Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=377f9b2f4529e0ac702fd7b91e216afd0adc959e
Commit:     377f9b2f4529e0ac702fd7b91e216afd0adc959e
Parent:     ef7fbf59e6f780a0fa03536839e3c42e9ce40ad1
Author:     Tom Tucker <[EMAIL PROTECTED]>
AuthorDate: Wed Dec 12 16:13:21 2007 -0600
Committer:  J. Bruce Fields <[EMAIL PROTECTED]>
CommitDate: Fri Feb 1 16:42:14 2008 -0500

    rdma: SVCRDMA Core Transport Services
    
    This file implements the core transport data management and I/O
    path. The I/O path for RDMA involves receiving callbacks on interrupt
    context. Since all the svc transport locks are _bh locks we enqueue the
    transport on a list, schedule a tasklet to dequeue data indications from
    the RDMA completion queue. The tasklet in turn takes _bh locks to
    enqueue receive data indications on a list for the transport. The
    svc_rdma_recvfrom transport function dequeues data from this list in an
    NFSD thread context.
    
    Signed-off-by: Tom Tucker <[EMAIL PROTECTED]>
    Acked-by: Neil Brown <[EMAIL PROTECTED]>
    Signed-off-by: J. Bruce Fields <[EMAIL PROTECTED]>
---
 net/sunrpc/xprtrdma/svc_rdma_transport.c | 1080 ++++++++++++++++++++++++++++++
 1 files changed, 1080 insertions(+), 0 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c 
b/net/sunrpc/xprtrdma/svc_rdma_transport.c
new file mode 100644
index 0000000..f09444c
--- /dev/null
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -0,0 +1,1080 @@
+/*
+ * Copyright (c) 2005-2007 Network Appliance, Inc. 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 BSD-type
+ * 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.
+ *
+ *      Neither the name of the Network Appliance, Inc. nor the names of
+ *      its contributors may be used to endorse or promote products
+ *      derived from this software without specific prior written
+ *      permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Author: Tom Tucker <[EMAIL PROTECTED]>
+ */
+
+#include <linux/sunrpc/svc_xprt.h>
+#include <linux/sunrpc/debug.h>
+#include <linux/sunrpc/rpc_rdma.h>
+#include <linux/spinlock.h>
+#include <rdma/ib_verbs.h>
+#include <rdma/rdma_cm.h>
+#include <linux/sunrpc/svc_rdma.h>
+
+#define RPCDBG_FACILITY        RPCDBG_SVCXPRT
+
+static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
+                                       struct sockaddr *sa, int salen,
+                                       int flags);
+static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt);
+static void svc_rdma_release_rqst(struct svc_rqst *);
+static void rdma_destroy_xprt(struct svcxprt_rdma *xprt);
+static void dto_tasklet_func(unsigned long data);
+static void svc_rdma_detach(struct svc_xprt *xprt);
+static void svc_rdma_free(struct svc_xprt *xprt);
+static int svc_rdma_has_wspace(struct svc_xprt *xprt);
+static void rq_cq_reap(struct svcxprt_rdma *xprt);
+static void sq_cq_reap(struct svcxprt_rdma *xprt);
+
+DECLARE_TASKLET(dto_tasklet, dto_tasklet_func, 0UL);
+static DEFINE_SPINLOCK(dto_lock);
+static LIST_HEAD(dto_xprt_q);
+
+static struct svc_xprt_ops svc_rdma_ops = {
+       .xpo_create = svc_rdma_create,
+       .xpo_recvfrom = svc_rdma_recvfrom,
+       .xpo_sendto = svc_rdma_sendto,
+       .xpo_release_rqst = svc_rdma_release_rqst,
+       .xpo_detach = svc_rdma_detach,
+       .xpo_free = svc_rdma_free,
+       .xpo_prep_reply_hdr = svc_rdma_prep_reply_hdr,
+       .xpo_has_wspace = svc_rdma_has_wspace,
+       .xpo_accept = svc_rdma_accept,
+};
+
+struct svc_xprt_class svc_rdma_class = {
+       .xcl_name = "rdma",
+       .xcl_owner = THIS_MODULE,
+       .xcl_ops = &svc_rdma_ops,
+       .xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
+};
+
+static int rdma_bump_context_cache(struct svcxprt_rdma *xprt)
+{
+       int target;
+       int at_least_one = 0;
+       struct svc_rdma_op_ctxt *ctxt;
+
+       target = min(xprt->sc_ctxt_cnt + xprt->sc_ctxt_bump,
+                    xprt->sc_ctxt_max);
+
+       spin_lock_bh(&xprt->sc_ctxt_lock);
+       while (xprt->sc_ctxt_cnt < target) {
+               xprt->sc_ctxt_cnt++;
+               spin_unlock_bh(&xprt->sc_ctxt_lock);
+
+               ctxt = kmalloc(sizeof(*ctxt), GFP_KERNEL);
+
+               spin_lock_bh(&xprt->sc_ctxt_lock);
+               if (ctxt) {
+                       at_least_one = 1;
+                       ctxt->next = xprt->sc_ctxt_head;
+                       xprt->sc_ctxt_head = ctxt;
+               } else {
+                       /* kmalloc failed...give up for now */
+                       xprt->sc_ctxt_cnt--;
+                       break;
+               }
+       }
+       spin_unlock_bh(&xprt->sc_ctxt_lock);
+       dprintk("svcrdma: sc_ctxt_max=%d, sc_ctxt_cnt=%d\n",
+               xprt->sc_ctxt_max, xprt->sc_ctxt_cnt);
+       return at_least_one;
+}
+
+struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
+{
+       struct svc_rdma_op_ctxt *ctxt;
+
+       while (1) {
+               spin_lock_bh(&xprt->sc_ctxt_lock);
+               if (unlikely(xprt->sc_ctxt_head == NULL)) {
+                       /* Try to bump my cache. */
+                       spin_unlock_bh(&xprt->sc_ctxt_lock);
+
+                       if (rdma_bump_context_cache(xprt))
+                               continue;
+
+                       printk(KERN_INFO "svcrdma: sleeping waiting for "
+                              "context memory on xprt=%p\n",
+                              xprt);
+                       schedule_timeout_uninterruptible(msecs_to_jiffies(500));
+                       continue;
+               }
+               ctxt = xprt->sc_ctxt_head;
+               xprt->sc_ctxt_head = ctxt->next;
+               spin_unlock_bh(&xprt->sc_ctxt_lock);
+               ctxt->xprt = xprt;
+               INIT_LIST_HEAD(&ctxt->dto_q);
+               ctxt->count = 0;
+               break;
+       }
+       return ctxt;
+}
+
+void svc_rdma_put_context(struct svc_rdma_op_ctxt *ctxt, int free_pages)
+{
+       struct svcxprt_rdma *xprt;
+       int i;
+
+       BUG_ON(!ctxt);
+       xprt = ctxt->xprt;
+       if (free_pages)
+               for (i = 0; i < ctxt->count; i++)
+                       put_page(ctxt->pages[i]);
+
+       for (i = 0; i < ctxt->count; i++)
+               dma_unmap_single(xprt->sc_cm_id->device->dma_device,
+                                ctxt->sge[i].addr,
+                                ctxt->sge[i].length,
+                                ctxt->direction);
+       spin_lock_bh(&xprt->sc_ctxt_lock);
+       ctxt->next = xprt->sc_ctxt_head;
+       xprt->sc_ctxt_head = ctxt;
+       spin_unlock_bh(&xprt->sc_ctxt_lock);
+}
+
+/* ib_cq event handler */
+static void cq_event_handler(struct ib_event *event, void *context)
+{
+       struct svc_xprt *xprt = context;
+       dprintk("svcrdma: received CQ event id=%d, context=%p\n",
+               event->event, context);
+       set_bit(XPT_CLOSE, &xprt->xpt_flags);
+}
+
+/* QP event handler */
+static void qp_event_handler(struct ib_event *event, void *context)
+{
+       struct svc_xprt *xprt = context;
+
+       switch (event->event) {
+       /* These are considered benign events */
+       case IB_EVENT_PATH_MIG:
+       case IB_EVENT_COMM_EST:
+       case IB_EVENT_SQ_DRAINED:
+       case IB_EVENT_QP_LAST_WQE_REACHED:
+               dprintk("svcrdma: QP event %d received for QP=%p\n",
+                       event->event, event->element.qp);
+               break;
+       /* These are considered fatal events */
+       case IB_EVENT_PATH_MIG_ERR:
+       case IB_EVENT_QP_FATAL:
+       case IB_EVENT_QP_REQ_ERR:
+       case IB_EVENT_QP_ACCESS_ERR:
+       case IB_EVENT_DEVICE_FATAL:
+       default:
+               dprintk("svcrdma: QP ERROR event %d received for QP=%p, "
+                       "closing transport\n",
+                       event->event, event->element.qp);
+               set_bit(XPT_CLOSE, &xprt->xpt_flags);
+               break;
+       }
+}
+
+/*
+ * Data Transfer Operation Tasklet
+ *
+ * Walks a list of transports with I/O pending, removing entries as
+ * they are added to the server's I/O pending list. Two bits indicate
+ * if SQ, RQ, or both have I/O pending. The dto_lock is an irqsave
+ * spinlock that serializes access to the transport list with the RQ
+ * and SQ interrupt handlers.
+ */
+static void dto_tasklet_func(unsigned long data)
+{
+       struct svcxprt_rdma *xprt;
+       unsigned long flags;
+
+       spin_lock_irqsave(&dto_lock, flags);
+       while (!list_empty(&dto_xprt_q)) {
+               xprt = list_entry(dto_xprt_q.next,
+                                 struct svcxprt_rdma, sc_dto_q);
+               list_del_init(&xprt->sc_dto_q);
+               spin_unlock_irqrestore(&dto_lock, flags);
+
+               if (test_and_clear_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags)) {
+                       ib_req_notify_cq(xprt->sc_rq_cq, IB_CQ_NEXT_COMP);
+                       rq_cq_reap(xprt);
+                       set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
+                       /*
+                        * If data arrived before established event,
+                        * don't enqueue. This defers RPC I/O until the
+                        * RDMA connection is complete.
+                        */
+                       if (!test_bit(RDMAXPRT_CONN_PENDING, &xprt->sc_flags))
+                               svc_xprt_enqueue(&xprt->sc_xprt);
+               }
+
+               if (test_and_clear_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags)) {
+                       ib_req_notify_cq(xprt->sc_sq_cq, IB_CQ_NEXT_COMP);
+                       sq_cq_reap(xprt);
+               }
+
+               spin_lock_irqsave(&dto_lock, flags);
+       }
+       spin_unlock_irqrestore(&dto_lock, flags);
+}
+
+/*
+ * Receive Queue Completion Handler
+ *
+ * Since an RQ completion handler is called on interrupt context, we
+ * need to defer the handling of the I/O to a tasklet
+ */
+static void rq_comp_handler(struct ib_cq *cq, void *cq_context)
+{
+       struct svcxprt_rdma *xprt = cq_context;
+       unsigned long flags;
+
+       /*
+        * Set the bit regardless of whether or not it's on the list
+        * because it may be on the list already due to an SQ
+        * completion.
+       */
+       set_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags);
+
+       /*
+        * If this transport is not already on the DTO transport queue,
+        * add it
+        */
+       spin_lock_irqsave(&dto_lock, flags);
+       if (list_empty(&xprt->sc_dto_q))
+               list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
+       spin_unlock_irqrestore(&dto_lock, flags);
+
+       /* Tasklet does all the work to avoid irqsave locks. */
+       tasklet_schedule(&dto_tasklet);
+}
+
+/*
+ * rq_cq_reap - Process the RQ CQ.
+ *
+ * Take all completing WC off the CQE and enqueue the associated DTO
+ * context on the dto_q for the transport.
+ */
+static void rq_cq_reap(struct svcxprt_rdma *xprt)
+{
+       int ret;
+       struct ib_wc wc;
+       struct svc_rdma_op_ctxt *ctxt = NULL;
+
+       atomic_inc(&rdma_stat_rq_poll);
+
+       spin_lock_bh(&xprt->sc_rq_dto_lock);
+       while ((ret = ib_poll_cq(xprt->sc_rq_cq, 1, &wc)) > 0) {
+               ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
+               ctxt->wc_status = wc.status;
+               ctxt->byte_len = wc.byte_len;
+               if (wc.status != IB_WC_SUCCESS) {
+                       /* Close the transport */
+                       set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
+                       svc_rdma_put_context(ctxt, 1);
+                       continue;
+               }
+               list_add_tail(&ctxt->dto_q, &xprt->sc_rq_dto_q);
+       }
+       spin_unlock_bh(&xprt->sc_rq_dto_lock);
+
+       if (ctxt)
+               atomic_inc(&rdma_stat_rq_prod);
+}
+
+/*
+ * Send Queue Completion Handler - potentially called on interrupt context.
+ */
+static void sq_cq_reap(struct svcxprt_rdma *xprt)
+{
+       struct svc_rdma_op_ctxt *ctxt = NULL;
+       struct ib_wc wc;
+       struct ib_cq *cq = xprt->sc_sq_cq;
+       int ret;
+
+       atomic_inc(&rdma_stat_sq_poll);
+       while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
+               ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
+               xprt = ctxt->xprt;
+
+               if (wc.status != IB_WC_SUCCESS)
+                       /* Close the transport */
+                       set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
+
+               /* Decrement used SQ WR count */
+               atomic_dec(&xprt->sc_sq_count);
+               wake_up(&xprt->sc_send_wait);
+
+               switch (ctxt->wr_op) {
+               case IB_WR_SEND:
+               case IB_WR_RDMA_WRITE:
+                       svc_rdma_put_context(ctxt, 1);
+                       break;
+
+               case IB_WR_RDMA_READ:
+                       if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
+                               set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
+                               set_bit(RDMACTXT_F_READ_DONE, &ctxt->flags);
+                               spin_lock_bh(&xprt->sc_read_complete_lock);
+                               list_add_tail(&ctxt->dto_q,
+                                             &xprt->sc_read_complete_q);
+                               spin_unlock_bh(&xprt->sc_read_complete_lock);
+                               svc_xprt_enqueue(&xprt->sc_xprt);
+                       }
+                       break;
+
+               default:
+                       printk(KERN_ERR "svcrdma: unexpected completion type, "
+                              "opcode=%d, status=%d\n",
+                              wc.opcode, wc.status);
+                       break;
+               }
+       }
+
+       if (ctxt)
+               atomic_inc(&rdma_stat_sq_prod);
+}
+
+static void sq_comp_handler(struct ib_cq *cq, void *cq_context)
+{
+       struct svcxprt_rdma *xprt = cq_context;
+       unsigned long flags;
+
+       /*
+        * Set the bit regardless of whether or not it's on the list
+        * because it may be on the list already due to an RQ
+        * completion.
+       */
+       set_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags);
+
+       /*
+        * If this transport is not already on the DTO transport queue,
+        * add it
+        */
+       spin_lock_irqsave(&dto_lock, flags);
+       if (list_empty(&xprt->sc_dto_q))
+               list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
+       spin_unlock_irqrestore(&dto_lock, flags);
+
+       /* Tasklet does all the work to avoid irqsave locks. */
+       tasklet_schedule(&dto_tasklet);
+}
+
+static void create_context_cache(struct svcxprt_rdma *xprt,
+                                int ctxt_count, int ctxt_bump, int ctxt_max)
+{
+       struct svc_rdma_op_ctxt *ctxt;
+       int i;
+
+       xprt->sc_ctxt_max = ctxt_max;
+       xprt->sc_ctxt_bump = ctxt_bump;
+       xprt->sc_ctxt_cnt = 0;
+       xprt->sc_ctxt_head = NULL;
+       for (i = 0; i < ctxt_count; i++) {
+               ctxt = kmalloc(sizeof(*ctxt), GFP_KERNEL);
+               if (ctxt) {
+                       ctxt->next = xprt->sc_ctxt_head;
+                       xprt->sc_ctxt_head = ctxt;
+                       xprt->sc_ctxt_cnt++;
+               }
+       }
+}
+
+static void destroy_context_cache(struct svc_rdma_op_ctxt *ctxt)
+{
+       struct svc_rdma_op_ctxt *next;
+       if (!ctxt)
+               return;
+
+       do {
+               next = ctxt->next;
+               kfree(ctxt);
+               ctxt = next;
+       } while (next);
+}
+
+static struct svcxprt_rdma *rdma_create_xprt(struct svc_serv *serv,
+                                            int listener)
+{
+       struct svcxprt_rdma *cma_xprt = kzalloc(sizeof *cma_xprt, GFP_KERNEL);
+
+       if (!cma_xprt)
+               return NULL;
+       svc_xprt_init(&svc_rdma_class, &cma_xprt->sc_xprt, serv);
+       INIT_LIST_HEAD(&cma_xprt->sc_accept_q);
+       INIT_LIST_HEAD(&cma_xprt->sc_dto_q);
+       INIT_LIST_HEAD(&cma_xprt->sc_rq_dto_q);
+       INIT_LIST_HEAD(&cma_xprt->sc_read_complete_q);
+       init_waitqueue_head(&cma_xprt->sc_send_wait);
+
+       spin_lock_init(&cma_xprt->sc_lock);
+       spin_lock_init(&cma_xprt->sc_read_complete_lock);
+       spin_lock_init(&cma_xprt->sc_ctxt_lock);
+       spin_lock_init(&cma_xprt->sc_rq_dto_lock);
+
+       cma_xprt->sc_ord = svcrdma_ord;
+
+       cma_xprt->sc_max_req_size = svcrdma_max_req_size;
+       cma_xprt->sc_max_requests = svcrdma_max_requests;
+       cma_xprt->sc_sq_depth = svcrdma_max_requests * RPCRDMA_SQ_DEPTH_MULT;
+       atomic_set(&cma_xprt->sc_sq_count, 0);
+
+       if (!listener) {
+               int reqs = cma_xprt->sc_max_requests;
+               create_context_cache(cma_xprt,
+                                    reqs << 1, /* starting size */
+                                    reqs,      /* bump amount */
+                                    reqs +
+                                    cma_xprt->sc_sq_depth +
+                                    RPCRDMA_MAX_THREADS + 1); /* max */
+               if (!cma_xprt->sc_ctxt_head) {
+                       kfree(cma_xprt);
+                       return NULL;
+               }
+               clear_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);
+       } else
+               set_bit(XPT_LISTENER, &cma_xprt->sc_xprt.xpt_flags);
+
+       return cma_xprt;
+}
+
+struct page *svc_rdma_get_page(void)
+{
+       struct page *page;
+
+       while ((page = alloc_page(GFP_KERNEL)) == NULL) {
+               /* If we can't get memory, wait a bit and try again */
+               printk(KERN_INFO "svcrdma: out of memory...retrying in 1000 "
+                      "jiffies.\n");
+               schedule_timeout_uninterruptible(msecs_to_jiffies(1000));
+       }
+       return page;
+}
+
+int svc_rdma_post_recv(struct svcxprt_rdma *xprt)
+{
+       struct ib_recv_wr recv_wr, *bad_recv_wr;
+       struct svc_rdma_op_ctxt *ctxt;
+       struct page *page;
+       unsigned long pa;
+       int sge_no;
+       int buflen;
+       int ret;
+
+       ctxt = svc_rdma_get_context(xprt);
+       buflen = 0;
+       ctxt->direction = DMA_FROM_DEVICE;
+       for (sge_no = 0; buflen < xprt->sc_max_req_size; sge_no++) {
+               BUG_ON(sge_no >= xprt->sc_max_sge);
+               page = svc_rdma_get_page();
+               ctxt->pages[sge_no] = page;
+               pa = ib_dma_map_page(xprt->sc_cm_id->device,
+                                    page, 0, PAGE_SIZE,
+                                    DMA_FROM_DEVICE);
+               ctxt->sge[sge_no].addr = pa;
+               ctxt->sge[sge_no].length = PAGE_SIZE;
+               ctxt->sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
+               buflen += PAGE_SIZE;
+       }
+       ctxt->count = sge_no;
+       recv_wr.next = NULL;
+       recv_wr.sg_list = &ctxt->sge[0];
+       recv_wr.num_sge = ctxt->count;
+       recv_wr.wr_id = (u64)(unsigned long)ctxt;
+
+       ret = ib_post_recv(xprt->sc_qp, &recv_wr, &bad_recv_wr);
+       return ret;
+}
+
+/*
+ * This function handles the CONNECT_REQUEST event on a listening
+ * endpoint. It is passed the cma_id for the _new_ connection. The context in
+ * this cma_id is inherited from the listening cma_id and is the svc_xprt
+ * structure for the listening endpoint.
+ *
+ * This function creates a new xprt for the new connection and enqueues it on
+ * the accept queue for the listent xprt. When the listen thread is kicked, it
+ * will call the recvfrom method on the listen xprt which will accept the new
+ * connection.
+ */
+static void handle_connect_req(struct rdma_cm_id *new_cma_id)
+{
+       struct svcxprt_rdma *listen_xprt = new_cma_id->context;
+       struct svcxprt_rdma *newxprt;
+
+       /* Create a new transport */
+       newxprt = rdma_create_xprt(listen_xprt->sc_xprt.xpt_server, 0);
+       if (!newxprt) {
+               dprintk("svcrdma: failed to create new transport\n");
+               return;
+       }
+       newxprt->sc_cm_id = new_cma_id;
+       new_cma_id->context = newxprt;
+       dprintk("svcrdma: Creating newxprt=%p, cm_id=%p, listenxprt=%p\n",
+               newxprt, newxprt->sc_cm_id, listen_xprt);
+
+       /*
+        * Enqueue the new transport on the accept queue of the listening
+        * transport
+        */
+       spin_lock_bh(&listen_xprt->sc_lock);
+       list_add_tail(&newxprt->sc_accept_q, &listen_xprt->sc_accept_q);
+       spin_unlock_bh(&listen_xprt->sc_lock);
+
+       /*
+        * Can't use svc_xprt_received here because we are not on a
+        * rqstp thread
+       */
+       set_bit(XPT_CONN, &listen_xprt->sc_xprt.xpt_flags);
+       svc_xprt_enqueue(&listen_xprt->sc_xprt);
+}
+
+/*
+ * Handles events generated on the listening endpoint. These events will be
+ * either be incoming connect requests or adapter removal  events.
+ */
+static int rdma_listen_handler(struct rdma_cm_id *cma_id,
+                              struct rdma_cm_event *event)
+{
+       struct svcxprt_rdma *xprt = cma_id->context;
+       int ret = 0;
+
+       switch (event->event) {
+       case RDMA_CM_EVENT_CONNECT_REQUEST:
+               dprintk("svcrdma: Connect request on cma_id=%p, xprt = %p, "
+                       "event=%d\n", cma_id, cma_id->context, event->event);
+               handle_connect_req(cma_id);
+               break;
+
+       case RDMA_CM_EVENT_ESTABLISHED:
+               /* Accept complete */
+               dprintk("svcrdma: Connection completed on LISTEN xprt=%p, "
+                       "cm_id=%p\n", xprt, cma_id);
+               break;
+
+       case RDMA_CM_EVENT_DEVICE_REMOVAL:
+               dprintk("svcrdma: Device removal xprt=%p, cm_id=%p\n",
+                       xprt, cma_id);
+               if (xprt)
+                       set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
+               break;
+
+       default:
+               dprintk("svcrdma: Unexpected event on listening endpoint %p, "
+                       "event=%d\n", cma_id, event->event);
+               break;
+       }
+
+       return ret;
+}
+
+static int rdma_cma_handler(struct rdma_cm_id *cma_id,
+                           struct rdma_cm_event *event)
+{
+       struct svc_xprt *xprt = cma_id->context;
+       struct svcxprt_rdma *rdma =
+               container_of(xprt, struct svcxprt_rdma, sc_xprt);
+       switch (event->event) {
+       case RDMA_CM_EVENT_ESTABLISHED:
+               /* Accept complete */
+               dprintk("svcrdma: Connection completed on DTO xprt=%p, "
+                       "cm_id=%p\n", xprt, cma_id);
+               clear_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags);
+               svc_xprt_enqueue(xprt);
+               break;
+       case RDMA_CM_EVENT_DISCONNECTED:
+               dprintk("svcrdma: Disconnect on DTO xprt=%p, cm_id=%p\n",
+                       xprt, cma_id);
+               if (xprt) {
+                       set_bit(XPT_CLOSE, &xprt->xpt_flags);
+                       svc_xprt_enqueue(xprt);
+               }
+               break;
+       case RDMA_CM_EVENT_DEVICE_REMOVAL:
+               dprintk("svcrdma: Device removal cma_id=%p, xprt = %p, "
+                       "event=%d\n", cma_id, xprt, event->event);
+               if (xprt) {
+                       set_bit(XPT_CLOSE, &xprt->xpt_flags);
+                       svc_xprt_enqueue(xprt);
+               }
+               break;
+       default:
+               dprintk("svcrdma: Unexpected event on DTO endpoint %p, "
+                       "event=%d\n", cma_id, event->event);
+               break;
+       }
+       return 0;
+}
+
+/*
+ * Create a listening RDMA service endpoint.
+ */
+static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
+                                       struct sockaddr *sa, int salen,
+                                       int flags)
+{
+       struct rdma_cm_id *listen_id;
+       struct svcxprt_rdma *cma_xprt;
+       struct svc_xprt *xprt;
+       int ret;
+
+       dprintk("svcrdma: Creating RDMA socket\n");
+
+       cma_xprt = rdma_create_xprt(serv, 1);
+       if (!cma_xprt)
+               return ERR_PTR(ENOMEM);
+       xprt = &cma_xprt->sc_xprt;
+
+       listen_id = rdma_create_id(rdma_listen_handler, cma_xprt, RDMA_PS_TCP);
+       if (IS_ERR(listen_id)) {
+               rdma_destroy_xprt(cma_xprt);
+               dprintk("svcrdma: rdma_create_id failed = %ld\n",
+                       PTR_ERR(listen_id));
+               return (void *)listen_id;
+       }
+       ret = rdma_bind_addr(listen_id, sa);
+       if (ret) {
+               rdma_destroy_xprt(cma_xprt);
+               rdma_destroy_id(listen_id);
+               dprintk("svcrdma: rdma_bind_addr failed = %d\n", ret);
+               return ERR_PTR(ret);
+       }
+       cma_xprt->sc_cm_id = listen_id;
+
+       ret = rdma_listen(listen_id, RPCRDMA_LISTEN_BACKLOG);
+       if (ret) {
+               rdma_destroy_id(listen_id);
+               rdma_destroy_xprt(cma_xprt);
+               dprintk("svcrdma: rdma_listen failed = %d\n", ret);
+       }
+
+       /*
+        * We need to use the address from the cm_id in case the
+        * caller specified 0 for the port number.
+        */
+       sa = (struct sockaddr *)&cma_xprt->sc_cm_id->route.addr.src_addr;
+       svc_xprt_set_local(&cma_xprt->sc_xprt, sa, salen);
+
+       return &cma_xprt->sc_xprt;
+}
+
+/*
+ * This is the xpo_recvfrom function for listening endpoints. Its
+ * purpose is to accept incoming connections. The CMA callback handler
+ * has already created a new transport and attached it to the new CMA
+ * ID.
+ *
+ * There is a queue of pending connections hung on the listening
+ * transport. This queue contains the new svc_xprt structure. This
+ * function takes svc_xprt structures off the accept_q and completes
+ * the connection.
+ */
+static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
+{
+       struct svcxprt_rdma *listen_rdma;
+       struct svcxprt_rdma *newxprt = NULL;
+       struct rdma_conn_param conn_param;
+       struct ib_qp_init_attr qp_attr;
+       struct ib_device_attr devattr;
+       struct sockaddr *sa;
+       int ret;
+       int i;
+
+       listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt);
+       clear_bit(XPT_CONN, &xprt->xpt_flags);
+       /* Get the next entry off the accept list */
+       spin_lock_bh(&listen_rdma->sc_lock);
+       if (!list_empty(&listen_rdma->sc_accept_q)) {
+               newxprt = list_entry(listen_rdma->sc_accept_q.next,
+                                    struct svcxprt_rdma, sc_accept_q);
+               list_del_init(&newxprt->sc_accept_q);
+       }
+       if (!list_empty(&listen_rdma->sc_accept_q))
+               set_bit(XPT_CONN, &listen_rdma->sc_xprt.xpt_flags);
+       spin_unlock_bh(&listen_rdma->sc_lock);
+       if (!newxprt)
+               return NULL;
+
+       dprintk("svcrdma: newxprt from accept queue = %p, cm_id=%p\n",
+               newxprt, newxprt->sc_cm_id);
+
+       ret = ib_query_device(newxprt->sc_cm_id->device, &devattr);
+       if (ret) {
+               dprintk("svcrdma: could not query device attributes on "
+                       "device %p, rc=%d\n", newxprt->sc_cm_id->device, ret);
+               goto errout;
+       }
+
+       /* Qualify the transport resource defaults with the
+        * capabilities of this particular device */
+       newxprt->sc_max_sge = min((size_t)devattr.max_sge,
+                                 (size_t)RPCSVC_MAXPAGES);
+       newxprt->sc_max_requests = min((size_t)devattr.max_qp_wr,
+                                  (size_t)svcrdma_max_requests);
+       newxprt->sc_sq_depth = RPCRDMA_SQ_DEPTH_MULT * newxprt->sc_max_requests;
+
+       newxprt->sc_ord =  min((size_t)devattr.max_qp_rd_atom,
+                              (size_t)svcrdma_ord);
+
+       newxprt->sc_pd = ib_alloc_pd(newxprt->sc_cm_id->device);
+       if (IS_ERR(newxprt->sc_pd)) {
+               dprintk("svcrdma: error creating PD for connect request\n");
+               goto errout;
+       }
+       newxprt->sc_sq_cq = ib_create_cq(newxprt->sc_cm_id->device,
+                                        sq_comp_handler,
+                                        cq_event_handler,
+                                        newxprt,
+                                        newxprt->sc_sq_depth,
+                                        0);
+       if (IS_ERR(newxprt->sc_sq_cq)) {
+               dprintk("svcrdma: error creating SQ CQ for connect request\n");
+               goto errout;
+       }
+       newxprt->sc_rq_cq = ib_create_cq(newxprt->sc_cm_id->device,
+                                        rq_comp_handler,
+                                        cq_event_handler,
+                                        newxprt,
+                                        newxprt->sc_max_requests,
+                                        0);
+       if (IS_ERR(newxprt->sc_rq_cq)) {
+               dprintk("svcrdma: error creating RQ CQ for connect request\n");
+               goto errout;
+       }
+
+       memset(&qp_attr, 0, sizeof qp_attr);
+       qp_attr.event_handler = qp_event_handler;
+       qp_attr.qp_context = &newxprt->sc_xprt;
+       qp_attr.cap.max_send_wr = newxprt->sc_sq_depth;
+       qp_attr.cap.max_recv_wr = newxprt->sc_max_requests;
+       qp_attr.cap.max_send_sge = newxprt->sc_max_sge;
+       qp_attr.cap.max_recv_sge = newxprt->sc_max_sge;
+       qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
+       qp_attr.qp_type = IB_QPT_RC;
+       qp_attr.send_cq = newxprt->sc_sq_cq;
+       qp_attr.recv_cq = newxprt->sc_rq_cq;
+       dprintk("svcrdma: newxprt->sc_cm_id=%p, newxprt->sc_pd=%p\n"
+               "    cm_id->device=%p, sc_pd->device=%p\n"
+               "    cap.max_send_wr = %d\n"
+               "    cap.max_recv_wr = %d\n"
+               "    cap.max_send_sge = %d\n"
+               "    cap.max_recv_sge = %d\n",
+               newxprt->sc_cm_id, newxprt->sc_pd,
+               newxprt->sc_cm_id->device, newxprt->sc_pd->device,
+               qp_attr.cap.max_send_wr,
+               qp_attr.cap.max_recv_wr,
+               qp_attr.cap.max_send_sge,
+               qp_attr.cap.max_recv_sge);
+
+       ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd, &qp_attr);
+       if (ret) {
+               /*
+                * XXX: This is a hack. We need a xx_request_qp interface
+                * that will adjust the qp_attr's with a best-effort
+                * number
+                */
+               qp_attr.cap.max_send_sge -= 2;
+               qp_attr.cap.max_recv_sge -= 2;
+               ret = rdma_create_qp(newxprt->sc_cm_id, newxprt->sc_pd,
+                                    &qp_attr);
+               if (ret) {
+                       dprintk("svcrdma: failed to create QP, ret=%d\n", ret);
+                       goto errout;
+               }
+               newxprt->sc_max_sge = qp_attr.cap.max_send_sge;
+               newxprt->sc_max_sge = qp_attr.cap.max_recv_sge;
+               newxprt->sc_sq_depth = qp_attr.cap.max_send_wr;
+               newxprt->sc_max_requests = qp_attr.cap.max_recv_wr;
+       }
+       newxprt->sc_qp = newxprt->sc_cm_id->qp;
+
+       /* Register all of physical memory */
+       newxprt->sc_phys_mr = ib_get_dma_mr(newxprt->sc_pd,
+                                           IB_ACCESS_LOCAL_WRITE |
+                                           IB_ACCESS_REMOTE_WRITE);
+       if (IS_ERR(newxprt->sc_phys_mr)) {
+               dprintk("svcrdma: Failed to create DMA MR ret=%d\n", ret);
+               goto errout;
+       }
+
+       /* Post receive buffers */
+       for (i = 0; i < newxprt->sc_max_requests; i++) {
+               ret = svc_rdma_post_recv(newxprt);
+               if (ret) {
+                       dprintk("svcrdma: failure posting receive buffers\n");
+                       goto errout;
+               }
+       }
+
+       /* Swap out the handler */
+       newxprt->sc_cm_id->event_handler = rdma_cma_handler;
+
+       /* Accept Connection */
+       set_bit(RDMAXPRT_CONN_PENDING, &newxprt->sc_flags);
+       memset(&conn_param, 0, sizeof conn_param);
+       conn_param.responder_resources = 0;
+       conn_param.initiator_depth = newxprt->sc_ord;
+       ret = rdma_accept(newxprt->sc_cm_id, &conn_param);
+       if (ret) {
+               dprintk("svcrdma: failed to accept new connection, ret=%d\n",
+                      ret);
+               goto errout;
+       }
+
+       dprintk("svcrdma: new connection %p accepted with the following "
+               "attributes:\n"
+               "    local_ip        : %d.%d.%d.%d\n"
+               "    local_port      : %d\n"
+               "    remote_ip       : %d.%d.%d.%d\n"
+               "    remote_port     : %d\n"
+               "    max_sge         : %d\n"
+               "    sq_depth        : %d\n"
+               "    max_requests    : %d\n"
+               "    ord             : %d\n",
+               newxprt,
+               NIPQUAD(((struct sockaddr_in *)&newxprt->sc_cm_id->
+                        route.addr.src_addr)->sin_addr.s_addr),
+               ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
+                      route.addr.src_addr)->sin_port),
+               NIPQUAD(((struct sockaddr_in *)&newxprt->sc_cm_id->
+                        route.addr.dst_addr)->sin_addr.s_addr),
+               ntohs(((struct sockaddr_in *)&newxprt->sc_cm_id->
+                      route.addr.dst_addr)->sin_port),
+               newxprt->sc_max_sge,
+               newxprt->sc_sq_depth,
+               newxprt->sc_max_requests,
+               newxprt->sc_ord);
+
+       /* Set the local and remote addresses in the transport */
+       sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr;
+       svc_xprt_set_remote(&newxprt->sc_xprt, sa, svc_addr_len(sa));
+       sa = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr;
+       svc_xprt_set_local(&newxprt->sc_xprt, sa, svc_addr_len(sa));
+
+       ib_req_notify_cq(newxprt->sc_sq_cq, IB_CQ_NEXT_COMP);
+       ib_req_notify_cq(newxprt->sc_rq_cq, IB_CQ_NEXT_COMP);
+       return &newxprt->sc_xprt;
+
+ errout:
+       dprintk("svcrdma: failure accepting new connection rc=%d.\n", ret);
+       rdma_destroy_id(newxprt->sc_cm_id);
+       rdma_destroy_xprt(newxprt);
+       return NULL;
+}
+
+/*
+ * Post an RQ WQE to the RQ when the rqst is being released. This
+ * effectively returns an RQ credit to the client. The rq_xprt_ctxt
+ * will be null if the request is deferred due to an RDMA_READ or the
+ * transport had no data ready (EAGAIN). Note that an RPC deferred in
+ * svc_process will still return the credit, this is because the data
+ * is copied and no longer consume a WQE/WC.
+ */
+static void svc_rdma_release_rqst(struct svc_rqst *rqstp)
+{
+       int err;
+       struct svcxprt_rdma *rdma =
+               container_of(rqstp->rq_xprt, struct svcxprt_rdma, sc_xprt);
+       if (rqstp->rq_xprt_ctxt) {
+               BUG_ON(rqstp->rq_xprt_ctxt != rdma);
+               err = svc_rdma_post_recv(rdma);
+               if (err)
+                       dprintk("svcrdma: failed to post an RQ WQE error=%d\n",
+                               err);
+       }
+       rqstp->rq_xprt_ctxt = NULL;
+}
+
+/* Disable data ready events for this connection */
+static void svc_rdma_detach(struct svc_xprt *xprt)
+{
+       struct svcxprt_rdma *rdma =
+               container_of(xprt, struct svcxprt_rdma, sc_xprt);
+       unsigned long flags;
+
+       dprintk("svc: svc_rdma_detach(%p)\n", xprt);
+       /*
+        * Shutdown the connection. This will ensure we don't get any
+        * more events from the provider.
+        */
+       rdma_disconnect(rdma->sc_cm_id);
+       rdma_destroy_id(rdma->sc_cm_id);
+
+       /* We may already be on the DTO list */
+       spin_lock_irqsave(&dto_lock, flags);
+       if (!list_empty(&rdma->sc_dto_q))
+               list_del_init(&rdma->sc_dto_q);
+       spin_unlock_irqrestore(&dto_lock, flags);
+}
+
+static void svc_rdma_free(struct svc_xprt *xprt)
+{
+       struct svcxprt_rdma *rdma = (struct svcxprt_rdma *)xprt;
+       dprintk("svcrdma: svc_rdma_free(%p)\n", rdma);
+       rdma_destroy_xprt(rdma);
+       kfree(rdma);
+}
+
+static void rdma_destroy_xprt(struct svcxprt_rdma *xprt)
+{
+       if (xprt->sc_qp && !IS_ERR(xprt->sc_qp))
+               ib_destroy_qp(xprt->sc_qp);
+
+       if (xprt->sc_sq_cq && !IS_ERR(xprt->sc_sq_cq))
+               ib_destroy_cq(xprt->sc_sq_cq);
+
+       if (xprt->sc_rq_cq && !IS_ERR(xprt->sc_rq_cq))
+               ib_destroy_cq(xprt->sc_rq_cq);
+
+       if (xprt->sc_phys_mr && !IS_ERR(xprt->sc_phys_mr))
+               ib_dereg_mr(xprt->sc_phys_mr);
+
+       if (xprt->sc_pd && !IS_ERR(xprt->sc_pd))
+               ib_dealloc_pd(xprt->sc_pd);
+
+       destroy_context_cache(xprt->sc_ctxt_head);
+}
+
+static int svc_rdma_has_wspace(struct svc_xprt *xprt)
+{
+       struct svcxprt_rdma *rdma =
+               container_of(xprt, struct svcxprt_rdma, sc_xprt);
+
+       /*
+        * If there are fewer SQ WR available than required to send a
+        * simple response, return false.
+        */
+       if ((rdma->sc_sq_depth - atomic_read(&rdma->sc_sq_count) < 3))
+               return 0;
+
+       /*
+        * ...or there are already waiters on the SQ,
+        * return false.
+        */
+       if (waitqueue_active(&rdma->sc_send_wait))
+               return 0;
+
+       /* Otherwise return true. */
+       return 1;
+}
+
+int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
+{
+       struct ib_send_wr *bad_wr;
+       int ret;
+
+       if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
+               return 0;
+
+       BUG_ON(wr->send_flags != IB_SEND_SIGNALED);
+       BUG_ON(((struct svc_rdma_op_ctxt *)(unsigned long)wr->wr_id)->wr_op !=
+               wr->opcode);
+       /* If the SQ is full, wait until an SQ entry is available */
+       while (1) {
+               spin_lock_bh(&xprt->sc_lock);
+               if (xprt->sc_sq_depth == atomic_read(&xprt->sc_sq_count)) {
+                       spin_unlock_bh(&xprt->sc_lock);
+                       atomic_inc(&rdma_stat_sq_starve);
+                       /* See if we can reap some SQ WR */
+                       sq_cq_reap(xprt);
+
+                       /* Wait until SQ WR available if SQ still full */
+                       wait_event(xprt->sc_send_wait,
+                                  atomic_read(&xprt->sc_sq_count) <
+                                  xprt->sc_sq_depth);
+                       continue;
+               }
+               /* Bumped used SQ WR count and post */
+               ret = ib_post_send(xprt->sc_qp, wr, &bad_wr);
+               if (!ret)
+                       atomic_inc(&xprt->sc_sq_count);
+               else
+                       dprintk("svcrdma: failed to post SQ WR rc=%d, "
+                              "sc_sq_count=%d, sc_sq_depth=%d\n",
+                              ret, atomic_read(&xprt->sc_sq_count),
+                              xprt->sc_sq_depth);
+               spin_unlock_bh(&xprt->sc_lock);
+               break;
+       }
+       return ret;
+}
+
+int svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
+                       enum rpcrdma_errcode err)
+{
+       struct ib_send_wr err_wr;
+       struct ib_sge sge;
+       struct page *p;
+       struct svc_rdma_op_ctxt *ctxt;
+       u32 *va;
+       int length;
+       int ret;
+
+       p = svc_rdma_get_page();
+       va = page_address(p);
+
+       /* XDR encode error */
+       length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);
+
+       /* Prepare SGE for local address */
+       sge.addr = ib_dma_map_page(xprt->sc_cm_id->device,
+                                  p, 0, PAGE_SIZE, DMA_FROM_DEVICE);
+       sge.lkey = xprt->sc_phys_mr->lkey;
+       sge.length = length;
+
+       ctxt = svc_rdma_get_context(xprt);
+       ctxt->count = 1;
+       ctxt->pages[0] = p;
+
+       /* Prepare SEND WR */
+       memset(&err_wr, 0, sizeof err_wr);
+       ctxt->wr_op = IB_WR_SEND;
+       err_wr.wr_id = (unsigned long)ctxt;
+       err_wr.sg_list = &sge;
+       err_wr.num_sge = 1;
+       err_wr.opcode = IB_WR_SEND;
+       err_wr.send_flags = IB_SEND_SIGNALED;
+
+       /* Post It */
+       ret = svc_rdma_send(xprt, &err_wr);
+       if (ret) {
+               dprintk("svcrdma: Error posting send = %d\n", ret);
+               svc_rdma_put_context(ctxt, 1);
+       }
+
+       return ret;
+}
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