+1 ibw function +1 bugfix

[Samba.git] / ctdb / ib / ibwrapper.c

/*
 * Unix SMB/CIFS implementation.
 * Wrap Infiniband calls.
 *
 * Copyright (C) Sven Oehme <oehmes@de.ibm.com> 2006
 *
 * Major code contributions by Peter Somogyi <psomogyi@gamax.hu>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <malloc.h>
#include <assert.h>
#include <unistd.h>

#include "includes.h"
#include "lib/events/events.h"
#include "ibwrapper.h"

#include <rdma/rdma_cma.h>

#include "ibwrapper_internal.h"
#include "lib/util/dlinklist.h"

#define IBW_LASTERR_BUFSIZE 512
static char ibw_lasterr[IBW_LASTERR_BUFSIZE];

static void ibw_event_handler_verbs(struct event_context *ev,
        struct fd_event *fde, uint16_t flags, void *private_data);
static int ibw_fill_cq(struct ibw_conn *conn);
static inline int ibw_wc_recv(struct ibw_conn *conn, struct ibv_wc *wc);
static inline int ibw_wc_send(struct ibw_conn *conn, struct ibv_wc *wc);

static void *ibw_alloc_mr(struct ibw_ctx_priv *pctx, struct ibw_conn_priv *pconn,
        uint32_t n, struct ibv_mr **ppmr)
{
        void *buf;

        DEBUG(10, ("ibw_alloc_mr(cmid=%u, n=%u)\n", (uint32_t)pconn->cm_id, n));
        buf = memalign(pctx->pagesize, n);
        if (!buf) {
                sprintf(ibw_lasterr, "couldn't allocate memory\n");
                return NULL;
        }

        *ppmr = ibv_reg_mr(pctx->pd, buf, n, IBV_ACCESS_LOCAL_WRITE);
        if (!*ppmr) {
                sprintf(ibw_lasterr, "couldn't allocate mr\n");
                free(buf);
                return NULL;
        }

        return buf;
}

static void ibw_free_mr(char **ppbuf, struct ibv_mr **ppmr)
{
        DEBUG(10, ("ibw_free_mr(%u %u)\n", (uint32_t)*ppbuf, (uint32_t)*ppmr));
        if (*ppmr!=NULL) {
                ibv_dereg_mr(*ppmr);
                *ppmr = NULL;
        }
        if (*ppbuf) {
                free(*ppbuf);
                *ppbuf = NULL;
        }
}

static int ibw_init_memory(struct ibw_conn *conn)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        struct ibw_opts *opts = &pctx->opts;
        int     i;
        struct ibw_wr   *p;

        DEBUG(10, ("ibw_init_memory(cmid: %u)\n", (uint32_t)pconn->cm_id));
        pconn->buf_send = ibw_alloc_mr(pctx, pconn,
                opts->max_send_wr * opts->avg_send_size, &pconn->mr_send);
        if (!pconn->buf_send) {
                sprintf(ibw_lasterr, "couldn't allocate work send buf\n");
                return -1;
        }

        pconn->buf_recv = ibw_alloc_mr(pctx, pconn,
                opts->max_recv_wr * opts->recv_bufsize, &pconn->mr_recv);
        if (!pconn->buf_recv) {
                sprintf(ibw_lasterr, "couldn't allocate work recv buf\n");
                return -1;
        }

        pconn->wr_index = talloc_size(pconn, opts->max_send_wr * sizeof(struct ibw_wr *));
        assert(pconn->wr_index!=NULL);

        for(i=0; i<opts->max_send_wr; i++) {
                p = pconn->wr_index[i] = talloc_zero(pconn, struct ibw_wr);
                p->msg = pconn->buf_send + (i * opts->avg_send_size);
                p->wr_id = i + opts->max_recv_wr;

                DLIST_ADD(pconn->wr_list_avail, p);
        }

        return 0;
}

static int ibw_ctx_priv_destruct(struct ibw_ctx_priv *pctx)
{
        DEBUG(10, ("ibw_ctx_priv_destruct(%u)\n", (uint32_t)pctx));

        if (pctx->pd) {
                ibv_dealloc_pd(pctx->pd);
                pctx->pd = NULL;
        }

        /* destroy cm */
        if (pctx->cm_channel) {
                rdma_destroy_event_channel(pctx->cm_channel);
                pctx->cm_channel = NULL;
        }
        if (pctx->cm_channel_event) {
                /* TODO: do we have to do this here? */
                talloc_free(pctx->cm_channel_event);
                pctx->cm_channel_event = NULL;
        }
        if (pctx->cm_id) {
                rdma_destroy_id(pctx->cm_id);
                pctx->cm_id = NULL;
        }

        return 0;
}

static int ibw_ctx_destruct(struct ibw_ctx *ctx)
{
        DEBUG(10, ("ibw_ctx_destruct(%u)\n", (uint32_t)ctx));
        return 0;
}

static int ibw_conn_priv_destruct(struct ibw_conn_priv *pconn)
{
        DEBUG(10, ("ibw_conn_priv_destruct(%u, cmid: %u)\n",
                (uint32_t)pconn, (uint32_t)pconn->cm_id));

        /* free memory regions */
        ibw_free_mr(&pconn->buf_send, &pconn->mr_send);
        ibw_free_mr(&pconn->buf_recv, &pconn->mr_recv);

        /* pconn->wr_index is freed by talloc */
        /* pconn->wr_index[i] are freed by talloc */

        /* destroy verbs */
        if (pconn->cm_id->qp) {
                ibv_destroy_qp(pconn->cm_id->qp);
                pconn->cm_id->qp = NULL;
        }
        if (pconn->cq) {
                ibv_destroy_cq(pconn->cq);
                pconn->cq = NULL;
        }
        if (pconn->verbs_channel) {
                ibv_destroy_comp_channel(pconn->verbs_channel);
                pconn->verbs_channel = NULL;
        }
        if (pconn->verbs_channel_event) {
                /* TODO: do we have to do this here? */
                talloc_free(pconn->verbs_channel_event);
                pconn->verbs_channel_event = NULL;
        }
        if (pconn->cm_id) {
                rdma_destroy_id(pconn->cm_id);
                pconn->cm_id = NULL;
        }
        return 0;
}

static int ibw_conn_destruct(struct ibw_conn *conn)
{
        DEBUG(10, ("ibw_conn_destruct(%u)\n", (uint32_t)conn));
        
        /* important here: ctx is a talloc _parent_ */
        DLIST_REMOVE(conn->ctx->conn_list, conn);
        return 0;
}

static struct ibw_conn *ibw_conn_new(struct ibw_ctx *ctx)
{
        struct ibw_conn *conn;
        struct ibw_conn_priv *pconn;

        conn = talloc_zero(ctx, struct ibw_conn);
        assert(conn!=NULL);
        talloc_set_destructor(conn, ibw_conn_destruct);

        pconn = talloc_zero(ctx, struct ibw_conn_priv);
        assert(pconn!=NULL);
        talloc_set_destructor(pconn, ibw_conn_priv_destruct);

        conn->ctx = ctx;

        DLIST_ADD(ctx->conn_list, conn);

        return conn;
}

static int ibw_setup_cq_qp(struct ibw_conn *conn)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        struct ibv_qp_init_attr init_attr;
        int rc;

        DEBUG(10, ("ibw_setup_cq_qp(cmid: %u)\n", (uint32_t)pconn->cm_id));

        /* init mr */
        if (ibw_init_memory(conn))
                return -1;

        /* init verbs */
        pconn->verbs_channel = ibv_create_comp_channel(pconn->cm_id->verbs);
        if (!pconn->verbs_channel) {
                sprintf(ibw_lasterr, "ibv_create_comp_channel failed %d\n", errno);
                return -1;
        }
        DEBUG(10, ("created channel %p\n", pconn->verbs_channel));

        pconn->verbs_channel_event = event_add_fd(pctx->ectx, conn,
                pconn->verbs_channel->fd, EVENT_FD_READ, ibw_event_handler_verbs, conn);

        /* init cq */
        pconn->cq = ibv_create_cq(pconn->cm_id->verbs,
                pctx->opts.max_recv_wr + pctx->opts.max_send_wr,
                conn, pconn->verbs_channel, 0);
        if (pconn->cq==NULL) {
                sprintf(ibw_lasterr, "ibv_create_cq failed\n");
                return -1;
        }

        rc = ibv_req_notify_cq(pconn->cq, 0);
        if (rc) {
                sprintf(ibw_lasterr, "ibv_req_notify_cq failed with %d\n", rc);
                return rc;
        }

        /* init qp */
        memset(&init_attr, 0, sizeof(init_attr));
        init_attr.cap.max_send_wr = pctx->opts.max_send_wr;
        init_attr.cap.max_recv_wr = pctx->opts.max_recv_wr;
        init_attr.cap.max_recv_sge = 1;
        init_attr.cap.max_send_sge = 1;
        init_attr.qp_type = IBV_QPT_RC;
        init_attr.send_cq = pconn->cq;
        init_attr.recv_cq = pconn->cq;

        rc = rdma_create_qp(pconn->cm_id, pctx->pd, &init_attr);
        if (rc) {
                sprintf(ibw_lasterr, "rdma_create_qp failed with %d\n", rc);
                return rc;
        }
        /* elase result is in pconn->cm_id->qp */

        return ibw_fill_cq(conn);
}

static int ibw_refill_cq_recv(struct ibw_conn *conn)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        int     rc;
        struct ibv_sge list = {
                .addr   = (uintptr_t) NULL,
                .length = pctx->opts.recv_bufsize,
                .lkey   = pconn->mr_recv->lkey
        };
        struct ibv_recv_wr wr = {
                .wr_id      = 0,
                .sg_list    = &list,
                .num_sge    = 1,
        };
        struct ibv_recv_wr *bad_wr;

        DEBUG(10, ("ibw_refill_cq_recv(cmid: %u)\n", (uint32_t)pconn->cm_id));

        list.addr = (uintptr_t) pconn->buf_recv + pctx->opts.recv_bufsize * pconn->recv_index;
        wr.wr_id = pconn->recv_index;
        pconn->recv_index = (pconn->recv_index + 1) % pctx->opts.max_recv_wr;

        rc = ibv_post_recv(pconn->cm_id->qp, &wr, &bad_wr);
        if (rc) {
                sprintf(ibw_lasterr, "ibv_post_recv failed with %d\n", rc);
                DEBUG(0, (ibw_lasterr));
                return -2;
        }

        return 0;
}

static int ibw_fill_cq(struct ibw_conn *conn)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        int     i, rc;
        struct ibv_sge list = {
                .addr   = (uintptr_t) NULL,
                .length = pctx->opts.recv_bufsize,
                .lkey   = pconn->mr_recv->lkey
        };
        struct ibv_recv_wr wr = {
                .wr_id      = 0,
                .sg_list    = &list,
                .num_sge    = 1,
        };
        struct ibv_recv_wr *bad_wr;

        DEBUG(10, ("ibw_fill_cq(cmid: %u)\n", (uint32_t)pconn->cm_id));

        for(i = pctx->opts.max_recv_wr; i!=0; i--) {
                list.addr = (uintptr_t) pconn->buf_recv + pctx->opts.recv_bufsize * pconn->recv_index;
                wr.wr_id = pconn->recv_index;
                pconn->recv_index = (pconn->recv_index + 1) % pctx->opts.max_recv_wr;

                rc = ibv_post_recv(pconn->cm_id->qp, &wr, &bad_wr);
                if (rc) {
                        sprintf(ibw_lasterr, "ibv_post_recv failed with %d\n", rc);
                        DEBUG(0, (ibw_lasterr));
                        return -2;
                }
        }

        return 0;
}

static int ibw_manage_connect(struct ibw_conn *conn, struct rdma_cm_id *cma_id)
{
        struct rdma_conn_param conn_param;
        int     rc;

        DEBUG(10, ("ibw_manage_connect(cmid: %u)", (uint32_t)cma_id));
        rc = ibw_setup_cq_qp(conn);
        if (rc)
                return -1;

        /* cm connect */
        memset(&conn_param, 0, sizeof conn_param);
        conn_param.responder_resources = 1;
        conn_param.initiator_depth = 1;
        conn_param.retry_count = 10;

        rc = rdma_connect(cma_id, &conn_param);
        if (rc)
                sprintf(ibw_lasterr, "rdma_connect error %d\n", rc);

        return rc;
}

static void ibw_event_handler_cm(struct event_context *ev,
        struct fd_event *fde, uint16_t flags, void *private_data)
{
        int     rc;
        struct ibw_ctx  *ctx = talloc_get_type(private_data, struct ibw_ctx);
        struct ibw_ctx_priv *pctx = talloc_get_type(ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn *conn = NULL;
        struct ibw_conn_priv *pconn = NULL;
        struct rdma_cm_id *cma_id = NULL;
        struct rdma_cm_event *event = NULL;

        assert(ctx!=NULL);

        rc = rdma_get_cm_event(pctx->cm_channel, &event);
        if (rc) {
                ctx->state = IBWS_ERROR;
                sprintf(ibw_lasterr, "rdma_get_cm_event error %d\n", rc);
                goto error;
        }
        cma_id = event->id;

        DEBUG(10, ("cma_event type %d cma_id %p (%s)\n", event->event, cma_id,
                  (cma_id == pctx->cm_id) ? "parent" : "child"));

        switch (event->event) {
        case RDMA_CM_EVENT_ADDR_RESOLVED:
                /* continuing from ibw_connect ... */
                rc = rdma_resolve_route(cma_id, 2000);
                if (rc) {
                        sprintf(ibw_lasterr, "rdma_resolve_route error %d\n", rc);
                        goto error;
                }
                /* continued at RDMA_CM_EVENT_ROUTE_RESOLVED */
                break;

        case RDMA_CM_EVENT_ROUTE_RESOLVED:
                /* after RDMA_CM_EVENT_ADDR_RESOLVED: */
                assert(cma_id->context!=NULL);
                conn = talloc_get_type(cma_id->context, struct ibw_conn);

                rc = ibw_manage_connect(conn, cma_id);
                if (rc)
                        goto error;

                break;

        case RDMA_CM_EVENT_CONNECT_REQUEST:
                ctx->state = IBWS_CONNECT_REQUEST;
                conn = ibw_conn_new(ctx);
                pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
                pconn->cm_id = cma_id; /* !!! event will be freed but id not */
                cma_id->context = (void *)conn;
                DEBUG(10, ("pconn->cm_id %p\n", pconn->cm_id));

                conn->state = IBWC_INIT;
                pctx->connstate_func(ctx, conn);

                /* continued at ibw_accept when invoked by the func above */
                if (!pconn->is_accepted) {
                        talloc_free(conn);
                        DEBUG(10, ("pconn->cm_id %p wasn't accepted\n", pconn->cm_id));
                } else {
                        if (ibw_setup_cq_qp(conn))
                                goto error;
                }

                /* TODO: clarify whether if it's needed by upper layer: */
                ctx->state = IBWS_READY;
                pctx->connstate_func(ctx, NULL);

                /* NOTE: more requests can arrive until RDMA_CM_EVENT_ESTABLISHED ! */
                break;

        case RDMA_CM_EVENT_ESTABLISHED:
                /* expected after ibw_accept and ibw_connect[not directly] */
                DEBUG(0, ("ESTABLISHED (conn: %u)\n", (unsigned int)cma_id->context));
                conn = talloc_get_type(cma_id->context, struct ibw_conn);
                assert(conn!=NULL); /* important assumption */

                /* client conn is up */
                conn->state = IBWC_CONNECTED;

                /* both ctx and conn have changed */
                pctx->connstate_func(ctx, conn);
                break;

        case RDMA_CM_EVENT_ADDR_ERROR:
        case RDMA_CM_EVENT_ROUTE_ERROR:
        case RDMA_CM_EVENT_CONNECT_ERROR:
        case RDMA_CM_EVENT_UNREACHABLE:
        case RDMA_CM_EVENT_REJECTED:
                sprintf(ibw_lasterr, "cma event %d, error %d\n", event->event, event->status);
                goto error;

        case RDMA_CM_EVENT_DISCONNECTED:
                if (cma_id!=pctx->cm_id) {
                        DEBUG(0, ("client DISCONNECT event\n"));
                        conn = talloc_get_type(cma_id->context, struct ibw_conn);
                        conn->state = IBWC_DISCONNECTED;
                        pctx->connstate_func(NULL, conn);

                        talloc_free(conn);

                        /* if we are the last... */
                        if (ctx->conn_list==NULL)
                                rdma_disconnect(pctx->cm_id);
                } else {
                        DEBUG(0, ("server DISCONNECT event\n"));
                        ctx->state = IBWS_STOPPED; /* ??? TODO: try it... */
                        /* talloc_free(ctx) should be called within or after this func */
                        pctx->connstate_func(ctx, NULL);
                }
                break;

        case RDMA_CM_EVENT_DEVICE_REMOVAL:
                sprintf(ibw_lasterr, "cma detected device removal!\n");
                goto error;

        default:
                sprintf(ibw_lasterr, "unknown event %d\n", event->event);
                goto error;
        }

        if ((rc=rdma_ack_cm_event(event))) {
                sprintf(ibw_lasterr, "rdma_ack_cm_event failed with %d\n", rc);
                goto error;
        }

        return;
error:
        DEBUG(0, ("cm event handler: %s", ibw_lasterr));
        if (cma_id!=pctx->cm_id) {
                conn = talloc_get_type(cma_id->context, struct ibw_conn);
                if (conn)
                        conn->state = IBWC_ERROR;
                pctx->connstate_func(NULL, conn);
        } else {
                ctx->state = IBWS_ERROR;
                pctx->connstate_func(ctx, NULL);
        }
}

static void ibw_event_handler_verbs(struct event_context *ev,
        struct fd_event *fde, uint16_t flags, void *private_data)
{
        struct ibw_conn *conn = talloc_get_type(private_data, struct ibw_conn);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);

        struct ibv_wc wc;
        int rc;
        struct ibv_cq *ev_cq;
        void          *ev_ctx;

        DEBUG(10, ("ibw_event_handler_verbs(%u)\n", (uint32_t)flags));

        /* TODO: check whether if it's good to have more channels here... */
        rc = ibv_get_cq_event(pconn->verbs_channel, &ev_cq, &ev_ctx);
        if (rc) {
                sprintf(ibw_lasterr, "Failed to get cq_event with %d\n", rc);
                goto error;
        }
        if (ev_cq != pconn->cq) {
                sprintf(ibw_lasterr, "ev_cq(%u) != pconn->cq(%u)\n",
                        (unsigned int)ev_cq, (unsigned int)pconn->cq);
                goto error;
        }
        rc = ibv_req_notify_cq(pconn->cq, 0);
        if (rc) {
                sprintf(ibw_lasterr, "Couldn't request CQ notification (%d)\n", rc);
                goto error;
        }

        while((rc=ibv_poll_cq(pconn->cq, 1, &wc))==1) {
                if (wc.status) {
                        sprintf(ibw_lasterr, "cq completion failed status %d\n",
                                wc.status);
                        goto error;
                }

                switch(wc.opcode) {
                case IBV_WC_SEND:
                        DEBUG(10, ("send completion\n"));
                        if (ibw_wc_send(conn, &wc))
                                goto error;
                        break;

                case IBV_WC_RDMA_WRITE:
                        DEBUG(10, ("rdma write completion\n"));
                        break;
        
                case IBV_WC_RDMA_READ:
                        DEBUG(10, ("rdma read completion\n"));
                        break;

                case IBV_WC_RECV:
                        DEBUG(10, ("recv completion\n"));
                        if (ibw_wc_recv(conn, &wc))
                                goto error;
                        break;

                default:
                        sprintf(ibw_lasterr, "unknown completion %d\n", wc.opcode);
                        goto error;
                }
        }
        if (rc!=0) {
                sprintf(ibw_lasterr, "ibv_poll_cq error %d\n", rc);
                goto error;
        }

        return;
error:
        DEBUG(0, (ibw_lasterr));
        conn->state = IBWC_ERROR;
        pctx->connstate_func(NULL, conn);
}

static inline int ibw_wc_send(struct ibw_conn *conn, struct ibv_wc *wc)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        struct ibw_wr   *p;
        int     send_index;

        DEBUG(10, ("ibw_wc_send(cmid: %u, wr_id: %u, bl: %u)\n",
                (uint32_t)pconn->cm_id, (uint32_t)wc->wr_id, (uint32_t)wc->byte_len));

        assert(pconn->cm_id->qp->qp_num==wc->qp_num);
        assert(wc->wr_id > pctx->opts.max_recv_wr);
        send_index = wc->wr_id - pctx->opts.max_recv_wr;
        pconn->wr_sent--;

        if (send_index < pctx->opts.max_send_wr) {
                DEBUG(10, ("ibw_wc_send#1 %u", (int)wc->wr_id));
                p = pconn->wr_index[send_index];
                if (p->msg_large)
                        ibw_free_mr(&p->msg_large, &p->mr_large);
                DLIST_REMOVE(pconn->wr_list_used, p);
                DLIST_ADD(pconn->wr_list_avail, p);
        } else { /* "extra" request - not optimized */
                DEBUG(10, ("ibw_wc_send#2 %u", (int)wc->wr_id));
                for(p=pconn->extra_sent; p!=NULL; p=p->next)
                        if (p->wr_id==(int)wc->wr_id)
                                break;
                if (p==NULL) {
                        sprintf(ibw_lasterr, "failed to find wr_id %d\n", (int)wc->wr_id);
                                return -1;
                }
                ibw_free_mr(&p->msg_large, &p->mr_large);
                DLIST_REMOVE(pconn->extra_sent, p);
                DLIST_ADD(pconn->extra_avail, p);
        }

        if (pconn->queue) {
                char    *buf;

                DEBUG(10, ("ibw_wc_send#queue %u", (int)wc->wr_id));
                p = pconn->queue;
                DLIST_REMOVE(pconn->queue, p);

                buf = (p->msg_large!=NULL) ? p->msg_large : p->msg;
                ibw_send(conn, buf, p, ntohl(*(uint32_t *)buf));
        }

        return 0;
}

static inline int ibw_append_to_part(struct ibw_conn_priv *pconn,
        struct ibw_part *part, char **pp, uint32_t add_len, int info)
{
        DEBUG(10, ("ibw_append_to_part: cmid=%u, (bs=%u, len=%u, tr=%u), al=%u, i=%u\n",
                (uint32_t)pconn->cm_id, part->bufsize, part->len, part->to_read, add_len, info));

        /* allocate more if necessary - it's an "evergrowing" buffer... */
        if (part->len + add_len > part->bufsize) {
                if (part->buf==NULL) {
                        assert(part->len==0);
                        part->buf = talloc_size(pconn, add_len);
                        if (part->buf==NULL) {
                                sprintf(ibw_lasterr, "recv talloc_size error (%u) #%d\n",
                                        add_len, info);
                                return -1;
                        }
                        part->bufsize = add_len;
                } else {
                        part->buf = talloc_realloc_size(pconn,
                                part->buf, part->len + add_len);
                        if (part->buf==NULL) {
                                sprintf(ibw_lasterr, "recv realloc error (%u + %u) #%d\n",
                                        part->len, add_len, info);
                                return -1;
                        }
                }
                part->bufsize = part->len + add_len;
        }

        /* consume pp */
        memcpy(part->buf + part->len, *pp, add_len);
        *pp += add_len;
        part->len += add_len;
        part->to_read -= add_len;

        return 0;
}

static inline int ibw_wc_mem_threshold(struct ibw_conn_priv *pconn,
        struct ibw_part *part, uint32_t threshold)
{
        DEBUG(10, ("ibw_wc_mem_threshold: cmid=%u, (bs=%u, len=%u, tr=%u), thr=%u\n",
                (uint32_t)pconn->cm_id, part->bufsize, part->len, part->to_read, threshold));

        if (part->bufsize > threshold) {
                DEBUG(3, ("ibw_wc_mem_threshold: cmid=%u, %u > %u\n",
                        (uint32_t)pconn->cm_id, part->bufsize, threshold));
                talloc_free(part->buf);
                part->buf = talloc_size(pconn, threshold);
                if (part->buf==NULL) {
                        sprintf(ibw_lasterr, "talloc_size failed\n");
                        return -1;
                }
                part->bufsize = threshold;
        }
        return 0;
}

static inline int ibw_wc_recv(struct ibw_conn *conn, struct ibv_wc *wc)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        struct ibw_part *part = &pconn->part;
        char    *p;
        uint32_t        remain = wc->byte_len;

        DEBUG(10, ("ibw_wc_recv: cmid=%u, wr_id: %u, bl: %u\n",
                (uint32_t)pconn->cm_id, (uint32_t)wc->wr_id, remain));

        assert(pconn->cm_id->qp->qp_num==wc->qp_num);
        assert((int)wc->wr_id < pctx->opts.max_recv_wr);
        assert(wc->byte_len <= pctx->opts.recv_bufsize);

        p = pconn->buf_recv + ((int)wc->wr_id * pctx->opts.recv_bufsize);

        while(remain) {
                /* here always true: (part->len!=0 && part->to_read!=0) ||
                        (part->len==0 && part->to_read==0) */
                if (part->len) { /* is there a partial msg to be continued? */
                        int read_len = (part->to_read<=remain) ? part->to_read : remain;
                        if (ibw_append_to_part(pconn, part, &p, read_len, 421))
                                goto error;
                        remain -= read_len;

                        if (part->len<=sizeof(uint32_t) && part->to_read==0) {
                                assert(part->len==sizeof(uint32_t));
                                /* set it again now... */
                                part->to_read = ntohl(*((uint32_t *)(part->buf)));
                                if (part->to_read<sizeof(uint32_t)) {
                                        sprintf(ibw_lasterr, "got msglen=%u #2\n", part->to_read);
                                        goto error;
                                }
                                part->to_read -= sizeof(uint32_t); /* it's already read */
                        }

                        if (part->to_read==0) {
                                pctx->receive_func(conn, part->buf, part->len);
                                part->len = 0; /* tells not having partial data (any more) */
                                if (ibw_wc_mem_threshold(pconn, part, pctx->opts.recv_threshold))
                                        goto error;
                        }
                } else {
                        if (remain>=sizeof(uint32_t)) {
                                uint32_t msglen = ntohl(*(uint32_t *)p);
                                if (msglen<sizeof(uint32_t)) {
                                        sprintf(ibw_lasterr, "got msglen=%u\n", msglen);
                                        goto error;
                                }

                                /* mostly awaited case: */
                                if (msglen<=remain) {
                                        pctx->receive_func(conn, p, msglen);
                                        p += msglen;
                                        remain -= msglen;
                                } else {
                                        part->to_read = msglen;
                                        /* part->len is already 0 */
                                        if (ibw_append_to_part(pconn, part, &p, remain, 422))
                                                goto error;
                                        remain = 0; /* to be continued ... */
                                        /* part->to_read > 0 here */
                                }
                        } else { /* edge case: */
                                part->to_read = sizeof(uint32_t);
                                /* part->len is already 0 */
                                if (ibw_append_to_part(pconn, part, &p, remain, 423))
                                        goto error;
                                remain = 0;
                                /* part->to_read > 0 here */
                        }
                }
        } /* <remain> is always decreased at least by 1 */

        if (ibw_refill_cq_recv(conn))
                goto error;

        return 0;

error:
        DEBUG(0, ("ibw_wc_recv error: %s", ibw_lasterr));
        return -1;
}

static int ibw_process_init_attrs(struct ibw_initattr *attr, int nattr, struct ibw_opts *opts)
{
        int     i;
        const char *name, *value;

        DEBUG(10, ("ibw_process_init_attrs: nattr: %d\n", nattr));

        opts->max_send_wr = 256;
        opts->max_recv_wr = 1024;
        opts->avg_send_size = 1024;
        opts->recv_bufsize = 256;
        opts->recv_threshold = 1 * 1024 * 1024;

        for(i=0; i<nattr; i++) {
                name = attr[i].name;
                value = attr[i].value;

                assert(name!=NULL && value!=NULL);
                if (strcmp(name, "max_send_wr")==0)
                        opts->max_send_wr = atoi(value);
                else if (strcmp(name, "max_recv_wr")==0)
                        opts->max_recv_wr = atoi(value);
                else if (strcmp(name, "avg_send_size")==0)
                        opts->avg_send_size = atoi(value);
                else if (strcmp(name, "recv_bufsize")==0)
                        opts->recv_bufsize = atoi(value);
                else if (strcmp(name, "recv_threshold")==0)
                        opts->recv_threshold = atoi(value);
                else {
                        sprintf(ibw_lasterr, "ibw_init: unknown name %s\n", name);
                        return -1;
                }
        }
        return 0;
}

struct ibw_ctx *ibw_init(struct ibw_initattr *attr, int nattr,
        void *ctx_userdata,
        ibw_connstate_fn_t ibw_connstate,
        ibw_receive_fn_t ibw_receive,
        struct event_context *ectx)
{
        struct ibw_ctx *ctx = talloc_zero(NULL, struct ibw_ctx);
        struct ibw_ctx_priv *pctx;
        int     rc;

        DEBUG(10, ("ibw_init(ctx_userdata: %u, ectx: %u)\n",
                (uint32_t)ctx_userdata, (uint32_t)ectx));

        /* initialize basic data structures */
        memset(ibw_lasterr, 0, IBW_LASTERR_BUFSIZE);

        assert(ctx!=NULL);
        ibw_lasterr[0] = '\0';
        talloc_set_destructor(ctx, ibw_ctx_destruct);
        ctx->ctx_userdata = ctx_userdata;

        pctx = talloc_zero(ctx, struct ibw_ctx_priv);
        talloc_set_destructor(pctx, ibw_ctx_priv_destruct);
        ctx->internal = (void *)pctx;
        assert(pctx!=NULL);

        pctx->connstate_func = ibw_connstate;
        pctx->receive_func = ibw_receive;

        pctx->ectx = ectx;

        /* process attributes */
        if (ibw_process_init_attrs(attr, nattr, &pctx->opts))
                goto cleanup;

        /* init cm */
        pctx->cm_channel = rdma_create_event_channel();
        if (!pctx->cm_channel) {
                sprintf(ibw_lasterr, "rdma_create_event_channel error %d\n", errno);
                goto cleanup;
        }

        pctx->cm_channel_event = event_add_fd(pctx->ectx, pctx,
                pctx->cm_channel->fd, EVENT_FD_READ, ibw_event_handler_cm, ctx);

        rc = rdma_create_id(pctx->cm_channel, &pctx->cm_id, ctx, RDMA_PS_TCP);
        if (rc) {
                rc = errno;
                sprintf(ibw_lasterr, "rdma_create_id error %d\n", rc);
                goto cleanup;
        }
        DEBUG(10, ("created cm_id %p\n", pctx->cm_id));

        /* init verbs */
        pctx->pd = ibv_alloc_pd(pctx->cm_id->verbs);
        if (!pctx->pd) {
                sprintf(ibw_lasterr, "ibv_alloc_pd failed %d\n", errno);
                goto cleanup;
        }
        DEBUG(10, ("created pd %p\n", pctx->pd));

        pctx->pagesize = sysconf(_SC_PAGESIZE);

        return ctx;
        /* don't put code here */
cleanup:
        DEBUG(0, (ibw_lasterr));

        if (ctx)
                talloc_free(ctx);

        return NULL;
}

int ibw_stop(struct ibw_ctx *ctx)
{
        struct ibw_conn *p;

        DEBUG(10, ("ibw_stop\n"));
        for(p=ctx->conn_list; p!=NULL; p=p->next) {
                if (ctx->state==IBWC_ERROR || ctx->state==IBWC_CONNECTED) {
                        if (ibw_disconnect(p))
                                return -1;
                }
        }

        return 0;
}

int ibw_bind(struct ibw_ctx *ctx, struct sockaddr_in *my_addr)
{
        struct ibw_ctx_priv *pctx = (struct ibw_ctx_priv *)ctx->internal;
        int     rc;

        DEBUG(10, ("ibw_bind: addr=%s, port=%u\n",
                inet_ntoa(my_addr->sin_addr), my_addr->sin_port));
        rc = rdma_bind_addr(pctx->cm_id, (struct sockaddr *) my_addr);
        if (rc) {
                sprintf(ibw_lasterr, "rdma_bind_addr error %d\n", rc);
                DEBUG(0, (ibw_lasterr));
                return rc;
        }
        DEBUG(10, ("rdma_bind_addr successful\n"));

        return 0;
}

int ibw_listen(struct ibw_ctx *ctx, int backlog)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(ctx->internal, struct ibw_ctx_priv);
        int     rc;

        DEBUG(10, ("ibw_listen\n"));
        rc = rdma_listen(pctx->cm_id, backlog);
        if (rc) {
                sprintf(ibw_lasterr, "rdma_listen failed: %d\n", rc);
                DEBUG(0, (ibw_lasterr));
                return rc;
        }       

        return 0;
}

int ibw_accept(struct ibw_ctx *ctx, struct ibw_conn *conn, void *conn_userdata)
{
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        struct rdma_conn_param  conn_param;
        int     rc;

        DEBUG(10, ("ibw_accept: cmid=%u\n", (uint32_t)pconn->cm_id));
        conn->conn_userdata = conn_userdata;

        memset(&conn_param, 0, sizeof(struct rdma_conn_param));
        conn_param.responder_resources = 1;
        conn_param.initiator_depth = 1;
        rc = rdma_accept(pconn->cm_id, &conn_param);
        if (rc) {
                sprintf(ibw_lasterr, "rdma_accept failed %d\n", rc);
                DEBUG(0, (ibw_lasterr));
                return -1;;
        }

        pconn->is_accepted = 1;

        /* continued at RDMA_CM_EVENT_ESTABLISHED */

        return 0;
}

int ibw_connect(struct ibw_ctx *ctx, struct sockaddr_in *serv_addr, void *conn_userdata)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn *conn = NULL;
        struct ibw_conn_priv *pconn = NULL;
        int     rc;

        DEBUG(10, ("ibw_connect: cmid=%u, addr=%s, port=%u\n", (uint32_t)pconn->cm_id,
                inet_ntoa(serv_addr->sin_addr), serv_addr->sin_port));
        conn = ibw_conn_new(ctx);
        conn->conn_userdata = conn_userdata;
        pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);

        rc = rdma_create_id(pctx->cm_channel, &pconn->cm_id, conn, RDMA_PS_TCP);
        if (rc) {
                rc = errno;
                sprintf(ibw_lasterr, "rdma_create_id error %d\n", rc);
                return rc;
        }

        rc = rdma_resolve_addr(pconn->cm_id, NULL, (struct sockaddr *) &serv_addr, 2000);
        if (rc) {
                sprintf(ibw_lasterr, "rdma_resolve_addr error %d\n", rc);
                DEBUG(0, (ibw_lasterr));
                return -1;
        }

        /* continued at RDMA_CM_EVENT_ADDR_RESOLVED */

        return 0;
}

int ibw_disconnect(struct ibw_conn *conn)
{
        int     rc;
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);

        DEBUG(10, ("ibw_disconnect: cmid=%u\n", (uint32_t)pconn->cm_id));

        rc = rdma_disconnect(pctx->cm_id);
        if (rc) {
                sprintf(ibw_lasterr, "ibw_disconnect failed with %d", rc);
                DEBUG(0, (ibw_lasterr));
                return rc;
        }

        /* continued at RDMA_CM_EVENT_DISCONNECTED */

        return 0;
}

int ibw_alloc_send_buf(struct ibw_conn *conn, void **buf, void **key, uint32_t len)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        struct ibw_wr *p = pconn->wr_list_avail;

        if (p!=NULL) {
                DEBUG(10, ("ibw_alloc_send_buf#1: cmid=%u, len=%d\n", (uint32_t)pconn->cm_id, len));

                DLIST_REMOVE(pconn->wr_list_avail, p);
                DLIST_ADD(pconn->wr_list_used, p);

                if (len + sizeof(uint32_t) <= pctx->opts.avg_send_size) {
                        *buf = (void *)(p->msg + sizeof(uint32_t));
                } else {
                        p->msg_large = ibw_alloc_mr(pctx, pconn, len + sizeof(uint32_t), &p->mr_large);
                        if (!p->msg_large) {
                                sprintf(ibw_lasterr, "ibw_alloc_mr#1 failed\n");
                                goto error;
                        }
                        *buf = (void *)(p->msg_large + sizeof(uint32_t));
                }
        } else {
                DEBUG(10, ("ibw_alloc_send_buf#2: cmid=%u, len=%d\n", (uint32_t)pconn->cm_id, len));
                /* not optimized */
                p = pconn->extra_avail;
                if (!p) {
                        p = pconn->extra_avail = talloc_zero(pconn, struct ibw_wr);
                        if (p==NULL) {
                                sprintf(ibw_lasterr, "talloc_zero failed (emax: %u)", pconn->extra_max);
                                goto error;
                        }
                        p->wr_id = pctx->opts.max_send_wr + pconn->extra_max;
                        pconn->extra_max++;
                        switch(pconn->extra_max) {
                                case 1: DEBUG(2, ("warning: queue performed\n")); break;
                                case 10: DEBUG(0, ("warning: queue reached 10\n")); break;
                                case 100: DEBUG(0, ("warning: queue reached 100\n")); break;
                                case 1000: DEBUG(0, ("warning: queue reached 1000\n")); break;
                                default: break;
                        }
                }
                DLIST_REMOVE(pconn->extra_avail, p);

                p->msg_large = ibw_alloc_mr(pctx, pconn, len + sizeof(uint32_t), &p->mr_large);
                if (!p->msg_large) {
                        sprintf(ibw_lasterr, "ibw_alloc_mr#2 failed");
                        goto error;
                }
                *buf = (void *)(p->msg_large + sizeof(uint32_t));
        }

        *key = (void *)p;

        return 0;
error:
        DEBUG(0, ("ibw_alloc_send_buf error: %s\n", ibw_lasterr));
        return -1;
}


int ibw_send(struct ibw_conn *conn, void *buf, void *key, uint32_t len)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        struct ibw_wr *p = talloc_get_type(key, struct ibw_wr);
        int     rc;

        *((uint32_t *)buf) = htonl(len);

        /* can we send it right now? */
        if (pconn->wr_sent<=pctx->opts.max_send_wr) {
                struct ibv_sge list = {
                        .addr   = (uintptr_t) NULL,
                        .length = len,
                        .lkey   = 0
                };
                struct ibv_send_wr wr = {
                        .wr_id      = p->wr_id + pctx->opts.max_recv_wr,
                        .sg_list    = &list,
                        .num_sge    = 1,
                        .opcode     = IBV_WR_SEND,
                        .send_flags = IBV_SEND_SIGNALED,
                };
                struct ibv_send_wr *bad_wr;

                DEBUG(10, ("ibw_wc_send#1(cmid: %u, wrid: %u, n: %d)\n",
                        (uint32_t)pconn->cm_id, (uint32_t)wr.wr_id, len));

                if (p->msg_large==NULL) {
                        list.lkey = pconn->mr_send->lkey;
                        list.addr = (uintptr_t) p->msg;
                } else {
                        assert(p->mr_large!=NULL);
                        list.lkey = p->mr_large->lkey;
                        list.addr = (uintptr_t) p->msg_large;
                }

                rc = ibv_post_send(pconn->cm_id->qp, &wr, &bad_wr);
                if (rc) {
                        sprintf(ibw_lasterr, "ibv_post_send error %d (%d)\n",
                                rc, pconn->wr_sent);
                        DEBUG(0, (ibw_lasterr));
                } else {
                        /* good case */
                        if (p->wr_id>=pctx->opts.max_send_wr) {
                                /* we don't have prepared index for this, so that
                                 * we will have to find this later on */
                                DLIST_ADD(pconn->extra_sent, p);
                        }
                        pconn->wr_sent++;
                }
                return rc;
        } /* else put the request into our own queue: */

        DEBUG(10, ("ibw_wc_send#2(cmid: %u, len: %u)\n", (uint32_t)pconn->cm_id, len));

        /* to be sent by ibw_wc_send */
        DLIST_ADD_END(pconn->queue, p, struct ibw_wr *); /* TODO: optimize */

        return 0;
}

int ibw_cancel_send_buf(struct ibw_conn *conn, void *buf, void *key)
{
        struct ibw_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        struct ibw_wr *p = talloc_get_type(key, struct ibw_wr);

        assert(p!=NULL);
        assert(buf!=NULL);
        assert(conn!=NULL);

        if (p->msg_large)
                ibw_free_mr(&p->msg_large, &p->mr_large);

        /* parallel case */
        if (p->wr_id < pctx->opts.max_send_wr) {
                DEBUG(10, ("ibw_cancel_send_buf#1 %u", (int)p->wr_id));
                DLIST_REMOVE(pconn->wr_list_used, p);
                DLIST_ADD(pconn->wr_list_avail, p);
        } else { /* "extra" packet */
                DEBUG(10, ("ibw_cancel_send_buf#2 %u", (int)p->wr_id));
                DLIST_ADD(pconn->extra_avail, p);
        }

        return 0;
}

const char *ibw_getLastError(void)
{
        return ibw_lasterr;
}