1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
3 * Copyright (c) 2014-2017 Oracle. All rights reserved.
4 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
6 * This software is available to you under a choice of one of two
7 * licenses. You may choose to be licensed under the terms of the GNU
8 * General Public License (GPL) Version 2, available from the file
9 * COPYING in the main directory of this source tree, or the BSD-type
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
16 * Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
19 * Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
24 * Neither the name of the Network Appliance, Inc. nor the names of
25 * its contributors may be used to endorse or promote products
26 * derived from this software without specific prior written
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
45 * This file contains the guts of the RPC RDMA protocol, and
46 * does marshaling/unmarshaling, etc. It is also where interfacing
47 * to the Linux RPC framework lives.
50 #include <linux/highmem.h>
52 #include <linux/sunrpc/svc_rdma.h>
54 #include "xprt_rdma.h"
55 #include <trace/events/rpcrdma.h>
57 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
58 # define RPCDBG_FACILITY RPCDBG_TRANS
61 /* Returns size of largest RPC-over-RDMA header in a Call message
63 * The largest Call header contains a full-size Read list and a
64 * minimal Reply chunk.
66 static unsigned int rpcrdma_max_call_header_size(unsigned int maxsegs)
70 /* Fixed header fields and list discriminators */
71 size = RPCRDMA_HDRLEN_MIN;
73 /* Maximum Read list size */
74 size += maxsegs * rpcrdma_readchunk_maxsz * sizeof(__be32);
76 /* Minimal Read chunk size */
77 size += sizeof(__be32); /* segment count */
78 size += rpcrdma_segment_maxsz * sizeof(__be32);
79 size += sizeof(__be32); /* list discriminator */
84 /* Returns size of largest RPC-over-RDMA header in a Reply message
86 * There is only one Write list or one Reply chunk per Reply
87 * message. The larger list is the Write list.
89 static unsigned int rpcrdma_max_reply_header_size(unsigned int maxsegs)
93 /* Fixed header fields and list discriminators */
94 size = RPCRDMA_HDRLEN_MIN;
96 /* Maximum Write list size */
97 size += sizeof(__be32); /* segment count */
98 size += maxsegs * rpcrdma_segment_maxsz * sizeof(__be32);
99 size += sizeof(__be32); /* list discriminator */
105 * rpcrdma_set_max_header_sizes - Initialize inline payload sizes
106 * @ep: endpoint to initialize
108 * The max_inline fields contain the maximum size of an RPC message
109 * so the marshaling code doesn't have to repeat this calculation
112 void rpcrdma_set_max_header_sizes(struct rpcrdma_ep *ep)
114 unsigned int maxsegs = ep->re_max_rdma_segs;
116 ep->re_max_inline_send =
117 ep->re_inline_send - rpcrdma_max_call_header_size(maxsegs);
118 ep->re_max_inline_recv =
119 ep->re_inline_recv - rpcrdma_max_reply_header_size(maxsegs);
122 /* The client can send a request inline as long as the RPCRDMA header
123 * plus the RPC call fit under the transport's inline limit. If the
124 * combined call message size exceeds that limit, the client must use
125 * a Read chunk for this operation.
127 * A Read chunk is also required if sending the RPC call inline would
128 * exceed this device's max_sge limit.
130 static bool rpcrdma_args_inline(struct rpcrdma_xprt *r_xprt,
131 struct rpc_rqst *rqst)
133 struct xdr_buf *xdr = &rqst->rq_snd_buf;
134 struct rpcrdma_ep *ep = r_xprt->rx_ep;
135 unsigned int count, remaining, offset;
137 if (xdr->len > ep->re_max_inline_send)
141 remaining = xdr->page_len;
142 offset = offset_in_page(xdr->page_base);
143 count = RPCRDMA_MIN_SEND_SGES;
145 remaining -= min_t(unsigned int,
146 PAGE_SIZE - offset, remaining);
148 if (++count > ep->re_attr.cap.max_send_sge)
156 /* The client can't know how large the actual reply will be. Thus it
157 * plans for the largest possible reply for that particular ULP
158 * operation. If the maximum combined reply message size exceeds that
159 * limit, the client must provide a write list or a reply chunk for
162 static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
163 struct rpc_rqst *rqst)
165 return rqst->rq_rcv_buf.buflen <= r_xprt->rx_ep->re_max_inline_recv;
168 /* The client is required to provide a Reply chunk if the maximum
169 * size of the non-payload part of the RPC Reply is larger than
170 * the inline threshold.
173 rpcrdma_nonpayload_inline(const struct rpcrdma_xprt *r_xprt,
174 const struct rpc_rqst *rqst)
176 const struct xdr_buf *buf = &rqst->rq_rcv_buf;
178 return (buf->head[0].iov_len + buf->tail[0].iov_len) <
179 r_xprt->rx_ep->re_max_inline_recv;
182 /* ACL likes to be lazy in allocating pages. For TCP, these
183 * pages can be allocated during receive processing. Not true
184 * for RDMA, which must always provision receive buffers
188 rpcrdma_alloc_sparse_pages(struct xdr_buf *buf)
190 struct page **ppages;
194 ppages = buf->pages + (buf->page_base >> PAGE_SHIFT);
197 *ppages = alloc_page(GFP_NOWAIT | __GFP_NOWARN);
207 /* Split @vec on page boundaries into SGEs. FMR registers pages, not
208 * a byte range. Other modes coalesce these SGEs into a single MR
211 * Returns pointer to next available SGE, and bumps the total number
214 static struct rpcrdma_mr_seg *
215 rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg,
218 u32 remaining, page_offset;
221 base = vec->iov_base;
222 page_offset = offset_in_page(base);
223 remaining = vec->iov_len;
226 seg->mr_offset = base;
227 seg->mr_len = min_t(u32, PAGE_SIZE - page_offset, remaining);
228 remaining -= seg->mr_len;
237 /* Convert @xdrbuf into SGEs no larger than a page each. As they
238 * are registered, these SGEs are then coalesced into RDMA segments
239 * when the selected memreg mode supports it.
241 * Returns positive number of SGEs consumed, or a negative errno.
245 rpcrdma_convert_iovs(struct rpcrdma_xprt *r_xprt, struct xdr_buf *xdrbuf,
246 unsigned int pos, enum rpcrdma_chunktype type,
247 struct rpcrdma_mr_seg *seg)
249 unsigned long page_base;
251 struct page **ppages;
255 seg = rpcrdma_convert_kvec(&xdrbuf->head[0], seg, &n);
257 len = xdrbuf->page_len;
258 ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT);
259 page_base = offset_in_page(xdrbuf->page_base);
261 seg->mr_page = *ppages;
262 seg->mr_offset = (char *)page_base;
263 seg->mr_len = min_t(u32, PAGE_SIZE - page_base, len);
271 /* When encoding a Read chunk, the tail iovec contains an
272 * XDR pad and may be omitted.
274 if (type == rpcrdma_readch && r_xprt->rx_ep->re_implicit_roundup)
277 /* When encoding a Write chunk, some servers need to see an
278 * extra segment for non-XDR-aligned Write chunks. The upper
279 * layer provides space in the tail iovec that may be used
282 if (type == rpcrdma_writech && r_xprt->rx_ep->re_implicit_roundup)
285 if (xdrbuf->tail[0].iov_len)
286 seg = rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, &n);
289 if (unlikely(n > RPCRDMA_MAX_SEGS))
295 encode_rdma_segment(struct xdr_stream *xdr, struct rpcrdma_mr *mr)
299 p = xdr_reserve_space(xdr, 4 * sizeof(*p));
303 xdr_encode_rdma_segment(p, mr->mr_handle, mr->mr_length, mr->mr_offset);
308 encode_read_segment(struct xdr_stream *xdr, struct rpcrdma_mr *mr,
313 p = xdr_reserve_space(xdr, 6 * sizeof(*p));
317 *p++ = xdr_one; /* Item present */
318 xdr_encode_read_segment(p, position, mr->mr_handle, mr->mr_length,
323 static struct rpcrdma_mr_seg *rpcrdma_mr_prepare(struct rpcrdma_xprt *r_xprt,
324 struct rpcrdma_req *req,
325 struct rpcrdma_mr_seg *seg,
326 int nsegs, bool writing,
327 struct rpcrdma_mr **mr)
329 *mr = rpcrdma_mr_pop(&req->rl_free_mrs);
331 *mr = rpcrdma_mr_get(r_xprt);
334 trace_xprtrdma_mr_get(req);
338 rpcrdma_mr_push(*mr, &req->rl_registered);
339 return frwr_map(r_xprt, seg, nsegs, writing, req->rl_slot.rq_xid, *mr);
342 trace_xprtrdma_nomrs(req);
343 xprt_wait_for_buffer_space(&r_xprt->rx_xprt);
344 rpcrdma_mrs_refresh(r_xprt);
345 return ERR_PTR(-EAGAIN);
348 /* Register and XDR encode the Read list. Supports encoding a list of read
349 * segments that belong to a single read chunk.
351 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
353 * Read chunklist (a linked list):
354 * N elements, position P (same P for all chunks of same arg!):
355 * 1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
357 * Returns zero on success, or a negative errno if a failure occurred.
358 * @xdr is advanced to the next position in the stream.
360 * Only a single @pos value is currently supported.
362 static int rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt,
363 struct rpcrdma_req *req,
364 struct rpc_rqst *rqst,
365 enum rpcrdma_chunktype rtype)
367 struct xdr_stream *xdr = &req->rl_stream;
368 struct rpcrdma_mr_seg *seg;
369 struct rpcrdma_mr *mr;
373 if (rtype == rpcrdma_noch_pullup || rtype == rpcrdma_noch_mapped)
376 pos = rqst->rq_snd_buf.head[0].iov_len;
377 if (rtype == rpcrdma_areadch)
379 seg = req->rl_segments;
380 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_snd_buf, pos,
386 seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, false, &mr);
390 if (encode_read_segment(xdr, mr, pos) < 0)
393 trace_xprtrdma_chunk_read(rqst->rq_task, pos, mr, nsegs);
394 r_xprt->rx_stats.read_chunk_count++;
395 nsegs -= mr->mr_nents;
399 if (xdr_stream_encode_item_absent(xdr) < 0)
404 /* Register and XDR encode the Write list. Supports encoding a list
405 * containing one array of plain segments that belong to a single
408 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
410 * Write chunklist (a list of (one) counted array):
412 * 1 - N - HLOO - HLOO - ... - HLOO - 0
414 * Returns zero on success, or a negative errno if a failure occurred.
415 * @xdr is advanced to the next position in the stream.
417 * Only a single Write chunk is currently supported.
419 static int rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt,
420 struct rpcrdma_req *req,
421 struct rpc_rqst *rqst,
422 enum rpcrdma_chunktype wtype)
424 struct xdr_stream *xdr = &req->rl_stream;
425 struct rpcrdma_mr_seg *seg;
426 struct rpcrdma_mr *mr;
430 if (wtype != rpcrdma_writech)
433 seg = req->rl_segments;
434 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf,
435 rqst->rq_rcv_buf.head[0].iov_len,
440 if (xdr_stream_encode_item_present(xdr) < 0)
442 segcount = xdr_reserve_space(xdr, sizeof(*segcount));
443 if (unlikely(!segcount))
445 /* Actual value encoded below */
449 seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, true, &mr);
453 if (encode_rdma_segment(xdr, mr) < 0)
456 trace_xprtrdma_chunk_write(rqst->rq_task, mr, nsegs);
457 r_xprt->rx_stats.write_chunk_count++;
458 r_xprt->rx_stats.total_rdma_request += mr->mr_length;
460 nsegs -= mr->mr_nents;
463 /* Update count of segments in this Write chunk */
464 *segcount = cpu_to_be32(nchunks);
467 if (xdr_stream_encode_item_absent(xdr) < 0)
472 /* Register and XDR encode the Reply chunk. Supports encoding an array
473 * of plain segments that belong to a single write (reply) chunk.
475 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
477 * Reply chunk (a counted array):
479 * 1 - N - HLOO - HLOO - ... - HLOO
481 * Returns zero on success, or a negative errno if a failure occurred.
482 * @xdr is advanced to the next position in the stream.
484 static int rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt,
485 struct rpcrdma_req *req,
486 struct rpc_rqst *rqst,
487 enum rpcrdma_chunktype wtype)
489 struct xdr_stream *xdr = &req->rl_stream;
490 struct rpcrdma_mr_seg *seg;
491 struct rpcrdma_mr *mr;
495 if (wtype != rpcrdma_replych) {
496 if (xdr_stream_encode_item_absent(xdr) < 0)
501 seg = req->rl_segments;
502 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf, 0, wtype, seg);
506 if (xdr_stream_encode_item_present(xdr) < 0)
508 segcount = xdr_reserve_space(xdr, sizeof(*segcount));
509 if (unlikely(!segcount))
511 /* Actual value encoded below */
515 seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, true, &mr);
519 if (encode_rdma_segment(xdr, mr) < 0)
522 trace_xprtrdma_chunk_reply(rqst->rq_task, mr, nsegs);
523 r_xprt->rx_stats.reply_chunk_count++;
524 r_xprt->rx_stats.total_rdma_request += mr->mr_length;
526 nsegs -= mr->mr_nents;
529 /* Update count of segments in the Reply chunk */
530 *segcount = cpu_to_be32(nchunks);
535 static void rpcrdma_sendctx_done(struct kref *kref)
537 struct rpcrdma_req *req =
538 container_of(kref, struct rpcrdma_req, rl_kref);
539 struct rpcrdma_rep *rep = req->rl_reply;
541 rpcrdma_complete_rqst(rep);
542 rep->rr_rxprt->rx_stats.reply_waits_for_send++;
546 * rpcrdma_sendctx_unmap - DMA-unmap Send buffer
547 * @sc: sendctx containing SGEs to unmap
550 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc)
552 struct rpcrdma_regbuf *rb = sc->sc_req->rl_sendbuf;
555 if (!sc->sc_unmap_count)
558 /* The first two SGEs contain the transport header and
559 * the inline buffer. These are always left mapped so
560 * they can be cheaply re-used.
562 for (sge = &sc->sc_sges[2]; sc->sc_unmap_count;
563 ++sge, --sc->sc_unmap_count)
564 ib_dma_unmap_page(rdmab_device(rb), sge->addr, sge->length,
567 kref_put(&sc->sc_req->rl_kref, rpcrdma_sendctx_done);
570 /* Prepare an SGE for the RPC-over-RDMA transport header.
572 static void rpcrdma_prepare_hdr_sge(struct rpcrdma_xprt *r_xprt,
573 struct rpcrdma_req *req, u32 len)
575 struct rpcrdma_sendctx *sc = req->rl_sendctx;
576 struct rpcrdma_regbuf *rb = req->rl_rdmabuf;
577 struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
579 sge->addr = rdmab_addr(rb);
581 sge->lkey = rdmab_lkey(rb);
583 ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
587 /* The head iovec is straightforward, as it is usually already
588 * DMA-mapped. Sync the content that has changed.
590 static bool rpcrdma_prepare_head_iov(struct rpcrdma_xprt *r_xprt,
591 struct rpcrdma_req *req, unsigned int len)
593 struct rpcrdma_sendctx *sc = req->rl_sendctx;
594 struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
595 struct rpcrdma_regbuf *rb = req->rl_sendbuf;
597 if (!rpcrdma_regbuf_dma_map(r_xprt, rb))
600 sge->addr = rdmab_addr(rb);
602 sge->lkey = rdmab_lkey(rb);
604 ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
609 /* If there is a page list present, DMA map and prepare an
610 * SGE for each page to be sent.
612 static bool rpcrdma_prepare_pagelist(struct rpcrdma_req *req,
615 struct rpcrdma_sendctx *sc = req->rl_sendctx;
616 struct rpcrdma_regbuf *rb = req->rl_sendbuf;
617 unsigned int page_base, len, remaining;
618 struct page **ppages;
621 ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
622 page_base = offset_in_page(xdr->page_base);
623 remaining = xdr->page_len;
625 sge = &sc->sc_sges[req->rl_wr.num_sge++];
626 len = min_t(unsigned int, PAGE_SIZE - page_base, remaining);
627 sge->addr = ib_dma_map_page(rdmab_device(rb), *ppages,
628 page_base, len, DMA_TO_DEVICE);
629 if (ib_dma_mapping_error(rdmab_device(rb), sge->addr))
630 goto out_mapping_err;
633 sge->lkey = rdmab_lkey(rb);
635 sc->sc_unmap_count++;
644 trace_xprtrdma_dma_maperr(sge->addr);
648 /* The tail iovec may include an XDR pad for the page list,
649 * as well as additional content, and may not reside in the
650 * same page as the head iovec.
652 static bool rpcrdma_prepare_tail_iov(struct rpcrdma_req *req,
654 unsigned int page_base, unsigned int len)
656 struct rpcrdma_sendctx *sc = req->rl_sendctx;
657 struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
658 struct rpcrdma_regbuf *rb = req->rl_sendbuf;
659 struct page *page = virt_to_page(xdr->tail[0].iov_base);
661 sge->addr = ib_dma_map_page(rdmab_device(rb), page, page_base, len,
663 if (ib_dma_mapping_error(rdmab_device(rb), sge->addr))
664 goto out_mapping_err;
667 sge->lkey = rdmab_lkey(rb);
668 ++sc->sc_unmap_count;
672 trace_xprtrdma_dma_maperr(sge->addr);
676 /* Copy the tail to the end of the head buffer.
678 static void rpcrdma_pullup_tail_iov(struct rpcrdma_xprt *r_xprt,
679 struct rpcrdma_req *req,
684 dst = (unsigned char *)xdr->head[0].iov_base;
685 dst += xdr->head[0].iov_len + xdr->page_len;
686 memmove(dst, xdr->tail[0].iov_base, xdr->tail[0].iov_len);
687 r_xprt->rx_stats.pullup_copy_count += xdr->tail[0].iov_len;
690 /* Copy pagelist content into the head buffer.
692 static void rpcrdma_pullup_pagelist(struct rpcrdma_xprt *r_xprt,
693 struct rpcrdma_req *req,
696 unsigned int len, page_base, remaining;
697 struct page **ppages;
698 unsigned char *src, *dst;
700 dst = (unsigned char *)xdr->head[0].iov_base;
701 dst += xdr->head[0].iov_len;
702 ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
703 page_base = offset_in_page(xdr->page_base);
704 remaining = xdr->page_len;
706 src = page_address(*ppages);
708 len = min_t(unsigned int, PAGE_SIZE - page_base, remaining);
709 memcpy(dst, src, len);
710 r_xprt->rx_stats.pullup_copy_count += len;
719 /* Copy the contents of @xdr into @rl_sendbuf and DMA sync it.
720 * When the head, pagelist, and tail are small, a pull-up copy
721 * is considerably less costly than DMA mapping the components
725 * - the caller has already verified that the total length
726 * of the RPC Call body will fit into @rl_sendbuf.
728 static bool rpcrdma_prepare_noch_pullup(struct rpcrdma_xprt *r_xprt,
729 struct rpcrdma_req *req,
732 if (unlikely(xdr->tail[0].iov_len))
733 rpcrdma_pullup_tail_iov(r_xprt, req, xdr);
735 if (unlikely(xdr->page_len))
736 rpcrdma_pullup_pagelist(r_xprt, req, xdr);
738 /* The whole RPC message resides in the head iovec now */
739 return rpcrdma_prepare_head_iov(r_xprt, req, xdr->len);
742 static bool rpcrdma_prepare_noch_mapped(struct rpcrdma_xprt *r_xprt,
743 struct rpcrdma_req *req,
746 struct kvec *tail = &xdr->tail[0];
748 if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len))
751 if (!rpcrdma_prepare_pagelist(req, xdr))
754 if (!rpcrdma_prepare_tail_iov(req, xdr,
755 offset_in_page(tail->iov_base),
759 if (req->rl_sendctx->sc_unmap_count)
760 kref_get(&req->rl_kref);
764 static bool rpcrdma_prepare_readch(struct rpcrdma_xprt *r_xprt,
765 struct rpcrdma_req *req,
768 if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len))
771 /* If there is a Read chunk, the page list is being handled
772 * via explicit RDMA, and thus is skipped here.
775 /* Do not include the tail if it is only an XDR pad */
776 if (xdr->tail[0].iov_len > 3) {
777 unsigned int page_base, len;
779 /* If the content in the page list is an odd length,
780 * xdr_write_pages() adds a pad at the beginning of
781 * the tail iovec. Force the tail's non-pad content to
782 * land at the next XDR position in the Send message.
784 page_base = offset_in_page(xdr->tail[0].iov_base);
785 len = xdr->tail[0].iov_len;
786 page_base += len & 3;
788 if (!rpcrdma_prepare_tail_iov(req, xdr, page_base, len))
790 kref_get(&req->rl_kref);
797 * rpcrdma_prepare_send_sges - Construct SGEs for a Send WR
798 * @r_xprt: controlling transport
799 * @req: context of RPC Call being marshalled
800 * @hdrlen: size of transport header, in bytes
801 * @xdr: xdr_buf containing RPC Call
802 * @rtype: chunk type being encoded
804 * Returns 0 on success; otherwise a negative errno is returned.
806 inline int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
807 struct rpcrdma_req *req, u32 hdrlen,
809 enum rpcrdma_chunktype rtype)
814 req->rl_sendctx = rpcrdma_sendctx_get_locked(r_xprt);
815 if (!req->rl_sendctx)
817 req->rl_sendctx->sc_unmap_count = 0;
818 req->rl_sendctx->sc_req = req;
819 kref_init(&req->rl_kref);
820 req->rl_wr.wr_cqe = &req->rl_sendctx->sc_cqe;
821 req->rl_wr.sg_list = req->rl_sendctx->sc_sges;
822 req->rl_wr.num_sge = 0;
823 req->rl_wr.opcode = IB_WR_SEND;
825 rpcrdma_prepare_hdr_sge(r_xprt, req, hdrlen);
829 case rpcrdma_noch_pullup:
830 if (!rpcrdma_prepare_noch_pullup(r_xprt, req, xdr))
833 case rpcrdma_noch_mapped:
834 if (!rpcrdma_prepare_noch_mapped(r_xprt, req, xdr))
838 if (!rpcrdma_prepare_readch(r_xprt, req, xdr))
841 case rpcrdma_areadch:
850 rpcrdma_sendctx_unmap(req->rl_sendctx);
852 trace_xprtrdma_prepsend_failed(&req->rl_slot, ret);
857 * rpcrdma_marshal_req - Marshal and send one RPC request
858 * @r_xprt: controlling transport
859 * @rqst: RPC request to be marshaled
861 * For the RPC in "rqst", this function:
862 * - Chooses the transfer mode (eg., RDMA_MSG or RDMA_NOMSG)
863 * - Registers Read, Write, and Reply chunks
864 * - Constructs the transport header
865 * - Posts a Send WR to send the transport header and request
868 * %0 if the RPC was sent successfully,
869 * %-ENOTCONN if the connection was lost,
870 * %-EAGAIN if the caller should call again with the same arguments,
871 * %-ENOBUFS if the caller should call again after a delay,
872 * %-EMSGSIZE if the transport header is too small,
873 * %-EIO if a permanent problem occurred while marshaling.
876 rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst)
878 struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
879 struct xdr_stream *xdr = &req->rl_stream;
880 enum rpcrdma_chunktype rtype, wtype;
881 struct xdr_buf *buf = &rqst->rq_snd_buf;
886 if (unlikely(rqst->rq_rcv_buf.flags & XDRBUF_SPARSE_PAGES)) {
887 ret = rpcrdma_alloc_sparse_pages(&rqst->rq_rcv_buf);
892 rpcrdma_set_xdrlen(&req->rl_hdrbuf, 0);
893 xdr_init_encode(xdr, &req->rl_hdrbuf, rdmab_data(req->rl_rdmabuf),
896 /* Fixed header fields */
898 p = xdr_reserve_space(xdr, 4 * sizeof(*p));
902 *p++ = rpcrdma_version;
903 *p++ = r_xprt->rx_buf.rb_max_requests;
905 /* When the ULP employs a GSS flavor that guarantees integrity
906 * or privacy, direct data placement of individual data items
909 ddp_allowed = !test_bit(RPCAUTH_AUTH_DATATOUCH,
910 &rqst->rq_cred->cr_auth->au_flags);
913 * Chunks needed for results?
915 * o If the expected result is under the inline threshold, all ops
917 * o Large read ops return data as write chunk(s), header as
919 * o Large non-read ops return as a single reply chunk.
921 if (rpcrdma_results_inline(r_xprt, rqst))
922 wtype = rpcrdma_noch;
923 else if ((ddp_allowed && rqst->rq_rcv_buf.flags & XDRBUF_READ) &&
924 rpcrdma_nonpayload_inline(r_xprt, rqst))
925 wtype = rpcrdma_writech;
927 wtype = rpcrdma_replych;
930 * Chunks needed for arguments?
932 * o If the total request is under the inline threshold, all ops
933 * are sent as inline.
934 * o Large write ops transmit data as read chunk(s), header as
936 * o Large non-write ops are sent with the entire message as a
937 * single read chunk (protocol 0-position special case).
939 * This assumes that the upper layer does not present a request
940 * that both has a data payload, and whose non-data arguments
941 * by themselves are larger than the inline threshold.
943 if (rpcrdma_args_inline(r_xprt, rqst)) {
945 rtype = buf->len < rdmab_length(req->rl_sendbuf) ?
946 rpcrdma_noch_pullup : rpcrdma_noch_mapped;
947 } else if (ddp_allowed && buf->flags & XDRBUF_WRITE) {
949 rtype = rpcrdma_readch;
951 r_xprt->rx_stats.nomsg_call_count++;
953 rtype = rpcrdma_areadch;
956 /* This implementation supports the following combinations
957 * of chunk lists in one RPC-over-RDMA Call message:
962 * - Read list + Reply chunk
964 * It might not yet support the following combinations:
966 * - Read list + Write list
968 * It does not support the following combinations:
970 * - Write list + Reply chunk
971 * - Read list + Write list + Reply chunk
973 * This implementation supports only a single chunk in each
974 * Read or Write list. Thus for example the client cannot
975 * send a Call message with a Position Zero Read chunk and a
976 * regular Read chunk at the same time.
978 ret = rpcrdma_encode_read_list(r_xprt, req, rqst, rtype);
981 ret = rpcrdma_encode_write_list(r_xprt, req, rqst, wtype);
984 ret = rpcrdma_encode_reply_chunk(r_xprt, req, rqst, wtype);
988 ret = rpcrdma_prepare_send_sges(r_xprt, req, req->rl_hdrbuf.len,
993 trace_xprtrdma_marshal(req, rtype, wtype);
997 trace_xprtrdma_marshal_failed(rqst, ret);
998 r_xprt->rx_stats.failed_marshal_count++;
1003 static void __rpcrdma_update_cwnd_locked(struct rpc_xprt *xprt,
1004 struct rpcrdma_buffer *buf,
1007 buf->rb_credits = grant;
1008 xprt->cwnd = grant << RPC_CWNDSHIFT;
1011 static void rpcrdma_update_cwnd(struct rpcrdma_xprt *r_xprt, u32 grant)
1013 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
1015 spin_lock(&xprt->transport_lock);
1016 __rpcrdma_update_cwnd_locked(xprt, &r_xprt->rx_buf, grant);
1017 spin_unlock(&xprt->transport_lock);
1021 * rpcrdma_reset_cwnd - Reset the xprt's congestion window
1022 * @r_xprt: controlling transport instance
1024 * Prepare @r_xprt for the next connection by reinitializing
1025 * its credit grant to one (see RFC 8166, Section 3.3.3).
1027 void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt)
1029 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
1031 spin_lock(&xprt->transport_lock);
1033 __rpcrdma_update_cwnd_locked(xprt, &r_xprt->rx_buf, 1);
1034 spin_unlock(&xprt->transport_lock);
1038 * rpcrdma_inline_fixup - Scatter inline received data into rqst's iovecs
1039 * @rqst: controlling RPC request
1040 * @srcp: points to RPC message payload in receive buffer
1041 * @copy_len: remaining length of receive buffer content
1042 * @pad: Write chunk pad bytes needed (zero for pure inline)
1044 * The upper layer has set the maximum number of bytes it can
1045 * receive in each component of rq_rcv_buf. These values are set in
1046 * the head.iov_len, page_len, tail.iov_len, and buflen fields.
1048 * Unlike the TCP equivalent (xdr_partial_copy_from_skb), in
1049 * many cases this function simply updates iov_base pointers in
1050 * rq_rcv_buf to point directly to the received reply data, to
1051 * avoid copying reply data.
1053 * Returns the count of bytes which had to be memcopied.
1055 static unsigned long
1056 rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
1058 unsigned long fixup_copy_count;
1059 int i, npages, curlen;
1061 struct page **ppages;
1064 /* The head iovec is redirected to the RPC reply message
1065 * in the receive buffer, to avoid a memcopy.
1067 rqst->rq_rcv_buf.head[0].iov_base = srcp;
1068 rqst->rq_private_buf.head[0].iov_base = srcp;
1070 /* The contents of the receive buffer that follow
1071 * head.iov_len bytes are copied into the page list.
1073 curlen = rqst->rq_rcv_buf.head[0].iov_len;
1074 if (curlen > copy_len)
1079 ppages = rqst->rq_rcv_buf.pages +
1080 (rqst->rq_rcv_buf.page_base >> PAGE_SHIFT);
1081 page_base = offset_in_page(rqst->rq_rcv_buf.page_base);
1082 fixup_copy_count = 0;
1083 if (copy_len && rqst->rq_rcv_buf.page_len) {
1086 pagelist_len = rqst->rq_rcv_buf.page_len;
1087 if (pagelist_len > copy_len)
1088 pagelist_len = copy_len;
1089 npages = PAGE_ALIGN(page_base + pagelist_len) >> PAGE_SHIFT;
1090 for (i = 0; i < npages; i++) {
1091 curlen = PAGE_SIZE - page_base;
1092 if (curlen > pagelist_len)
1093 curlen = pagelist_len;
1095 destp = kmap_atomic(ppages[i]);
1096 memcpy(destp + page_base, srcp, curlen);
1097 flush_dcache_page(ppages[i]);
1098 kunmap_atomic(destp);
1101 fixup_copy_count += curlen;
1102 pagelist_len -= curlen;
1108 /* Implicit padding for the last segment in a Write
1109 * chunk is inserted inline at the front of the tail
1110 * iovec. The upper layer ignores the content of
1111 * the pad. Simply ensure inline content in the tail
1112 * that follows the Write chunk is properly aligned.
1118 /* The tail iovec is redirected to the remaining data
1119 * in the receive buffer, to avoid a memcopy.
1121 if (copy_len || pad) {
1122 rqst->rq_rcv_buf.tail[0].iov_base = srcp;
1123 rqst->rq_private_buf.tail[0].iov_base = srcp;
1126 if (fixup_copy_count)
1127 trace_xprtrdma_fixup(rqst, fixup_copy_count);
1128 return fixup_copy_count;
1131 /* By convention, backchannel calls arrive via rdma_msg type
1132 * messages, and never populate the chunk lists. This makes
1133 * the RPC/RDMA header small and fixed in size, so it is
1134 * straightforward to check the RPC header's direction field.
1137 rpcrdma_is_bcall(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
1138 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1140 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
1141 struct xdr_stream *xdr = &rep->rr_stream;
1144 if (rep->rr_proc != rdma_msg)
1147 /* Peek at stream contents without advancing. */
1148 p = xdr_inline_decode(xdr, 0);
1151 if (xdr_item_is_present(p++))
1153 if (xdr_item_is_present(p++))
1155 if (xdr_item_is_present(p++))
1159 if (*p++ != rep->rr_xid)
1161 if (*p != cpu_to_be32(RPC_CALL))
1164 /* No bc service. */
1165 if (xprt->bc_serv == NULL)
1168 /* Now that we are sure this is a backchannel call,
1169 * advance to the RPC header.
1171 p = xdr_inline_decode(xdr, 3 * sizeof(*p));
1175 rpcrdma_bc_receive_call(r_xprt, rep);
1179 pr_warn("RPC/RDMA short backward direction call\n");
1182 #else /* CONFIG_SUNRPC_BACKCHANNEL */
1186 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1188 static int decode_rdma_segment(struct xdr_stream *xdr, u32 *length)
1194 p = xdr_inline_decode(xdr, 4 * sizeof(*p));
1198 xdr_decode_rdma_segment(p, &handle, length, &offset);
1199 trace_xprtrdma_decode_seg(handle, *length, offset);
1203 static int decode_write_chunk(struct xdr_stream *xdr, u32 *length)
1205 u32 segcount, seglength;
1208 p = xdr_inline_decode(xdr, sizeof(*p));
1213 segcount = be32_to_cpup(p);
1214 while (segcount--) {
1215 if (decode_rdma_segment(xdr, &seglength))
1217 *length += seglength;
1223 /* In RPC-over-RDMA Version One replies, a Read list is never
1224 * expected. This decoder is a stub that returns an error if
1225 * a Read list is present.
1227 static int decode_read_list(struct xdr_stream *xdr)
1231 p = xdr_inline_decode(xdr, sizeof(*p));
1234 if (unlikely(xdr_item_is_present(p)))
1239 /* Supports only one Write chunk in the Write list
1241 static int decode_write_list(struct xdr_stream *xdr, u32 *length)
1250 p = xdr_inline_decode(xdr, sizeof(*p));
1253 if (xdr_item_is_absent(p))
1258 if (decode_write_chunk(xdr, &chunklen))
1260 *length += chunklen;
1266 static int decode_reply_chunk(struct xdr_stream *xdr, u32 *length)
1270 p = xdr_inline_decode(xdr, sizeof(*p));
1275 if (xdr_item_is_present(p))
1276 if (decode_write_chunk(xdr, length))
1282 rpcrdma_decode_msg(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
1283 struct rpc_rqst *rqst)
1285 struct xdr_stream *xdr = &rep->rr_stream;
1286 u32 writelist, replychunk, rpclen;
1289 /* Decode the chunk lists */
1290 if (decode_read_list(xdr))
1292 if (decode_write_list(xdr, &writelist))
1294 if (decode_reply_chunk(xdr, &replychunk))
1297 /* RDMA_MSG sanity checks */
1298 if (unlikely(replychunk))
1301 /* Build the RPC reply's Payload stream in rqst->rq_rcv_buf */
1302 base = (char *)xdr_inline_decode(xdr, 0);
1303 rpclen = xdr_stream_remaining(xdr);
1304 r_xprt->rx_stats.fixup_copy_count +=
1305 rpcrdma_inline_fixup(rqst, base, rpclen, writelist & 3);
1307 r_xprt->rx_stats.total_rdma_reply += writelist;
1308 return rpclen + xdr_align_size(writelist);
1312 rpcrdma_decode_nomsg(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
1314 struct xdr_stream *xdr = &rep->rr_stream;
1315 u32 writelist, replychunk;
1317 /* Decode the chunk lists */
1318 if (decode_read_list(xdr))
1320 if (decode_write_list(xdr, &writelist))
1322 if (decode_reply_chunk(xdr, &replychunk))
1325 /* RDMA_NOMSG sanity checks */
1326 if (unlikely(writelist))
1328 if (unlikely(!replychunk))
1331 /* Reply chunk buffer already is the reply vector */
1332 r_xprt->rx_stats.total_rdma_reply += replychunk;
1337 rpcrdma_decode_error(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
1338 struct rpc_rqst *rqst)
1340 struct xdr_stream *xdr = &rep->rr_stream;
1343 p = xdr_inline_decode(xdr, sizeof(*p));
1349 p = xdr_inline_decode(xdr, 2 * sizeof(*p));
1352 dprintk("RPC: %s: server reports "
1353 "version error (%u-%u), xid %08x\n", __func__,
1354 be32_to_cpup(p), be32_to_cpu(*(p + 1)),
1355 be32_to_cpu(rep->rr_xid));
1358 dprintk("RPC: %s: server reports "
1359 "header decoding error, xid %08x\n", __func__,
1360 be32_to_cpu(rep->rr_xid));
1363 dprintk("RPC: %s: server reports "
1364 "unrecognized error %d, xid %08x\n", __func__,
1365 be32_to_cpup(p), be32_to_cpu(rep->rr_xid));
1371 /* Perform XID lookup, reconstruction of the RPC reply, and
1372 * RPC completion while holding the transport lock to ensure
1373 * the rep, rqst, and rq_task pointers remain stable.
1375 void rpcrdma_complete_rqst(struct rpcrdma_rep *rep)
1377 struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
1378 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
1379 struct rpc_rqst *rqst = rep->rr_rqst;
1382 switch (rep->rr_proc) {
1384 status = rpcrdma_decode_msg(r_xprt, rep, rqst);
1387 status = rpcrdma_decode_nomsg(r_xprt, rep);
1390 status = rpcrdma_decode_error(r_xprt, rep, rqst);
1399 spin_lock(&xprt->queue_lock);
1400 xprt_complete_rqst(rqst->rq_task, status);
1401 xprt_unpin_rqst(rqst);
1402 spin_unlock(&xprt->queue_lock);
1406 trace_xprtrdma_reply_hdr(rep);
1407 r_xprt->rx_stats.bad_reply_count++;
1408 rqst->rq_task->tk_status = status;
1413 static void rpcrdma_reply_done(struct kref *kref)
1415 struct rpcrdma_req *req =
1416 container_of(kref, struct rpcrdma_req, rl_kref);
1418 rpcrdma_complete_rqst(req->rl_reply);
1422 * rpcrdma_reply_handler - Process received RPC/RDMA messages
1423 * @rep: Incoming rpcrdma_rep object to process
1425 * Errors must result in the RPC task either being awakened, or
1426 * allowed to timeout, to discover the errors at that time.
1428 void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
1430 struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
1431 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
1432 struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1433 struct rpcrdma_req *req;
1434 struct rpc_rqst *rqst;
1438 /* Any data means we had a useful conversation, so
1439 * then we don't need to delay the next reconnect.
1441 if (xprt->reestablish_timeout)
1442 xprt->reestablish_timeout = 0;
1444 /* Fixed transport header fields */
1445 xdr_init_decode(&rep->rr_stream, &rep->rr_hdrbuf,
1446 rep->rr_hdrbuf.head[0].iov_base, NULL);
1447 p = xdr_inline_decode(&rep->rr_stream, 4 * sizeof(*p));
1449 goto out_shortreply;
1451 rep->rr_vers = *p++;
1452 credits = be32_to_cpu(*p++);
1453 rep->rr_proc = *p++;
1455 if (rep->rr_vers != rpcrdma_version)
1456 goto out_badversion;
1458 if (rpcrdma_is_bcall(r_xprt, rep))
1461 /* Match incoming rpcrdma_rep to an rpcrdma_req to
1462 * get context for handling any incoming chunks.
1464 spin_lock(&xprt->queue_lock);
1465 rqst = xprt_lookup_rqst(xprt, rep->rr_xid);
1468 xprt_pin_rqst(rqst);
1469 spin_unlock(&xprt->queue_lock);
1472 credits = 1; /* don't deadlock */
1473 else if (credits > r_xprt->rx_ep->re_max_requests)
1474 credits = r_xprt->rx_ep->re_max_requests;
1475 rpcrdma_post_recvs(r_xprt, credits + (buf->rb_bc_srv_max_requests << 1),
1477 if (buf->rb_credits != credits)
1478 rpcrdma_update_cwnd(r_xprt, credits);
1480 req = rpcr_to_rdmar(rqst);
1481 if (req->rl_reply) {
1482 trace_xprtrdma_leaked_rep(rqst, req->rl_reply);
1483 rpcrdma_recv_buffer_put(req->rl_reply);
1485 req->rl_reply = rep;
1486 rep->rr_rqst = rqst;
1488 trace_xprtrdma_reply(rqst->rq_task, rep, req, credits);
1490 if (rep->rr_wc_flags & IB_WC_WITH_INVALIDATE)
1491 frwr_reminv(rep, &req->rl_registered);
1492 if (!list_empty(&req->rl_registered))
1493 frwr_unmap_async(r_xprt, req);
1494 /* LocalInv completion will complete the RPC */
1496 kref_put(&req->rl_kref, rpcrdma_reply_done);
1500 trace_xprtrdma_reply_vers(rep);
1504 spin_unlock(&xprt->queue_lock);
1505 trace_xprtrdma_reply_rqst(rep);
1509 trace_xprtrdma_reply_short(rep);
1512 rpcrdma_recv_buffer_put(rep);