/*
 * 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) 2002, 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.
 */

#define DEBUG_SUBSYSTEM S_RPC

#include "../../include/linux/libcfs/libcfs.h"
# ifdef __mips64__
#  include <linux/kernel.h>
# endif

#include "../include/obd_class.h"
#include "../include/lustre_net.h"
#include "../include/lustre_sec.h"
#include "ptlrpc_internal.h"

lnet_handle_eq_t   ptlrpc_eq_h;

/*
 *  Client's outgoing request callback
 */
void request_out_callback(lnet_event_t *ev)
{
        struct ptlrpc_cb_id *cbid = ev->md.user_ptr;
        struct ptlrpc_request *req = cbid->cbid_arg;
        bool wakeup = false;

        LASSERT(ev->type == LNET_EVENT_SEND || ev->type == LNET_EVENT_UNLINK);
        LASSERT(ev->unlinked);

        DEBUG_REQ(D_NET, req, "type %d, status %d", ev->type, ev->status);

        sptlrpc_request_out_callback(req);

        spin_lock(&req->rq_lock);
        req->rq_real_sent = ktime_get_real_seconds();
        req->rq_req_unlinked = 1;
        /* reply_in_callback happened before request_out_callback? */
        if (req->rq_reply_unlinked)
                wakeup = true;

        if (ev->type == LNET_EVENT_UNLINK || ev->status != 0) {
                /* Failed send: make it seem like the reply timed out, just
                 * like failing sends in client.c does currently...
                 */
                req->rq_net_err = 1;
                wakeup = true;
        }

        if (wakeup)
                ptlrpc_client_wake_req(req);

        spin_unlock(&req->rq_lock);

        ptlrpc_req_finished(req);
}

/*
 * Client's incoming reply callback
 */
void reply_in_callback(lnet_event_t *ev)
{
        struct ptlrpc_cb_id *cbid = ev->md.user_ptr;
        struct ptlrpc_request *req = cbid->cbid_arg;

        DEBUG_REQ(D_NET, req, "type %d, status %d", ev->type, ev->status);

        LASSERT(ev->type == LNET_EVENT_PUT || ev->type == LNET_EVENT_UNLINK);
        LASSERT(ev->md.start == req->rq_repbuf);
        LASSERT(ev->offset + ev->mlength <= req->rq_repbuf_len);
        /* We've set LNET_MD_MANAGE_REMOTE for all outgoing requests
         * for adaptive timeouts' early reply.
         */
        LASSERT((ev->md.options & LNET_MD_MANAGE_REMOTE) != 0);

        spin_lock(&req->rq_lock);

        req->rq_receiving_reply = 0;
        req->rq_early = 0;
        if (ev->unlinked)
                req->rq_reply_unlinked = 1;

        if (ev->status)
                goto out_wake;

        if (ev->type == LNET_EVENT_UNLINK) {
                LASSERT(ev->unlinked);
                DEBUG_REQ(D_NET, req, "unlink");
                goto out_wake;
        }

        if (ev->mlength < ev->rlength) {
                CDEBUG(D_RPCTRACE, "truncate req %p rpc %d - %d+%d\n", req,
                       req->rq_replen, ev->rlength, ev->offset);
                req->rq_reply_truncated = 1;
                req->rq_replied = 1;
                req->rq_status = -EOVERFLOW;
                req->rq_nob_received = ev->rlength + ev->offset;
                goto out_wake;
        }

        if ((ev->offset == 0) &&
            ((lustre_msghdr_get_flags(req->rq_reqmsg) & MSGHDR_AT_SUPPORT))) {
                /* Early reply */
                DEBUG_REQ(D_ADAPTTO, req,
                          "Early reply received: mlen=%u offset=%d replen=%d replied=%d unlinked=%d",
                          ev->mlength, ev->offset,
                          req->rq_replen, req->rq_replied, ev->unlinked);

                req->rq_early_count++; /* number received, client side */

                /* already got the real reply or buffers are already unlinked */
                if (req->rq_replied || req->rq_reply_unlinked == 1)
                        goto out_wake;

                req->rq_early = 1;
                req->rq_reply_off = ev->offset;
                req->rq_nob_received = ev->mlength;
                /* And we're still receiving */
                req->rq_receiving_reply = 1;
        } else {
                /* Real reply */
                req->rq_rep_swab_mask = 0;
                req->rq_replied = 1;
                /* Got reply, no resend required */
                req->rq_resend = 0;
                req->rq_reply_off = ev->offset;
                req->rq_nob_received = ev->mlength;
                /* LNetMDUnlink can't be called under the LNET_LOCK,
                 * so we must unlink in ptlrpc_unregister_reply
                 */
                DEBUG_REQ(D_INFO, req,
                          "reply in flags=%x mlen=%u offset=%d replen=%d",
                          lustre_msg_get_flags(req->rq_reqmsg),
                          ev->mlength, ev->offset, req->rq_replen);
        }

        req->rq_import->imp_last_reply_time = ktime_get_real_seconds();

out_wake:
        /* NB don't unlock till after wakeup; req can disappear under us
         * since we don't have our own ref
         */
        ptlrpc_client_wake_req(req);
        spin_unlock(&req->rq_lock);
}

/*
 * Client's bulk has been written/read
 */
void client_bulk_callback(lnet_event_t *ev)
{
        struct ptlrpc_cb_id *cbid = ev->md.user_ptr;
        struct ptlrpc_bulk_desc *desc = cbid->cbid_arg;
        struct ptlrpc_request *req;

        LASSERT((desc->bd_type == BULK_PUT_SINK &&
                 ev->type == LNET_EVENT_PUT) ||
                (desc->bd_type == BULK_GET_SOURCE &&
                 ev->type == LNET_EVENT_GET) ||
                ev->type == LNET_EVENT_UNLINK);
        LASSERT(ev->unlinked);

        if (CFS_FAIL_CHECK_ORSET(OBD_FAIL_PTLRPC_CLIENT_BULK_CB, CFS_FAIL_ONCE))
                ev->status = -EIO;

        if (CFS_FAIL_CHECK_ORSET(OBD_FAIL_PTLRPC_CLIENT_BULK_CB2,
                                 CFS_FAIL_ONCE))
                ev->status = -EIO;

        CDEBUG((ev->status == 0) ? D_NET : D_ERROR,
               "event type %d, status %d, desc %p\n",
               ev->type, ev->status, desc);

        spin_lock(&desc->bd_lock);
        req = desc->bd_req;
        LASSERT(desc->bd_md_count > 0);
        desc->bd_md_count--;

        if (ev->type != LNET_EVENT_UNLINK && ev->status == 0) {
                desc->bd_nob_transferred += ev->mlength;
                desc->bd_sender = ev->sender;
        } else {
                /* start reconnect and resend if network error hit */
                spin_lock(&req->rq_lock);
                req->rq_net_err = 1;
                spin_unlock(&req->rq_lock);
        }

        if (ev->status != 0)
                desc->bd_failure = 1;

        /* NB don't unlock till after wakeup; desc can disappear under us
         * otherwise
         */
        if (desc->bd_md_count == 0)
                ptlrpc_client_wake_req(desc->bd_req);

        spin_unlock(&desc->bd_lock);
}

/*
 * We will have percpt request history list for ptlrpc service in upcoming
 * patches because we don't want to be serialized by current per-service
 * history operations. So we require history ID can (somehow) show arriving
 * order w/o grabbing global lock, and user can sort them in userspace.
 *
 * This is how we generate history ID for ptlrpc_request:
 * ----------------------------------------------------
 * |  32 bits  |  16 bits  | (16 - X)bits  |  X bits  |
 * ----------------------------------------------------
 * |  seconds  | usec / 16 |   sequence    | CPT id   |
 * ----------------------------------------------------
 *
 * it might not be precise but should be good enough.
 */

#define REQS_CPT_BITS(svcpt)    ((svcpt)->scp_service->srv_cpt_bits)

#define REQS_SEC_SHIFT          32
#define REQS_USEC_SHIFT         16
#define REQS_SEQ_SHIFT(svcpt)   REQS_CPT_BITS(svcpt)

static void ptlrpc_req_add_history(struct ptlrpc_service_part *svcpt,
                                   struct ptlrpc_request *req)
{
        __u64 sec = req->rq_arrival_time.tv_sec;
        __u32 usec = req->rq_arrival_time.tv_nsec / NSEC_PER_USEC / 16; /* usec / 16 */
        __u64 new_seq;

        /* set sequence ID for request and add it to history list,
         * it must be called with hold svcpt::scp_lock
         */

        new_seq = (sec << REQS_SEC_SHIFT) |
                  (usec << REQS_USEC_SHIFT) |
                  (svcpt->scp_cpt < 0 ? 0 : svcpt->scp_cpt);

        if (new_seq > svcpt->scp_hist_seq) {
                /* This handles the initial case of scp_hist_seq == 0 or
                 * we just jumped into a new time window
                 */
                svcpt->scp_hist_seq = new_seq;
        } else {
                LASSERT(REQS_SEQ_SHIFT(svcpt) < REQS_USEC_SHIFT);
                /* NB: increase sequence number in current usec bucket,
                 * however, it's possible that we used up all bits for
                 * sequence and jumped into the next usec bucket (future time),
                 * then we hope there will be less RPCs per bucket at some
                 * point, and sequence will catch up again
                 */
                svcpt->scp_hist_seq += (1U << REQS_SEQ_SHIFT(svcpt));
                new_seq = svcpt->scp_hist_seq;
        }

        req->rq_history_seq = new_seq;

        list_add_tail(&req->rq_history_list, &svcpt->scp_hist_reqs);
}

/*
 * Server's incoming request callback
 */
void request_in_callback(lnet_event_t *ev)
{
        struct ptlrpc_cb_id *cbid = ev->md.user_ptr;
        struct ptlrpc_request_buffer_desc *rqbd = cbid->cbid_arg;
        struct ptlrpc_service_part *svcpt = rqbd->rqbd_svcpt;
        struct ptlrpc_service *service = svcpt->scp_service;
        struct ptlrpc_request *req;

        LASSERT(ev->type == LNET_EVENT_PUT ||
                ev->type == LNET_EVENT_UNLINK);
        LASSERT((char *)ev->md.start >= rqbd->rqbd_buffer);
        LASSERT((char *)ev->md.start + ev->offset + ev->mlength <=
                rqbd->rqbd_buffer + service->srv_buf_size);

        CDEBUG((ev->status == 0) ? D_NET : D_ERROR,
               "event type %d, status %d, service %s\n",
               ev->type, ev->status, service->srv_name);

        if (ev->unlinked) {
                /* If this is the last request message to fit in the
                 * request buffer we can use the request object embedded in
                 * rqbd.  Note that if we failed to allocate a request,
                 * we'd have to re-post the rqbd, which we can't do in this
                 * context.
                 */
                req = &rqbd->rqbd_req;
                memset(req, 0, sizeof(*req));
        } else {
                LASSERT(ev->type == LNET_EVENT_PUT);
                if (ev->status != 0) {
                        /* We moaned above already... */
                        return;
                }
                req = ptlrpc_request_cache_alloc(GFP_ATOMIC);
                if (!req) {
                        CERROR("Can't allocate incoming request descriptor: Dropping %s RPC from %s\n",
                               service->srv_name,
                               libcfs_id2str(ev->initiator));
                        return;
                }
        }

        ptlrpc_srv_req_init(req);
        /* NB we ABSOLUTELY RELY on req being zeroed, so pointers are NULL,
         * flags are reset and scalars are zero.  We only set the message
         * size to non-zero if this was a successful receive.
         */
        req->rq_xid = ev->match_bits;
        req->rq_reqbuf = ev->md.start + ev->offset;
        if (ev->type == LNET_EVENT_PUT && ev->status == 0)
                req->rq_reqdata_len = ev->mlength;
        ktime_get_real_ts64(&req->rq_arrival_time);
        req->rq_peer = ev->initiator;
        req->rq_self = ev->target.nid;
        req->rq_rqbd = rqbd;
        req->rq_phase = RQ_PHASE_NEW;
        if (ev->type == LNET_EVENT_PUT)
                CDEBUG(D_INFO, "incoming req@%p x%llu msgsize %u\n",
                       req, req->rq_xid, ev->mlength);

        CDEBUG(D_RPCTRACE, "peer: %s\n", libcfs_id2str(req->rq_peer));

        spin_lock(&svcpt->scp_lock);

        ptlrpc_req_add_history(svcpt, req);

        if (ev->unlinked) {
                svcpt->scp_nrqbds_posted--;
                CDEBUG(D_INFO, "Buffer complete: %d buffers still posted\n",
                       svcpt->scp_nrqbds_posted);

                /* Normally, don't complain about 0 buffers posted; LNET won't
                 * drop incoming reqs since we set the portal lazy
                 */
                if (test_req_buffer_pressure &&
                    ev->type != LNET_EVENT_UNLINK &&
                    svcpt->scp_nrqbds_posted == 0)
                        CWARN("All %s request buffers busy\n",
                              service->srv_name);

                /* req takes over the network's ref on rqbd */
        } else {
                /* req takes a ref on rqbd */
                rqbd->rqbd_refcount++;
        }

        list_add_tail(&req->rq_list, &svcpt->scp_req_incoming);
        svcpt->scp_nreqs_incoming++;

        /* NB everything can disappear under us once the request
         * has been queued and we unlock, so do the wake now...
         */
        wake_up(&svcpt->scp_waitq);

        spin_unlock(&svcpt->scp_lock);
}

/*
 *  Server's outgoing reply callback
 */
void reply_out_callback(lnet_event_t *ev)
{
        struct ptlrpc_cb_id *cbid = ev->md.user_ptr;
        struct ptlrpc_reply_state *rs = cbid->cbid_arg;
        struct ptlrpc_service_part *svcpt = rs->rs_svcpt;

        LASSERT(ev->type == LNET_EVENT_SEND ||
                ev->type == LNET_EVENT_ACK ||
                ev->type == LNET_EVENT_UNLINK);

        if (!rs->rs_difficult) {
                /* 'Easy' replies have no further processing so I drop the
                 * net's ref on 'rs'
                 */
                LASSERT(ev->unlinked);
                ptlrpc_rs_decref(rs);
                return;
        }

        LASSERT(rs->rs_on_net);

        if (ev->unlinked) {
                /* Last network callback. The net's ref on 'rs' stays put
                 * until ptlrpc_handle_rs() is done with it
                 */
                spin_lock(&svcpt->scp_rep_lock);
                spin_lock(&rs->rs_lock);

                rs->rs_on_net = 0;
                if (!rs->rs_no_ack ||
                    rs->rs_transno <=
                    rs->rs_export->exp_obd->obd_last_committed)
                        ptlrpc_schedule_difficult_reply(rs);

                spin_unlock(&rs->rs_lock);
                spin_unlock(&svcpt->scp_rep_lock);
        }
}

static void ptlrpc_master_callback(lnet_event_t *ev)
{
        struct ptlrpc_cb_id *cbid = ev->md.user_ptr;
        void (*callback)(lnet_event_t *ev) = cbid->cbid_fn;

        /* Honestly, it's best to find out early. */
        LASSERT(cbid->cbid_arg != LP_POISON);
        LASSERT(callback == request_out_callback ||
                callback == reply_in_callback ||
                callback == client_bulk_callback ||
                callback == request_in_callback ||
                callback == reply_out_callback);

        callback(ev);
}

int ptlrpc_uuid_to_peer(struct obd_uuid *uuid,
                        lnet_process_id_t *peer, lnet_nid_t *self)
{
        int best_dist = 0;
        __u32 best_order = 0;
        int count = 0;
        int rc = -ENOENT;
        int dist;
        __u32 order;
        lnet_nid_t dst_nid;
        lnet_nid_t src_nid;

        peer->pid = LNET_PID_LUSTRE;

        /* Choose the matching UUID that's closest */
        while (lustre_uuid_to_peer(uuid->uuid, &dst_nid, count++) == 0) {
                dist = LNetDist(dst_nid, &src_nid, &order);
                if (dist < 0)
                        continue;

                if (dist == 0) {                /* local! use loopback LND */
                        peer->nid = *self = LNET_MKNID(LNET_MKNET(LOLND, 0), 0);
                        rc = 0;
                        break;
                }

                if (rc < 0 ||
                    dist < best_dist ||
                    (dist == best_dist && order < best_order)) {
                        best_dist = dist;
                        best_order = order;

                        peer->nid = dst_nid;
                        *self = src_nid;
                        rc = 0;
                }
        }

        CDEBUG(D_NET, "%s->%s\n", uuid->uuid, libcfs_id2str(*peer));
        return rc;
}

static void ptlrpc_ni_fini(void)
{
        wait_queue_head_t waitq;
        struct l_wait_info lwi;
        int rc;
        int retries;

        /* Wait for the event queue to become idle since there may still be
         * messages in flight with pending events (i.e. the fire-and-forget
         * messages == client requests and "non-difficult" server
         * replies
         */

        for (retries = 0;; retries++) {
                rc = LNetEQFree(ptlrpc_eq_h);
                switch (rc) {
                default:
                        LBUG();

                case 0:
                        LNetNIFini();
                        return;

                case -EBUSY:
                        if (retries != 0)
                                CWARN("Event queue still busy\n");

                        /* Wait for a bit */
                        init_waitqueue_head(&waitq);
                        lwi = LWI_TIMEOUT(cfs_time_seconds(2), NULL, NULL);
                        l_wait_event(waitq, 0, &lwi);
                        break;
                }
        }
        /* notreached */
}

static lnet_pid_t ptl_get_pid(void)
{
        lnet_pid_t pid;

        pid = LNET_PID_LUSTRE;
        return pid;
}

static int ptlrpc_ni_init(void)
{
        int rc;
        lnet_pid_t pid;

        pid = ptl_get_pid();
        CDEBUG(D_NET, "My pid is: %x\n", pid);

        /* We're not passing any limits yet... */
        rc = LNetNIInit(pid);
        if (rc < 0) {
                CDEBUG(D_NET, "Can't init network interface: %d\n", rc);
                return rc;
        }

        /* CAVEAT EMPTOR: how we process portals events is _radically_
         * different depending on...
         */
        /* kernel LNet calls our master callback when there are new event,
         * because we are guaranteed to get every event via callback,
         * so we just set EQ size to 0 to avoid overhead of serializing
         * enqueue/dequeue operations in LNet.
         */
        rc = LNetEQAlloc(0, ptlrpc_master_callback, &ptlrpc_eq_h);
        if (rc == 0)
                return 0;

        CERROR("Failed to allocate event queue: %d\n", rc);
        LNetNIFini();

        return rc;
}

int ptlrpc_init_portals(void)
{
        int rc = ptlrpc_ni_init();

        if (rc != 0) {
                CERROR("network initialisation failed\n");
                return rc;
        }
        rc = ptlrpcd_addref();
        if (rc == 0)
                return 0;

        CERROR("rpcd initialisation failed\n");
        ptlrpc_ni_fini();
        return rc;
}

void ptlrpc_exit_portals(void)
{
        ptlrpcd_decref();
        ptlrpc_ni_fini();
}