters.rpcs_dropped++;
                spin_unlock(&srpc_data.rpc_glock);
        }

        if (rpc->srpc_done)
                (*rpc->srpc_done) (rpc);
        LASSERT(!rpc->srpc_bulk);

        spin_lock(&scd->scd_lock);

        if (rpc->srpc_reqstbuf) {
                /*
                 * NB might drop sv_lock in srpc_service_recycle_buffer, but
                 * sv won't go away for scd_rpc_active must not be empty
                 */
                srpc_service_recycle_buffer(scd, rpc->srpc_reqstbuf);
                rpc->srpc_reqstbuf = NULL;
        }

        list_del(&rpc->srpc_list); /* from scd->scd_rpc_active */

        /*
         * No one can schedule me now since:
         * - I'm not on scd_rpc_active.
         * - all LNet events have been fired.
         * Cancel pending schedules and prevent future schedule attempts:
         */
        LASSERT(rpc->srpc_ev.ev_fired);

        if (!sv->sv_shuttingdown && !list_empty(&scd->scd_buf_blocked)) {
                buffer = list_entry(scd->scd_buf_blocked.next,
                                    struct srpc_buffer, buf_list);
                list_del(&buffer->buf_list);

                srpc_init_server_rpc(rpc, scd, buffer);
                list_add_tail(&rpc->srpc_list, &scd->scd_rpc_active);
                swi_schedule_workitem(&rpc->srpc_wi);
        } else {
                list_add(&rpc->srpc_list, &scd->scd_rpc_free);
        }

        spin_unlock(&scd->scd_lock);
}

/* handles an incoming RPC */
void
srpc_handle_rpc(struct swi_workitem *wi)
{
        struct srpc_server_rpc *rpc = container_of(wi, struct srpc_server_rpc, srpc_wi);
        struct srpc_service_cd *scd = rpc->srpc_scd;
        struct srpc_service *sv = scd->scd_svc;
        struct srpc_event *ev = &rpc->srpc_ev;
        int rc = 0;

        LASSERT(wi == &rpc->srpc_wi);

        spin_lock(&scd->scd_lock);

        if (sv->sv_shuttingdown || rpc->srpc_aborted) {
                spin_unlock(&scd->scd_lock);

                if (rpc->srpc_bulk)
                        LNetMDUnlink(rpc->srpc_bulk->bk_mdh);
                LNetMDUnlink(rpc->srpc_replymdh);

                if (ev->ev_fired) { /* no more event, OK to finish */
                        srpc_server_rpc_done(rpc, -ESHUTDOWN);
                }
                return;
        }

        spin_unlock(&scd->scd_lock);

        switch (wi->swi_state) {
        default:
                LBUG();
        case SWI_STATE_NEWBORN: {
                struct srpc_msg *msg;
                struct srpc_generic_reply *reply;

                msg = &rpc->srpc_reqstbuf->buf_msg;
                reply = &rpc->srpc_replymsg.msg_body.reply;

                if (!msg->msg_magic) {
                        /* moaned already in srpc_lnet_ev_handler */

                        srpc_server_rpc_done(rpc, EBADMSG);
                        return;
                }

                srpc_unpack_msg_hdr(msg);
                if (msg->msg_version != SRPC_MSG_VERSION) {
                        CWARN("Version mismatch: %u, %u expected, from %s\n",
                              msg->msg_version, SRPC_MSG_VERSION,
                              libcfs_id2str(rpc->srpc_peer));
                        reply->status = EPROTO;
                        /* drop through and send reply */
                } else {
                        reply->status = 0;
                        rc = (*sv->sv_handler)(rpc);
                        LASSERT(!reply->status || !rpc->srpc_bulk);
                        if (rc) {
                                srpc_server_rpc_done(rpc, rc);
                                return;
                        }
                }

                wi->swi_state = SWI_STATE_BULK_STARTED;

                if (rpc->srpc_bulk) {
                        rc = srpc_do_bulk(rpc);
                        if (!rc)
                                return; /* wait for bulk */

                        LASSERT(ev->ev_fired);
                        ev->ev_status = rc;
                }
        }
                /* fall through */
        case SWI_STATE_BULK_STARTED:
                LASSERT(!rpc->srpc_bulk || ev->ev_fired);

                if (rpc->srpc_bulk) {
                        rc = ev->ev_status;

                        if (sv->sv_bulk_ready)
                                rc = (*sv->sv_bulk_ready) (rpc, rc);

                        if (rc) {
                                srpc_server_rpc_done(rpc, rc);
                                return;
                        }
                }

                wi->swi_state = SWI_STATE_REPLY_SUBMITTED;
                rc = srpc_send_reply(rpc);
                if (!rc)
                        return; /* wait for reply */
                srpc_server_rpc_done(rpc, rc);
                return;

        case SWI_STATE_REPLY_SUBMITTED:
                if (!ev->ev_fired) {
                        CERROR("RPC %p: bulk %p, service %d\n",
                               rpc, rpc->srpc_bulk, sv->sv_id);
                        CERROR("Event: status %d, type %d, lnet %d\n",
                               ev->ev_status, ev->ev_type, ev->ev_lnet);
                        LASSERT(ev->ev_fired);
                }

                wi->swi_state = SWI_STATE_DONE;
                srpc_server_rpc_done(rpc, ev->ev_status);
                return;
        }
}

static void
srpc_client_rpc_expired(void *data)
{
        struct srpc_client_rpc *rpc = data;

        CWARN("Client RPC expired: service %d, peer %s, timeout %d.\n",
              rpc->crpc_service, libcfs_id2str(rpc->crpc_dest),
              rpc->crpc_timeout);

        spin_lock(&rpc->crpc_lock);

        rpc->crpc_timeout = 0;
        srpc_abort_rpc(rpc, -ETIMEDOUT);

        spin_unlock(&rpc->crpc_lock);

        spin_lock(&srpc_data.rpc_glock);
        srpc_data.rpc_counters.rpcs_expired++;
        spin_unlock(&srpc_data.rpc_glock);
}

static void
srpc_add_client_rpc_timer(struct srpc_client_rpc *rpc)
{
        struct stt_timer *timer = &rpc->crpc_timer;

        if (!rpc->crpc_timeout)
                return;

        INIT_LIST_HEAD(&timer->stt_list);
        timer->stt_data = rpc;
        timer->stt_func = srpc_client_rpc_expired;
        timer->stt_expires = ktime_get_real_seconds() + rpc->crpc_timeout;
        stt_add_timer(timer);
}

/*
 * Called with rpc->crpc_lock held.
 *
 * Upon exit the RPC expiry timer is not queued and the handler is not
 * running on any CPU.
 */
static void
srpc_del_client_rpc_timer(struct srpc_client_rpc *rpc)
{
        /* timer not planted or already exploded */
        if (!rpc->crpc_timeout)
                return;

        /* timer successfully defused */
        if (stt_del_timer(&rpc->crpc_timer))
                return;

        /* timer detonated, wait for it to explode */
        while (rpc->crpc_timeout) {
                spin_unlock(&rpc->crpc_lock);

                schedule();

                spin_lock(&rpc->crpc_lock);
        }
}

static void
srpc_client_rpc_done(struct srpc_client_rpc *rpc, int status)
{
        struct swi_workitem *wi = &rpc->crpc_wi;

        LASSERT(status || wi->swi_state == SWI_STATE_DONE);

        spin_lock(&rpc->crpc_lock);

        rpc->crpc_closed = 1;
        if (!rpc->crpc_status)
                rpc->crpc_status = status;

        srpc_del_client_rpc_timer(rpc);

        CDEBUG_LIMIT(!status ? D_NET : D_NETERROR,
                     "Client RPC done: service %d, peer %s, status %s:%d:%d\n",
                     rpc->crpc_service, libcfs_id2str(rpc->crpc_dest),
                     swi_state2str(wi->swi_state), rpc->crpc_aborted, status);

        /*
         * No one can schedule me now since:
         * - RPC timer has been defused.
         * - all LNet events have been fired.
         * - crpc_closed has been set, preventing srpc_abort_rpc from
         *   scheduling me.
         * Cancel pending schedules and prevent future schedule attempts:
         */
        LASSERT(!srpc_event_pending(rpc));

        spin_unlock(&rpc->crpc_lock);

        (*rpc->crpc_done)(rpc);
}

/* sends an outgoing RPC */
void
srpc_send_rpc(struct swi_workitem *wi)
{
        int rc = 0;
        struct srpc_client_rpc *rpc;
        struct srpc_msg *reply;
        int do_bulk;

        LASSERT(wi);

        rpc = container_of(wi, struct srpc_client_rpc, crpc_wi);

        LASSERT(rpc);
        LASSERT(wi == &rpc->crpc_wi);

        reply = &rpc->crpc_replymsg;
        do_bulk = rpc->crpc_bulk.bk_niov > 0;

        spin_lock(&rpc->crpc_lock);

        if (rpc->crpc_aborted) {
                spin_unlock(&rpc->crpc_lock);
                goto abort;
        }

        spin_unlock(&rpc->crpc_lock);

        switch (wi->swi_state) {
        default:
                LBUG();
        case SWI_STATE_NEWBORN:
                LASSERT(!srpc_event_pending(rpc));

                rc = srpc_prepare_reply(rpc);
                if (rc) {
                        srpc_client_rpc_done(rpc, rc);
                        return;
                }

                rc = srpc_prepare_bulk(rpc);
                if (rc)
                        break;

                wi->swi_state = SWI_STATE_REQUEST_SUBMITTED;
                rc = srpc_send_request(rpc);
                break;

        case SWI_STATE_REQUEST_SUBMITTED:
                /*
                 * CAVEAT EMPTOR: rqtev, rpyev, and bulkev may come in any
                 * order; however, they're processed in a strict order:
                 * rqt, rpy, and bulk.
                 */
                if (!rpc->crpc_reqstev.ev_fired)
                        break;

                rc = rpc->crpc_reqstev.ev_status;
                if (rc)
                        break;

                wi->swi_state = SWI_STATE_REQUEST_SENT;
                /* perhaps more events */
                /* fall through */
        case SWI_STATE_REQUEST_SENT: {
                enum srpc_msg_type type = srpc_service2reply(rpc->crpc_service);

                if (!rpc->crpc_replyev.ev_fired)
                        break;

                rc = rpc->crpc_replyev.ev_status;
                if (rc)
                        break;

                srpc_unpack_msg_hdr(reply);
                if (reply->msg_type != type ||
                    (reply->msg_magic != SRPC_MSG_MAGIC &&
                     reply->msg_magic != __swab32(SRPC_MSG_MAGIC))) {
                        CWARN("Bad message from %s: type %u (%d expected), magic %u (%d expected).\n",
                              libcfs_id2str(rpc->crpc_dest),
                              reply->msg_type, type,
                              reply->msg_magic, SRPC_MSG_MAGIC);
                        rc = -EBADMSG;
                        break;
                }

                if (do_bulk && reply->msg_body.reply.status) {
                        CWARN("Remote error %d at %s, unlink bulk buffer in case peer didn't initiate bulk transfer\n",
                              reply->msg_body.reply.status,
                              libcfs_id2str(rpc->crpc_dest));
                        LNetMDUnlink(rpc->crpc_bulk.bk_mdh);
                }

                wi->swi_state = SWI_STATE_REPLY_RECEIVED;
        }
                /* fall through */
        case SWI_STATE_REPLY_RECEIVED:
                if (do_bulk && !rpc->crpc_bulkev.ev_fired)
                        break;

                rc = do_bulk ? rpc->crpc_bulkev.ev_status : 0;

                /*
                 * Bulk buffer was unlinked due to remote error. Clear error
                 * since reply buffer still contains valid data.
                 * NB rpc->crpc_done shouldn't look into bulk data in case of
                 * remote error.
                 */
                if (do_bulk && rpc->crpc_bulkev.ev_lnet == LNET_EVENT_UNLINK &&
                    !rpc->crpc_status && reply->msg_body.reply.status)
                        rc = 0;

                wi->swi_state = SWI_STATE_DONE;
                srpc_client_rpc_done(rpc, rc);
                return;
        }

        if (rc) {
                spin_lock(&rpc->crpc_lock);
                srpc_abort_rpc(rpc, rc);
                spin_unlock(&rpc->crpc_lock);
        }

abort:
        if (rpc->crpc_aborted) {
                LNetMDUnlink(rpc->crpc_reqstmdh);
                LNetMDUnlink(rpc->crpc_replymdh);
                LNetMDUnlink(rpc->crpc_bulk.bk_mdh);

                if (!srpc_event_pending(rpc)) {
                        srpc_client_rpc_done(rpc, -EINTR);
                        return;
                }
        }
}

struct srpc_client_rpc *
srpc_create_client_rpc(struct lnet_process_id peer, int service,
                       int nbulkiov, int bulklen,
                       void (*rpc_done)(struct srpc_client_rpc *),
                       void (*rpc_fini)(struct srpc_client_rpc *), void *priv)
{
        struct srpc_client_rpc *rpc;

        rpc = kzalloc(offsetof(struct srpc_client_rpc,
                               crpc_bulk.bk_iovs[nbulkiov]), GFP_KERNEL);
        if (!rpc)
                return NULL;

        srpc_init_client_rpc(rpc, peer, service, nbulkiov,
                             bulklen, rpc_done, rpc_fini, priv);
        return rpc;
}

/* called with rpc->crpc_lock held */
void
srpc_abort_rpc(struct srpc_client_rpc *rpc, int why)
{
        LASSERT(why);

        if (rpc->crpc_aborted ||        /* already aborted */
            rpc->crpc_closed)           /* callback imminent */
                return;

        CDEBUG(D_NET, "Aborting RPC: service %d, peer %s, state %s, why %d\n",
               rpc->crpc_service, libcfs_id2str(rpc->crpc_dest),
               swi_state2str(rpc->crpc_wi.swi_state), why);

        rpc->crpc_aborted = 1;
        rpc->crpc_status = why;
        swi_schedule_workitem(&rpc->crpc_wi);
}

/* called with rpc->crpc_lock held */
void
srpc_post_rpc(struct srpc_client_rpc *rpc)
{
        LASSERT(!rpc->crpc_aborted);
        LASSERT(srpc_data.rpc_state == SRPC_STATE_RUNNING);

        CDEBUG(D_NET, "Posting RPC: peer %s, service %d, timeout %d\n",
               libcfs_id2str(rpc->crpc_dest), rpc->crpc_service,
               rpc->crpc_timeout);

        srpc_add_client_rpc_timer(rpc);
        swi_schedule_workitem(&rpc->crpc_wi);
}

int
srpc_send_reply(struct srpc_server_rpc *rpc)
{
        struct srpc_event *ev = &rpc->srpc_ev;
        struct srpc_msg *msg = &rpc->srpc_replymsg;
        struct srpc_buffer *buffer = rpc->srpc_reqstbuf;
        struct srpc_service_cd *scd = rpc->srpc_scd;
        struct srpc_service *sv = scd->scd_svc;
        __u64 rpyid;
        int rc;

        LASSERT(buffer);
        rpyid = buffer->buf_msg.msg_body.reqst.rpyid;

        spin_lock(&scd->scd_lock);

        if (!sv->sv_shuttingdown && !srpc_serv_is_framework(sv)) {
                /*
                 * Repost buffer before replying since test client
                 * might send me another RPC once it gets the reply
                 */
                if (srpc_service_post_buffer(scd, buffer))
                        CWARN("Failed to repost %s buffer\n", sv->sv_name);
                rpc->srpc_reqstbuf = NULL;
        }

        spin_unlock(&scd->scd_lock);

        ev->ev_fired = 0;
        ev->ev_data = rpc;
        ev->ev_type = SRPC_REPLY_SENT;

        msg->msg_magic = SRPC_MSG_MAGIC;
        msg->msg_version = SRPC_MSG_VERSION;
        msg->msg_type = srpc_service2reply(sv->sv_id);

        rc = srpc_post_active_rdma(SRPC_RDMA_PORTAL, rpyid, msg,
                                   sizeof(*msg), LNET_MD_OP_PUT,
                                   rpc->srpc_peer, rpc->srpc_self,
                                   &rpc->srpc_replymdh, ev);
        if (rc)
                ev->ev_fired = 1; /* no more event expected */
        return rc;
}

/* when in kernel always called with LNET_LOCK() held, and in thread context */
static void
srpc_lnet_ev_handler(struct lnet_event *ev)
{
        struct srpc_service_cd *scd;
        struct srpc_event *rpcev = ev->md.user_ptr;
        struct srpc_client_rpc *crpc;
        struct srpc_server_rpc *srpc;
        struct srpc_buffer *buffer;
        struct srpc_service *sv;
        struct srpc_msg *msg;
        enum srpc_msg_type type;

        LASSERT(!in_interrupt());

        if (ev->status) {
                __u32 errors;

                spin_lock(&srpc_data.rpc_glock);
                if (ev->status != -ECANCELED) /* cancellation is not error */
                        srpc_data.rpc_counters.errors++;
                errors = srpc_data.rpc_counters.errors;
                spin_unlock(&srpc_data.rpc_glock);

                CNETERR("LNet event status %d type %d, RPC errors %u\n",
                        ev->status, ev->type, errors);
        }

        rpcev->ev_lnet = ev->type;

        switch (rpcev->ev_type) {
        default:
                CERROR("Unknown event: status %d, type %d, lnet %d\n",
                       rpcev->ev_status, rpcev->ev_type, rpcev->ev_lnet);
                LBUG();
        case SRPC_REQUEST_SENT:
                if (!ev->status && ev->type != LNET_EVENT_UNLINK) {
                        spin_lock(&srpc_data.rpc_glock);
                        srpc_data.rpc_counters.rpcs_sent++;
                        spin_unlock(&srpc_data.rpc_glock);
                }
                /* fall through */
        case SRPC_REPLY_RCVD:
        case SRPC_BULK_REQ_RCVD:
                crpc = rpcev->ev_data;

                if (rpcev != &crpc->crpc_reqstev &&
                    rpcev != &crpc->crpc_replyev &&
                    rpcev != &crpc->crpc_bulkev) {
                        CERROR("rpcev %p, crpc %p, reqstev %p, replyev %p, bulkev %p\n",
                               rpcev, crpc, &crpc->crpc_reqstev,
                               &crpc->crpc_replyev, &crpc->crpc_bulkev);
                        CERROR("Bad event: status %d, type %d, lnet %d\n",
                               rpcev->ev_status, rpcev->ev_type, rpcev->ev_lnet);
                        LBUG();
                }

                spin_lock(&crpc->crpc_lock);

                LASSERT(!rpcev->ev_fired);
                rpcev->ev_fired = 1;
                rpcev->ev_status = (ev->type == LNET_EVENT_UNLINK) ?
                                                -EINTR : ev->status;
                swi_schedule_workitem(&crpc->crpc_wi);

                spin_unlock(&crpc->crpc_lock);
                break;

        case SRPC_REQUEST_RCVD:
                scd = rpcev->ev_data;
                sv = scd->scd_svc;

                LASSERT(rpcev == &scd->scd_ev);

                spin_lock(&scd->scd_lock);

                LASSERT(ev->unlinked);
                LASSERT(ev->type == LNET_EVENT_PUT ||
                        ev->type == LNET_EVENT_UNLINK);
                LASSERT(ev->type != LNET_EVENT_UNLINK ||
                        sv->sv_shuttingdown);

                buffer = container_of(ev->md.start, struct srpc_buffer, buf_msg);
                buffer->buf_peer = ev->initiator;
                buffer->buf_self = ev->target.nid;

                LASSERT(scd->scd_buf_nposted > 0);
                scd->scd_buf_nposted--;

                if (sv->sv_shuttingdown) {
                        /*
                         * Leave buffer on scd->scd_buf_nposted since
                         * srpc_finish_service needs to traverse it.
                         */
                        spin_unlock(&scd->scd_lock);
                        break;
                }

                if (scd->scd_buf_err_stamp &&
                    scd->scd_buf_err_stamp < ktime_get_real_seconds()) {
                        /* re-enable adding buffer */
                        scd->scd_buf_err_stamp = 0;
                        scd->scd_buf_err = 0;
                }

                if (!scd->scd_buf_err &&        /* adding buffer is enabled */
                    !scd->scd_buf_adjust &&
                    scd->scd_buf_nposted < scd->scd_buf_low) {
                        scd->scd_buf_adjust = max(scd->scd_buf_total / 2,
                                                  SFW_TEST_WI_MIN);
                        swi_schedule_workitem(&scd->scd_buf_wi);
                }

                list_del(&buffer->buf_list); /* from scd->scd_buf_posted */
                msg = &buffer->buf_msg;
                type = srpc_service2request(sv->sv_id);

                if (ev->status || ev->mlength != sizeof(*msg) ||
                    (msg->msg_type != type &&
                     msg->msg_type != __swab32(type)) ||
                    (msg->msg_magic != SRPC_MSG_MAGIC &&
                     msg->msg_magic != __swab32(SRPC_MSG_MAGIC))) {
                        CERROR("Dropping RPC (%s) from %s: status %d mlength %d type %u magic %u.\n",
                               sv->sv_name, libcfs_id2str(ev->initiator),
                               ev->status, ev->mlength,
                               msg->msg_type, msg->msg_magic);

                        /*
                         * NB can't call srpc_service_recycle_buffer here since
                         * it may call LNetM[DE]Attach. The invalid magic tells
                         * srpc_handle_rpc to drop this RPC
                         */
                        msg->msg_magic = 0;
                }

                if (!list_empty(&scd->scd_rpc_free)) {
                        srpc = list_entry(scd->scd_rpc_free.next,
                                          struct srpc_server_rpc,
                                          srpc_list);
                        list_del(&srpc->srpc_list);

                        srpc_init_server_rpc(srpc, scd, buffer);
                        list_add_tail(&srpc->srpc_list,
                                      &scd->scd_rpc_active);
                        swi_schedule_workitem(&srpc->srpc_wi);
                } else {
                        list_add_tail(&buffer->buf_list,
                                      &scd->scd_buf_blocked);
                }

                spin_unlock(&scd->scd_lock);

                spin_lock(&srpc_data.rpc_glock);
                srpc_data.rpc_counters.rpcs_rcvd++;
                spin_unlock(&srpc_data.rpc_glock);
                break;

        case SRPC_BULK_GET_RPLD:
                LASSERT(ev->type == LNET_EVENT_SEND ||
                        ev->type == LNET_EVENT_REPLY ||
                        ev->type == LNET_EVENT_UNLINK);

                if (!ev->unlinked)
                        break; /* wait for final event */
                /* fall through */
        case SRPC_BULK_PUT_SENT:
                if (!ev->status && ev->type != LNET_EVENT_UNLINK) {
                        spin_lock(&srpc_data.rpc_glock);

                        if (rpcev->ev_type == SRPC_BULK_GET_RPLD)
                                srpc_data.rpc_counters.bulk_get += ev->mlength;
                        else
                                srpc_data.rpc_counters.bulk_put += ev->mlength;

                        spin_unlock(&srpc_data.rpc_glock);
                }
                /* fall through */
        case SRPC_REPLY_SENT:
                srpc = rpcev->ev_data;
                scd = srpc->srpc_scd;

                LASSERT(rpcev == &srpc->srpc_ev);

                spin_lock(&scd->scd_lock);

                rpcev->ev_fired = 1;
                rpcev->ev_status = (ev->type == LNET_EVENT_UNLINK) ?
                                   -EINTR : ev->status;
                swi_schedule_workitem(&srpc->srpc_wi);

                spin_unlock(&scd->scd_lock);
                break;
        }
}

int
srpc_startup(void)
{
        int rc;

        memset(&srpc_data, 0, sizeof(struct smoketest_rpc));
        spin_lock_init(&srpc_data.rpc_glock);

        /* 1 second pause to avoid timestamp reuse */
        set_current_state(TASK_UNINTERRUPTIBLE);
        schedule_timeout(HZ);
        srpc_data.rpc_matchbits = ((__u64)ktime_get_real_seconds()) << 48;

        srpc_data.rpc_state = SRPC_STATE_NONE;

        rc = LNetNIInit(LNET_PID_LUSTRE);
        if (rc < 0) {
                CERROR("LNetNIInit() has failed: %d\n", rc);
                return rc;
        }

        srpc_data.rpc_state = SRPC_STATE_NI_INIT;

        LNetInvalidateEQHandle(&srpc_data.rpc_lnet_eq);
        rc = LNetEQAlloc(0, srpc_lnet_ev_handler, &srpc_data.rpc_lnet_eq);
        if (rc) {
                CERROR("LNetEQAlloc() has failed: %d\n", rc);
                goto bail;
        }

        rc = LNetSetLazyPortal(SRPC_FRAMEWORK_REQUEST_PORTAL);
        LASSERT(!rc);
        rc = LNetSetLazyPortal(SRPC_REQUEST_PORTAL);
        LASSERT(!rc);

        srpc_data.rpc_state = SRPC_STATE_EQ_INIT;

        rc = stt_startup();

bail:
        if (rc)
                srpc_shutdown();
        else
                srpc_data.rpc_state = SRPC_STATE_RUNNING;

        return rc;
}

void
srpc_shutdown(void)
{
        int i;
        int rc;
        int state;

        state = srpc_data.rpc_state;
        srpc_data.rpc_state = SRPC_STATE_STOPPING;

        switch (state) {
        default:
                LBUG();
        case SRPC_STATE_RUNNING:
                spin_lock(&srpc_data.rpc_glock);

                for (i = 0; i <= SRPC_SERVICE_MAX_ID; i++) {
                        struct srpc_service *sv = srpc_data.rpc_services[i];

                        LASSERTF(!sv, "service not empty: id %d, name %s\n",
                                 i, sv->sv_name);
                }

                spin_unlock(&srpc_data.rpc_glock);

                stt_shutdown();
                /* fall through */
        case SRPC_STATE_EQ_INIT:
                rc = LNetClearLazyPortal(SRPC_FRAMEWORK_REQUEST_PORTAL);
                rc = LNetClearLazyPortal(SRPC_REQUEST_PORTAL);
                LASSERT(!rc);
                rc = LNetEQFree(srpc_data.rpc_lnet_eq);
                LASSERT(!rc); /* the EQ should have no user by now */
                /* fall through */
        case SRPC_STATE_NI_INIT:
                LNetNIFini();
        }
}