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linux/net/sunrpc/xprtrdma/svc_rdma_sendto.c
Chuck Lever 5fdca65314 svcrdma: Renovate sendto chunk list parsing
The current sendto code appears to support clients that provide only
one of a Read list, a Write list, or a Reply chunk. My reading of
that code is that it doesn't support the following cases:

 - Read list + Write list
 - Read list + Reply chunk
 - Write list + Reply chunk
 - Read list + Write list + Reply chunk

The protocol allows more than one Read or Write chunk in those
lists. Some clients do send a Read list and Reply chunk
simultaneously. NFSv4 WRITE uses a Read list for the data payload,
and a Reply chunk because the GETATTR result in the reply can
contain a large object like an ACL.

Generalize one of the sendto code paths needed to support all of
the above cases, and attempt to ensure that only one pass is done
through the RPC Call's transport header to gather chunk list
information for building the reply.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2016-11-30 17:31:12 -05:00

711 lines
19 KiB
C

/*
* Copyright (c) 2014 Open Grid Computing, Inc. All rights reserved.
* Copyright (c) 2005-2006 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/debug.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <linux/spinlock.h>
#include <asm/unaligned.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
#include <linux/sunrpc/svc_rdma.h>
#define RPCDBG_FACILITY RPCDBG_SVCXPRT
static u32 xdr_padsize(u32 len)
{
return (len & 3) ? (4 - (len & 3)) : 0;
}
int svc_rdma_map_xdr(struct svcxprt_rdma *xprt,
struct xdr_buf *xdr,
struct svc_rdma_req_map *vec,
bool write_chunk_present)
{
int sge_no;
u32 sge_bytes;
u32 page_bytes;
u32 page_off;
int page_no;
if (xdr->len !=
(xdr->head[0].iov_len + xdr->page_len + xdr->tail[0].iov_len)) {
pr_err("svcrdma: %s: XDR buffer length error\n", __func__);
return -EIO;
}
/* Skip the first sge, this is for the RPCRDMA header */
sge_no = 1;
/* Head SGE */
vec->sge[sge_no].iov_base = xdr->head[0].iov_base;
vec->sge[sge_no].iov_len = xdr->head[0].iov_len;
sge_no++;
/* pages SGE */
page_no = 0;
page_bytes = xdr->page_len;
page_off = xdr->page_base;
while (page_bytes) {
vec->sge[sge_no].iov_base =
page_address(xdr->pages[page_no]) + page_off;
sge_bytes = min_t(u32, page_bytes, (PAGE_SIZE - page_off));
page_bytes -= sge_bytes;
vec->sge[sge_no].iov_len = sge_bytes;
sge_no++;
page_no++;
page_off = 0; /* reset for next time through loop */
}
/* Tail SGE */
if (xdr->tail[0].iov_len) {
unsigned char *base = xdr->tail[0].iov_base;
size_t len = xdr->tail[0].iov_len;
u32 xdr_pad = xdr_padsize(xdr->page_len);
if (write_chunk_present && xdr_pad) {
base += xdr_pad;
len -= xdr_pad;
}
if (len) {
vec->sge[sge_no].iov_base = base;
vec->sge[sge_no].iov_len = len;
sge_no++;
}
}
dprintk("svcrdma: %s: sge_no %d page_no %d "
"page_base %u page_len %u head_len %zu tail_len %zu\n",
__func__, sge_no, page_no, xdr->page_base, xdr->page_len,
xdr->head[0].iov_len, xdr->tail[0].iov_len);
vec->count = sge_no;
return 0;
}
static dma_addr_t dma_map_xdr(struct svcxprt_rdma *xprt,
struct xdr_buf *xdr,
u32 xdr_off, size_t len, int dir)
{
struct page *page;
dma_addr_t dma_addr;
if (xdr_off < xdr->head[0].iov_len) {
/* This offset is in the head */
xdr_off += (unsigned long)xdr->head[0].iov_base & ~PAGE_MASK;
page = virt_to_page(xdr->head[0].iov_base);
} else {
xdr_off -= xdr->head[0].iov_len;
if (xdr_off < xdr->page_len) {
/* This offset is in the page list */
xdr_off += xdr->page_base;
page = xdr->pages[xdr_off >> PAGE_SHIFT];
xdr_off &= ~PAGE_MASK;
} else {
/* This offset is in the tail */
xdr_off -= xdr->page_len;
xdr_off += (unsigned long)
xdr->tail[0].iov_base & ~PAGE_MASK;
page = virt_to_page(xdr->tail[0].iov_base);
}
}
dma_addr = ib_dma_map_page(xprt->sc_cm_id->device, page, xdr_off,
min_t(size_t, PAGE_SIZE, len), dir);
return dma_addr;
}
/* Parse the RPC Call's transport header.
*/
static void svc_rdma_get_write_arrays(struct rpcrdma_msg *rmsgp,
struct rpcrdma_write_array **write,
struct rpcrdma_write_array **reply)
{
__be32 *p;
p = (__be32 *)&rmsgp->rm_body.rm_chunks[0];
/* Read list */
while (*p++ != xdr_zero)
p += 5;
/* Write list */
if (*p != xdr_zero) {
*write = (struct rpcrdma_write_array *)p;
while (*p++ != xdr_zero)
p += 1 + be32_to_cpu(*p) * 4;
} else {
*write = NULL;
p++;
}
/* Reply chunk */
if (*p != xdr_zero)
*reply = (struct rpcrdma_write_array *)p;
else
*reply = NULL;
}
/* RPC-over-RDMA Version One private extension: Remote Invalidation.
* Responder's choice: requester signals it can handle Send With
* Invalidate, and responder chooses one rkey to invalidate.
*
* Find a candidate rkey to invalidate when sending a reply. Picks the
* first rkey it finds in the chunks lists.
*
* Returns zero if RPC's chunk lists are empty.
*/
static u32 svc_rdma_get_inv_rkey(struct rpcrdma_msg *rdma_argp,
struct rpcrdma_write_array *wr_ary,
struct rpcrdma_write_array *rp_ary)
{
struct rpcrdma_read_chunk *rd_ary;
struct rpcrdma_segment *arg_ch;
u32 inv_rkey;
inv_rkey = 0;
rd_ary = (struct rpcrdma_read_chunk *)&rdma_argp->rm_body.rm_chunks[0];
if (rd_ary->rc_discrim != xdr_zero) {
inv_rkey = be32_to_cpu(rd_ary->rc_target.rs_handle);
goto out;
}
if (wr_ary && be32_to_cpu(wr_ary->wc_nchunks)) {
arg_ch = &wr_ary->wc_array[0].wc_target;
inv_rkey = be32_to_cpu(arg_ch->rs_handle);
goto out;
}
if (rp_ary && be32_to_cpu(rp_ary->wc_nchunks)) {
arg_ch = &rp_ary->wc_array[0].wc_target;
inv_rkey = be32_to_cpu(arg_ch->rs_handle);
goto out;
}
out:
dprintk("svcrdma: Send With Invalidate rkey=%08x\n", inv_rkey);
return inv_rkey;
}
/* Assumptions:
* - The specified write_len can be represented in sc_max_sge * PAGE_SIZE
*/
static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp,
u32 rmr, u64 to,
u32 xdr_off, int write_len,
struct svc_rdma_req_map *vec)
{
struct ib_rdma_wr write_wr;
struct ib_sge *sge;
int xdr_sge_no;
int sge_no;
int sge_bytes;
int sge_off;
int bc;
struct svc_rdma_op_ctxt *ctxt;
if (vec->count > RPCSVC_MAXPAGES) {
pr_err("svcrdma: Too many pages (%lu)\n", vec->count);
return -EIO;
}
dprintk("svcrdma: RDMA_WRITE rmr=%x, to=%llx, xdr_off=%d, "
"write_len=%d, vec->sge=%p, vec->count=%lu\n",
rmr, (unsigned long long)to, xdr_off,
write_len, vec->sge, vec->count);
ctxt = svc_rdma_get_context(xprt);
ctxt->direction = DMA_TO_DEVICE;
sge = ctxt->sge;
/* Find the SGE associated with xdr_off */
for (bc = xdr_off, xdr_sge_no = 1; bc && xdr_sge_no < vec->count;
xdr_sge_no++) {
if (vec->sge[xdr_sge_no].iov_len > bc)
break;
bc -= vec->sge[xdr_sge_no].iov_len;
}
sge_off = bc;
bc = write_len;
sge_no = 0;
/* Copy the remaining SGE */
while (bc != 0) {
sge_bytes = min_t(size_t,
bc, vec->sge[xdr_sge_no].iov_len-sge_off);
sge[sge_no].length = sge_bytes;
sge[sge_no].addr =
dma_map_xdr(xprt, &rqstp->rq_res, xdr_off,
sge_bytes, DMA_TO_DEVICE);
xdr_off += sge_bytes;
if (ib_dma_mapping_error(xprt->sc_cm_id->device,
sge[sge_no].addr))
goto err;
svc_rdma_count_mappings(xprt, ctxt);
sge[sge_no].lkey = xprt->sc_pd->local_dma_lkey;
ctxt->count++;
sge_off = 0;
sge_no++;
xdr_sge_no++;
if (xdr_sge_no > vec->count) {
pr_err("svcrdma: Too many sges (%d)\n", xdr_sge_no);
goto err;
}
bc -= sge_bytes;
if (sge_no == xprt->sc_max_sge)
break;
}
/* Prepare WRITE WR */
memset(&write_wr, 0, sizeof write_wr);
ctxt->cqe.done = svc_rdma_wc_write;
write_wr.wr.wr_cqe = &ctxt->cqe;
write_wr.wr.sg_list = &sge[0];
write_wr.wr.num_sge = sge_no;
write_wr.wr.opcode = IB_WR_RDMA_WRITE;
write_wr.wr.send_flags = IB_SEND_SIGNALED;
write_wr.rkey = rmr;
write_wr.remote_addr = to;
/* Post It */
atomic_inc(&rdma_stat_write);
if (svc_rdma_send(xprt, &write_wr.wr))
goto err;
return write_len - bc;
err:
svc_rdma_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 0);
return -EIO;
}
noinline
static int send_write_chunks(struct svcxprt_rdma *xprt,
struct rpcrdma_write_array *wr_ary,
struct rpcrdma_msg *rdma_resp,
struct svc_rqst *rqstp,
struct svc_rdma_req_map *vec)
{
u32 xfer_len = rqstp->rq_res.page_len;
int write_len;
u32 xdr_off;
int chunk_off;
int chunk_no;
int nchunks;
struct rpcrdma_write_array *res_ary;
int ret;
res_ary = (struct rpcrdma_write_array *)
&rdma_resp->rm_body.rm_chunks[1];
/* Write chunks start at the pagelist */
nchunks = be32_to_cpu(wr_ary->wc_nchunks);
for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
xfer_len && chunk_no < nchunks;
chunk_no++) {
struct rpcrdma_segment *arg_ch;
u64 rs_offset;
arg_ch = &wr_ary->wc_array[chunk_no].wc_target;
write_len = min(xfer_len, be32_to_cpu(arg_ch->rs_length));
/* Prepare the response chunk given the length actually
* written */
xdr_decode_hyper((__be32 *)&arg_ch->rs_offset, &rs_offset);
svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
arg_ch->rs_handle,
arg_ch->rs_offset,
write_len);
chunk_off = 0;
while (write_len) {
ret = send_write(xprt, rqstp,
be32_to_cpu(arg_ch->rs_handle),
rs_offset + chunk_off,
xdr_off,
write_len,
vec);
if (ret <= 0)
goto out_err;
chunk_off += ret;
xdr_off += ret;
xfer_len -= ret;
write_len -= ret;
}
}
/* Update the req with the number of chunks actually used */
svc_rdma_xdr_encode_write_list(rdma_resp, chunk_no);
return rqstp->rq_res.page_len;
out_err:
pr_err("svcrdma: failed to send write chunks, rc=%d\n", ret);
return -EIO;
}
noinline
static int send_reply_chunks(struct svcxprt_rdma *xprt,
struct rpcrdma_write_array *rp_ary,
struct rpcrdma_msg *rdma_resp,
struct svc_rqst *rqstp,
struct svc_rdma_req_map *vec)
{
u32 xfer_len = rqstp->rq_res.len;
int write_len;
u32 xdr_off;
int chunk_no;
int chunk_off;
int nchunks;
struct rpcrdma_segment *ch;
struct rpcrdma_write_array *res_ary;
int ret;
/* XXX: need to fix when reply lists occur with read-list and or
* write-list */
res_ary = (struct rpcrdma_write_array *)
&rdma_resp->rm_body.rm_chunks[2];
/* xdr offset starts at RPC message */
nchunks = be32_to_cpu(rp_ary->wc_nchunks);
for (xdr_off = 0, chunk_no = 0;
xfer_len && chunk_no < nchunks;
chunk_no++) {
u64 rs_offset;
ch = &rp_ary->wc_array[chunk_no].wc_target;
write_len = min(xfer_len, be32_to_cpu(ch->rs_length));
/* Prepare the reply chunk given the length actually
* written */
xdr_decode_hyper((__be32 *)&ch->rs_offset, &rs_offset);
svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no,
ch->rs_handle, ch->rs_offset,
write_len);
chunk_off = 0;
while (write_len) {
ret = send_write(xprt, rqstp,
be32_to_cpu(ch->rs_handle),
rs_offset + chunk_off,
xdr_off,
write_len,
vec);
if (ret <= 0)
goto out_err;
chunk_off += ret;
xdr_off += ret;
xfer_len -= ret;
write_len -= ret;
}
}
/* Update the req with the number of chunks actually used */
svc_rdma_xdr_encode_reply_array(res_ary, chunk_no);
return rqstp->rq_res.len;
out_err:
pr_err("svcrdma: failed to send reply chunks, rc=%d\n", ret);
return -EIO;
}
/* This function prepares the portion of the RPCRDMA message to be
* sent in the RDMA_SEND. This function is called after data sent via
* RDMA has already been transmitted. There are three cases:
* - The RPCRDMA header, RPC header, and payload are all sent in a
* single RDMA_SEND. This is the "inline" case.
* - The RPCRDMA header and some portion of the RPC header and data
* are sent via this RDMA_SEND and another portion of the data is
* sent via RDMA.
* - The RPCRDMA header [NOMSG] is sent in this RDMA_SEND and the RPC
* header and data are all transmitted via RDMA.
* In all three cases, this function prepares the RPCRDMA header in
* sge[0], the 'type' parameter indicates the type to place in the
* RPCRDMA header, and the 'byte_count' field indicates how much of
* the XDR to include in this RDMA_SEND. NB: The offset of the payload
* to send is zero in the XDR.
*/
static int send_reply(struct svcxprt_rdma *rdma,
struct svc_rqst *rqstp,
struct page *page,
struct rpcrdma_msg *rdma_resp,
struct svc_rdma_req_map *vec,
int byte_count,
u32 inv_rkey)
{
struct svc_rdma_op_ctxt *ctxt;
struct ib_send_wr send_wr;
u32 xdr_off;
int sge_no;
int sge_bytes;
int page_no;
int pages;
int ret = -EIO;
/* Prepare the context */
ctxt = svc_rdma_get_context(rdma);
ctxt->direction = DMA_TO_DEVICE;
ctxt->pages[0] = page;
ctxt->count = 1;
/* Prepare the SGE for the RPCRDMA Header */
ctxt->sge[0].lkey = rdma->sc_pd->local_dma_lkey;
ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp);
ctxt->sge[0].addr =
ib_dma_map_page(rdma->sc_cm_id->device, page, 0,
ctxt->sge[0].length, DMA_TO_DEVICE);
if (ib_dma_mapping_error(rdma->sc_cm_id->device, ctxt->sge[0].addr))
goto err;
svc_rdma_count_mappings(rdma, ctxt);
ctxt->direction = DMA_TO_DEVICE;
/* Map the payload indicated by 'byte_count' */
xdr_off = 0;
for (sge_no = 1; byte_count && sge_no < vec->count; sge_no++) {
sge_bytes = min_t(size_t, vec->sge[sge_no].iov_len, byte_count);
byte_count -= sge_bytes;
ctxt->sge[sge_no].addr =
dma_map_xdr(rdma, &rqstp->rq_res, xdr_off,
sge_bytes, DMA_TO_DEVICE);
xdr_off += sge_bytes;
if (ib_dma_mapping_error(rdma->sc_cm_id->device,
ctxt->sge[sge_no].addr))
goto err;
svc_rdma_count_mappings(rdma, ctxt);
ctxt->sge[sge_no].lkey = rdma->sc_pd->local_dma_lkey;
ctxt->sge[sge_no].length = sge_bytes;
}
if (byte_count != 0) {
pr_err("svcrdma: Could not map %d bytes\n", byte_count);
goto err;
}
/* Save all respages in the ctxt and remove them from the
* respages array. They are our pages until the I/O
* completes.
*/
pages = rqstp->rq_next_page - rqstp->rq_respages;
for (page_no = 0; page_no < pages; page_no++) {
ctxt->pages[page_no+1] = rqstp->rq_respages[page_no];
ctxt->count++;
rqstp->rq_respages[page_no] = NULL;
}
rqstp->rq_next_page = rqstp->rq_respages + 1;
if (sge_no > rdma->sc_max_sge) {
pr_err("svcrdma: Too many sges (%d)\n", sge_no);
goto err;
}
memset(&send_wr, 0, sizeof send_wr);
ctxt->cqe.done = svc_rdma_wc_send;
send_wr.wr_cqe = &ctxt->cqe;
send_wr.sg_list = ctxt->sge;
send_wr.num_sge = sge_no;
if (inv_rkey) {
send_wr.opcode = IB_WR_SEND_WITH_INV;
send_wr.ex.invalidate_rkey = inv_rkey;
} else
send_wr.opcode = IB_WR_SEND;
send_wr.send_flags = IB_SEND_SIGNALED;
ret = svc_rdma_send(rdma, &send_wr);
if (ret)
goto err;
return 0;
err:
svc_rdma_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 1);
return ret;
}
void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
{
}
int svc_rdma_sendto(struct svc_rqst *rqstp)
{
struct svc_xprt *xprt = rqstp->rq_xprt;
struct svcxprt_rdma *rdma =
container_of(xprt, struct svcxprt_rdma, sc_xprt);
struct rpcrdma_msg *rdma_argp;
struct rpcrdma_msg *rdma_resp;
struct rpcrdma_write_array *wr_ary, *rp_ary;
enum rpcrdma_proc reply_type;
int ret;
int inline_bytes;
struct page *res_page;
struct svc_rdma_req_map *vec;
u32 inv_rkey;
dprintk("svcrdma: sending response for rqstp=%p\n", rqstp);
/* Get the RDMA request header. The receive logic always
* places this at the start of page 0.
*/
rdma_argp = page_address(rqstp->rq_pages[0]);
svc_rdma_get_write_arrays(rdma_argp, &wr_ary, &rp_ary);
inv_rkey = 0;
if (rdma->sc_snd_w_inv)
inv_rkey = svc_rdma_get_inv_rkey(rdma_argp, wr_ary, rp_ary);
/* Build an req vec for the XDR */
vec = svc_rdma_get_req_map(rdma);
ret = svc_rdma_map_xdr(rdma, &rqstp->rq_res, vec, wr_ary != NULL);
if (ret)
goto err0;
inline_bytes = rqstp->rq_res.len;
/* Create the RDMA response header */
ret = -ENOMEM;
res_page = alloc_page(GFP_KERNEL);
if (!res_page)
goto err0;
rdma_resp = page_address(res_page);
if (rp_ary)
reply_type = RDMA_NOMSG;
else
reply_type = RDMA_MSG;
svc_rdma_xdr_encode_reply_header(rdma, rdma_argp,
rdma_resp, reply_type);
/* Send any write-chunk data and build resp write-list */
if (wr_ary) {
ret = send_write_chunks(rdma, wr_ary, rdma_resp, rqstp, vec);
if (ret < 0)
goto err1;
inline_bytes -= ret + xdr_padsize(ret);
}
/* Send any reply-list data and update resp reply-list */
if (rp_ary) {
ret = send_reply_chunks(rdma, rp_ary, rdma_resp, rqstp, vec);
if (ret < 0)
goto err1;
inline_bytes -= ret;
}
/* Post a fresh Receive buffer _before_ sending the reply */
ret = svc_rdma_post_recv(rdma, GFP_KERNEL);
if (ret)
goto err1;
ret = send_reply(rdma, rqstp, res_page, rdma_resp, vec,
inline_bytes, inv_rkey);
if (ret < 0)
goto err0;
svc_rdma_put_req_map(rdma, vec);
dprintk("svcrdma: send_reply returns %d\n", ret);
return ret;
err1:
put_page(res_page);
err0:
svc_rdma_put_req_map(rdma, vec);
pr_err("svcrdma: Could not send reply, err=%d. Closing transport.\n",
ret);
set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
return -ENOTCONN;
}
void svc_rdma_send_error(struct svcxprt_rdma *xprt, struct rpcrdma_msg *rmsgp,
int status)
{
struct ib_send_wr err_wr;
struct page *p;
struct svc_rdma_op_ctxt *ctxt;
enum rpcrdma_errcode err;
__be32 *va;
int length;
int ret;
ret = svc_rdma_repost_recv(xprt, GFP_KERNEL);
if (ret)
return;
p = alloc_page(GFP_KERNEL);
if (!p)
return;
va = page_address(p);
/* XDR encode an error reply */
err = ERR_CHUNK;
if (status == -EPROTONOSUPPORT)
err = ERR_VERS;
length = svc_rdma_xdr_encode_error(xprt, rmsgp, err, va);
ctxt = svc_rdma_get_context(xprt);
ctxt->direction = DMA_TO_DEVICE;
ctxt->count = 1;
ctxt->pages[0] = p;
/* Prepare SGE for local address */
ctxt->sge[0].lkey = xprt->sc_pd->local_dma_lkey;
ctxt->sge[0].length = length;
ctxt->sge[0].addr = ib_dma_map_page(xprt->sc_cm_id->device,
p, 0, length, DMA_TO_DEVICE);
if (ib_dma_mapping_error(xprt->sc_cm_id->device, ctxt->sge[0].addr)) {
dprintk("svcrdma: Error mapping buffer for protocol error\n");
svc_rdma_put_context(ctxt, 1);
return;
}
svc_rdma_count_mappings(xprt, ctxt);
/* Prepare SEND WR */
memset(&err_wr, 0, sizeof(err_wr));
ctxt->cqe.done = svc_rdma_wc_send;
err_wr.wr_cqe = &ctxt->cqe;
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);
}
}