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linux-zen-desktop/net/sunrpc/xprtrdma/rpc_rdma.c

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2023-08-30 17:31:07 +02:00
// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
* Copyright (c) 2014-2020, Oracle and/or its affiliates.
* Copyright (c) 2003-2007 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.
*/
/*
* rpc_rdma.c
*
* This file contains the guts of the RPC RDMA protocol, and
* does marshaling/unmarshaling, etc. It is also where interfacing
* to the Linux RPC framework lives.
*/
#include <linux/highmem.h>
#include <linux/sunrpc/svc_rdma.h>
#include "xprt_rdma.h"
#include <trace/events/rpcrdma.h>
/* Returns size of largest RPC-over-RDMA header in a Call message
*
* The largest Call header contains a full-size Read list and a
* minimal Reply chunk.
*/
static unsigned int rpcrdma_max_call_header_size(unsigned int maxsegs)
{
unsigned int size;
/* Fixed header fields and list discriminators */
size = RPCRDMA_HDRLEN_MIN;
/* Maximum Read list size */
size += maxsegs * rpcrdma_readchunk_maxsz * sizeof(__be32);
/* Minimal Read chunk size */
size += sizeof(__be32); /* segment count */
size += rpcrdma_segment_maxsz * sizeof(__be32);
size += sizeof(__be32); /* list discriminator */
return size;
}
/* Returns size of largest RPC-over-RDMA header in a Reply message
*
* There is only one Write list or one Reply chunk per Reply
* message. The larger list is the Write list.
*/
static unsigned int rpcrdma_max_reply_header_size(unsigned int maxsegs)
{
unsigned int size;
/* Fixed header fields and list discriminators */
size = RPCRDMA_HDRLEN_MIN;
/* Maximum Write list size */
size += sizeof(__be32); /* segment count */
size += maxsegs * rpcrdma_segment_maxsz * sizeof(__be32);
size += sizeof(__be32); /* list discriminator */
return size;
}
/**
* rpcrdma_set_max_header_sizes - Initialize inline payload sizes
* @ep: endpoint to initialize
*
* The max_inline fields contain the maximum size of an RPC message
* so the marshaling code doesn't have to repeat this calculation
* for every RPC.
*/
void rpcrdma_set_max_header_sizes(struct rpcrdma_ep *ep)
{
unsigned int maxsegs = ep->re_max_rdma_segs;
ep->re_max_inline_send =
ep->re_inline_send - rpcrdma_max_call_header_size(maxsegs);
ep->re_max_inline_recv =
ep->re_inline_recv - rpcrdma_max_reply_header_size(maxsegs);
}
/* The client can send a request inline as long as the RPCRDMA header
* plus the RPC call fit under the transport's inline limit. If the
* combined call message size exceeds that limit, the client must use
* a Read chunk for this operation.
*
* A Read chunk is also required if sending the RPC call inline would
* exceed this device's max_sge limit.
*/
static bool rpcrdma_args_inline(struct rpcrdma_xprt *r_xprt,
struct rpc_rqst *rqst)
{
struct xdr_buf *xdr = &rqst->rq_snd_buf;
struct rpcrdma_ep *ep = r_xprt->rx_ep;
unsigned int count, remaining, offset;
if (xdr->len > ep->re_max_inline_send)
return false;
if (xdr->page_len) {
remaining = xdr->page_len;
offset = offset_in_page(xdr->page_base);
count = RPCRDMA_MIN_SEND_SGES;
while (remaining) {
remaining -= min_t(unsigned int,
PAGE_SIZE - offset, remaining);
offset = 0;
if (++count > ep->re_attr.cap.max_send_sge)
return false;
}
}
return true;
}
/* The client can't know how large the actual reply will be. Thus it
* plans for the largest possible reply for that particular ULP
* operation. If the maximum combined reply message size exceeds that
* limit, the client must provide a write list or a reply chunk for
* this request.
*/
static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
struct rpc_rqst *rqst)
{
return rqst->rq_rcv_buf.buflen <= r_xprt->rx_ep->re_max_inline_recv;
}
/* The client is required to provide a Reply chunk if the maximum
* size of the non-payload part of the RPC Reply is larger than
* the inline threshold.
*/
static bool
rpcrdma_nonpayload_inline(const struct rpcrdma_xprt *r_xprt,
const struct rpc_rqst *rqst)
{
const struct xdr_buf *buf = &rqst->rq_rcv_buf;
return (buf->head[0].iov_len + buf->tail[0].iov_len) <
r_xprt->rx_ep->re_max_inline_recv;
}
/* ACL likes to be lazy in allocating pages. For TCP, these
* pages can be allocated during receive processing. Not true
* for RDMA, which must always provision receive buffers
* up front.
*/
static noinline int
rpcrdma_alloc_sparse_pages(struct xdr_buf *buf)
{
struct page **ppages;
int len;
len = buf->page_len;
ppages = buf->pages + (buf->page_base >> PAGE_SHIFT);
while (len > 0) {
if (!*ppages)
*ppages = alloc_page(GFP_NOWAIT | __GFP_NOWARN);
if (!*ppages)
return -ENOBUFS;
ppages++;
len -= PAGE_SIZE;
}
return 0;
}
/* Convert @vec to a single SGL element.
*
* Returns pointer to next available SGE, and bumps the total number
* of SGEs consumed.
*/
static struct rpcrdma_mr_seg *
rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg,
unsigned int *n)
{
seg->mr_page = virt_to_page(vec->iov_base);
seg->mr_offset = offset_in_page(vec->iov_base);
seg->mr_len = vec->iov_len;
++seg;
++(*n);
return seg;
}
/* Convert @xdrbuf into SGEs no larger than a page each. As they
* are registered, these SGEs are then coalesced into RDMA segments
* when the selected memreg mode supports it.
*
* Returns positive number of SGEs consumed, or a negative errno.
*/
static int
rpcrdma_convert_iovs(struct rpcrdma_xprt *r_xprt, struct xdr_buf *xdrbuf,
unsigned int pos, enum rpcrdma_chunktype type,
struct rpcrdma_mr_seg *seg)
{
unsigned long page_base;
unsigned int len, n;
struct page **ppages;
n = 0;
if (pos == 0)
seg = rpcrdma_convert_kvec(&xdrbuf->head[0], seg, &n);
len = xdrbuf->page_len;
ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT);
page_base = offset_in_page(xdrbuf->page_base);
while (len) {
seg->mr_page = *ppages;
seg->mr_offset = page_base;
seg->mr_len = min_t(u32, PAGE_SIZE - page_base, len);
len -= seg->mr_len;
++ppages;
++seg;
++n;
page_base = 0;
}
if (type == rpcrdma_readch || type == rpcrdma_writech)
goto out;
if (xdrbuf->tail[0].iov_len)
rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, &n);
out:
if (unlikely(n > RPCRDMA_MAX_SEGS))
return -EIO;
return n;
}
static int
encode_rdma_segment(struct xdr_stream *xdr, struct rpcrdma_mr *mr)
{
__be32 *p;
p = xdr_reserve_space(xdr, 4 * sizeof(*p));
if (unlikely(!p))
return -EMSGSIZE;
xdr_encode_rdma_segment(p, mr->mr_handle, mr->mr_length, mr->mr_offset);
return 0;
}
static int
encode_read_segment(struct xdr_stream *xdr, struct rpcrdma_mr *mr,
u32 position)
{
__be32 *p;
p = xdr_reserve_space(xdr, 6 * sizeof(*p));
if (unlikely(!p))
return -EMSGSIZE;
*p++ = xdr_one; /* Item present */
xdr_encode_read_segment(p, position, mr->mr_handle, mr->mr_length,
mr->mr_offset);
return 0;
}
static struct rpcrdma_mr_seg *rpcrdma_mr_prepare(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req,
struct rpcrdma_mr_seg *seg,
int nsegs, bool writing,
struct rpcrdma_mr **mr)
{
*mr = rpcrdma_mr_pop(&req->rl_free_mrs);
if (!*mr) {
*mr = rpcrdma_mr_get(r_xprt);
if (!*mr)
goto out_getmr_err;
(*mr)->mr_req = req;
}
rpcrdma_mr_push(*mr, &req->rl_registered);
return frwr_map(r_xprt, seg, nsegs, writing, req->rl_slot.rq_xid, *mr);
out_getmr_err:
trace_xprtrdma_nomrs_err(r_xprt, req);
xprt_wait_for_buffer_space(&r_xprt->rx_xprt);
rpcrdma_mrs_refresh(r_xprt);
return ERR_PTR(-EAGAIN);
}
/* Register and XDR encode the Read list. Supports encoding a list of read
* segments that belong to a single read chunk.
*
* Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
*
* Read chunklist (a linked list):
* N elements, position P (same P for all chunks of same arg!):
* 1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
*
* Returns zero on success, or a negative errno if a failure occurred.
* @xdr is advanced to the next position in the stream.
*
* Only a single @pos value is currently supported.
*/
static int rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req,
struct rpc_rqst *rqst,
enum rpcrdma_chunktype rtype)
{
struct xdr_stream *xdr = &req->rl_stream;
struct rpcrdma_mr_seg *seg;
struct rpcrdma_mr *mr;
unsigned int pos;
int nsegs;
if (rtype == rpcrdma_noch_pullup || rtype == rpcrdma_noch_mapped)
goto done;
pos = rqst->rq_snd_buf.head[0].iov_len;
if (rtype == rpcrdma_areadch)
pos = 0;
seg = req->rl_segments;
nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_snd_buf, pos,
rtype, seg);
if (nsegs < 0)
return nsegs;
do {
seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, false, &mr);
if (IS_ERR(seg))
return PTR_ERR(seg);
if (encode_read_segment(xdr, mr, pos) < 0)
return -EMSGSIZE;
trace_xprtrdma_chunk_read(rqst->rq_task, pos, mr, nsegs);
r_xprt->rx_stats.read_chunk_count++;
nsegs -= mr->mr_nents;
} while (nsegs);
done:
if (xdr_stream_encode_item_absent(xdr) < 0)
return -EMSGSIZE;
return 0;
}
/* Register and XDR encode the Write list. Supports encoding a list
* containing one array of plain segments that belong to a single
* write chunk.
*
* Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
*
* Write chunklist (a list of (one) counted array):
* N elements:
* 1 - N - HLOO - HLOO - ... - HLOO - 0
*
* Returns zero on success, or a negative errno if a failure occurred.
* @xdr is advanced to the next position in the stream.
*
* Only a single Write chunk is currently supported.
*/
static int rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req,
struct rpc_rqst *rqst,
enum rpcrdma_chunktype wtype)
{
struct xdr_stream *xdr = &req->rl_stream;
struct rpcrdma_ep *ep = r_xprt->rx_ep;
struct rpcrdma_mr_seg *seg;
struct rpcrdma_mr *mr;
int nsegs, nchunks;
__be32 *segcount;
if (wtype != rpcrdma_writech)
goto done;
seg = req->rl_segments;
nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf,
rqst->rq_rcv_buf.head[0].iov_len,
wtype, seg);
if (nsegs < 0)
return nsegs;
if (xdr_stream_encode_item_present(xdr) < 0)
return -EMSGSIZE;
segcount = xdr_reserve_space(xdr, sizeof(*segcount));
if (unlikely(!segcount))
return -EMSGSIZE;
/* Actual value encoded below */
nchunks = 0;
do {
seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, true, &mr);
if (IS_ERR(seg))
return PTR_ERR(seg);
if (encode_rdma_segment(xdr, mr) < 0)
return -EMSGSIZE;
trace_xprtrdma_chunk_write(rqst->rq_task, mr, nsegs);
r_xprt->rx_stats.write_chunk_count++;
r_xprt->rx_stats.total_rdma_request += mr->mr_length;
nchunks++;
nsegs -= mr->mr_nents;
} while (nsegs);
if (xdr_pad_size(rqst->rq_rcv_buf.page_len)) {
if (encode_rdma_segment(xdr, ep->re_write_pad_mr) < 0)
return -EMSGSIZE;
trace_xprtrdma_chunk_wp(rqst->rq_task, ep->re_write_pad_mr,
nsegs);
r_xprt->rx_stats.write_chunk_count++;
r_xprt->rx_stats.total_rdma_request += mr->mr_length;
nchunks++;
nsegs -= mr->mr_nents;
}
/* Update count of segments in this Write chunk */
*segcount = cpu_to_be32(nchunks);
done:
if (xdr_stream_encode_item_absent(xdr) < 0)
return -EMSGSIZE;
return 0;
}
/* Register and XDR encode the Reply chunk. Supports encoding an array
* of plain segments that belong to a single write (reply) chunk.
*
* Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
*
* Reply chunk (a counted array):
* N elements:
* 1 - N - HLOO - HLOO - ... - HLOO
*
* Returns zero on success, or a negative errno if a failure occurred.
* @xdr is advanced to the next position in the stream.
*/
static int rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req,
struct rpc_rqst *rqst,
enum rpcrdma_chunktype wtype)
{
struct xdr_stream *xdr = &req->rl_stream;
struct rpcrdma_mr_seg *seg;
struct rpcrdma_mr *mr;
int nsegs, nchunks;
__be32 *segcount;
if (wtype != rpcrdma_replych) {
if (xdr_stream_encode_item_absent(xdr) < 0)
return -EMSGSIZE;
return 0;
}
seg = req->rl_segments;
nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf, 0, wtype, seg);
if (nsegs < 0)
return nsegs;
if (xdr_stream_encode_item_present(xdr) < 0)
return -EMSGSIZE;
segcount = xdr_reserve_space(xdr, sizeof(*segcount));
if (unlikely(!segcount))
return -EMSGSIZE;
/* Actual value encoded below */
nchunks = 0;
do {
seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, true, &mr);
if (IS_ERR(seg))
return PTR_ERR(seg);
if (encode_rdma_segment(xdr, mr) < 0)
return -EMSGSIZE;
trace_xprtrdma_chunk_reply(rqst->rq_task, mr, nsegs);
r_xprt->rx_stats.reply_chunk_count++;
r_xprt->rx_stats.total_rdma_request += mr->mr_length;
nchunks++;
nsegs -= mr->mr_nents;
} while (nsegs);
/* Update count of segments in the Reply chunk */
*segcount = cpu_to_be32(nchunks);
return 0;
}
static void rpcrdma_sendctx_done(struct kref *kref)
{
struct rpcrdma_req *req =
container_of(kref, struct rpcrdma_req, rl_kref);
struct rpcrdma_rep *rep = req->rl_reply;
rpcrdma_complete_rqst(rep);
rep->rr_rxprt->rx_stats.reply_waits_for_send++;
}
/**
* rpcrdma_sendctx_unmap - DMA-unmap Send buffer
* @sc: sendctx containing SGEs to unmap
*
*/
void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc)
{
struct rpcrdma_regbuf *rb = sc->sc_req->rl_sendbuf;
struct ib_sge *sge;
if (!sc->sc_unmap_count)
return;
/* The first two SGEs contain the transport header and
* the inline buffer. These are always left mapped so
* they can be cheaply re-used.
*/
for (sge = &sc->sc_sges[2]; sc->sc_unmap_count;
++sge, --sc->sc_unmap_count)
ib_dma_unmap_page(rdmab_device(rb), sge->addr, sge->length,
DMA_TO_DEVICE);
kref_put(&sc->sc_req->rl_kref, rpcrdma_sendctx_done);
}
/* Prepare an SGE for the RPC-over-RDMA transport header.
*/
static void rpcrdma_prepare_hdr_sge(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req, u32 len)
{
struct rpcrdma_sendctx *sc = req->rl_sendctx;
struct rpcrdma_regbuf *rb = req->rl_rdmabuf;
struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
sge->addr = rdmab_addr(rb);
sge->length = len;
sge->lkey = rdmab_lkey(rb);
ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
DMA_TO_DEVICE);
}
/* The head iovec is straightforward, as it is usually already
* DMA-mapped. Sync the content that has changed.
*/
static bool rpcrdma_prepare_head_iov(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req, unsigned int len)
{
struct rpcrdma_sendctx *sc = req->rl_sendctx;
struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
struct rpcrdma_regbuf *rb = req->rl_sendbuf;
if (!rpcrdma_regbuf_dma_map(r_xprt, rb))
return false;
sge->addr = rdmab_addr(rb);
sge->length = len;
sge->lkey = rdmab_lkey(rb);
ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
DMA_TO_DEVICE);
return true;
}
/* If there is a page list present, DMA map and prepare an
* SGE for each page to be sent.
*/
static bool rpcrdma_prepare_pagelist(struct rpcrdma_req *req,
struct xdr_buf *xdr)
{
struct rpcrdma_sendctx *sc = req->rl_sendctx;
struct rpcrdma_regbuf *rb = req->rl_sendbuf;
unsigned int page_base, len, remaining;
struct page **ppages;
struct ib_sge *sge;
ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
page_base = offset_in_page(xdr->page_base);
remaining = xdr->page_len;
while (remaining) {
sge = &sc->sc_sges[req->rl_wr.num_sge++];
len = min_t(unsigned int, PAGE_SIZE - page_base, remaining);
sge->addr = ib_dma_map_page(rdmab_device(rb), *ppages,
page_base, len, DMA_TO_DEVICE);
if (ib_dma_mapping_error(rdmab_device(rb), sge->addr))
goto out_mapping_err;
sge->length = len;
sge->lkey = rdmab_lkey(rb);
sc->sc_unmap_count++;
ppages++;
remaining -= len;
page_base = 0;
}
return true;
out_mapping_err:
trace_xprtrdma_dma_maperr(sge->addr);
return false;
}
/* The tail iovec may include an XDR pad for the page list,
* as well as additional content, and may not reside in the
* same page as the head iovec.
*/
static bool rpcrdma_prepare_tail_iov(struct rpcrdma_req *req,
struct xdr_buf *xdr,
unsigned int page_base, unsigned int len)
{
struct rpcrdma_sendctx *sc = req->rl_sendctx;
struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
struct rpcrdma_regbuf *rb = req->rl_sendbuf;
struct page *page = virt_to_page(xdr->tail[0].iov_base);
sge->addr = ib_dma_map_page(rdmab_device(rb), page, page_base, len,
DMA_TO_DEVICE);
if (ib_dma_mapping_error(rdmab_device(rb), sge->addr))
goto out_mapping_err;
sge->length = len;
sge->lkey = rdmab_lkey(rb);
++sc->sc_unmap_count;
return true;
out_mapping_err:
trace_xprtrdma_dma_maperr(sge->addr);
return false;
}
/* Copy the tail to the end of the head buffer.
*/
static void rpcrdma_pullup_tail_iov(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req,
struct xdr_buf *xdr)
{
unsigned char *dst;
dst = (unsigned char *)xdr->head[0].iov_base;
dst += xdr->head[0].iov_len + xdr->page_len;
memmove(dst, xdr->tail[0].iov_base, xdr->tail[0].iov_len);
r_xprt->rx_stats.pullup_copy_count += xdr->tail[0].iov_len;
}
/* Copy pagelist content into the head buffer.
*/
static void rpcrdma_pullup_pagelist(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req,
struct xdr_buf *xdr)
{
unsigned int len, page_base, remaining;
struct page **ppages;
unsigned char *src, *dst;
dst = (unsigned char *)xdr->head[0].iov_base;
dst += xdr->head[0].iov_len;
ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
page_base = offset_in_page(xdr->page_base);
remaining = xdr->page_len;
while (remaining) {
src = page_address(*ppages);
src += page_base;
len = min_t(unsigned int, PAGE_SIZE - page_base, remaining);
memcpy(dst, src, len);
r_xprt->rx_stats.pullup_copy_count += len;
ppages++;
dst += len;
remaining -= len;
page_base = 0;
}
}
/* Copy the contents of @xdr into @rl_sendbuf and DMA sync it.
* When the head, pagelist, and tail are small, a pull-up copy
* is considerably less costly than DMA mapping the components
* of @xdr.
*
* Assumptions:
* - the caller has already verified that the total length
* of the RPC Call body will fit into @rl_sendbuf.
*/
static bool rpcrdma_prepare_noch_pullup(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req,
struct xdr_buf *xdr)
{
if (unlikely(xdr->tail[0].iov_len))
rpcrdma_pullup_tail_iov(r_xprt, req, xdr);
if (unlikely(xdr->page_len))
rpcrdma_pullup_pagelist(r_xprt, req, xdr);
/* The whole RPC message resides in the head iovec now */
return rpcrdma_prepare_head_iov(r_xprt, req, xdr->len);
}
static bool rpcrdma_prepare_noch_mapped(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req,
struct xdr_buf *xdr)
{
struct kvec *tail = &xdr->tail[0];
if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len))
return false;
if (xdr->page_len)
if (!rpcrdma_prepare_pagelist(req, xdr))
return false;
if (tail->iov_len)
if (!rpcrdma_prepare_tail_iov(req, xdr,
offset_in_page(tail->iov_base),
tail->iov_len))
return false;
if (req->rl_sendctx->sc_unmap_count)
kref_get(&req->rl_kref);
return true;
}
static bool rpcrdma_prepare_readch(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req,
struct xdr_buf *xdr)
{
if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len))
return false;
/* If there is a Read chunk, the page list is being handled
* via explicit RDMA, and thus is skipped here.
*/
/* Do not include the tail if it is only an XDR pad */
if (xdr->tail[0].iov_len > 3) {
unsigned int page_base, len;
/* If the content in the page list is an odd length,
* xdr_write_pages() adds a pad at the beginning of
* the tail iovec. Force the tail's non-pad content to
* land at the next XDR position in the Send message.
*/
page_base = offset_in_page(xdr->tail[0].iov_base);
len = xdr->tail[0].iov_len;
page_base += len & 3;
len -= len & 3;
if (!rpcrdma_prepare_tail_iov(req, xdr, page_base, len))
return false;
kref_get(&req->rl_kref);
}
return true;
}
/**
* rpcrdma_prepare_send_sges - Construct SGEs for a Send WR
* @r_xprt: controlling transport
* @req: context of RPC Call being marshalled
* @hdrlen: size of transport header, in bytes
* @xdr: xdr_buf containing RPC Call
* @rtype: chunk type being encoded
*
* Returns 0 on success; otherwise a negative errno is returned.
*/
inline int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req, u32 hdrlen,
struct xdr_buf *xdr,
enum rpcrdma_chunktype rtype)
{
int ret;
ret = -EAGAIN;
req->rl_sendctx = rpcrdma_sendctx_get_locked(r_xprt);
if (!req->rl_sendctx)
goto out_nosc;
req->rl_sendctx->sc_unmap_count = 0;
req->rl_sendctx->sc_req = req;
kref_init(&req->rl_kref);
req->rl_wr.wr_cqe = &req->rl_sendctx->sc_cqe;
req->rl_wr.sg_list = req->rl_sendctx->sc_sges;
req->rl_wr.num_sge = 0;
req->rl_wr.opcode = IB_WR_SEND;
rpcrdma_prepare_hdr_sge(r_xprt, req, hdrlen);
ret = -EIO;
switch (rtype) {
case rpcrdma_noch_pullup:
if (!rpcrdma_prepare_noch_pullup(r_xprt, req, xdr))
goto out_unmap;
break;
case rpcrdma_noch_mapped:
if (!rpcrdma_prepare_noch_mapped(r_xprt, req, xdr))
goto out_unmap;
break;
case rpcrdma_readch:
if (!rpcrdma_prepare_readch(r_xprt, req, xdr))
goto out_unmap;
break;
case rpcrdma_areadch:
break;
default:
goto out_unmap;
}
return 0;
out_unmap:
rpcrdma_sendctx_unmap(req->rl_sendctx);
out_nosc:
trace_xprtrdma_prepsend_failed(&req->rl_slot, ret);
return ret;
}
/**
* rpcrdma_marshal_req - Marshal and send one RPC request
* @r_xprt: controlling transport
* @rqst: RPC request to be marshaled
*
* For the RPC in "rqst", this function:
* - Chooses the transfer mode (eg., RDMA_MSG or RDMA_NOMSG)
* - Registers Read, Write, and Reply chunks
* - Constructs the transport header
* - Posts a Send WR to send the transport header and request
*
* Returns:
* %0 if the RPC was sent successfully,
* %-ENOTCONN if the connection was lost,
* %-EAGAIN if the caller should call again with the same arguments,
* %-ENOBUFS if the caller should call again after a delay,
* %-EMSGSIZE if the transport header is too small,
* %-EIO if a permanent problem occurred while marshaling.
*/
int
rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst)
{
struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
struct xdr_stream *xdr = &req->rl_stream;
enum rpcrdma_chunktype rtype, wtype;
struct xdr_buf *buf = &rqst->rq_snd_buf;
bool ddp_allowed;
__be32 *p;
int ret;
if (unlikely(rqst->rq_rcv_buf.flags & XDRBUF_SPARSE_PAGES)) {
ret = rpcrdma_alloc_sparse_pages(&rqst->rq_rcv_buf);
if (ret)
return ret;
}
rpcrdma_set_xdrlen(&req->rl_hdrbuf, 0);
xdr_init_encode(xdr, &req->rl_hdrbuf, rdmab_data(req->rl_rdmabuf),
rqst);
/* Fixed header fields */
ret = -EMSGSIZE;
p = xdr_reserve_space(xdr, 4 * sizeof(*p));
if (!p)
goto out_err;
*p++ = rqst->rq_xid;
*p++ = rpcrdma_version;
*p++ = r_xprt->rx_buf.rb_max_requests;
/* When the ULP employs a GSS flavor that guarantees integrity
* or privacy, direct data placement of individual data items
* is not allowed.
*/
ddp_allowed = !test_bit(RPCAUTH_AUTH_DATATOUCH,
&rqst->rq_cred->cr_auth->au_flags);
/*
* Chunks needed for results?
*
* o If the expected result is under the inline threshold, all ops
* return as inline.
* o Large read ops return data as write chunk(s), header as
* inline.
* o Large non-read ops return as a single reply chunk.
*/
if (rpcrdma_results_inline(r_xprt, rqst))
wtype = rpcrdma_noch;
else if ((ddp_allowed && rqst->rq_rcv_buf.flags & XDRBUF_READ) &&
rpcrdma_nonpayload_inline(r_xprt, rqst))
wtype = rpcrdma_writech;
else
wtype = rpcrdma_replych;
/*
* Chunks needed for arguments?
*
* o If the total request is under the inline threshold, all ops
* are sent as inline.
* o Large write ops transmit data as read chunk(s), header as
* inline.
* o Large non-write ops are sent with the entire message as a
* single read chunk (protocol 0-position special case).
*
* This assumes that the upper layer does not present a request
* that both has a data payload, and whose non-data arguments
* by themselves are larger than the inline threshold.
*/
if (rpcrdma_args_inline(r_xprt, rqst)) {
*p++ = rdma_msg;
rtype = buf->len < rdmab_length(req->rl_sendbuf) ?
rpcrdma_noch_pullup : rpcrdma_noch_mapped;
} else if (ddp_allowed && buf->flags & XDRBUF_WRITE) {
*p++ = rdma_msg;
rtype = rpcrdma_readch;
} else {
r_xprt->rx_stats.nomsg_call_count++;
*p++ = rdma_nomsg;
rtype = rpcrdma_areadch;
}
/* This implementation supports the following combinations
* of chunk lists in one RPC-over-RDMA Call message:
*
* - Read list
* - Write list
* - Reply chunk
* - Read list + Reply chunk
*
* It might not yet support the following combinations:
*
* - Read list + Write list
*
* It does not support the following combinations:
*
* - Write list + Reply chunk
* - Read list + Write list + Reply chunk
*
* This implementation supports only a single chunk in each
* Read or Write list. Thus for example the client cannot
* send a Call message with a Position Zero Read chunk and a
* regular Read chunk at the same time.
*/
ret = rpcrdma_encode_read_list(r_xprt, req, rqst, rtype);
if (ret)
goto out_err;
ret = rpcrdma_encode_write_list(r_xprt, req, rqst, wtype);
if (ret)
goto out_err;
ret = rpcrdma_encode_reply_chunk(r_xprt, req, rqst, wtype);
if (ret)
goto out_err;
ret = rpcrdma_prepare_send_sges(r_xprt, req, req->rl_hdrbuf.len,
buf, rtype);
if (ret)
goto out_err;
trace_xprtrdma_marshal(req, rtype, wtype);
return 0;
out_err:
trace_xprtrdma_marshal_failed(rqst, ret);
r_xprt->rx_stats.failed_marshal_count++;
frwr_reset(req);
return ret;
}
static void __rpcrdma_update_cwnd_locked(struct rpc_xprt *xprt,
struct rpcrdma_buffer *buf,
u32 grant)
{
buf->rb_credits = grant;
xprt->cwnd = grant << RPC_CWNDSHIFT;
}
static void rpcrdma_update_cwnd(struct rpcrdma_xprt *r_xprt, u32 grant)
{
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
spin_lock(&xprt->transport_lock);
__rpcrdma_update_cwnd_locked(xprt, &r_xprt->rx_buf, grant);
spin_unlock(&xprt->transport_lock);
}
/**
* rpcrdma_reset_cwnd - Reset the xprt's congestion window
* @r_xprt: controlling transport instance
*
* Prepare @r_xprt for the next connection by reinitializing
* its credit grant to one (see RFC 8166, Section 3.3.3).
*/
void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt)
{
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
spin_lock(&xprt->transport_lock);
xprt->cong = 0;
__rpcrdma_update_cwnd_locked(xprt, &r_xprt->rx_buf, 1);
spin_unlock(&xprt->transport_lock);
}
/**
* rpcrdma_inline_fixup - Scatter inline received data into rqst's iovecs
* @rqst: controlling RPC request
* @srcp: points to RPC message payload in receive buffer
* @copy_len: remaining length of receive buffer content
* @pad: Write chunk pad bytes needed (zero for pure inline)
*
* The upper layer has set the maximum number of bytes it can
* receive in each component of rq_rcv_buf. These values are set in
* the head.iov_len, page_len, tail.iov_len, and buflen fields.
*
* Unlike the TCP equivalent (xdr_partial_copy_from_skb), in
* many cases this function simply updates iov_base pointers in
* rq_rcv_buf to point directly to the received reply data, to
* avoid copying reply data.
*
* Returns the count of bytes which had to be memcopied.
*/
static unsigned long
rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
{
unsigned long fixup_copy_count;
int i, npages, curlen;
char *destp;
struct page **ppages;
int page_base;
/* The head iovec is redirected to the RPC reply message
* in the receive buffer, to avoid a memcopy.
*/
rqst->rq_rcv_buf.head[0].iov_base = srcp;
rqst->rq_private_buf.head[0].iov_base = srcp;
/* The contents of the receive buffer that follow
* head.iov_len bytes are copied into the page list.
*/
curlen = rqst->rq_rcv_buf.head[0].iov_len;
if (curlen > copy_len)
curlen = copy_len;
srcp += curlen;
copy_len -= curlen;
ppages = rqst->rq_rcv_buf.pages +
(rqst->rq_rcv_buf.page_base >> PAGE_SHIFT);
page_base = offset_in_page(rqst->rq_rcv_buf.page_base);
fixup_copy_count = 0;
if (copy_len && rqst->rq_rcv_buf.page_len) {
int pagelist_len;
pagelist_len = rqst->rq_rcv_buf.page_len;
if (pagelist_len > copy_len)
pagelist_len = copy_len;
npages = PAGE_ALIGN(page_base + pagelist_len) >> PAGE_SHIFT;
for (i = 0; i < npages; i++) {
curlen = PAGE_SIZE - page_base;
if (curlen > pagelist_len)
curlen = pagelist_len;
destp = kmap_atomic(ppages[i]);
memcpy(destp + page_base, srcp, curlen);
flush_dcache_page(ppages[i]);
kunmap_atomic(destp);
srcp += curlen;
copy_len -= curlen;
fixup_copy_count += curlen;
pagelist_len -= curlen;
if (!pagelist_len)
break;
page_base = 0;
}
/* Implicit padding for the last segment in a Write
* chunk is inserted inline at the front of the tail
* iovec. The upper layer ignores the content of
* the pad. Simply ensure inline content in the tail
* that follows the Write chunk is properly aligned.
*/
if (pad)
srcp -= pad;
}
/* The tail iovec is redirected to the remaining data
* in the receive buffer, to avoid a memcopy.
*/
if (copy_len || pad) {
rqst->rq_rcv_buf.tail[0].iov_base = srcp;
rqst->rq_private_buf.tail[0].iov_base = srcp;
}
if (fixup_copy_count)
trace_xprtrdma_fixup(rqst, fixup_copy_count);
return fixup_copy_count;
}
/* By convention, backchannel calls arrive via rdma_msg type
* messages, and never populate the chunk lists. This makes
* the RPC/RDMA header small and fixed in size, so it is
* straightforward to check the RPC header's direction field.
*/
static bool
rpcrdma_is_bcall(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
{
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
struct xdr_stream *xdr = &rep->rr_stream;
__be32 *p;
if (rep->rr_proc != rdma_msg)
return false;
/* Peek at stream contents without advancing. */
p = xdr_inline_decode(xdr, 0);
/* Chunk lists */
if (xdr_item_is_present(p++))
return false;
if (xdr_item_is_present(p++))
return false;
if (xdr_item_is_present(p++))
return false;
/* RPC header */
if (*p++ != rep->rr_xid)
return false;
if (*p != cpu_to_be32(RPC_CALL))
return false;
/* No bc service. */
if (xprt->bc_serv == NULL)
return false;
/* Now that we are sure this is a backchannel call,
* advance to the RPC header.
*/
p = xdr_inline_decode(xdr, 3 * sizeof(*p));
if (unlikely(!p))
return true;
rpcrdma_bc_receive_call(r_xprt, rep);
return true;
}
#else /* CONFIG_SUNRPC_BACKCHANNEL */
{
return false;
}
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
static int decode_rdma_segment(struct xdr_stream *xdr, u32 *length)
{
u32 handle;
u64 offset;
__be32 *p;
p = xdr_inline_decode(xdr, 4 * sizeof(*p));
if (unlikely(!p))
return -EIO;
xdr_decode_rdma_segment(p, &handle, length, &offset);
trace_xprtrdma_decode_seg(handle, *length, offset);
return 0;
}
static int decode_write_chunk(struct xdr_stream *xdr, u32 *length)
{
u32 segcount, seglength;
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(*p));
if (unlikely(!p))
return -EIO;
*length = 0;
segcount = be32_to_cpup(p);
while (segcount--) {
if (decode_rdma_segment(xdr, &seglength))
return -EIO;
*length += seglength;
}
return 0;
}
/* In RPC-over-RDMA Version One replies, a Read list is never
* expected. This decoder is a stub that returns an error if
* a Read list is present.
*/
static int decode_read_list(struct xdr_stream *xdr)
{
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(*p));
if (unlikely(!p))
return -EIO;
if (unlikely(xdr_item_is_present(p)))
return -EIO;
return 0;
}
/* Supports only one Write chunk in the Write list
*/
static int decode_write_list(struct xdr_stream *xdr, u32 *length)
{
u32 chunklen;
bool first;
__be32 *p;
*length = 0;
first = true;
do {
p = xdr_inline_decode(xdr, sizeof(*p));
if (unlikely(!p))
return -EIO;
if (xdr_item_is_absent(p))
break;
if (!first)
return -EIO;
if (decode_write_chunk(xdr, &chunklen))
return -EIO;
*length += chunklen;
first = false;
} while (true);
return 0;
}
static int decode_reply_chunk(struct xdr_stream *xdr, u32 *length)
{
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(*p));
if (unlikely(!p))
return -EIO;
*length = 0;
if (xdr_item_is_present(p))
if (decode_write_chunk(xdr, length))
return -EIO;
return 0;
}
static int
rpcrdma_decode_msg(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
struct rpc_rqst *rqst)
{
struct xdr_stream *xdr = &rep->rr_stream;
u32 writelist, replychunk, rpclen;
char *base;
/* Decode the chunk lists */
if (decode_read_list(xdr))
return -EIO;
if (decode_write_list(xdr, &writelist))
return -EIO;
if (decode_reply_chunk(xdr, &replychunk))
return -EIO;
/* RDMA_MSG sanity checks */
if (unlikely(replychunk))
return -EIO;
/* Build the RPC reply's Payload stream in rqst->rq_rcv_buf */
base = (char *)xdr_inline_decode(xdr, 0);
rpclen = xdr_stream_remaining(xdr);
r_xprt->rx_stats.fixup_copy_count +=
rpcrdma_inline_fixup(rqst, base, rpclen, writelist & 3);
r_xprt->rx_stats.total_rdma_reply += writelist;
return rpclen + xdr_align_size(writelist);
}
static noinline int
rpcrdma_decode_nomsg(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
{
struct xdr_stream *xdr = &rep->rr_stream;
u32 writelist, replychunk;
/* Decode the chunk lists */
if (decode_read_list(xdr))
return -EIO;
if (decode_write_list(xdr, &writelist))
return -EIO;
if (decode_reply_chunk(xdr, &replychunk))
return -EIO;
/* RDMA_NOMSG sanity checks */
if (unlikely(writelist))
return -EIO;
if (unlikely(!replychunk))
return -EIO;
/* Reply chunk buffer already is the reply vector */
r_xprt->rx_stats.total_rdma_reply += replychunk;
return replychunk;
}
static noinline int
rpcrdma_decode_error(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
struct rpc_rqst *rqst)
{
struct xdr_stream *xdr = &rep->rr_stream;
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(*p));
if (unlikely(!p))
return -EIO;
switch (*p) {
case err_vers:
p = xdr_inline_decode(xdr, 2 * sizeof(*p));
if (!p)
break;
trace_xprtrdma_err_vers(rqst, p, p + 1);
break;
case err_chunk:
trace_xprtrdma_err_chunk(rqst);
break;
default:
trace_xprtrdma_err_unrecognized(rqst, p);
}
return -EIO;
}
/**
* rpcrdma_unpin_rqst - Release rqst without completing it
* @rep: RPC/RDMA Receive context
*
* This is done when a connection is lost so that a Reply
* can be dropped and its matching Call can be subsequently
* retransmitted on a new connection.
*/
void rpcrdma_unpin_rqst(struct rpcrdma_rep *rep)
{
struct rpc_xprt *xprt = &rep->rr_rxprt->rx_xprt;
struct rpc_rqst *rqst = rep->rr_rqst;
struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
req->rl_reply = NULL;
rep->rr_rqst = NULL;
spin_lock(&xprt->queue_lock);
xprt_unpin_rqst(rqst);
spin_unlock(&xprt->queue_lock);
}
/**
* rpcrdma_complete_rqst - Pass completed rqst back to RPC
* @rep: RPC/RDMA Receive context
*
* Reconstruct the RPC reply and complete the transaction
* while @rqst is still pinned to ensure the rep, rqst, and
* rq_task pointers remain stable.
*/
void rpcrdma_complete_rqst(struct rpcrdma_rep *rep)
{
struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
struct rpc_rqst *rqst = rep->rr_rqst;
int status;
switch (rep->rr_proc) {
case rdma_msg:
status = rpcrdma_decode_msg(r_xprt, rep, rqst);
break;
case rdma_nomsg:
status = rpcrdma_decode_nomsg(r_xprt, rep);
break;
case rdma_error:
status = rpcrdma_decode_error(r_xprt, rep, rqst);
break;
default:
status = -EIO;
}
if (status < 0)
goto out_badheader;
out:
spin_lock(&xprt->queue_lock);
xprt_complete_rqst(rqst->rq_task, status);
xprt_unpin_rqst(rqst);
spin_unlock(&xprt->queue_lock);
return;
out_badheader:
trace_xprtrdma_reply_hdr_err(rep);
r_xprt->rx_stats.bad_reply_count++;
rqst->rq_task->tk_status = status;
status = 0;
goto out;
}
static void rpcrdma_reply_done(struct kref *kref)
{
struct rpcrdma_req *req =
container_of(kref, struct rpcrdma_req, rl_kref);
rpcrdma_complete_rqst(req->rl_reply);
}
/**
* rpcrdma_reply_handler - Process received RPC/RDMA messages
* @rep: Incoming rpcrdma_rep object to process
*
* Errors must result in the RPC task either being awakened, or
* allowed to timeout, to discover the errors at that time.
*/
void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
{
struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_req *req;
struct rpc_rqst *rqst;
u32 credits;
__be32 *p;
/* Any data means we had a useful conversation, so
* then we don't need to delay the next reconnect.
*/
if (xprt->reestablish_timeout)
xprt->reestablish_timeout = 0;
/* Fixed transport header fields */
xdr_init_decode(&rep->rr_stream, &rep->rr_hdrbuf,
rep->rr_hdrbuf.head[0].iov_base, NULL);
p = xdr_inline_decode(&rep->rr_stream, 4 * sizeof(*p));
if (unlikely(!p))
goto out_shortreply;
rep->rr_xid = *p++;
rep->rr_vers = *p++;
credits = be32_to_cpu(*p++);
rep->rr_proc = *p++;
if (rep->rr_vers != rpcrdma_version)
goto out_badversion;
if (rpcrdma_is_bcall(r_xprt, rep))
return;
/* Match incoming rpcrdma_rep to an rpcrdma_req to
* get context for handling any incoming chunks.
*/
spin_lock(&xprt->queue_lock);
rqst = xprt_lookup_rqst(xprt, rep->rr_xid);
if (!rqst)
goto out_norqst;
xprt_pin_rqst(rqst);
spin_unlock(&xprt->queue_lock);
if (credits == 0)
credits = 1; /* don't deadlock */
else if (credits > r_xprt->rx_ep->re_max_requests)
credits = r_xprt->rx_ep->re_max_requests;
rpcrdma_post_recvs(r_xprt, credits + (buf->rb_bc_srv_max_requests << 1),
false);
if (buf->rb_credits != credits)
rpcrdma_update_cwnd(r_xprt, credits);
req = rpcr_to_rdmar(rqst);
if (unlikely(req->rl_reply))
rpcrdma_rep_put(buf, req->rl_reply);
req->rl_reply = rep;
rep->rr_rqst = rqst;
trace_xprtrdma_reply(rqst->rq_task, rep, credits);
if (rep->rr_wc_flags & IB_WC_WITH_INVALIDATE)
frwr_reminv(rep, &req->rl_registered);
if (!list_empty(&req->rl_registered))
frwr_unmap_async(r_xprt, req);
/* LocalInv completion will complete the RPC */
else
kref_put(&req->rl_kref, rpcrdma_reply_done);
return;
out_badversion:
trace_xprtrdma_reply_vers_err(rep);
goto out;
out_norqst:
spin_unlock(&xprt->queue_lock);
trace_xprtrdma_reply_rqst_err(rep);
goto out;
out_shortreply:
trace_xprtrdma_reply_short_err(rep);
out:
rpcrdma_rep_put(buf, rep);
}