- 根目录:
- net
- sunrpc
- xprtrdma
- svc_rdma_transport.c
/*
* 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 <tom@opengridcomputing.com>
*/
#include <linux/sunrpc/svc_xprt.h>
#include <linux/sunrpc/debug.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/workqueue.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 net *net,
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 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);
static 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,
};
/* WR context cache. Created in svc_rdma.c */
extern struct kmem_cache *svc_rdma_ctxt_cachep;
/* Workqueue created in svc_rdma.c */
extern struct workqueue_struct *svc_rdma_wq;
struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
{
struct svc_rdma_op_ctxt *ctxt;
while (1) {
ctxt = kmem_cache_alloc(svc_rdma_ctxt_cachep, GFP_KERNEL);
if (ctxt)
break;
schedule_timeout_uninterruptible(msecs_to_jiffies(500));
}
ctxt->xprt = xprt;
INIT_LIST_HEAD(&ctxt->dto_q);
ctxt->count = 0;
ctxt->frmr = NULL;
atomic_inc(&xprt->sc_ctxt_used);
return ctxt;
}
void svc_rdma_unmap_dma(struct svc_rdma_op_ctxt *ctxt)
{
struct svcxprt_rdma *xprt = ctxt->xprt;
int i;
for (i = 0; i < ctxt->count && ctxt->sge[i].length; i++) {
/*
* Unmap the DMA addr in the SGE if the lkey matches
* the sc_dma_lkey, otherwise, ignore it since it is
* an FRMR lkey and will be unmapped later when the
* last WR that uses it completes.
*/
if (ctxt->sge[i].lkey == xprt->sc_dma_lkey) {
atomic_dec(&xprt->sc_dma_used);
ib_dma_unmap_page(xprt->sc_cm_id->device,
ctxt->sge[i].addr,
ctxt->sge[i].length,
ctxt->direction);
}
}
}
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]);
kmem_cache_free(svc_rdma_ctxt_cachep, ctxt);
atomic_dec(&xprt->sc_ctxt_used);
}
/* Temporary NFS request map cache. Created in svc_rdma.c */
extern struct kmem_cache *svc_rdma_map_cachep;
/*
* Temporary NFS req mappings are shared across all transport
* instances. These are short lived and should be bounded by the number
* of concurrent server threads * depth of the SQ.
*/
struct svc_rdma_req_map *svc_rdma_get_req_map(void)
{
struct svc_rdma_req_map *map;
while (1) {
map = kmem_cache_alloc(svc_rdma_map_cachep, GFP_KERNEL);
if (map)
break;
schedule_timeout_uninterruptible(msecs_to_jiffies(500));
}
map->count = 0;
map->frmr = NULL;
return map;
}
void svc_rdma_put_req_map(struct svc_rdma_req_map *map)
{
kmem_cache_free(svc_rdma_map_cachep, map);
}
/* 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);
rq_cq_reap(xprt);
sq_cq_reap(xprt);
svc_xprt_put(&xprt->sc_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;
/* Guard against unconditional flush call for destroyed QP */
if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
return;
/*
* 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)) {
svc_xprt_get(&xprt->sc_xprt);
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.
*
* Note that caller must hold a transport reference.
*/
static void rq_cq_reap(struct svcxprt_rdma *xprt)
{
int ret;
struct ib_wc wc;
struct svc_rdma_op_ctxt *ctxt = NULL;
if (!test_and_clear_bit(RDMAXPRT_RQ_PENDING, &xprt->sc_flags))
return;
ib_req_notify_cq(xprt->sc_rq_cq, IB_CQ_NEXT_COMP);
atomic_inc(&rdma_stat_rq_poll);
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;
svc_rdma_unmap_dma(ctxt);
if (wc.status != IB_WC_SUCCESS) {
/* Close the transport */
dprintk("svcrdma: transport closing putting ctxt %p\n", ctxt);
set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
svc_rdma_put_context(ctxt, 1);
svc_xprt_put(&xprt->sc_xprt);
continue;
}
spin_lock_bh(&xprt->sc_rq_dto_lock);
list_add_tail(&ctxt->dto_q, &xprt->sc_rq_dto_q);
spin_unlock_bh(&xprt->sc_rq_dto_lock);
svc_xprt_put(&xprt->sc_xprt);
}
if (ctxt)
atomic_inc(&rdma_stat_rq_prod);
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);
}
/*
* Processs a completion context
*/
static void process_context(struct svcxprt_rdma *xprt,
struct svc_rdma_op_ctxt *ctxt)
{
svc_rdma_unmap_dma(ctxt);
switch (ctxt->wr_op) {
case IB_WR_SEND:
if (test_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags))
svc_rdma_put_frmr(xprt, ctxt->frmr);
svc_rdma_put_context(ctxt, 1);
break;
case IB_WR_RDMA_WRITE:
svc_rdma_put_context(ctxt, 0);
break;
case IB_WR_RDMA_READ:
case IB_WR_RDMA_READ_WITH_INV:
if (test_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags)) {
struct svc_rdma_op_ctxt *read_hdr = ctxt->read_hdr;
BUG_ON(!read_hdr);
if (test_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags))
svc_rdma_put_frmr(xprt, ctxt->frmr);
spin_lock_bh(&xprt->sc_rq_dto_lock);
set_bit(XPT_DATA, &xprt->sc_xprt.xpt_flags);
list_add_tail(&read_hdr->dto_q,
&xprt->sc_read_complete_q);
spin_unlock_bh(&xprt->sc_rq_dto_lock);
svc_xprt_enqueue(&xprt->sc_xprt);
}
svc_rdma_put_context(ctxt, 0);
break;
default:
printk(KERN_ERR "svcrdma: unexpected completion type, "
"opcode=%d\n",
ctxt->wr_op);
break;
}
}
/*
* Send Queue Completion Handler - potentially called on interrupt context.
*
* Note that caller must hold a transport reference.
*/
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;
if (!test_and_clear_bit(RDMAXPRT_SQ_PENDING, &xprt->sc_flags))
return;
ib_req_notify_cq(xprt->sc_sq_cq, IB_CQ_NEXT_COMP);
atomic_inc(&rdma_stat_sq_poll);
while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
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);
ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
if (ctxt)
process_context(xprt, ctxt);
svc_xprt_put(&xprt->sc_xprt);
}
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;
/* Guard against unconditional flush call for destroyed QP */
if (atomic_read(&xprt->sc_xprt.xpt_ref.refcount)==0)
return;
/*
* 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)) {
svc_xprt_get(&xprt->sc_xprt);
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 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_LIST_HEAD(&cma_xprt->sc_frmr_q);
init_waitqueue_head(&cma_xprt->sc_send_wait);
spin_lock_init(&cma_xprt->sc_lock);
spin_lock_init(&cma_xprt->sc_rq_dto_lock);
spin_lock_init(&cma_xprt->sc_frmr_q_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);
atomic_set(&cma_xprt->sc_ctxt_used, 0);
if (listener)
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;
dma_addr_t 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);
if (ib_dma_mapping_error(xprt->sc_cm_id->device, pa))
goto err_put_ctxt;
atomic_inc(&xprt->sc_dma_used);
ctxt->sge[sge_no].addr = pa;
ctxt->sge[sge_no].length = PAGE_SIZE;
ctxt->sge[sge_no].lkey = xprt->sc_dma_lkey;
ctxt->count = sge_no + 1;
buflen += PAGE_SIZE;
}
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;
svc_xprt_get(&xprt->sc_xprt);
ret = ib_post_recv(xprt->sc_qp, &recv_wr, &bad_recv_wr);
if (ret) {
svc_rdma_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 1);
svc_xprt_put(&xprt->sc_xprt);
}
return ret;
err_put_ctxt:
svc_rdma_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 1);
return -ENOMEM;
}
/*
* 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, size_t client_ird)
{
struct svcxprt_rdma *listen_xprt = new_cma_id->context;
struct svcxprt_rdma *newxprt;
struct sockaddr *sa;
/* 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);
/* Save client advertised inbound read limit for use later in accept. */
newxprt->sc_ord = client_ird;
/* 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));
/*
* 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,
event->param.conn.initiator_depth);
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 */
svc_xprt_get(xprt);
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);
svc_xprt_put(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 net *net,
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");
if (sa->sa_family != AF_INET) {
dprintk("svcrdma: Address family %d is not supported.\n", sa->sa_family);
return ERR_PTR(-EAFNOSUPPORT);
}
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)) {
ret = PTR_ERR(listen_id);
dprintk("svcrdma: rdma_create_id failed = %d\n", ret);
goto err0;
}
ret = rdma_bind_addr(listen_id, sa);
if (ret) {
dprintk("svcrdma: rdma_bind_addr failed = %d\n", ret);
goto err1;
}
cma_xprt->sc_cm_id = listen_id;
ret = rdma_listen(listen_id, RPCRDMA_LISTEN_BACKLOG);
if (ret) {
dprintk("svcrdma: rdma_listen failed = %d\n", ret);
goto err1;
}
/*
* 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;
err1:
rdma_destroy_id(listen_id);
err0:
kfree(cma_xprt);
return ERR_PTR(ret);
}
static struct svc_rdma_fastreg_mr *rdma_alloc_frmr(struct svcxprt_rdma *xprt)
{
struct ib_mr *mr;
struct ib_fast_reg_page_list *pl;
struct svc_rdma_fastreg_mr *frmr;
frmr = kmalloc(sizeof(*frmr), GFP_KERNEL);
if (!frmr)
goto err;
mr = ib_alloc_fast_reg_mr(xprt->sc_pd, RPCSVC_MAXPAGES);
if (IS_ERR(mr))
goto err_free_frmr;
pl = ib_alloc_fast_reg_page_list(xprt->sc_cm_id->device,
RPCSVC_MAXPAGES);
if (IS_ERR(pl))
goto err_free_mr;
frmr->mr = mr;
frmr->page_list = pl;
INIT_LIST_HEAD(&frmr->frmr_list);
return frmr;
err_free_mr:
ib_dereg_mr(mr);
err_free_frmr:
kfree(frmr);
err:
return ERR_PTR(-ENOMEM);
}
static void rdma_dealloc_frmr_q(struct svcxprt_rdma *xprt)
{
struct svc_rdma_fastreg_mr *frmr;
while (!list_empty(&xprt->sc_frmr_q)) {
frmr = list_entry(xprt->sc_frmr_q.next,
struct svc_rdma_fastreg_mr, frmr_list);
list_del_init(&frmr->frmr_list);
ib_dereg_mr(frmr->mr);
ib_free_fast_reg_page_list(frmr->page_list);
kfree(frmr);
}
}
struct svc_rdma_fastreg_mr *svc_rdma_get_frmr(struct svcxprt_rdma *rdma)
{
struct svc_rdma_fastreg_mr *frmr = NULL;
spin_lock_bh(&rdma->sc_frmr_q_lock);
if (!list_empty(&rdma->sc_frmr_q)) {
frmr = list_entry(rdma->sc_frmr_q.next,
struct svc_rdma_fastreg_mr, frmr_list);
list_del_init(&frmr->frmr_list);
frmr->map_len = 0;
frmr->page_list_len = 0;
}
spin_unlock_bh(&rdma->sc_frmr_q_lock);
if (frmr)
return frmr;
return rdma_alloc_frmr(rdma);
}
static void frmr_unmap_dma(struct svcxprt_rdma *xprt,
struct svc_rdma_fastreg_mr *frmr)
{
int page_no;
for (page_no = 0; page_no < frmr->page_list_len; page_no++) {
dma_addr_t addr = frmr->page_list->page_list[page_no];
if (ib_dma_mapping_error(frmr->mr->device, addr))
continue;
atomic_dec(&xprt->sc_dma_used);
ib_dma_unmap_page(frmr->mr->device, addr, PAGE_SIZE,
frmr->direction);
}
}
void svc_rdma_put_frmr(struct svcxprt_rdma *rdma,
struct svc_rdma_fastreg_mr *frmr)
{
if (frmr) {
frmr_unmap_dma(rdma, frmr);
spin_lock_bh(&rdma->sc_frmr_q_lock);
BUG_ON(!list_empty(&frmr->frmr_list));
list_add(&frmr->frmr_list, &rdma->sc_frmr_q);
spin_unlock_bh(&rdma->sc_frmr_q_lock);
}
}
/*
* 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;
int uninitialized_var(dma_mr_acc);
int need_dma_mr;
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;
/*
* Limit ORD based on client limit, local device limit, and
* configured svcrdma limit.
*/
newxprt->sc_ord = min_t(size_t, devattr.max_qp_rd_atom, newxprt->sc_ord);
newxprt->sc_ord = min_t(size_t, svcrdma_ord, newxprt->sc_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;
/*
* Use the most secure set of MR resources based on the
* transport type and available memory management features in
* the device. Here's the table implemented below:
*
* Fast Global DMA Remote WR
* Reg LKEY MR Access
* Sup'd Sup'd Needed Needed
*
* IWARP N N Y Y
* N Y Y Y
* Y N Y N
* Y Y N -
*
* IB N N Y N
* N Y N -
* Y N Y N
* Y Y N -
*
* NB: iWARP requires remote write access for the data sink
* of an RDMA_READ. IB does not.
*/
if (devattr.device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
newxprt->sc_frmr_pg_list_len =
devattr.max_fast_reg_page_list_len;
newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_FAST_REG;
}
/*
* Determine if a DMA MR is required and if so, what privs are required
*/
switch (rdma_node_get_transport(newxprt->sc_cm_id->device->node_type)) {
case RDMA_TRANSPORT_IWARP:
newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
if (!(newxprt->sc_dev_caps & SVCRDMA_DEVCAP_FAST_REG)) {
need_dma_mr = 1;
dma_mr_acc =
(IB_ACCESS_LOCAL_WRITE |
IB_ACCESS_REMOTE_WRITE);
} else if (!(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
need_dma_mr = 1;
dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
} else
need_dma_mr = 0;
break;
case RDMA_TRANSPORT_IB:
if (!(devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)) {
need_dma_mr = 1;
dma_mr_acc = IB_ACCESS_LOCAL_WRITE;
} else
need_dma_mr = 0;
break;
default:
goto errout;
}
/* Create the DMA MR if needed, otherwise, use the DMA LKEY */
if (need_dma_mr) {
/* Register all of physical memory */
newxprt->sc_phys_mr =
ib_get_dma_mr(newxprt->sc_pd, dma_mr_acc);
if (IS_ERR(newxprt->sc_phys_mr)) {
dprintk("svcrdma: Failed to create DMA MR ret=%d\n",
ret);
goto errout;
}
newxprt->sc_dma_lkey = newxprt->sc_phys_mr->lkey;
} else
newxprt->sc_dma_lkey =
newxprt->sc_cm_id->device->local_dma_lkey;
/* 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;
/*
* Arm the CQs for the SQ and RQ before accepting so we can't
* miss the first message
*/
ib_req_notify_cq(newxprt->sc_sq_cq, IB_CQ_NEXT_COMP);
ib_req_notify_cq(newxprt->sc_rq_cq, IB_CQ_NEXT_COMP);
/* 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 : %pI4\n"
" local_port : %d\n"
" remote_ip : %pI4\n"
" remote_port : %d\n"
" max_sge : %d\n"
" sq_depth : %d\n"
" max_requests : %d\n"
" ord : %d\n",
newxprt,
&((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),
&((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);
return &newxprt->sc_xprt;
errout:
dprintk("svcrdma: failure accepting new connection rc=%d.\n", ret);
/* Take a reference in case the DTO handler runs */
svc_xprt_get(&newxprt->sc_xprt);
if (newxprt->sc_qp && !IS_ERR(newxprt->sc_qp))
ib_destroy_qp(newxprt->sc_qp);
rdma_destroy_id(newxprt->sc_cm_id);
/* This call to put will destroy the transport */
svc_xprt_put(&newxprt->sc_xprt);
return NULL;
}
static void svc_rdma_release_rqst(struct svc_rqst *rqstp)
{
}
/*
* When connected, an svc_xprt has at least two references:
*
* - A reference held by the cm_id between the ESTABLISHED and
* DISCONNECTED events. If the remote peer disconnected first, this
* reference could be gone.
*
* - A reference held by the svc_recv code that called this function
* as part of close processing.
*
* At a minimum one references should still be held.
*/
static void svc_rdma_detach(struct svc_xprt *xprt)
{
struct svcxprt_rdma *rdma =
container_of(xprt, struct svcxprt_rdma, sc_xprt);
dprintk("svc: svc_rdma_detach(%p)\n", xprt);
/* Disconnect and flush posted WQE */
rdma_disconnect(rdma->sc_cm_id);
}
static void __svc_rdma_free(struct work_struct *work)
{
struct svcxprt_rdma *rdma =
container_of(work, struct svcxprt_rdma, sc_work);
dprintk("svcrdma: svc_rdma_free(%p)\n", rdma);
/* We should only be called from kref_put */
BUG_ON(atomic_read(&rdma->sc_xprt.xpt_ref.refcount) != 0);
/*
* Destroy queued, but not processed read completions. Note
* that this cleanup has to be done before destroying the
* cm_id because the device ptr is needed to unmap the dma in
* svc_rdma_put_context.
*/
while (!list_empty(&rdma->sc_read_complete_q)) {
struct svc_rdma_op_ctxt *ctxt;
ctxt = list_entry(rdma->sc_read_complete_q.next,
struct svc_rdma_op_ctxt,
dto_q);
list_del_init(&ctxt->dto_q);
svc_rdma_put_context(ctxt, 1);
}
/* Destroy queued, but not processed recv completions */
while (!list_empty(&rdma->sc_rq_dto_q)) {
struct svc_rdma_op_ctxt *ctxt;
ctxt = list_entry(rdma->sc_rq_dto_q.next,
struct svc_rdma_op_ctxt,
dto_q);
list_del_init(&ctxt->dto_q);
svc_rdma_put_context(ctxt, 1);
}
/* Warn if we leaked a resource or under-referenced */
WARN_ON(atomic_read(&rdma->sc_ctxt_used) != 0);
WARN_ON(atomic_read(&rdma->sc_dma_used) != 0);
/* De-allocate fastreg mr */
rdma_dealloc_frmr_q(rdma);
/* Destroy the QP if present (not a listener) */
if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
ib_destroy_qp(rdma->sc_qp);
if (rdma->sc_sq_cq && !IS_ERR(rdma->sc_sq_cq))
ib_destroy_cq(rdma->sc_sq_cq);
if (rdma->sc_rq_cq && !IS_ERR(rdma->sc_rq_cq))
ib_destroy_cq(rdma->sc_rq_cq);
if (rdma->sc_phys_mr && !IS_ERR(rdma->sc_phys_mr))
ib_dereg_mr(rdma->sc_phys_mr);
if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
ib_dealloc_pd(rdma->sc_pd);
/* Destroy the CM ID */
rdma_destroy_id(rdma->sc_cm_id);
kfree(rdma);
}
static void svc_rdma_free(struct svc_xprt *xprt)
{
struct svcxprt_rdma *rdma =
container_of(xprt, struct svcxprt_rdma, sc_xprt);
INIT_WORK(&rdma->sc_work, __svc_rdma_free);
queue_work(svc_rdma_wq, &rdma->sc_work);
}
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;
}
/*
* Attempt to register the kvec representing the RPC memory with the
* device.
*
* Returns:
* NULL : The device does not support fastreg or there were no more
* fastreg mr.
* frmr : The kvec register request was successfully posted.
* <0 : An error was encountered attempting to register the kvec.
*/
int svc_rdma_fastreg(struct svcxprt_rdma *xprt,
struct svc_rdma_fastreg_mr *frmr)
{
struct ib_send_wr fastreg_wr;
u8 key;
/* Bump the key */
key = (u8)(frmr->mr->lkey & 0x000000FF);
ib_update_fast_reg_key(frmr->mr, ++key);
/* Prepare FASTREG WR */
memset(&fastreg_wr, 0, sizeof fastreg_wr);
fastreg_wr.opcode = IB_WR_FAST_REG_MR;
fastreg_wr.send_flags = IB_SEND_SIGNALED;
fastreg_wr.wr.fast_reg.iova_start = (unsigned long)frmr->kva;
fastreg_wr.wr.fast_reg.page_list = frmr->page_list;
fastreg_wr.wr.fast_reg.page_list_len = frmr->page_list_len;
fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
fastreg_wr.wr.fast_reg.length = frmr->map_len;
fastreg_wr.wr.fast_reg.access_flags = frmr->access_flags;
fastreg_wr.wr.fast_reg.rkey = frmr->mr->lkey;
return svc_rdma_send(xprt, &fastreg_wr);
}
int svc_rdma_send(struct svcxprt_rdma *xprt, struct ib_send_wr *wr)
{
struct ib_send_wr *bad_wr, *n_wr;
int wr_count;
int i;
int ret;
if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
return -ENOTCONN;
BUG_ON(wr->send_flags != IB_SEND_SIGNALED);
wr_count = 1;
for (n_wr = wr->next; n_wr; n_wr = n_wr->next)
wr_count++;
/* 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) + wr_count) {
spin_unlock_bh(&xprt->sc_lock);
atomic_inc(&rdma_stat_sq_starve);
/* See if we can opportunistically reap SQ WR to make room */
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);
if (test_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags))
return -ENOTCONN;
continue;
}
/* Take a transport ref for each WR posted */
for (i = 0; i < wr_count; i++)
svc_xprt_get(&xprt->sc_xprt);
/* Bump used SQ WR count and post */
atomic_add(wr_count, &xprt->sc_sq_count);
ret = ib_post_send(xprt->sc_qp, wr, &bad_wr);
if (ret) {
set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
atomic_sub(wr_count, &xprt->sc_sq_count);
for (i = 0; i < wr_count; i ++)
svc_xprt_put(&xprt->sc_xprt);
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);
if (ret)
wake_up(&xprt->sc_send_wait);
break;
}
return ret;
}
void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
enum rpcrdma_errcode err)
{
struct ib_send_wr err_wr;
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);
ctxt = svc_rdma_get_context(xprt);
ctxt->direction = DMA_FROM_DEVICE;
ctxt->count = 1;
ctxt->pages[0] = p;
/* Prepare SGE for local address */
ctxt->sge[0].addr = ib_dma_map_page(xprt->sc_cm_id->device,
p, 0, length, DMA_FROM_DEVICE);
if (ib_dma_mapping_error(xprt->sc_cm_id->device, ctxt->sge[0].addr)) {
put_page(p);
svc_rdma_put_context(ctxt, 1);
return;
}
atomic_inc(&xprt->sc_dma_used);
ctxt->sge[0].lkey = xprt->sc_dma_lkey;
ctxt->sge[0].length = length;
/* 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 = ctxt->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 %d posting send for protocol error\n",
ret);
svc_rdma_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 1);
}
}