Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / infiniband / ulp / ipoib / ipoib_cm.c
diff --git a/kernel/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/kernel/drivers/infiniband/ulp/ipoib/ipoib_cm.c
new file mode 100644 (file)
index 0000000..cf32a77
--- /dev/null
@@ -0,0 +1,1615 @@
+/*
+ * Copyright (c) 2006 Mellanox Technologies. All rights reserved
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <rdma/ib_cm.h>
+#include <net/dst.h>
+#include <net/icmp.h>
+#include <linux/icmpv6.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/moduleparam.h>
+
+#include "ipoib.h"
+
+int ipoib_max_conn_qp = 128;
+
+module_param_named(max_nonsrq_conn_qp, ipoib_max_conn_qp, int, 0444);
+MODULE_PARM_DESC(max_nonsrq_conn_qp,
+                "Max number of connected-mode QPs per interface "
+                "(applied only if shared receive queue is not available)");
+
+#ifdef CONFIG_INFINIBAND_IPOIB_DEBUG_DATA
+static int data_debug_level;
+
+module_param_named(cm_data_debug_level, data_debug_level, int, 0644);
+MODULE_PARM_DESC(cm_data_debug_level,
+                "Enable data path debug tracing for connected mode if > 0");
+#endif
+
+#define IPOIB_CM_IETF_ID 0x1000000000000000ULL
+
+#define IPOIB_CM_RX_UPDATE_TIME (256 * HZ)
+#define IPOIB_CM_RX_TIMEOUT     (2 * 256 * HZ)
+#define IPOIB_CM_RX_DELAY       (3 * 256 * HZ)
+#define IPOIB_CM_RX_UPDATE_MASK (0x3)
+
+static struct ib_qp_attr ipoib_cm_err_attr = {
+       .qp_state = IB_QPS_ERR
+};
+
+#define IPOIB_CM_RX_DRAIN_WRID 0xffffffff
+
+static struct ib_send_wr ipoib_cm_rx_drain_wr = {
+       .wr_id = IPOIB_CM_RX_DRAIN_WRID,
+       .opcode = IB_WR_SEND,
+};
+
+static int ipoib_cm_tx_handler(struct ib_cm_id *cm_id,
+                              struct ib_cm_event *event);
+
+static void ipoib_cm_dma_unmap_rx(struct ipoib_dev_priv *priv, int frags,
+                                 u64 mapping[IPOIB_CM_RX_SG])
+{
+       int i;
+
+       ib_dma_unmap_single(priv->ca, mapping[0], IPOIB_CM_HEAD_SIZE, DMA_FROM_DEVICE);
+
+       for (i = 0; i < frags; ++i)
+               ib_dma_unmap_page(priv->ca, mapping[i + 1], PAGE_SIZE, DMA_FROM_DEVICE);
+}
+
+static int ipoib_cm_post_receive_srq(struct net_device *dev, int id)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ib_recv_wr *bad_wr;
+       int i, ret;
+
+       priv->cm.rx_wr.wr_id = id | IPOIB_OP_CM | IPOIB_OP_RECV;
+
+       for (i = 0; i < priv->cm.num_frags; ++i)
+               priv->cm.rx_sge[i].addr = priv->cm.srq_ring[id].mapping[i];
+
+       ret = ib_post_srq_recv(priv->cm.srq, &priv->cm.rx_wr, &bad_wr);
+       if (unlikely(ret)) {
+               ipoib_warn(priv, "post srq failed for buf %d (%d)\n", id, ret);
+               ipoib_cm_dma_unmap_rx(priv, priv->cm.num_frags - 1,
+                                     priv->cm.srq_ring[id].mapping);
+               dev_kfree_skb_any(priv->cm.srq_ring[id].skb);
+               priv->cm.srq_ring[id].skb = NULL;
+       }
+
+       return ret;
+}
+
+static int ipoib_cm_post_receive_nonsrq(struct net_device *dev,
+                                       struct ipoib_cm_rx *rx,
+                                       struct ib_recv_wr *wr,
+                                       struct ib_sge *sge, int id)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ib_recv_wr *bad_wr;
+       int i, ret;
+
+       wr->wr_id = id | IPOIB_OP_CM | IPOIB_OP_RECV;
+
+       for (i = 0; i < IPOIB_CM_RX_SG; ++i)
+               sge[i].addr = rx->rx_ring[id].mapping[i];
+
+       ret = ib_post_recv(rx->qp, wr, &bad_wr);
+       if (unlikely(ret)) {
+               ipoib_warn(priv, "post recv failed for buf %d (%d)\n", id, ret);
+               ipoib_cm_dma_unmap_rx(priv, IPOIB_CM_RX_SG - 1,
+                                     rx->rx_ring[id].mapping);
+               dev_kfree_skb_any(rx->rx_ring[id].skb);
+               rx->rx_ring[id].skb = NULL;
+       }
+
+       return ret;
+}
+
+static struct sk_buff *ipoib_cm_alloc_rx_skb(struct net_device *dev,
+                                            struct ipoib_cm_rx_buf *rx_ring,
+                                            int id, int frags,
+                                            u64 mapping[IPOIB_CM_RX_SG],
+                                            gfp_t gfp)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct sk_buff *skb;
+       int i;
+
+       skb = dev_alloc_skb(IPOIB_CM_HEAD_SIZE + 12);
+       if (unlikely(!skb))
+               return NULL;
+
+       /*
+        * IPoIB adds a 4 byte header. So we need 12 more bytes to align the
+        * IP header to a multiple of 16.
+        */
+       skb_reserve(skb, 12);
+
+       mapping[0] = ib_dma_map_single(priv->ca, skb->data, IPOIB_CM_HEAD_SIZE,
+                                      DMA_FROM_DEVICE);
+       if (unlikely(ib_dma_mapping_error(priv->ca, mapping[0]))) {
+               dev_kfree_skb_any(skb);
+               return NULL;
+       }
+
+       for (i = 0; i < frags; i++) {
+               struct page *page = alloc_page(gfp);
+
+               if (!page)
+                       goto partial_error;
+               skb_fill_page_desc(skb, i, page, 0, PAGE_SIZE);
+
+               mapping[i + 1] = ib_dma_map_page(priv->ca, page,
+                                                0, PAGE_SIZE, DMA_FROM_DEVICE);
+               if (unlikely(ib_dma_mapping_error(priv->ca, mapping[i + 1])))
+                       goto partial_error;
+       }
+
+       rx_ring[id].skb = skb;
+       return skb;
+
+partial_error:
+
+       ib_dma_unmap_single(priv->ca, mapping[0], IPOIB_CM_HEAD_SIZE, DMA_FROM_DEVICE);
+
+       for (; i > 0; --i)
+               ib_dma_unmap_page(priv->ca, mapping[i], PAGE_SIZE, DMA_FROM_DEVICE);
+
+       dev_kfree_skb_any(skb);
+       return NULL;
+}
+
+static void ipoib_cm_free_rx_ring(struct net_device *dev,
+                                 struct ipoib_cm_rx_buf *rx_ring)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       int i;
+
+       for (i = 0; i < ipoib_recvq_size; ++i)
+               if (rx_ring[i].skb) {
+                       ipoib_cm_dma_unmap_rx(priv, IPOIB_CM_RX_SG - 1,
+                                             rx_ring[i].mapping);
+                       dev_kfree_skb_any(rx_ring[i].skb);
+               }
+
+       vfree(rx_ring);
+}
+
+static void ipoib_cm_start_rx_drain(struct ipoib_dev_priv *priv)
+{
+       struct ib_send_wr *bad_wr;
+       struct ipoib_cm_rx *p;
+
+       /* We only reserved 1 extra slot in CQ for drain WRs, so
+        * make sure we have at most 1 outstanding WR. */
+       if (list_empty(&priv->cm.rx_flush_list) ||
+           !list_empty(&priv->cm.rx_drain_list))
+               return;
+
+       /*
+        * QPs on flush list are error state.  This way, a "flush
+        * error" WC will be immediately generated for each WR we post.
+        */
+       p = list_entry(priv->cm.rx_flush_list.next, typeof(*p), list);
+       if (ib_post_send(p->qp, &ipoib_cm_rx_drain_wr, &bad_wr))
+               ipoib_warn(priv, "failed to post drain wr\n");
+
+       list_splice_init(&priv->cm.rx_flush_list, &priv->cm.rx_drain_list);
+}
+
+static void ipoib_cm_rx_event_handler(struct ib_event *event, void *ctx)
+{
+       struct ipoib_cm_rx *p = ctx;
+       struct ipoib_dev_priv *priv = netdev_priv(p->dev);
+       unsigned long flags;
+
+       if (event->event != IB_EVENT_QP_LAST_WQE_REACHED)
+               return;
+
+       spin_lock_irqsave(&priv->lock, flags);
+       list_move(&p->list, &priv->cm.rx_flush_list);
+       p->state = IPOIB_CM_RX_FLUSH;
+       ipoib_cm_start_rx_drain(priv);
+       spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static struct ib_qp *ipoib_cm_create_rx_qp(struct net_device *dev,
+                                          struct ipoib_cm_rx *p)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ib_qp_init_attr attr = {
+               .event_handler = ipoib_cm_rx_event_handler,
+               .send_cq = priv->recv_cq, /* For drain WR */
+               .recv_cq = priv->recv_cq,
+               .srq = priv->cm.srq,
+               .cap.max_send_wr = 1, /* For drain WR */
+               .cap.max_send_sge = 1, /* FIXME: 0 Seems not to work */
+               .sq_sig_type = IB_SIGNAL_ALL_WR,
+               .qp_type = IB_QPT_RC,
+               .qp_context = p,
+       };
+
+       if (!ipoib_cm_has_srq(dev)) {
+               attr.cap.max_recv_wr  = ipoib_recvq_size;
+               attr.cap.max_recv_sge = IPOIB_CM_RX_SG;
+       }
+
+       return ib_create_qp(priv->pd, &attr);
+}
+
+static int ipoib_cm_modify_rx_qp(struct net_device *dev,
+                                struct ib_cm_id *cm_id, struct ib_qp *qp,
+                                unsigned psn)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ib_qp_attr qp_attr;
+       int qp_attr_mask, ret;
+
+       qp_attr.qp_state = IB_QPS_INIT;
+       ret = ib_cm_init_qp_attr(cm_id, &qp_attr, &qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to init QP attr for INIT: %d\n", ret);
+               return ret;
+       }
+       ret = ib_modify_qp(qp, &qp_attr, qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to modify QP to INIT: %d\n", ret);
+               return ret;
+       }
+       qp_attr.qp_state = IB_QPS_RTR;
+       ret = ib_cm_init_qp_attr(cm_id, &qp_attr, &qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to init QP attr for RTR: %d\n", ret);
+               return ret;
+       }
+       qp_attr.rq_psn = psn;
+       ret = ib_modify_qp(qp, &qp_attr, qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to modify QP to RTR: %d\n", ret);
+               return ret;
+       }
+
+       /*
+        * Current Mellanox HCA firmware won't generate completions
+        * with error for drain WRs unless the QP has been moved to
+        * RTS first. This work-around leaves a window where a QP has
+        * moved to error asynchronously, but this will eventually get
+        * fixed in firmware, so let's not error out if modify QP
+        * fails.
+        */
+       qp_attr.qp_state = IB_QPS_RTS;
+       ret = ib_cm_init_qp_attr(cm_id, &qp_attr, &qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to init QP attr for RTS: %d\n", ret);
+               return 0;
+       }
+       ret = ib_modify_qp(qp, &qp_attr, qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to modify QP to RTS: %d\n", ret);
+               return 0;
+       }
+
+       return 0;
+}
+
+static void ipoib_cm_init_rx_wr(struct net_device *dev,
+                               struct ib_recv_wr *wr,
+                               struct ib_sge *sge)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       int i;
+
+       for (i = 0; i < priv->cm.num_frags; ++i)
+               sge[i].lkey = priv->mr->lkey;
+
+       sge[0].length = IPOIB_CM_HEAD_SIZE;
+       for (i = 1; i < priv->cm.num_frags; ++i)
+               sge[i].length = PAGE_SIZE;
+
+       wr->next    = NULL;
+       wr->sg_list = sge;
+       wr->num_sge = priv->cm.num_frags;
+}
+
+static int ipoib_cm_nonsrq_init_rx(struct net_device *dev, struct ib_cm_id *cm_id,
+                                  struct ipoib_cm_rx *rx)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct {
+               struct ib_recv_wr wr;
+               struct ib_sge sge[IPOIB_CM_RX_SG];
+       } *t;
+       int ret;
+       int i;
+
+       rx->rx_ring = vzalloc(ipoib_recvq_size * sizeof *rx->rx_ring);
+       if (!rx->rx_ring) {
+               printk(KERN_WARNING "%s: failed to allocate CM non-SRQ ring (%d entries)\n",
+                      priv->ca->name, ipoib_recvq_size);
+               return -ENOMEM;
+       }
+
+       t = kmalloc(sizeof *t, GFP_KERNEL);
+       if (!t) {
+               ret = -ENOMEM;
+               goto err_free;
+       }
+
+       ipoib_cm_init_rx_wr(dev, &t->wr, t->sge);
+
+       spin_lock_irq(&priv->lock);
+
+       if (priv->cm.nonsrq_conn_qp >= ipoib_max_conn_qp) {
+               spin_unlock_irq(&priv->lock);
+               ib_send_cm_rej(cm_id, IB_CM_REJ_NO_QP, NULL, 0, NULL, 0);
+               ret = -EINVAL;
+               goto err_free;
+       } else
+               ++priv->cm.nonsrq_conn_qp;
+
+       spin_unlock_irq(&priv->lock);
+
+       for (i = 0; i < ipoib_recvq_size; ++i) {
+               if (!ipoib_cm_alloc_rx_skb(dev, rx->rx_ring, i, IPOIB_CM_RX_SG - 1,
+                                          rx->rx_ring[i].mapping,
+                                          GFP_KERNEL)) {
+                       ipoib_warn(priv, "failed to allocate receive buffer %d\n", i);
+                       ret = -ENOMEM;
+                       goto err_count;
+               }
+               ret = ipoib_cm_post_receive_nonsrq(dev, rx, &t->wr, t->sge, i);
+               if (ret) {
+                       ipoib_warn(priv, "ipoib_cm_post_receive_nonsrq "
+                                  "failed for buf %d\n", i);
+                       ret = -EIO;
+                       goto err_count;
+               }
+       }
+
+       rx->recv_count = ipoib_recvq_size;
+
+       kfree(t);
+
+       return 0;
+
+err_count:
+       spin_lock_irq(&priv->lock);
+       --priv->cm.nonsrq_conn_qp;
+       spin_unlock_irq(&priv->lock);
+
+err_free:
+       kfree(t);
+       ipoib_cm_free_rx_ring(dev, rx->rx_ring);
+
+       return ret;
+}
+
+static int ipoib_cm_send_rep(struct net_device *dev, struct ib_cm_id *cm_id,
+                            struct ib_qp *qp, struct ib_cm_req_event_param *req,
+                            unsigned psn)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ipoib_cm_data data = {};
+       struct ib_cm_rep_param rep = {};
+
+       data.qpn = cpu_to_be32(priv->qp->qp_num);
+       data.mtu = cpu_to_be32(IPOIB_CM_BUF_SIZE);
+
+       rep.private_data = &data;
+       rep.private_data_len = sizeof data;
+       rep.flow_control = 0;
+       rep.rnr_retry_count = req->rnr_retry_count;
+       rep.srq = ipoib_cm_has_srq(dev);
+       rep.qp_num = qp->qp_num;
+       rep.starting_psn = psn;
+       return ib_send_cm_rep(cm_id, &rep);
+}
+
+static int ipoib_cm_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
+{
+       struct net_device *dev = cm_id->context;
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ipoib_cm_rx *p;
+       unsigned psn;
+       int ret;
+
+       ipoib_dbg(priv, "REQ arrived\n");
+       p = kzalloc(sizeof *p, GFP_KERNEL);
+       if (!p)
+               return -ENOMEM;
+       p->dev = dev;
+       p->id = cm_id;
+       cm_id->context = p;
+       p->state = IPOIB_CM_RX_LIVE;
+       p->jiffies = jiffies;
+       INIT_LIST_HEAD(&p->list);
+
+       p->qp = ipoib_cm_create_rx_qp(dev, p);
+       if (IS_ERR(p->qp)) {
+               ret = PTR_ERR(p->qp);
+               goto err_qp;
+       }
+
+       psn = prandom_u32() & 0xffffff;
+       ret = ipoib_cm_modify_rx_qp(dev, cm_id, p->qp, psn);
+       if (ret)
+               goto err_modify;
+
+       if (!ipoib_cm_has_srq(dev)) {
+               ret = ipoib_cm_nonsrq_init_rx(dev, cm_id, p);
+               if (ret)
+                       goto err_modify;
+       }
+
+       spin_lock_irq(&priv->lock);
+       queue_delayed_work(priv->wq,
+                          &priv->cm.stale_task, IPOIB_CM_RX_DELAY);
+       /* Add this entry to passive ids list head, but do not re-add it
+        * if IB_EVENT_QP_LAST_WQE_REACHED has moved it to flush list. */
+       p->jiffies = jiffies;
+       if (p->state == IPOIB_CM_RX_LIVE)
+               list_move(&p->list, &priv->cm.passive_ids);
+       spin_unlock_irq(&priv->lock);
+
+       ret = ipoib_cm_send_rep(dev, cm_id, p->qp, &event->param.req_rcvd, psn);
+       if (ret) {
+               ipoib_warn(priv, "failed to send REP: %d\n", ret);
+               if (ib_modify_qp(p->qp, &ipoib_cm_err_attr, IB_QP_STATE))
+                       ipoib_warn(priv, "unable to move qp to error state\n");
+       }
+       return 0;
+
+err_modify:
+       ib_destroy_qp(p->qp);
+err_qp:
+       kfree(p);
+       return ret;
+}
+
+static int ipoib_cm_rx_handler(struct ib_cm_id *cm_id,
+                              struct ib_cm_event *event)
+{
+       struct ipoib_cm_rx *p;
+       struct ipoib_dev_priv *priv;
+
+       switch (event->event) {
+       case IB_CM_REQ_RECEIVED:
+               return ipoib_cm_req_handler(cm_id, event);
+       case IB_CM_DREQ_RECEIVED:
+               p = cm_id->context;
+               ib_send_cm_drep(cm_id, NULL, 0);
+               /* Fall through */
+       case IB_CM_REJ_RECEIVED:
+               p = cm_id->context;
+               priv = netdev_priv(p->dev);
+               if (ib_modify_qp(p->qp, &ipoib_cm_err_attr, IB_QP_STATE))
+                       ipoib_warn(priv, "unable to move qp to error state\n");
+               /* Fall through */
+       default:
+               return 0;
+       }
+}
+/* Adjust length of skb with fragments to match received data */
+static void skb_put_frags(struct sk_buff *skb, unsigned int hdr_space,
+                         unsigned int length, struct sk_buff *toskb)
+{
+       int i, num_frags;
+       unsigned int size;
+
+       /* put header into skb */
+       size = min(length, hdr_space);
+       skb->tail += size;
+       skb->len += size;
+       length -= size;
+
+       num_frags = skb_shinfo(skb)->nr_frags;
+       for (i = 0; i < num_frags; i++) {
+               skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+               if (length == 0) {
+                       /* don't need this page */
+                       skb_fill_page_desc(toskb, i, skb_frag_page(frag),
+                                          0, PAGE_SIZE);
+                       --skb_shinfo(skb)->nr_frags;
+               } else {
+                       size = min(length, (unsigned) PAGE_SIZE);
+
+                       skb_frag_size_set(frag, size);
+                       skb->data_len += size;
+                       skb->truesize += size;
+                       skb->len += size;
+                       length -= size;
+               }
+       }
+}
+
+void ipoib_cm_handle_rx_wc(struct net_device *dev, struct ib_wc *wc)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ipoib_cm_rx_buf *rx_ring;
+       unsigned int wr_id = wc->wr_id & ~(IPOIB_OP_CM | IPOIB_OP_RECV);
+       struct sk_buff *skb, *newskb;
+       struct ipoib_cm_rx *p;
+       unsigned long flags;
+       u64 mapping[IPOIB_CM_RX_SG];
+       int frags;
+       int has_srq;
+       struct sk_buff *small_skb;
+
+       ipoib_dbg_data(priv, "cm recv completion: id %d, status: %d\n",
+                      wr_id, wc->status);
+
+       if (unlikely(wr_id >= ipoib_recvq_size)) {
+               if (wr_id == (IPOIB_CM_RX_DRAIN_WRID & ~(IPOIB_OP_CM | IPOIB_OP_RECV))) {
+                       spin_lock_irqsave(&priv->lock, flags);
+                       list_splice_init(&priv->cm.rx_drain_list, &priv->cm.rx_reap_list);
+                       ipoib_cm_start_rx_drain(priv);
+                       queue_work(priv->wq, &priv->cm.rx_reap_task);
+                       spin_unlock_irqrestore(&priv->lock, flags);
+               } else
+                       ipoib_warn(priv, "cm recv completion event with wrid %d (> %d)\n",
+                                  wr_id, ipoib_recvq_size);
+               return;
+       }
+
+       p = wc->qp->qp_context;
+
+       has_srq = ipoib_cm_has_srq(dev);
+       rx_ring = has_srq ? priv->cm.srq_ring : p->rx_ring;
+
+       skb = rx_ring[wr_id].skb;
+
+       if (unlikely(wc->status != IB_WC_SUCCESS)) {
+               ipoib_dbg(priv, "cm recv error "
+                          "(status=%d, wrid=%d vend_err %x)\n",
+                          wc->status, wr_id, wc->vendor_err);
+               ++dev->stats.rx_dropped;
+               if (has_srq)
+                       goto repost;
+               else {
+                       if (!--p->recv_count) {
+                               spin_lock_irqsave(&priv->lock, flags);
+                               list_move(&p->list, &priv->cm.rx_reap_list);
+                               spin_unlock_irqrestore(&priv->lock, flags);
+                               queue_work(priv->wq, &priv->cm.rx_reap_task);
+                       }
+                       return;
+               }
+       }
+
+       if (unlikely(!(wr_id & IPOIB_CM_RX_UPDATE_MASK))) {
+               if (p && time_after_eq(jiffies, p->jiffies + IPOIB_CM_RX_UPDATE_TIME)) {
+                       spin_lock_irqsave(&priv->lock, flags);
+                       p->jiffies = jiffies;
+                       /* Move this entry to list head, but do not re-add it
+                        * if it has been moved out of list. */
+                       if (p->state == IPOIB_CM_RX_LIVE)
+                               list_move(&p->list, &priv->cm.passive_ids);
+                       spin_unlock_irqrestore(&priv->lock, flags);
+               }
+       }
+
+       if (wc->byte_len < IPOIB_CM_COPYBREAK) {
+               int dlen = wc->byte_len;
+
+               small_skb = dev_alloc_skb(dlen + 12);
+               if (small_skb) {
+                       skb_reserve(small_skb, 12);
+                       ib_dma_sync_single_for_cpu(priv->ca, rx_ring[wr_id].mapping[0],
+                                                  dlen, DMA_FROM_DEVICE);
+                       skb_copy_from_linear_data(skb, small_skb->data, dlen);
+                       ib_dma_sync_single_for_device(priv->ca, rx_ring[wr_id].mapping[0],
+                                                     dlen, DMA_FROM_DEVICE);
+                       skb_put(small_skb, dlen);
+                       skb = small_skb;
+                       goto copied;
+               }
+       }
+
+       frags = PAGE_ALIGN(wc->byte_len - min(wc->byte_len,
+                                             (unsigned)IPOIB_CM_HEAD_SIZE)) / PAGE_SIZE;
+
+       newskb = ipoib_cm_alloc_rx_skb(dev, rx_ring, wr_id, frags,
+                                      mapping, GFP_ATOMIC);
+       if (unlikely(!newskb)) {
+               /*
+                * If we can't allocate a new RX buffer, dump
+                * this packet and reuse the old buffer.
+                */
+               ipoib_dbg(priv, "failed to allocate receive buffer %d\n", wr_id);
+               ++dev->stats.rx_dropped;
+               goto repost;
+       }
+
+       ipoib_cm_dma_unmap_rx(priv, frags, rx_ring[wr_id].mapping);
+       memcpy(rx_ring[wr_id].mapping, mapping, (frags + 1) * sizeof *mapping);
+
+       ipoib_dbg_data(priv, "received %d bytes, SLID 0x%04x\n",
+                      wc->byte_len, wc->slid);
+
+       skb_put_frags(skb, IPOIB_CM_HEAD_SIZE, wc->byte_len, newskb);
+
+copied:
+       skb->protocol = ((struct ipoib_header *) skb->data)->proto;
+       skb_reset_mac_header(skb);
+       skb_pull(skb, IPOIB_ENCAP_LEN);
+
+       ++dev->stats.rx_packets;
+       dev->stats.rx_bytes += skb->len;
+
+       skb->dev = dev;
+       /* XXX get correct PACKET_ type here */
+       skb->pkt_type = PACKET_HOST;
+       netif_receive_skb(skb);
+
+repost:
+       if (has_srq) {
+               if (unlikely(ipoib_cm_post_receive_srq(dev, wr_id)))
+                       ipoib_warn(priv, "ipoib_cm_post_receive_srq failed "
+                                  "for buf %d\n", wr_id);
+       } else {
+               if (unlikely(ipoib_cm_post_receive_nonsrq(dev, p,
+                                                         &priv->cm.rx_wr,
+                                                         priv->cm.rx_sge,
+                                                         wr_id))) {
+                       --p->recv_count;
+                       ipoib_warn(priv, "ipoib_cm_post_receive_nonsrq failed "
+                                  "for buf %d\n", wr_id);
+               }
+       }
+}
+
+static inline int post_send(struct ipoib_dev_priv *priv,
+                           struct ipoib_cm_tx *tx,
+                           unsigned int wr_id,
+                           u64 addr, int len)
+{
+       struct ib_send_wr *bad_wr;
+
+       priv->tx_sge[0].addr          = addr;
+       priv->tx_sge[0].length        = len;
+
+       priv->tx_wr.num_sge     = 1;
+       priv->tx_wr.wr_id       = wr_id | IPOIB_OP_CM;
+
+       return ib_post_send(tx->qp, &priv->tx_wr, &bad_wr);
+}
+
+void ipoib_cm_send(struct net_device *dev, struct sk_buff *skb, struct ipoib_cm_tx *tx)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ipoib_cm_tx_buf *tx_req;
+       u64 addr;
+       int rc;
+
+       if (unlikely(skb->len > tx->mtu)) {
+               ipoib_warn(priv, "packet len %d (> %d) too long to send, dropping\n",
+                          skb->len, tx->mtu);
+               ++dev->stats.tx_dropped;
+               ++dev->stats.tx_errors;
+               ipoib_cm_skb_too_long(dev, skb, tx->mtu - IPOIB_ENCAP_LEN);
+               return;
+       }
+
+       ipoib_dbg_data(priv, "sending packet: head 0x%x length %d connection 0x%x\n",
+                      tx->tx_head, skb->len, tx->qp->qp_num);
+
+       /*
+        * We put the skb into the tx_ring _before_ we call post_send()
+        * because it's entirely possible that the completion handler will
+        * run before we execute anything after the post_send().  That
+        * means we have to make sure everything is properly recorded and
+        * our state is consistent before we call post_send().
+        */
+       tx_req = &tx->tx_ring[tx->tx_head & (ipoib_sendq_size - 1)];
+       tx_req->skb = skb;
+       addr = ib_dma_map_single(priv->ca, skb->data, skb->len, DMA_TO_DEVICE);
+       if (unlikely(ib_dma_mapping_error(priv->ca, addr))) {
+               ++dev->stats.tx_errors;
+               dev_kfree_skb_any(skb);
+               return;
+       }
+
+       tx_req->mapping = addr;
+
+       skb_orphan(skb);
+       skb_dst_drop(skb);
+
+       rc = post_send(priv, tx, tx->tx_head & (ipoib_sendq_size - 1),
+                      addr, skb->len);
+       if (unlikely(rc)) {
+               ipoib_warn(priv, "post_send failed, error %d\n", rc);
+               ++dev->stats.tx_errors;
+               ib_dma_unmap_single(priv->ca, addr, skb->len, DMA_TO_DEVICE);
+               dev_kfree_skb_any(skb);
+       } else {
+               dev->trans_start = jiffies;
+               ++tx->tx_head;
+
+               if (++priv->tx_outstanding == ipoib_sendq_size) {
+                       ipoib_dbg(priv, "TX ring 0x%x full, stopping kernel net queue\n",
+                                 tx->qp->qp_num);
+                       netif_stop_queue(dev);
+                       rc = ib_req_notify_cq(priv->send_cq,
+                               IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
+                       if (rc < 0)
+                               ipoib_warn(priv, "request notify on send CQ failed\n");
+                       else if (rc)
+                               ipoib_send_comp_handler(priv->send_cq, dev);
+               }
+       }
+}
+
+void ipoib_cm_handle_tx_wc(struct net_device *dev, struct ib_wc *wc)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ipoib_cm_tx *tx = wc->qp->qp_context;
+       unsigned int wr_id = wc->wr_id & ~IPOIB_OP_CM;
+       struct ipoib_cm_tx_buf *tx_req;
+       unsigned long flags;
+
+       ipoib_dbg_data(priv, "cm send completion: id %d, status: %d\n",
+                      wr_id, wc->status);
+
+       if (unlikely(wr_id >= ipoib_sendq_size)) {
+               ipoib_warn(priv, "cm send completion event with wrid %d (> %d)\n",
+                          wr_id, ipoib_sendq_size);
+               return;
+       }
+
+       tx_req = &tx->tx_ring[wr_id];
+
+       ib_dma_unmap_single(priv->ca, tx_req->mapping, tx_req->skb->len, DMA_TO_DEVICE);
+
+       /* FIXME: is this right? Shouldn't we only increment on success? */
+       ++dev->stats.tx_packets;
+       dev->stats.tx_bytes += tx_req->skb->len;
+
+       dev_kfree_skb_any(tx_req->skb);
+
+       netif_tx_lock(dev);
+
+       ++tx->tx_tail;
+       if (unlikely(--priv->tx_outstanding == ipoib_sendq_size >> 1) &&
+           netif_queue_stopped(dev) &&
+           test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
+               netif_wake_queue(dev);
+
+       if (wc->status != IB_WC_SUCCESS &&
+           wc->status != IB_WC_WR_FLUSH_ERR) {
+               struct ipoib_neigh *neigh;
+
+               ipoib_dbg(priv, "failed cm send event "
+                          "(status=%d, wrid=%d vend_err %x)\n",
+                          wc->status, wr_id, wc->vendor_err);
+
+               spin_lock_irqsave(&priv->lock, flags);
+               neigh = tx->neigh;
+
+               if (neigh) {
+                       neigh->cm = NULL;
+                       ipoib_neigh_free(neigh);
+
+                       tx->neigh = NULL;
+               }
+
+               if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &tx->flags)) {
+                       list_move(&tx->list, &priv->cm.reap_list);
+                       queue_work(priv->wq, &priv->cm.reap_task);
+               }
+
+               clear_bit(IPOIB_FLAG_OPER_UP, &tx->flags);
+
+               spin_unlock_irqrestore(&priv->lock, flags);
+       }
+
+       netif_tx_unlock(dev);
+}
+
+int ipoib_cm_dev_open(struct net_device *dev)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       int ret;
+
+       if (!IPOIB_CM_SUPPORTED(dev->dev_addr))
+               return 0;
+
+       priv->cm.id = ib_create_cm_id(priv->ca, ipoib_cm_rx_handler, dev);
+       if (IS_ERR(priv->cm.id)) {
+               printk(KERN_WARNING "%s: failed to create CM ID\n", priv->ca->name);
+               ret = PTR_ERR(priv->cm.id);
+               goto err_cm;
+       }
+
+       ret = ib_cm_listen(priv->cm.id, cpu_to_be64(IPOIB_CM_IETF_ID | priv->qp->qp_num),
+                          0, NULL);
+       if (ret) {
+               printk(KERN_WARNING "%s: failed to listen on ID 0x%llx\n", priv->ca->name,
+                      IPOIB_CM_IETF_ID | priv->qp->qp_num);
+               goto err_listen;
+       }
+
+       return 0;
+
+err_listen:
+       ib_destroy_cm_id(priv->cm.id);
+err_cm:
+       priv->cm.id = NULL;
+       return ret;
+}
+
+static void ipoib_cm_free_rx_reap_list(struct net_device *dev)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ipoib_cm_rx *rx, *n;
+       LIST_HEAD(list);
+
+       spin_lock_irq(&priv->lock);
+       list_splice_init(&priv->cm.rx_reap_list, &list);
+       spin_unlock_irq(&priv->lock);
+
+       list_for_each_entry_safe(rx, n, &list, list) {
+               ib_destroy_cm_id(rx->id);
+               ib_destroy_qp(rx->qp);
+               if (!ipoib_cm_has_srq(dev)) {
+                       ipoib_cm_free_rx_ring(priv->dev, rx->rx_ring);
+                       spin_lock_irq(&priv->lock);
+                       --priv->cm.nonsrq_conn_qp;
+                       spin_unlock_irq(&priv->lock);
+               }
+               kfree(rx);
+       }
+}
+
+void ipoib_cm_dev_stop(struct net_device *dev)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ipoib_cm_rx *p;
+       unsigned long begin;
+       int ret;
+
+       if (!IPOIB_CM_SUPPORTED(dev->dev_addr) || !priv->cm.id)
+               return;
+
+       ib_destroy_cm_id(priv->cm.id);
+       priv->cm.id = NULL;
+
+       spin_lock_irq(&priv->lock);
+       while (!list_empty(&priv->cm.passive_ids)) {
+               p = list_entry(priv->cm.passive_ids.next, typeof(*p), list);
+               list_move(&p->list, &priv->cm.rx_error_list);
+               p->state = IPOIB_CM_RX_ERROR;
+               spin_unlock_irq(&priv->lock);
+               ret = ib_modify_qp(p->qp, &ipoib_cm_err_attr, IB_QP_STATE);
+               if (ret)
+                       ipoib_warn(priv, "unable to move qp to error state: %d\n", ret);
+               spin_lock_irq(&priv->lock);
+       }
+
+       /* Wait for all RX to be drained */
+       begin = jiffies;
+
+       while (!list_empty(&priv->cm.rx_error_list) ||
+              !list_empty(&priv->cm.rx_flush_list) ||
+              !list_empty(&priv->cm.rx_drain_list)) {
+               if (time_after(jiffies, begin + 5 * HZ)) {
+                       ipoib_warn(priv, "RX drain timing out\n");
+
+                       /*
+                        * assume the HW is wedged and just free up everything.
+                        */
+                       list_splice_init(&priv->cm.rx_flush_list,
+                                        &priv->cm.rx_reap_list);
+                       list_splice_init(&priv->cm.rx_error_list,
+                                        &priv->cm.rx_reap_list);
+                       list_splice_init(&priv->cm.rx_drain_list,
+                                        &priv->cm.rx_reap_list);
+                       break;
+               }
+               spin_unlock_irq(&priv->lock);
+               msleep(1);
+               ipoib_drain_cq(dev);
+               spin_lock_irq(&priv->lock);
+       }
+
+       spin_unlock_irq(&priv->lock);
+
+       ipoib_cm_free_rx_reap_list(dev);
+
+       cancel_delayed_work(&priv->cm.stale_task);
+}
+
+static int ipoib_cm_rep_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
+{
+       struct ipoib_cm_tx *p = cm_id->context;
+       struct ipoib_dev_priv *priv = netdev_priv(p->dev);
+       struct ipoib_cm_data *data = event->private_data;
+       struct sk_buff_head skqueue;
+       struct ib_qp_attr qp_attr;
+       int qp_attr_mask, ret;
+       struct sk_buff *skb;
+
+       p->mtu = be32_to_cpu(data->mtu);
+
+       if (p->mtu <= IPOIB_ENCAP_LEN) {
+               ipoib_warn(priv, "Rejecting connection: mtu %d <= %d\n",
+                          p->mtu, IPOIB_ENCAP_LEN);
+               return -EINVAL;
+       }
+
+       qp_attr.qp_state = IB_QPS_RTR;
+       ret = ib_cm_init_qp_attr(cm_id, &qp_attr, &qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to init QP attr for RTR: %d\n", ret);
+               return ret;
+       }
+
+       qp_attr.rq_psn = 0 /* FIXME */;
+       ret = ib_modify_qp(p->qp, &qp_attr, qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to modify QP to RTR: %d\n", ret);
+               return ret;
+       }
+
+       qp_attr.qp_state = IB_QPS_RTS;
+       ret = ib_cm_init_qp_attr(cm_id, &qp_attr, &qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to init QP attr for RTS: %d\n", ret);
+               return ret;
+       }
+       ret = ib_modify_qp(p->qp, &qp_attr, qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to modify QP to RTS: %d\n", ret);
+               return ret;
+       }
+
+       skb_queue_head_init(&skqueue);
+
+       spin_lock_irq(&priv->lock);
+       set_bit(IPOIB_FLAG_OPER_UP, &p->flags);
+       if (p->neigh)
+               while ((skb = __skb_dequeue(&p->neigh->queue)))
+                       __skb_queue_tail(&skqueue, skb);
+       spin_unlock_irq(&priv->lock);
+
+       while ((skb = __skb_dequeue(&skqueue))) {
+               skb->dev = p->dev;
+               if (dev_queue_xmit(skb))
+                       ipoib_warn(priv, "dev_queue_xmit failed "
+                                  "to requeue packet\n");
+       }
+
+       ret = ib_send_cm_rtu(cm_id, NULL, 0);
+       if (ret) {
+               ipoib_warn(priv, "failed to send RTU: %d\n", ret);
+               return ret;
+       }
+       return 0;
+}
+
+static struct ib_qp *ipoib_cm_create_tx_qp(struct net_device *dev, struct ipoib_cm_tx *tx)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ib_qp_init_attr attr = {
+               .send_cq                = priv->recv_cq,
+               .recv_cq                = priv->recv_cq,
+               .srq                    = priv->cm.srq,
+               .cap.max_send_wr        = ipoib_sendq_size,
+               .cap.max_send_sge       = 1,
+               .sq_sig_type            = IB_SIGNAL_ALL_WR,
+               .qp_type                = IB_QPT_RC,
+               .qp_context             = tx,
+               .create_flags           = IB_QP_CREATE_USE_GFP_NOIO
+       };
+
+       struct ib_qp *tx_qp;
+
+       tx_qp = ib_create_qp(priv->pd, &attr);
+       if (PTR_ERR(tx_qp) == -EINVAL) {
+               ipoib_warn(priv, "can't use GFP_NOIO for QPs on device %s, using GFP_KERNEL\n",
+                          priv->ca->name);
+               attr.create_flags &= ~IB_QP_CREATE_USE_GFP_NOIO;
+               tx_qp = ib_create_qp(priv->pd, &attr);
+       }
+       return tx_qp;
+}
+
+static int ipoib_cm_send_req(struct net_device *dev,
+                            struct ib_cm_id *id, struct ib_qp *qp,
+                            u32 qpn,
+                            struct ib_sa_path_rec *pathrec)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ipoib_cm_data data = {};
+       struct ib_cm_req_param req = {};
+
+       data.qpn = cpu_to_be32(priv->qp->qp_num);
+       data.mtu = cpu_to_be32(IPOIB_CM_BUF_SIZE);
+
+       req.primary_path                = pathrec;
+       req.alternate_path              = NULL;
+       req.service_id                  = cpu_to_be64(IPOIB_CM_IETF_ID | qpn);
+       req.qp_num                      = qp->qp_num;
+       req.qp_type                     = qp->qp_type;
+       req.private_data                = &data;
+       req.private_data_len            = sizeof data;
+       req.flow_control                = 0;
+
+       req.starting_psn                = 0; /* FIXME */
+
+       /*
+        * Pick some arbitrary defaults here; we could make these
+        * module parameters if anyone cared about setting them.
+        */
+       req.responder_resources         = 4;
+       req.remote_cm_response_timeout  = 20;
+       req.local_cm_response_timeout   = 20;
+       req.retry_count                 = 0; /* RFC draft warns against retries */
+       req.rnr_retry_count             = 0; /* RFC draft warns against retries */
+       req.max_cm_retries              = 15;
+       req.srq                         = ipoib_cm_has_srq(dev);
+       return ib_send_cm_req(id, &req);
+}
+
+static int ipoib_cm_modify_tx_init(struct net_device *dev,
+                                 struct ib_cm_id *cm_id, struct ib_qp *qp)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ib_qp_attr qp_attr;
+       int qp_attr_mask, ret;
+       ret = ib_find_pkey(priv->ca, priv->port, priv->pkey, &qp_attr.pkey_index);
+       if (ret) {
+               ipoib_warn(priv, "pkey 0x%x not found: %d\n", priv->pkey, ret);
+               return ret;
+       }
+
+       qp_attr.qp_state = IB_QPS_INIT;
+       qp_attr.qp_access_flags = IB_ACCESS_LOCAL_WRITE;
+       qp_attr.port_num = priv->port;
+       qp_attr_mask = IB_QP_STATE | IB_QP_ACCESS_FLAGS | IB_QP_PKEY_INDEX | IB_QP_PORT;
+
+       ret = ib_modify_qp(qp, &qp_attr, qp_attr_mask);
+       if (ret) {
+               ipoib_warn(priv, "failed to modify tx QP to INIT: %d\n", ret);
+               return ret;
+       }
+       return 0;
+}
+
+static int ipoib_cm_tx_init(struct ipoib_cm_tx *p, u32 qpn,
+                           struct ib_sa_path_rec *pathrec)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(p->dev);
+       int ret;
+
+       p->tx_ring = __vmalloc(ipoib_sendq_size * sizeof *p->tx_ring,
+                              GFP_NOIO, PAGE_KERNEL);
+       if (!p->tx_ring) {
+               ipoib_warn(priv, "failed to allocate tx ring\n");
+               ret = -ENOMEM;
+               goto err_tx;
+       }
+       memset(p->tx_ring, 0, ipoib_sendq_size * sizeof *p->tx_ring);
+
+       p->qp = ipoib_cm_create_tx_qp(p->dev, p);
+       if (IS_ERR(p->qp)) {
+               ret = PTR_ERR(p->qp);
+               ipoib_warn(priv, "failed to allocate tx qp: %d\n", ret);
+               goto err_qp;
+       }
+
+       p->id = ib_create_cm_id(priv->ca, ipoib_cm_tx_handler, p);
+       if (IS_ERR(p->id)) {
+               ret = PTR_ERR(p->id);
+               ipoib_warn(priv, "failed to create tx cm id: %d\n", ret);
+               goto err_id;
+       }
+
+       ret = ipoib_cm_modify_tx_init(p->dev, p->id,  p->qp);
+       if (ret) {
+               ipoib_warn(priv, "failed to modify tx qp to rtr: %d\n", ret);
+               goto err_modify;
+       }
+
+       ret = ipoib_cm_send_req(p->dev, p->id, p->qp, qpn, pathrec);
+       if (ret) {
+               ipoib_warn(priv, "failed to send cm req: %d\n", ret);
+               goto err_send_cm;
+       }
+
+       ipoib_dbg(priv, "Request connection 0x%x for gid %pI6 qpn 0x%x\n",
+                 p->qp->qp_num, pathrec->dgid.raw, qpn);
+
+       return 0;
+
+err_send_cm:
+err_modify:
+       ib_destroy_cm_id(p->id);
+err_id:
+       p->id = NULL;
+       ib_destroy_qp(p->qp);
+err_qp:
+       p->qp = NULL;
+       vfree(p->tx_ring);
+err_tx:
+       return ret;
+}
+
+static void ipoib_cm_tx_destroy(struct ipoib_cm_tx *p)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(p->dev);
+       struct ipoib_cm_tx_buf *tx_req;
+       unsigned long begin;
+
+       ipoib_dbg(priv, "Destroy active connection 0x%x head 0x%x tail 0x%x\n",
+                 p->qp ? p->qp->qp_num : 0, p->tx_head, p->tx_tail);
+
+       if (p->id)
+               ib_destroy_cm_id(p->id);
+
+       if (p->tx_ring) {
+               /* Wait for all sends to complete */
+               begin = jiffies;
+               while ((int) p->tx_tail - (int) p->tx_head < 0) {
+                       if (time_after(jiffies, begin + 5 * HZ)) {
+                               ipoib_warn(priv, "timing out; %d sends not completed\n",
+                                          p->tx_head - p->tx_tail);
+                               goto timeout;
+                       }
+
+                       msleep(1);
+               }
+       }
+
+timeout:
+
+       while ((int) p->tx_tail - (int) p->tx_head < 0) {
+               tx_req = &p->tx_ring[p->tx_tail & (ipoib_sendq_size - 1)];
+               ib_dma_unmap_single(priv->ca, tx_req->mapping, tx_req->skb->len,
+                                   DMA_TO_DEVICE);
+               dev_kfree_skb_any(tx_req->skb);
+               ++p->tx_tail;
+               netif_tx_lock_bh(p->dev);
+               if (unlikely(--priv->tx_outstanding == ipoib_sendq_size >> 1) &&
+                   netif_queue_stopped(p->dev) &&
+                   test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
+                       netif_wake_queue(p->dev);
+               netif_tx_unlock_bh(p->dev);
+       }
+
+       if (p->qp)
+               ib_destroy_qp(p->qp);
+
+       vfree(p->tx_ring);
+       kfree(p);
+}
+
+static int ipoib_cm_tx_handler(struct ib_cm_id *cm_id,
+                              struct ib_cm_event *event)
+{
+       struct ipoib_cm_tx *tx = cm_id->context;
+       struct ipoib_dev_priv *priv = netdev_priv(tx->dev);
+       struct net_device *dev = priv->dev;
+       struct ipoib_neigh *neigh;
+       unsigned long flags;
+       int ret;
+
+       switch (event->event) {
+       case IB_CM_DREQ_RECEIVED:
+               ipoib_dbg(priv, "DREQ received.\n");
+               ib_send_cm_drep(cm_id, NULL, 0);
+               break;
+       case IB_CM_REP_RECEIVED:
+               ipoib_dbg(priv, "REP received.\n");
+               ret = ipoib_cm_rep_handler(cm_id, event);
+               if (ret)
+                       ib_send_cm_rej(cm_id, IB_CM_REJ_CONSUMER_DEFINED,
+                                      NULL, 0, NULL, 0);
+               break;
+       case IB_CM_REQ_ERROR:
+       case IB_CM_REJ_RECEIVED:
+       case IB_CM_TIMEWAIT_EXIT:
+               ipoib_dbg(priv, "CM error %d.\n", event->event);
+               netif_tx_lock_bh(dev);
+               spin_lock_irqsave(&priv->lock, flags);
+               neigh = tx->neigh;
+
+               if (neigh) {
+                       neigh->cm = NULL;
+                       ipoib_neigh_free(neigh);
+
+                       tx->neigh = NULL;
+               }
+
+               if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &tx->flags)) {
+                       list_move(&tx->list, &priv->cm.reap_list);
+                       queue_work(priv->wq, &priv->cm.reap_task);
+               }
+
+               spin_unlock_irqrestore(&priv->lock, flags);
+               netif_tx_unlock_bh(dev);
+               break;
+       default:
+               break;
+       }
+
+       return 0;
+}
+
+struct ipoib_cm_tx *ipoib_cm_create_tx(struct net_device *dev, struct ipoib_path *path,
+                                      struct ipoib_neigh *neigh)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ipoib_cm_tx *tx;
+
+       tx = kzalloc(sizeof *tx, GFP_ATOMIC);
+       if (!tx)
+               return NULL;
+
+       neigh->cm = tx;
+       tx->neigh = neigh;
+       tx->path = path;
+       tx->dev = dev;
+       list_add(&tx->list, &priv->cm.start_list);
+       set_bit(IPOIB_FLAG_INITIALIZED, &tx->flags);
+       queue_work(priv->wq, &priv->cm.start_task);
+       return tx;
+}
+
+void ipoib_cm_destroy_tx(struct ipoib_cm_tx *tx)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(tx->dev);
+       unsigned long flags;
+       if (test_and_clear_bit(IPOIB_FLAG_INITIALIZED, &tx->flags)) {
+               spin_lock_irqsave(&priv->lock, flags);
+               list_move(&tx->list, &priv->cm.reap_list);
+               queue_work(priv->wq, &priv->cm.reap_task);
+               ipoib_dbg(priv, "Reap connection for gid %pI6\n",
+                         tx->neigh->daddr + 4);
+               tx->neigh = NULL;
+               spin_unlock_irqrestore(&priv->lock, flags);
+       }
+}
+
+static void ipoib_cm_tx_start(struct work_struct *work)
+{
+       struct ipoib_dev_priv *priv = container_of(work, struct ipoib_dev_priv,
+                                                  cm.start_task);
+       struct net_device *dev = priv->dev;
+       struct ipoib_neigh *neigh;
+       struct ipoib_cm_tx *p;
+       unsigned long flags;
+       int ret;
+
+       struct ib_sa_path_rec pathrec;
+       u32 qpn;
+
+       netif_tx_lock_bh(dev);
+       spin_lock_irqsave(&priv->lock, flags);
+
+       while (!list_empty(&priv->cm.start_list)) {
+               p = list_entry(priv->cm.start_list.next, typeof(*p), list);
+               list_del_init(&p->list);
+               neigh = p->neigh;
+               qpn = IPOIB_QPN(neigh->daddr);
+               memcpy(&pathrec, &p->path->pathrec, sizeof pathrec);
+
+               spin_unlock_irqrestore(&priv->lock, flags);
+               netif_tx_unlock_bh(dev);
+
+               ret = ipoib_cm_tx_init(p, qpn, &pathrec);
+
+               netif_tx_lock_bh(dev);
+               spin_lock_irqsave(&priv->lock, flags);
+
+               if (ret) {
+                       neigh = p->neigh;
+                       if (neigh) {
+                               neigh->cm = NULL;
+                               ipoib_neigh_free(neigh);
+                       }
+                       list_del(&p->list);
+                       kfree(p);
+               }
+       }
+
+       spin_unlock_irqrestore(&priv->lock, flags);
+       netif_tx_unlock_bh(dev);
+}
+
+static void ipoib_cm_tx_reap(struct work_struct *work)
+{
+       struct ipoib_dev_priv *priv = container_of(work, struct ipoib_dev_priv,
+                                                  cm.reap_task);
+       struct net_device *dev = priv->dev;
+       struct ipoib_cm_tx *p;
+       unsigned long flags;
+
+       netif_tx_lock_bh(dev);
+       spin_lock_irqsave(&priv->lock, flags);
+
+       while (!list_empty(&priv->cm.reap_list)) {
+               p = list_entry(priv->cm.reap_list.next, typeof(*p), list);
+               list_del(&p->list);
+               spin_unlock_irqrestore(&priv->lock, flags);
+               netif_tx_unlock_bh(dev);
+               ipoib_cm_tx_destroy(p);
+               netif_tx_lock_bh(dev);
+               spin_lock_irqsave(&priv->lock, flags);
+       }
+
+       spin_unlock_irqrestore(&priv->lock, flags);
+       netif_tx_unlock_bh(dev);
+}
+
+static void ipoib_cm_skb_reap(struct work_struct *work)
+{
+       struct ipoib_dev_priv *priv = container_of(work, struct ipoib_dev_priv,
+                                                  cm.skb_task);
+       struct net_device *dev = priv->dev;
+       struct sk_buff *skb;
+       unsigned long flags;
+       unsigned mtu = priv->mcast_mtu;
+
+       netif_tx_lock_bh(dev);
+       spin_lock_irqsave(&priv->lock, flags);
+
+       while ((skb = skb_dequeue(&priv->cm.skb_queue))) {
+               spin_unlock_irqrestore(&priv->lock, flags);
+               netif_tx_unlock_bh(dev);
+
+               if (skb->protocol == htons(ETH_P_IP))
+                       icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
+#if IS_ENABLED(CONFIG_IPV6)
+               else if (skb->protocol == htons(ETH_P_IPV6))
+                       icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+#endif
+               dev_kfree_skb_any(skb);
+
+               netif_tx_lock_bh(dev);
+               spin_lock_irqsave(&priv->lock, flags);
+       }
+
+       spin_unlock_irqrestore(&priv->lock, flags);
+       netif_tx_unlock_bh(dev);
+}
+
+void ipoib_cm_skb_too_long(struct net_device *dev, struct sk_buff *skb,
+                          unsigned int mtu)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       int e = skb_queue_empty(&priv->cm.skb_queue);
+
+       if (skb_dst(skb))
+               skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
+
+       skb_queue_tail(&priv->cm.skb_queue, skb);
+       if (e)
+               queue_work(priv->wq, &priv->cm.skb_task);
+}
+
+static void ipoib_cm_rx_reap(struct work_struct *work)
+{
+       ipoib_cm_free_rx_reap_list(container_of(work, struct ipoib_dev_priv,
+                                               cm.rx_reap_task)->dev);
+}
+
+static void ipoib_cm_stale_task(struct work_struct *work)
+{
+       struct ipoib_dev_priv *priv = container_of(work, struct ipoib_dev_priv,
+                                                  cm.stale_task.work);
+       struct ipoib_cm_rx *p;
+       int ret;
+
+       spin_lock_irq(&priv->lock);
+       while (!list_empty(&priv->cm.passive_ids)) {
+               /* List is sorted by LRU, start from tail,
+                * stop when we see a recently used entry */
+               p = list_entry(priv->cm.passive_ids.prev, typeof(*p), list);
+               if (time_before_eq(jiffies, p->jiffies + IPOIB_CM_RX_TIMEOUT))
+                       break;
+               list_move(&p->list, &priv->cm.rx_error_list);
+               p->state = IPOIB_CM_RX_ERROR;
+               spin_unlock_irq(&priv->lock);
+               ret = ib_modify_qp(p->qp, &ipoib_cm_err_attr, IB_QP_STATE);
+               if (ret)
+                       ipoib_warn(priv, "unable to move qp to error state: %d\n", ret);
+               spin_lock_irq(&priv->lock);
+       }
+
+       if (!list_empty(&priv->cm.passive_ids))
+               queue_delayed_work(priv->wq,
+                                  &priv->cm.stale_task, IPOIB_CM_RX_DELAY);
+       spin_unlock_irq(&priv->lock);
+}
+
+
+static ssize_t show_mode(struct device *d, struct device_attribute *attr,
+                        char *buf)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(to_net_dev(d));
+
+       if (test_bit(IPOIB_FLAG_ADMIN_CM, &priv->flags))
+               return sprintf(buf, "connected\n");
+       else
+               return sprintf(buf, "datagram\n");
+}
+
+static ssize_t set_mode(struct device *d, struct device_attribute *attr,
+                       const char *buf, size_t count)
+{
+       struct net_device *dev = to_net_dev(d);
+       int ret;
+
+       if (!rtnl_trylock())
+               return restart_syscall();
+
+       ret = ipoib_set_mode(dev, buf);
+
+       rtnl_unlock();
+
+       if (!ret)
+               return count;
+
+       return ret;
+}
+
+static DEVICE_ATTR(mode, S_IWUSR | S_IRUGO, show_mode, set_mode);
+
+int ipoib_cm_add_mode_attr(struct net_device *dev)
+{
+       return device_create_file(&dev->dev, &dev_attr_mode);
+}
+
+static void ipoib_cm_create_srq(struct net_device *dev, int max_sge)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       struct ib_srq_init_attr srq_init_attr = {
+               .srq_type = IB_SRQT_BASIC,
+               .attr = {
+                       .max_wr  = ipoib_recvq_size,
+                       .max_sge = max_sge
+               }
+       };
+
+       priv->cm.srq = ib_create_srq(priv->pd, &srq_init_attr);
+       if (IS_ERR(priv->cm.srq)) {
+               if (PTR_ERR(priv->cm.srq) != -ENOSYS)
+                       printk(KERN_WARNING "%s: failed to allocate SRQ, error %ld\n",
+                              priv->ca->name, PTR_ERR(priv->cm.srq));
+               priv->cm.srq = NULL;
+               return;
+       }
+
+       priv->cm.srq_ring = vzalloc(ipoib_recvq_size * sizeof *priv->cm.srq_ring);
+       if (!priv->cm.srq_ring) {
+               printk(KERN_WARNING "%s: failed to allocate CM SRQ ring (%d entries)\n",
+                      priv->ca->name, ipoib_recvq_size);
+               ib_destroy_srq(priv->cm.srq);
+               priv->cm.srq = NULL;
+               return;
+       }
+
+}
+
+int ipoib_cm_dev_init(struct net_device *dev)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       int i, ret;
+       struct ib_device_attr attr;
+
+       INIT_LIST_HEAD(&priv->cm.passive_ids);
+       INIT_LIST_HEAD(&priv->cm.reap_list);
+       INIT_LIST_HEAD(&priv->cm.start_list);
+       INIT_LIST_HEAD(&priv->cm.rx_error_list);
+       INIT_LIST_HEAD(&priv->cm.rx_flush_list);
+       INIT_LIST_HEAD(&priv->cm.rx_drain_list);
+       INIT_LIST_HEAD(&priv->cm.rx_reap_list);
+       INIT_WORK(&priv->cm.start_task, ipoib_cm_tx_start);
+       INIT_WORK(&priv->cm.reap_task, ipoib_cm_tx_reap);
+       INIT_WORK(&priv->cm.skb_task, ipoib_cm_skb_reap);
+       INIT_WORK(&priv->cm.rx_reap_task, ipoib_cm_rx_reap);
+       INIT_DELAYED_WORK(&priv->cm.stale_task, ipoib_cm_stale_task);
+
+       skb_queue_head_init(&priv->cm.skb_queue);
+
+       ret = ib_query_device(priv->ca, &attr);
+       if (ret) {
+               printk(KERN_WARNING "ib_query_device() failed with %d\n", ret);
+               return ret;
+       }
+
+       ipoib_dbg(priv, "max_srq_sge=%d\n", attr.max_srq_sge);
+
+       attr.max_srq_sge = min_t(int, IPOIB_CM_RX_SG, attr.max_srq_sge);
+       ipoib_cm_create_srq(dev, attr.max_srq_sge);
+       if (ipoib_cm_has_srq(dev)) {
+               priv->cm.max_cm_mtu = attr.max_srq_sge * PAGE_SIZE - 0x10;
+               priv->cm.num_frags  = attr.max_srq_sge;
+               ipoib_dbg(priv, "max_cm_mtu = 0x%x, num_frags=%d\n",
+                         priv->cm.max_cm_mtu, priv->cm.num_frags);
+       } else {
+               priv->cm.max_cm_mtu = IPOIB_CM_MTU;
+               priv->cm.num_frags  = IPOIB_CM_RX_SG;
+       }
+
+       ipoib_cm_init_rx_wr(dev, &priv->cm.rx_wr, priv->cm.rx_sge);
+
+       if (ipoib_cm_has_srq(dev)) {
+               for (i = 0; i < ipoib_recvq_size; ++i) {
+                       if (!ipoib_cm_alloc_rx_skb(dev, priv->cm.srq_ring, i,
+                                                  priv->cm.num_frags - 1,
+                                                  priv->cm.srq_ring[i].mapping,
+                                                  GFP_KERNEL)) {
+                               ipoib_warn(priv, "failed to allocate "
+                                          "receive buffer %d\n", i);
+                               ipoib_cm_dev_cleanup(dev);
+                               return -ENOMEM;
+                       }
+
+                       if (ipoib_cm_post_receive_srq(dev, i)) {
+                               ipoib_warn(priv, "ipoib_cm_post_receive_srq "
+                                          "failed for buf %d\n", i);
+                               ipoib_cm_dev_cleanup(dev);
+                               return -EIO;
+                       }
+               }
+       }
+
+       priv->dev->dev_addr[0] = IPOIB_FLAGS_RC;
+       return 0;
+}
+
+void ipoib_cm_dev_cleanup(struct net_device *dev)
+{
+       struct ipoib_dev_priv *priv = netdev_priv(dev);
+       int ret;
+
+       if (!priv->cm.srq)
+               return;
+
+       ipoib_dbg(priv, "Cleanup ipoib connected mode.\n");
+
+       ret = ib_destroy_srq(priv->cm.srq);
+       if (ret)
+               ipoib_warn(priv, "ib_destroy_srq failed: %d\n", ret);
+
+       priv->cm.srq = NULL;
+       if (!priv->cm.srq_ring)
+               return;
+
+       ipoib_cm_free_rx_ring(dev, priv->cm.srq_ring);
+       priv->cm.srq_ring = NULL;
+}