add a machinereadable version of ctdb stats/statistics
[metze/ctdb/wip.git] / ib / ibwrapper.c
index dec183f900aeb430138d324d486d46220022d852..f6e71687f324856d16868e61ce8e9f458d512822 100644 (file)
@@ -8,7 +8,7 @@
  *
  * 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
+ * the Free Software Foundation; either version 3 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
@@ -17,8 +17,7 @@
  * 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.
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
 #include <stdlib.h>
@@ -38,6 +37,8 @@
 #include "lib/events/events.h"
 #include "ibwrapper.h"
 
+#include <infiniband/kern-abi.h>
+#include <rdma/rdma_cma_abi.h>
 #include <rdma/rdma_cma.h>
 
 #include "ibwrapper_internal.h"
 #define IBW_LASTERR_BUFSIZE 512
 static char ibw_lasterr[IBW_LASTERR_BUFSIZE];
 
+#define IBW_MAX_SEND_WR 256
+#define IBW_MAX_RECV_WR 1024
+#define IBW_RECV_BUFSIZE 256
+#define IBW_RECV_THRESHOLD (1 * 1024 * 1024)
+
 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 int ibw_wc_recv(struct ibw_conn *conn, struct ibv_wc *wc);
+static int ibw_wc_send(struct ibw_conn *conn, struct ibv_wc *wc);
+static int ibw_send_packet(struct ibw_conn *conn, void *buf, struct ibw_wr *p, uint32_t len);
 
 static void *ibw_alloc_mr(struct ibw_ctx_priv *pctx, struct ibw_conn_priv *pconn,
-       int n, struct ibv_mr **ppmr)
+       uint32_t n, struct ibv_mr **ppmr)
 {
        void *buf;
+
+       DEBUG(DEBUG_DEBUG, ("ibw_alloc_mr(cmid=%p, n=%u)\n", 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);
+       *ppmr = ibv_reg_mr(pconn->pd, buf, n, IBV_ACCESS_LOCAL_WRITE);
        if (!*ppmr) {
                sprintf(ibw_lasterr, "couldn't allocate mr\n");
                free(buf);
@@ -74,6 +83,7 @@ static void *ibw_alloc_mr(struct ibw_ctx_priv *pctx, struct ibw_conn_priv *pconn
 
 static void ibw_free_mr(char **ppbuf, struct ibv_mr **ppmr)
 {
+       DEBUG(DEBUG_DEBUG, ("ibw_free_mr(%p %p)\n", *ppbuf, *ppmr));
        if (*ppmr!=NULL) {
                ibv_dereg_mr(*ppmr);
                *ppmr = NULL;
@@ -92,8 +102,9 @@ static int ibw_init_memory(struct ibw_conn *conn)
        int     i;
        struct ibw_wr   *p;
 
+       DEBUG(DEBUG_DEBUG, ("ibw_init_memory(cmid: %p)\n", pconn->cm_id));
        pconn->buf_send = ibw_alloc_mr(pctx, pconn,
-               opts->max_send_wr * opts->avg_send_size, &pconn->mr_send);
+               opts->max_send_wr * opts->recv_bufsize, &pconn->mr_send);
        if (!pconn->buf_send) {
                sprintf(ibw_lasterr, "couldn't allocate work send buf\n");
                return -1;
@@ -111,8 +122,8 @@ static int ibw_init_memory(struct ibw_conn *conn)
 
        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;
+               p->buf = pconn->buf_send + (i * opts->recv_bufsize);
+               p->wr_id = i;
 
                DLIST_ADD(pconn->wr_list_avail, p);
        }
@@ -122,10 +133,7 @@ static int ibw_init_memory(struct ibw_conn *conn)
 
 static int ibw_ctx_priv_destruct(struct ibw_ctx_priv *pctx)
 {
-       if (pctx->pd) {
-               ibv_dealloc_pd(pctx->pd);
-               pctx->pd = NULL;
-       }
+       DEBUG(DEBUG_DEBUG, ("ibw_ctx_priv_destruct(%p)\n", pctx));
 
        /* destroy cm */
        if (pctx->cm_channel) {
@@ -147,64 +155,92 @@ static int ibw_ctx_priv_destruct(struct ibw_ctx_priv *pctx)
 
 static int ibw_ctx_destruct(struct ibw_ctx *ctx)
 {
+       DEBUG(DEBUG_DEBUG, ("ibw_ctx_destruct(%p)\n", ctx));
        return 0;
 }
 
 static int ibw_conn_priv_destruct(struct ibw_conn_priv *pconn)
 {
-       /* free memory regions */
-       ibw_free_mr(&pconn->buf_send, &pconn->mr_send);
-       ibw_free_mr(&pconn->buf_recv, &pconn->mr_recv);
+       DEBUG(DEBUG_DEBUG, ("ibw_conn_priv_destruct(%p, cmid: %p)\n",
+               pconn, pconn->cm_id));
 
        /* 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);
+       if (pconn->cm_id!=NULL && pconn->cm_id->qp!=NULL) {
+               rdma_destroy_qp(pconn->cm_id);
                pconn->cm_id->qp = NULL;
        }
-       if (pconn->cq) {
+
+       if (pconn->cq!=NULL) {
                ibv_destroy_cq(pconn->cq);
                pconn->cq = NULL;
        }
-       if (pconn->verbs_channel) {
+
+       if (pconn->verbs_channel!=NULL) {
                ibv_destroy_comp_channel(pconn->verbs_channel);
                pconn->verbs_channel = NULL;
        }
+
+       /* must be freed here because its order is important */
        if (pconn->verbs_channel_event) {
-               /* TODO: do we have to do this here? */
                talloc_free(pconn->verbs_channel_event);
                pconn->verbs_channel_event = NULL;
        }
+
+       /* free memory regions */
+       ibw_free_mr(&pconn->buf_send, &pconn->mr_send);
+       ibw_free_mr(&pconn->buf_recv, &pconn->mr_recv);
+
+       if (pconn->pd) {
+               ibv_dealloc_pd(pconn->pd);
+               pconn->pd = NULL;
+               DEBUG(DEBUG_DEBUG, ("pconn=%p pd deallocated\n", pconn));
+       }
+
        if (pconn->cm_id) {
                rdma_destroy_id(pconn->cm_id);
                pconn->cm_id = NULL;
+               DEBUG(DEBUG_DEBUG, ("pconn=%p cm_id destroyed\n", pconn));
        }
+
+       return 0;
+}
+
+static int ibw_wr_destruct(struct ibw_wr *wr)
+{
+       if (wr->buf_large!=NULL)
+               ibw_free_mr(&wr->buf_large, &wr->mr_large);
        return 0;
 }
 
 static int ibw_conn_destruct(struct ibw_conn *conn)
 {
+       DEBUG(DEBUG_DEBUG, ("ibw_conn_destruct(%p)\n", 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 *ibw_conn_new(struct ibw_ctx *ctx, TALLOC_CTX *mem_ctx)
 {
        struct ibw_conn *conn;
        struct ibw_conn_priv *pconn;
 
-       conn = talloc_zero(ctx, struct ibw_conn);
+       assert(ctx!=NULL);
+
+       conn = talloc_zero(mem_ctx, struct ibw_conn);
        assert(conn!=NULL);
        talloc_set_destructor(conn, ibw_conn_destruct);
 
-       pconn = talloc_zero(ctx, struct ibw_conn_priv);
+       pconn = talloc_zero(conn, struct ibw_conn_priv);
        assert(pconn!=NULL);
        talloc_set_destructor(pconn, ibw_conn_priv_destruct);
 
        conn->ctx = ctx;
+       conn->internal = (void *)pconn;
 
        DLIST_ADD(ctx->conn_list, conn);
 
@@ -216,11 +252,10 @@ 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;
+       struct ibv_qp_attr attr;
        int rc;
 
-       /* init mr */
-       if (ibw_init_memory(conn))
-               return -1;
+       DEBUG(DEBUG_DEBUG, ("ibw_setup_cq_qp(cmid: %p)\n", pconn->cm_id));
 
        /* init verbs */
        pconn->verbs_channel = ibv_create_comp_channel(pconn->cm_id->verbs);
@@ -228,11 +263,22 @@ static int ibw_setup_cq_qp(struct ibw_conn *conn)
                sprintf(ibw_lasterr, "ibv_create_comp_channel failed %d\n", errno);
                return -1;
        }
-       DEBUG(10, ("created channel %p\n", pconn->verbs_channel));
+       DEBUG(DEBUG_DEBUG, ("created channel %p\n", pconn->verbs_channel));
 
-       pconn->verbs_channel_event = event_add_fd(pctx->ectx, conn,
+       pconn->verbs_channel_event = event_add_fd(pctx->ectx, NULL, /* not pconn or conn */
                pconn->verbs_channel->fd, EVENT_FD_READ, ibw_event_handler_verbs, conn);
 
+       pconn->pd = ibv_alloc_pd(pconn->cm_id->verbs);
+       if (!pconn->pd) {
+               sprintf(ibw_lasterr, "ibv_alloc_pd failed %d\n", errno);
+               return -1;
+       }
+       DEBUG(DEBUG_DEBUG, ("created pd %p\n", pconn->pd));
+
+       /* init mr */
+       if (ibw_init_memory(conn))
+               return -1;
+
        /* init cq */
        pconn->cq = ibv_create_cq(pconn->cm_id->verbs,
                pctx->opts.max_recv_wr + pctx->opts.max_send_wr,
@@ -258,13 +304,19 @@ static int ibw_setup_cq_qp(struct ibw_conn *conn)
        init_attr.send_cq = pconn->cq;
        init_attr.recv_cq = pconn->cq;
 
-       rc = rdma_create_qp(pconn->cm_id, pctx->pd, &init_attr);
+       rc = rdma_create_qp(pconn->cm_id, pconn->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 */
 
+       rc = ibv_query_qp(pconn->cm_id->qp, &attr, IBV_QP_PATH_MTU, &init_attr);
+       if (rc) {
+               sprintf(ibw_lasterr, "ibv_query_qp failed with %d\n", rc);
+               return rc;
+       }
+
        return ibw_fill_cq(conn);
 }
 
@@ -274,25 +326,27 @@ static int ibw_refill_cq_recv(struct ibw_conn *conn)
        struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        int     rc;
        struct ibv_sge list = {
-               .addr   = (uintptr_t) NULL,
+               .addr   = (uintptr_t) NULL, /* filled below */
                .length = pctx->opts.recv_bufsize,
-               .lkey   = pconn->mr_recv->lkey
+               .lkey   = pconn->mr_recv->lkey /* always the same */
        };
        struct ibv_recv_wr wr = {
-               .wr_id      = 0,
+               .wr_id      = 0, /* filled below */
                .sg_list    = &list,
                .num_sge    = 1,
        };
        struct ibv_recv_wr *bad_wr;
 
+       DEBUG(DEBUG_DEBUG, ("ibw_refill_cq_recv(cmid: %p)\n", 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));
+               sprintf(ibw_lasterr, "refill/ibv_post_recv failed with %d\n", rc);
+               DEBUG(DEBUG_ERR, (ibw_lasterr));
                return -2;
        }
 
@@ -305,17 +359,19 @@ static int ibw_fill_cq(struct ibw_conn *conn)
        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,
+               .addr   = (uintptr_t) NULL, /* filled below */
                .length = pctx->opts.recv_bufsize,
-               .lkey   = pconn->mr_recv->lkey
+               .lkey   = pconn->mr_recv->lkey /* always the same */
        };
        struct ibv_recv_wr wr = {
-               .wr_id      = 0,
+               .wr_id      = 0, /* filled below */
                .sg_list    = &list,
                .num_sge    = 1,
        };
        struct ibv_recv_wr *bad_wr;
 
+       DEBUG(DEBUG_DEBUG, ("ibw_fill_cq(cmid: %p)\n", 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;
@@ -323,8 +379,8 @@ static int ibw_fill_cq(struct ibw_conn *conn)
 
                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));
+                       sprintf(ibw_lasterr, "fill/ibv_post_recv failed with %d\n", rc);
+                       DEBUG(DEBUG_ERR, (ibw_lasterr));
                        return -2;
                }
        }
@@ -332,13 +388,15 @@ static int ibw_fill_cq(struct ibw_conn *conn)
        return 0;
 }
 
-static int ibw_manage_connect(struct ibw_conn *conn, struct rdma_cm_id *cma_id)
+static int ibw_manage_connect(struct ibw_conn *conn)
 {
        struct rdma_conn_param conn_param;
+       struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
        int     rc;
 
-       rc = ibw_setup_cq_qp(conn);
-       if (rc)
+       DEBUG(DEBUG_DEBUG, ("ibw_manage_connect(cmid: %p)\n", pconn->cm_id));
+
+       if (ibw_setup_cq_qp(conn))
                return -1;
 
        /* cm connect */
@@ -347,7 +405,7 @@ static int ibw_manage_connect(struct ibw_conn *conn, struct rdma_cm_id *cma_id)
        conn_param.initiator_depth = 1;
        conn_param.retry_count = 10;
 
-       rc = rdma_connect(cma_id, &conn_param);
+       rc = rdma_connect(pconn->cm_id, &conn_param);
        if (rc)
                sprintf(ibw_lasterr, "rdma_connect error %d\n", rc);
 
@@ -370,16 +428,18 @@ static void ibw_event_handler_cm(struct event_context *ev,
        rc = rdma_get_cm_event(pctx->cm_channel, &event);
        if (rc) {
                ctx->state = IBWS_ERROR;
+               event = NULL;
                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,
+       DEBUG(DEBUG_DEBUG, ("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:
+               DEBUG(DEBUG_DEBUG, ("RDMA_CM_EVENT_ADDR_RESOLVED\n"));
                /* continuing from ibw_connect ... */
                rc = rdma_resolve_route(cma_id, 2000);
                if (rc) {
@@ -390,34 +450,39 @@ static void ibw_event_handler_cm(struct event_context *ev,
                break;
 
        case RDMA_CM_EVENT_ROUTE_RESOLVED:
+               DEBUG(DEBUG_DEBUG, ("RDMA_CM_EVENT_ROUTE_RESOLVED\n"));
                /* 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);
+               rc = ibw_manage_connect(conn);
                if (rc)
                        goto error;
 
                break;
 
        case RDMA_CM_EVENT_CONNECT_REQUEST:
+               DEBUG(DEBUG_DEBUG, ("RDMA_CM_EVENT_CONNECT_REQUEST\n"));
                ctx->state = IBWS_CONNECT_REQUEST;
-               conn = ibw_conn_new(ctx);
+               conn = ibw_conn_new(ctx, 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));
+               DEBUG(DEBUG_DEBUG, ("pconn->cm_id %p\n", pconn->cm_id));
+
+               if (ibw_setup_cq_qp(conn))
+                       goto error;
 
                conn->state = IBWC_INIT;
                pctx->connstate_func(ctx, conn);
 
                /* continued at ibw_accept when invoked by the func above */
                if (!pconn->is_accepted) {
+                       rc = rdma_reject(cma_id, NULL, 0);
+                       if (rc)
+                               DEBUG(DEBUG_ERR, ("rdma_reject failed with rc=%d\n", rc));
                        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;
+                       DEBUG(DEBUG_DEBUG, ("pconn->cm_id %p wasn't accepted\n", pconn->cm_id));
                }
 
                /* TODO: clarify whether if it's needed by upper layer: */
@@ -429,10 +494,12 @@ static void ibw_event_handler_cm(struct event_context *ev,
 
        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));
+               DEBUG(DEBUG_INFO, ("ESTABLISHED (conn: %p)\n", cma_id->context));
                conn = talloc_get_type(cma_id->context, struct ibw_conn);
                assert(conn!=NULL); /* important assumption */
 
+               DEBUG(DEBUG_DEBUG, ("ibw_setup_cq_qp succeeded (cmid=%p)\n", cma_id));
+
                /* client conn is up */
                conn->state = IBWC_CONNECTED;
 
@@ -441,30 +508,40 @@ static void ibw_event_handler_cm(struct event_context *ev,
                break;
 
        case RDMA_CM_EVENT_ADDR_ERROR:
+               sprintf(ibw_lasterr, "RDMA_CM_EVENT_ADDR_ERROR, error %d\n", event->status);
        case RDMA_CM_EVENT_ROUTE_ERROR:
+               sprintf(ibw_lasterr, "RDMA_CM_EVENT_ROUTE_ERROR, error %d\n", event->status);
        case RDMA_CM_EVENT_CONNECT_ERROR:
+               sprintf(ibw_lasterr, "RDMA_CM_EVENT_CONNECT_ERROR, error %d\n", event->status);
        case RDMA_CM_EVENT_UNREACHABLE:
-       case RDMA_CM_EVENT_REJECTED:
-               sprintf(ibw_lasterr, "cma event %d, error %d\n", event->event, event->status);
+               sprintf(ibw_lasterr, "RDMA_CM_EVENT_UNREACHABLE, error %d\n", event->status);
                goto error;
+       case RDMA_CM_EVENT_REJECTED:
+               sprintf(ibw_lasterr, "RDMA_CM_EVENT_REJECTED, error %d\n", event->status);
+               DEBUG(DEBUG_INFO, ("cm event handler: %s", ibw_lasterr));
+               conn = talloc_get_type(cma_id->context, struct ibw_conn);
+               if (conn) {
+                       /* must be done BEFORE connstate */
+                       if ((rc=rdma_ack_cm_event(event)))
+                               DEBUG(DEBUG_ERR, ("reject/rdma_ack_cm_event failed with %d\n", rc));
+                       event = NULL; /* not to touch cma_id or conn */
+                       conn->state = IBWC_ERROR;
+                       /* it should free the conn */
+                       pctx->connstate_func(NULL, conn);
+               }
+               break; /* this is not strictly an error */
 
        case RDMA_CM_EVENT_DISCONNECTED:
+               DEBUG(DEBUG_DEBUG, ("RDMA_CM_EVENT_DISCONNECTED\n"));
+               if ((rc=rdma_ack_cm_event(event)))
+                       DEBUG(DEBUG_ERR, ("disc/rdma_ack_cm_event failed with %d\n", rc));
+               event = NULL; /* don't ack more */
+
                if (cma_id!=pctx->cm_id) {
-                       DEBUG(0, ("client DISCONNECT event\n"));
+                       DEBUG(DEBUG_ERR, ("client DISCONNECT event cm_id=%p\n", cma_id));
                        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;
 
@@ -477,23 +554,33 @@ static void ibw_event_handler_cm(struct event_context *ev,
                goto error;
        }
 
-       if ((rc=rdma_ack_cm_event(event))) {
+       if (event!=NULL && (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);
+       DEBUG(DEBUG_ERR, ("cm event handler: %s", ibw_lasterr));
+
+       if (event!=NULL) {
+               if (cma_id!=NULL && 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);
+               }
+
+               if ((rc=rdma_ack_cm_event(event))!=0) {
+                       DEBUG(DEBUG_ERR, ("rdma_ack_cm_event failed with %d\n", rc));
+               }
        }
+
+       return;
 }
 
 static void ibw_event_handler_verbs(struct event_context *ev,
@@ -508,6 +595,8 @@ static void ibw_event_handler_verbs(struct event_context *ev,
        struct ibv_cq *ev_cq;
        void          *ev_ctx;
 
+       DEBUG(DEBUG_DEBUG, ("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) {
@@ -515,8 +604,7 @@ static void ibw_event_handler_verbs(struct event_context *ev,
                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);
+               sprintf(ibw_lasterr, "ev_cq(%p) != pconn->cq(%p)\n", ev_cq, pconn->cq);
                goto error;
        }
        rc = ibv_req_notify_cq(pconn->cq, 0);
@@ -527,28 +615,28 @@ static void ibw_event_handler_verbs(struct event_context *ev,
 
        while((rc=ibv_poll_cq(pconn->cq, 1, &wc))==1) {
                if (wc.status) {
-                       sprintf(ibw_lasterr, "cq completion failed status %d\n",
-                               wc.status);
+                       sprintf(ibw_lasterr, "cq completion failed status=%d, opcode=%d, rc=%d\n",
+                               wc.status, wc.opcode, rc);
                        goto error;
                }
 
                switch(wc.opcode) {
                case IBV_WC_SEND:
-                       DEBUG(10, ("send completion\n"));
+                       DEBUG(DEBUG_DEBUG, ("send completion\n"));
                        if (ibw_wc_send(conn, &wc))
                                goto error;
                        break;
 
                case IBV_WC_RDMA_WRITE:
-                       DEBUG(10, ("rdma write completion\n"));
+                       DEBUG(DEBUG_DEBUG, ("rdma write completion\n"));
                        break;
        
                case IBV_WC_RDMA_READ:
-                       DEBUG(10, ("rdma read completion\n"));
+                       DEBUG(DEBUG_DEBUG, ("rdma read completion\n"));
                        break;
 
                case IBV_WC_RECV:
-                       DEBUG(10, ("recv completion\n"));
+                       DEBUG(DEBUG_DEBUG, ("recv completion\n"));
                        if (ibw_wc_recv(conn, &wc))
                                goto error;
                        break;
@@ -563,82 +651,122 @@ static void ibw_event_handler_verbs(struct event_context *ev,
                goto error;
        }
 
+       ibv_ack_cq_events(pconn->cq, 1);
+
        return;
 error:
-       DEBUG(0, (ibw_lasterr));
-       conn->state = IBWC_ERROR;
-       pctx->connstate_func(NULL, conn);
+       ibv_ack_cq_events(pconn->cq, 1);
+
+       DEBUG(DEBUG_ERR, (ibw_lasterr));
+       
+       if (conn->state!=IBWC_ERROR) {
+               conn->state = IBWC_ERROR;
+               pctx->connstate_func(NULL, conn);
+       }
 }
 
-static inline int ibw_wc_send(struct ibw_conn *conn, struct ibv_wc *wc)
+static int ibw_process_queue(struct ibw_conn *conn)
+{
+       struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
+       struct ibw_ctx_priv *pctx;
+       struct ibw_wr   *p;
+       int     rc;
+       uint32_t        msg_size;
+
+       if (pconn->queue==NULL)
+               return 0; /* NOP */
+
+       p = pconn->queue;
+
+       /* we must have at least 1 fragment to send */
+       assert(p->queued_ref_cnt>0);
+       p->queued_ref_cnt--;
+
+       pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
+       msg_size = (p->queued_ref_cnt) ? pctx->opts.recv_bufsize : p->queued_rlen;
+
+       assert(p->queued_msg!=NULL);
+       assert(msg_size!=0);
+
+       DEBUG(DEBUG_DEBUG, ("ibw_process_queue refcnt=%d msgsize=%u\n",
+               p->queued_ref_cnt, msg_size));
+
+       rc = ibw_send_packet(conn, p->queued_msg, p, msg_size);
+
+       /* was this the last fragment? */
+       if (p->queued_ref_cnt) {
+               p->queued_msg += pctx->opts.recv_bufsize;
+       } else {
+               DLIST_REMOVE2(pconn->queue, p, qprev, qnext);
+               p->queued_msg = NULL;
+       }
+
+       return rc;
+}
+
+static 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(DEBUG_DEBUG, ("ibw_wc_send(cmid: %p, wr_id: %u, bl: %u)\n",
+               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);
+       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));
+               DEBUG(DEBUG_DEBUG, ("ibw_wc_send#1 %u\n", (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 {
-               DEBUG(10, ("ibw_wc_send#2 %u", (int)wc->wr_id));
-               for(p=pconn->queue_sent; p!=NULL; p=p->next)
-                       if (p->wr_id==(int)wc->wr_id)
+               if (p->buf_large!=NULL) {
+                       if (p->ref_cnt) {
+                               /* awaiting more of it... */
+                               p->ref_cnt--;
+                       } else {
+                               ibw_free_mr(&p->buf_large, &p->mr_large);
+                               DLIST_REMOVE(pconn->wr_list_used, p);
+                               DLIST_ADD(pconn->wr_list_avail, p);
+                       }
+               } else { /* nasty - but necessary */
+                       DLIST_REMOVE(pconn->wr_list_used, p);
+                       DLIST_ADD(pconn->wr_list_avail, p);
+               }
+       } else { /* "extra" request - not optimized */
+               DEBUG(DEBUG_DEBUG, ("ibw_wc_send#2 %u\n", (int)wc->wr_id));
+               for(p=pconn->extra_sent; p!=NULL; p=p->next)
+                       if ((p->wr_id + pctx->opts.max_recv_wr)==(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->queue_sent, p);
-               DLIST_ADD(pconn->queue_avail, p);
-       }
-
-       if (pconn->queue) {
-               struct ibv_sge list = {
-                       .addr   = (uintptr_t) NULL,
-                       .length = *(uint32_t *)(p->msg_large),
-                       .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;
-               int     rc;
-
-               p = pconn->queue;
-               DLIST_REMOVE(pconn->queue, p);
-               DLIST_ADD(pconn->queue_sent, p);
-               rc = ibv_post_send(pconn->cm_id->qp, &wr, &bad_wr);
-               if (rc) {
-                       sprintf(ibw_lasterr, "ibv_post_send failed with %d\n", rc);
-                       return -1;
+               if (p->ref_cnt) {
+                       p->ref_cnt--;
+               } else {
+                       ibw_free_mr(&p->buf_large, &p->mr_large);
+                       DLIST_REMOVE(pconn->extra_sent, p);
+                       DLIST_ADD(pconn->extra_avail, p);
                }
        }
 
-       return 0;
+       return ibw_process_queue(conn);
 }
 
-static inline int ibw_append_to_part(void *memctx, struct ibw_part *part,
-       char **pp, uint32_t add_len, int info)
+static int ibw_append_to_part(struct ibw_conn_priv *pconn,
+       struct ibw_part *part, char **pp, uint32_t add_len, int info)
 {
+       DEBUG(DEBUG_DEBUG, ("ibw_append_to_part: cmid=%p, (bs=%u, len=%u, tr=%u), al=%u, i=%u\n",
+               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(memctx, add_len);
+                       part->buf = talloc_size(pconn, add_len);
                        if (part->buf==NULL) {
                                sprintf(ibw_lasterr, "recv talloc_size error (%u) #%d\n",
                                        add_len, info);
@@ -646,7 +774,7 @@ static inline int ibw_append_to_part(void *memctx, struct ibw_part *part,
                        }
                        part->bufsize = add_len;
                } else {
-                       part->buf = talloc_realloc_size(memctx,
+                       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",
@@ -666,11 +794,17 @@ static inline int ibw_append_to_part(void *memctx, struct ibw_part *part,
        return 0;
 }
 
-static inline int ibw_wc_mem_threshold(void *memctx, struct ibw_part *part, uint32_t threshold)
+static int ibw_wc_mem_threshold(struct ibw_conn_priv *pconn,
+       struct ibw_part *part, uint32_t threshold)
 {
+       DEBUG(DEBUG_DEBUG, ("ibw_wc_mem_threshold: cmid=%p, (bs=%u, len=%u, tr=%u), thr=%u\n",
+               pconn->cm_id, part->bufsize, part->len, part->to_read, threshold));
+
        if (part->bufsize > threshold) {
+               DEBUG(DEBUG_DEBUG, ("ibw_wc_mem_threshold: cmid=%p, %u > %u\n",
+                       pconn->cm_id, part->bufsize, threshold));
                talloc_free(part->buf);
-               part->buf = talloc_size(memctx, threshold);
+               part->buf = talloc_size(pconn, threshold);
                if (part->buf==NULL) {
                        sprintf(ibw_lasterr, "talloc_size failed\n");
                        return -1;
@@ -680,13 +814,16 @@ static inline int ibw_wc_mem_threshold(void *memctx, struct ibw_part *part, uint
        return 0;
 }
 
-static inline int ibw_wc_recv(struct ibw_conn *conn, struct ibv_wc *wc)
+static 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;
+       uint32_t        remain = wc->byte_len;
+
+       DEBUG(DEBUG_DEBUG, ("ibw_wc_recv: cmid=%p, wr_id: %u, bl: %u\n",
+               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);
@@ -694,7 +831,6 @@ static inline int ibw_wc_recv(struct ibw_conn *conn, struct ibv_wc *wc)
 
        p = pconn->buf_recv + ((int)wc->wr_id * pctx->opts.recv_bufsize);
 
-       remain = wc->byte_len;
        while(remain) {
                /* here always true: (part->len!=0 && part->to_read!=0) ||
                        (part->len==0 && part->to_read==0) */
@@ -707,7 +843,7 @@ static inline int ibw_wc_recv(struct ibw_conn *conn, struct ibv_wc *wc)
                        if (part->len<=sizeof(uint32_t) && part->to_read==0) {
                                assert(part->len==sizeof(uint32_t));
                                /* set it again now... */
-                               part->to_read = *((uint32_t *)(part->buf));
+                               part->to_read = *((uint32_t *)(part->buf)); /* TODO: ntohl */
                                if (part->to_read<sizeof(uint32_t)) {
                                        sprintf(ibw_lasterr, "got msglen=%u #2\n", part->to_read);
                                        goto error;
@@ -716,14 +852,16 @@ static inline int ibw_wc_recv(struct ibw_conn *conn, struct ibv_wc *wc)
                        }
 
                        if (part->to_read==0) {
-                               pctx->receive_func(conn, part->buf, part->len);
+                               if (pctx->receive_func(conn, part->buf, part->len) != 0) {
+                                       goto error;
+                               }
                                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 = *(uint32_t *)p;
+                               uint32_t msglen = *(uint32_t *)p; /* TODO: ntohl */
                                if (msglen<sizeof(uint32_t)) {
                                        sprintf(ibw_lasterr, "got msglen=%u\n", msglen);
                                        goto error;
@@ -731,7 +869,9 @@ static inline int ibw_wc_recv(struct ibw_conn *conn, struct ibv_wc *wc)
 
                                /* mostly awaited case: */
                                if (msglen<=remain) {
-                                       pctx->receive_func(conn, p, msglen);
+                                       if (pctx->receive_func(conn, p, msglen) != 0) {
+                                               goto error;
+                                       }
                                        p += msglen;
                                        remain -= msglen;
                                } else {
@@ -759,7 +899,7 @@ static inline int ibw_wc_recv(struct ibw_conn *conn, struct ibv_wc *wc)
        return 0;
 
 error:
-       DEBUG(0, ("ibw_wc_recv error: %s", ibw_lasterr));
+       DEBUG(DEBUG_ERR, ("ibw_wc_recv error: %s", ibw_lasterr));
        return -1;
 }
 
@@ -768,11 +908,12 @@ static int ibw_process_init_attrs(struct ibw_initattr *attr, int nattr, struct i
        int     i;
        const char *name, *value;
 
-       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;
+       DEBUG(DEBUG_DEBUG, ("ibw_process_init_attrs: nattr: %d\n", nattr));
+
+       opts->max_send_wr = IBW_MAX_SEND_WR;
+       opts->max_recv_wr = IBW_MAX_RECV_WR;
+       opts->recv_bufsize = IBW_RECV_BUFSIZE;
+       opts->recv_threshold = IBW_RECV_THRESHOLD;
 
        for(i=0; i<nattr; i++) {
                name = attr[i].name;
@@ -783,8 +924,6 @@ static int ibw_process_init_attrs(struct ibw_initattr *attr, int nattr, struct i
                        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)
@@ -807,6 +946,8 @@ struct ibw_ctx *ibw_init(struct ibw_initattr *attr, int nattr,
        struct ibw_ctx_priv *pctx;
        int     rc;
 
+       DEBUG(DEBUG_DEBUG, ("ibw_init(ctx_userdata: %p, ectx: %p)\n", ctx_userdata, ectx));
+
        /* initialize basic data structures */
        memset(ibw_lasterr, 0, IBW_LASTERR_BUFSIZE);
 
@@ -839,28 +980,24 @@ struct ibw_ctx *ibw_init(struct ibw_initattr *attr, int nattr,
        pctx->cm_channel_event = event_add_fd(pctx->ectx, pctx,
                pctx->cm_channel->fd, EVENT_FD_READ, ibw_event_handler_cm, ctx);
 
+#if RDMA_USER_CM_MAX_ABI_VERSION >= 2
        rc = rdma_create_id(pctx->cm_channel, &pctx->cm_id, ctx, RDMA_PS_TCP);
+#else
+       rc = rdma_create_id(pctx->cm_channel, &pctx->cm_id, ctx);
+#endif
        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));
+       DEBUG(DEBUG_DEBUG, ("created cm_id %p\n", pctx->cm_id));
 
        pctx->pagesize = sysconf(_SC_PAGESIZE);
 
        return ctx;
        /* don't put code here */
 cleanup:
-       DEBUG(0, (ibw_lasterr));
+       DEBUG(DEBUG_ERR, (ibw_lasterr));
 
        if (ctx)
                talloc_free(ctx);
@@ -870,8 +1007,11 @@ cleanup:
 
 int ibw_stop(struct ibw_ctx *ctx)
 {
+       struct ibw_ctx_priv *pctx = (struct ibw_ctx_priv *)ctx->internal;
        struct ibw_conn *p;
 
+       DEBUG(DEBUG_DEBUG, ("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))
@@ -879,6 +1019,9 @@ int ibw_stop(struct ibw_ctx *ctx)
                }
        }
 
+       ctx->state = IBWS_STOPPED;
+       pctx->connstate_func(ctx, NULL);
+
        return 0;
 }
 
@@ -887,13 +1030,15 @@ 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(DEBUG_DEBUG, ("ibw_bind: addr=%s, port=%u\n",
+               inet_ntoa(my_addr->sin_addr), ntohs(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));
+               DEBUG(DEBUG_ERR, (ibw_lasterr));
                return rc;
        }
-       DEBUG(10, ("rdma_bind_addr successful\n"));
+       DEBUG(DEBUG_DEBUG, ("rdma_bind_addr successful\n"));
 
        return 0;
 }
@@ -903,13 +1048,13 @@ 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, ("rdma_listen...\n"));
+       DEBUG(DEBUG_DEBUG, ("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));
+               DEBUG(DEBUG_ERR, (ibw_lasterr));
                return rc;
-       }       
+       }
 
        return 0;
 }
@@ -920,6 +1065,7 @@ int ibw_accept(struct ibw_ctx *ctx, struct ibw_conn *conn, void *conn_userdata)
        struct rdma_conn_param  conn_param;
        int     rc;
 
+       DEBUG(DEBUG_DEBUG, ("ibw_accept: cmid=%p\n", pconn->cm_id));
        conn->conn_userdata = conn_userdata;
 
        memset(&conn_param, 0, sizeof(struct rdma_conn_param));
@@ -928,7 +1074,7 @@ int ibw_accept(struct ibw_ctx *ctx, struct ibw_conn *conn, void *conn_userdata)
        rc = rdma_accept(pconn->cm_id, &conn_param);
        if (rc) {
                sprintf(ibw_lasterr, "rdma_accept failed %d\n", rc);
-               DEBUG(0, (ibw_lasterr));
+               DEBUG(DEBUG_ERR, (ibw_lasterr));
                return -1;;
        }
 
@@ -939,28 +1085,44 @@ int ibw_accept(struct ibw_ctx *ctx, struct ibw_conn *conn, void *conn_userdata)
        return 0;
 }
 
-int ibw_connect(struct ibw_ctx *ctx, struct sockaddr_in *serv_addr, void *conn_userdata)
+int ibw_connect(struct ibw_conn *conn, 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_ctx_priv *pctx = talloc_get_type(conn->ctx->internal, struct ibw_ctx_priv);
        struct ibw_conn_priv *pconn = NULL;
        int     rc;
 
-       conn = ibw_conn_new(ctx);
+       assert(conn!=NULL);
+
        conn->conn_userdata = conn_userdata;
        pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
+       DEBUG(DEBUG_DEBUG, ("ibw_connect: addr=%s, port=%u\n", inet_ntoa(serv_addr->sin_addr),
+               ntohs(serv_addr->sin_port)));
 
+       /* clean previous - probably half - initialization */
+       if (ibw_conn_priv_destruct(pconn)) {
+               DEBUG(DEBUG_ERR, ("ibw_connect/ibw_pconn_destruct failed for cm_id=%p\n", pconn->cm_id));
+               return -1;
+       }
+
+       /* init cm */
+#if RDMA_USER_CM_MAX_ABI_VERSION >= 2
        rc = rdma_create_id(pctx->cm_channel, &pconn->cm_id, conn, RDMA_PS_TCP);
+#else
+       rc = rdma_create_id(pctx->cm_channel, &pconn->cm_id, conn);
+#endif
        if (rc) {
                rc = errno;
-               sprintf(ibw_lasterr, "rdma_create_id error %d\n", rc);
-               return rc;
+               sprintf(ibw_lasterr, "ibw_connect/rdma_create_id error %d\n", rc);
+               talloc_free(conn);
+               return -1;
        }
+       DEBUG(DEBUG_DEBUG, ("ibw_connect: rdma_create_id succeeded, cm_id=%p\n", pconn->cm_id));
 
-       rc = rdma_resolve_addr(pconn->cm_id, NULL, (struct sockaddr *) &serv_addr, 2000);
+       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));
+               DEBUG(DEBUG_ERR, (ibw_lasterr));
+               talloc_free(conn);
                return -1;
        }
 
@@ -972,89 +1134,112 @@ int ibw_connect(struct ibw_ctx *ctx, struct sockaddr_in *serv_addr, void *conn_u
 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);
 
-       rc = rdma_disconnect(pctx->cm_id);
-       if (rc) {
-               sprintf(ibw_lasterr, "ibw_disconnect failed with %d", rc);
-               DEBUG(0, (ibw_lasterr));
-               return rc;
-       }
+       DEBUG(DEBUG_DEBUG, ("ibw_disconnect: cmid=%p\n", pconn->cm_id));
 
-       /* continued at RDMA_CM_EVENT_DISCONNECTED */
+       assert(pconn!=NULL);
+
+       switch(conn->state) {
+       case IBWC_ERROR:
+               ibw_conn_priv_destruct(pconn); /* do this here right now */
+               break;
+       case IBWC_CONNECTED:
+               rc = rdma_disconnect(pconn->cm_id);
+               if (rc) {
+                       sprintf(ibw_lasterr, "ibw_disconnect failed with %d\n", rc);
+                       DEBUG(DEBUG_ERR, (ibw_lasterr));
+                       return rc;
+               }
+               break;
+       default:
+               DEBUG(DEBUG_DEBUG, ("invalid state for disconnect: %d\n", conn->state));
+               break;
+       }
 
        return 0;
 }
 
-int ibw_alloc_send_buf(struct ibw_conn *conn, void **buf, void **key, int n)
+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) {
+       if (p!=NULL) {
+               DEBUG(DEBUG_DEBUG, ("ibw_alloc_send_buf#1: cmid=%p, len=%d\n", pconn->cm_id, len));
+
                DLIST_REMOVE(pconn->wr_list_avail, p);
                DLIST_ADD(pconn->wr_list_used, p);
 
-               if (n + sizeof(long) <= pctx->opts.avg_send_size) {
-                       *buf = (void *)(p->msg + sizeof(long));
+               if (len <= pctx->opts.recv_bufsize) {
+                       *buf = (void *)p->buf;
                } else {
-                       p->msg_large = ibw_alloc_mr(pctx, pconn, n + sizeof(long), &p->mr_large);
-                       if (!p->msg_large) {
+                       p->buf_large = ibw_alloc_mr(pctx, pconn, len, &p->mr_large);
+                       if (p->buf_large==NULL) {
                                sprintf(ibw_lasterr, "ibw_alloc_mr#1 failed\n");
                                goto error;
                        }
-                       *buf = (void *)(p->msg_large + sizeof(long));
+                       *buf = (void *)p->buf_large;
                }
+               /* p->wr_id is already filled in ibw_init_memory */
        } else {
+               DEBUG(DEBUG_DEBUG, ("ibw_alloc_send_buf#2: cmid=%p, len=%d\n", pconn->cm_id, len));
                /* not optimized */
-               p = pconn->queue_avail;
+               p = pconn->extra_avail;
                if (!p) {
-                       p = pconn->queue_avail = talloc_zero(pconn, struct ibw_wr);
+                       p = pconn->extra_avail = talloc_zero(pconn, struct ibw_wr);
+                       talloc_set_destructor(p, ibw_wr_destruct);
                        if (p==NULL) {
-                               sprintf(ibw_lasterr, "talloc_zero failed (qmax: %u)", pconn->queue_max);
+                               sprintf(ibw_lasterr, "talloc_zero failed (emax: %u)\n", pconn->extra_max);
                                goto error;
                        }
-                       p->wr_id = pconn->queue_max + pctx->opts.max_send_wr;
-                       pconn->queue_max++;
-                       switch(pconn->queue_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;
+                       p->wr_id = pctx->opts.max_send_wr + pconn->extra_max;
+                       pconn->extra_max++;
+                       switch(pconn->extra_max) {
+                               case 1: DEBUG(DEBUG_INFO, ("warning: queue performed\n")); break;
+                               case 10: DEBUG(DEBUG_INFO, ("warning: queue reached 10\n")); break;
+                               case 100: DEBUG(DEBUG_INFO, ("warning: queue reached 100\n")); break;
+                               case 1000: DEBUG(DEBUG_INFO, ("warning: queue reached 1000\n")); break;
                                default: break;
                        }
                }
-               DLIST_REMOVE(pconn->queue_avail, p);
 
-               p->msg_large = ibw_alloc_mr(pctx, pconn, n + sizeof(long), &p->mr_large);
-               if (!p->msg_large) {
-                       sprintf(ibw_lasterr, "ibw_alloc_mr#2 failed");
+               p->buf_large = ibw_alloc_mr(pctx, pconn, len, &p->mr_large);
+               if (p->buf_large==NULL) {
+                       sprintf(ibw_lasterr, "ibw_alloc_mr#2 failed\n");
                        goto error;
                }
-               *buf = (void *)(p->msg_large + sizeof(long));
+               *buf = (void *)p->buf_large;
+
+               DLIST_REMOVE(pconn->extra_avail, p);
+               /* we don't have prepared index for this, so that
+                * we will have to find this by wr_id later on */
+               DLIST_ADD(pconn->extra_sent, p);
        }
 
        *key = (void *)p;
 
        return 0;
 error:
-       DEBUG(0, ("ibw_alloc_send_buf error: %s\n", ibw_lasterr));
+       DEBUG(DEBUG_ERR, ("ibw_alloc_send_buf error: %s", ibw_lasterr));
        return -1;
 }
 
 
-int ibw_send(struct ibw_conn *conn, void *buf, void *key, int n)
+static int ibw_send_packet(struct ibw_conn *conn, void *buf, struct ibw_wr *p, 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;
 
-       if (p->msg!=NULL) {
+       /* can we send it right now? */
+       if (pconn->wr_sent<pctx->opts.max_send_wr) {
+               struct ibv_send_wr *bad_wr;
                struct ibv_sge list = {
-                       .addr   = (uintptr_t) NULL,
-                       .length = n,
-                       .lkey   = 0
+                       .addr   = (uintptr_t)buf,
+                       .length = len,
+                       .lkey   = pconn->mr_send->lkey
                };
                struct ibv_send_wr wr = {
                        .wr_id      = p->wr_id + pctx->opts.max_recv_wr,
@@ -1063,29 +1248,113 @@ int ibw_send(struct ibw_conn *conn, void *buf, void *key, int n)
                        .opcode     = IBV_WR_SEND,
                        .send_flags = IBV_SEND_SIGNALED,
                };
-               struct ibv_send_wr *bad_wr;
 
-               if (n + sizeof(uint32_t)<=pctx->opts.avg_send_size) {
-                       assert((p->msg + sizeof(long))==(char *)buf);
-                       list.lkey = pconn->mr_send->lkey;
-                       list.addr = (uintptr_t) p->msg;
-       
-                       *((uint32_t *)p->msg) = htonl(n);
+               if (p->buf_large==NULL) {
+                       DEBUG(DEBUG_DEBUG, ("ibw_send#normal(cmid: %p, wrid: %u, n: %d)\n",
+                               pconn->cm_id, (uint32_t)wr.wr_id, len));
                } else {
-                       assert((p->msg_large + sizeof(long))==(char *)buf);
-                       assert(p->mr_large!=NULL);
+                       DEBUG(DEBUG_DEBUG, ("ibw_send#large(cmid: %p, wrid: %u, n: %d)\n",
+                               pconn->cm_id, (uint32_t)wr.wr_id, len));
                        list.lkey = p->mr_large->lkey;
-                       list.addr = (uintptr_t) p->msg_large;
-       
-                       *((uint32_t *)p->msg_large) = htonl(n);
                }
-               return ibv_post_send(pconn->cm_id->qp, &wr, &bad_wr);
-       } /* else: */
 
-       *((uint32_t *)p->msg_large) = htonl(n);
+               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);
+                       goto error;
+               }
+
+               pconn->wr_sent++;
+
+               return rc;
+       } /* else put the request into our own queue: */
+
+       DEBUG(DEBUG_DEBUG, ("ibw_send#queued(cmid: %p, len: %u)\n", pconn->cm_id, len));
+
+       /* TODO: clarify how to continue when state==IBWC_STOPPED */
 
        /* to be sent by ibw_wc_send */
-       DLIST_ADD_END(pconn->queue, p, struct ibw_wr *); /* TODO: optimize */
+       /* regardless "normal" or [a part of] "large" packet */
+       if (!p->queued_ref_cnt) {
+               DLIST_ADD_END2(pconn->queue, p, struct ibw_wr *,
+                       qprev, qnext); /* TODO: optimize */
+               p->queued_msg = buf;
+       }
+       p->queued_ref_cnt++;
+       p->queued_rlen = len; /* last wins; see ibw_wc_send */
+
+       return 0;
+error:
+       DEBUG(DEBUG_ERR, (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_wr *p = talloc_get_type(key, struct ibw_wr);
+       int     rc;
+
+       assert(len>=sizeof(uint32_t));
+       assert((*((uint32_t *)buf)==len)); /* TODO: htonl */
+
+       if (len > pctx->opts.recv_bufsize) {
+               struct ibw_conn_priv *pconn = talloc_get_type(conn->internal, struct ibw_conn_priv);
+               int     rlen = len;
+               char    *packet = (char *)buf;
+               uint32_t        recv_bufsize = pctx->opts.recv_bufsize;
+
+               DEBUG(DEBUG_DEBUG, ("ibw_send#frag(cmid: %p, buf: %p, len: %u)\n",
+                       pconn->cm_id, buf, len));
+
+               /* single threaded => no race here: */
+               assert(p->ref_cnt==0);
+               while(rlen > recv_bufsize) {
+                       rc = ibw_send_packet(conn, packet, p, recv_bufsize);
+                       if (rc)
+                               return rc;
+                       packet += recv_bufsize;
+                       rlen -= recv_bufsize;
+                       p->ref_cnt++; /* not good to have it in ibw_send_packet */
+               }
+               if (rlen) {
+                       rc = ibw_send_packet(conn, packet, p, rlen);
+                       p->ref_cnt++; /* not good to have it in ibw_send_packet */
+               }
+               p->ref_cnt--; /* for the same handling */
+       } else {
+               assert(p->ref_cnt==0);
+               assert(p->queued_ref_cnt==0);
+
+               rc = ibw_send_packet(conn, buf, p, len);
+       }
+       return rc;
+}
+
+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->buf_large!=NULL)
+               ibw_free_mr(&p->buf_large, &p->mr_large);
+
+       /* parallel case */
+       if (p->wr_id < pctx->opts.max_send_wr) {
+               DEBUG(DEBUG_DEBUG, ("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(DEBUG_DEBUG, ("ibw_cancel_send_buf#2 %u", (int)p->wr_id));
+               DLIST_REMOVE(pconn->extra_sent, p);
+               DLIST_ADD(pconn->extra_avail, p);
+       }
 
        return 0;
 }