diff options
Diffstat (limited to 'net/sunrpc/xprtrdma/rpc_rdma.c')
| -rw-r--r-- | net/sunrpc/xprtrdma/rpc_rdma.c | 1510 |
1 files changed, 1510 insertions, 0 deletions
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c new file mode 100644 index 000000000..190a4de23 --- /dev/null +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -0,0 +1,1510 @@ +// 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); +} |