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.
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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 /* Split @vec on page boundaries into SGEs. FMR registers pages, not
183 * a byte range. Other modes coalesce these SGEs into a single MR
186 * Returns pointer to next available SGE, and bumps the total number
189 static struct rpcrdma_mr_seg *
190 rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg,
193 u32 remaining, page_offset;
196 base = vec->iov_base;
197 page_offset = offset_in_page(base);
198 remaining = vec->iov_len;
201 seg->mr_offset = base;
202 seg->mr_len = min_t(u32, PAGE_SIZE - page_offset, remaining);
203 remaining -= seg->mr_len;
212 /* Convert @xdrbuf into SGEs no larger than a page each. As they
213 * are registered, these SGEs are then coalesced into RDMA segments
214 * when the selected memreg mode supports it.
216 * Returns positive number of SGEs consumed, or a negative errno.
220 rpcrdma_convert_iovs(struct rpcrdma_xprt *r_xprt, struct xdr_buf *xdrbuf,
221 unsigned int pos, enum rpcrdma_chunktype type,
222 struct rpcrdma_mr_seg *seg)
224 unsigned long page_base;
226 struct page **ppages;
230 seg = rpcrdma_convert_kvec(&xdrbuf->head[0], seg, &n);
232 len = xdrbuf->page_len;
233 ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT);
234 page_base = offset_in_page(xdrbuf->page_base);
236 /* ACL likes to be lazy in allocating pages - ACLs
237 * are small by default but can get huge.
239 if (unlikely(xdrbuf->flags & XDRBUF_SPARSE_PAGES)) {
241 *ppages = alloc_page(GFP_NOWAIT | __GFP_NOWARN);
245 seg->mr_page = *ppages;
246 seg->mr_offset = (char *)page_base;
247 seg->mr_len = min_t(u32, PAGE_SIZE - page_base, len);
255 /* When encoding a Read chunk, the tail iovec contains an
256 * XDR pad and may be omitted.
258 if (type == rpcrdma_readch && r_xprt->rx_ep->re_implicit_roundup)
261 /* When encoding a Write chunk, some servers need to see an
262 * extra segment for non-XDR-aligned Write chunks. The upper
263 * layer provides space in the tail iovec that may be used
266 if (type == rpcrdma_writech && r_xprt->rx_ep->re_implicit_roundup)
269 if (xdrbuf->tail[0].iov_len)
270 seg = rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, &n);
273 if (unlikely(n > RPCRDMA_MAX_SEGS))
279 encode_rdma_segment(struct xdr_stream *xdr, struct rpcrdma_mr *mr)
283 p = xdr_reserve_space(xdr, 4 * sizeof(*p));
287 xdr_encode_rdma_segment(p, mr->mr_handle, mr->mr_length, mr->mr_offset);
292 encode_read_segment(struct xdr_stream *xdr, struct rpcrdma_mr *mr,
297 p = xdr_reserve_space(xdr, 6 * sizeof(*p));
301 *p++ = xdr_one; /* Item present */
302 xdr_encode_read_segment(p, position, mr->mr_handle, mr->mr_length,
307 static struct rpcrdma_mr_seg *rpcrdma_mr_prepare(struct rpcrdma_xprt *r_xprt,
308 struct rpcrdma_req *req,
309 struct rpcrdma_mr_seg *seg,
310 int nsegs, bool writing,
311 struct rpcrdma_mr **mr)
313 *mr = rpcrdma_mr_pop(&req->rl_free_mrs);
315 *mr = rpcrdma_mr_get(r_xprt);
318 trace_xprtrdma_mr_get(req);
322 rpcrdma_mr_push(*mr, &req->rl_registered);
323 return frwr_map(r_xprt, seg, nsegs, writing, req->rl_slot.rq_xid, *mr);
326 trace_xprtrdma_nomrs(req);
327 xprt_wait_for_buffer_space(&r_xprt->rx_xprt);
328 rpcrdma_mrs_refresh(r_xprt);
329 return ERR_PTR(-EAGAIN);
332 /* Register and XDR encode the Read list. Supports encoding a list of read
333 * segments that belong to a single read chunk.
335 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
337 * Read chunklist (a linked list):
338 * N elements, position P (same P for all chunks of same arg!):
339 * 1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
341 * Returns zero on success, or a negative errno if a failure occurred.
342 * @xdr is advanced to the next position in the stream.
344 * Only a single @pos value is currently supported.
346 static int rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt,
347 struct rpcrdma_req *req,
348 struct rpc_rqst *rqst,
349 enum rpcrdma_chunktype rtype)
351 struct xdr_stream *xdr = &req->rl_stream;
352 struct rpcrdma_mr_seg *seg;
353 struct rpcrdma_mr *mr;
357 if (rtype == rpcrdma_noch_pullup || rtype == rpcrdma_noch_mapped)
360 pos = rqst->rq_snd_buf.head[0].iov_len;
361 if (rtype == rpcrdma_areadch)
363 seg = req->rl_segments;
364 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_snd_buf, pos,
370 seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, false, &mr);
374 if (encode_read_segment(xdr, mr, pos) < 0)
377 trace_xprtrdma_chunk_read(rqst->rq_task, pos, mr, nsegs);
378 r_xprt->rx_stats.read_chunk_count++;
379 nsegs -= mr->mr_nents;
383 if (xdr_stream_encode_item_absent(xdr) < 0)
388 /* Register and XDR encode the Write list. Supports encoding a list
389 * containing one array of plain segments that belong to a single
392 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
394 * Write chunklist (a list of (one) counted array):
396 * 1 - N - HLOO - HLOO - ... - HLOO - 0
398 * Returns zero on success, or a negative errno if a failure occurred.
399 * @xdr is advanced to the next position in the stream.
401 * Only a single Write chunk is currently supported.
403 static int rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt,
404 struct rpcrdma_req *req,
405 struct rpc_rqst *rqst,
406 enum rpcrdma_chunktype wtype)
408 struct xdr_stream *xdr = &req->rl_stream;
409 struct rpcrdma_mr_seg *seg;
410 struct rpcrdma_mr *mr;
414 if (wtype != rpcrdma_writech)
417 seg = req->rl_segments;
418 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf,
419 rqst->rq_rcv_buf.head[0].iov_len,
424 if (xdr_stream_encode_item_present(xdr) < 0)
426 segcount = xdr_reserve_space(xdr, sizeof(*segcount));
427 if (unlikely(!segcount))
429 /* Actual value encoded below */
433 seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, true, &mr);
437 if (encode_rdma_segment(xdr, mr) < 0)
440 trace_xprtrdma_chunk_write(rqst->rq_task, mr, nsegs);
441 r_xprt->rx_stats.write_chunk_count++;
442 r_xprt->rx_stats.total_rdma_request += mr->mr_length;
444 nsegs -= mr->mr_nents;
447 /* Update count of segments in this Write chunk */
448 *segcount = cpu_to_be32(nchunks);
451 if (xdr_stream_encode_item_absent(xdr) < 0)
456 /* Register and XDR encode the Reply chunk. Supports encoding an array
457 * of plain segments that belong to a single write (reply) chunk.
459 * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
461 * Reply chunk (a counted array):
463 * 1 - N - HLOO - HLOO - ... - HLOO
465 * Returns zero on success, or a negative errno if a failure occurred.
466 * @xdr is advanced to the next position in the stream.
468 static int rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt,
469 struct rpcrdma_req *req,
470 struct rpc_rqst *rqst,
471 enum rpcrdma_chunktype wtype)
473 struct xdr_stream *xdr = &req->rl_stream;
474 struct rpcrdma_mr_seg *seg;
475 struct rpcrdma_mr *mr;
479 if (wtype != rpcrdma_replych) {
480 if (xdr_stream_encode_item_absent(xdr) < 0)
485 seg = req->rl_segments;
486 nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf, 0, wtype, seg);
490 if (xdr_stream_encode_item_present(xdr) < 0)
492 segcount = xdr_reserve_space(xdr, sizeof(*segcount));
493 if (unlikely(!segcount))
495 /* Actual value encoded below */
499 seg = rpcrdma_mr_prepare(r_xprt, req, seg, nsegs, true, &mr);
503 if (encode_rdma_segment(xdr, mr) < 0)
506 trace_xprtrdma_chunk_reply(rqst->rq_task, mr, nsegs);
507 r_xprt->rx_stats.reply_chunk_count++;
508 r_xprt->rx_stats.total_rdma_request += mr->mr_length;
510 nsegs -= mr->mr_nents;
513 /* Update count of segments in the Reply chunk */
514 *segcount = cpu_to_be32(nchunks);
519 static void rpcrdma_sendctx_done(struct kref *kref)
521 struct rpcrdma_req *req =
522 container_of(kref, struct rpcrdma_req, rl_kref);
523 struct rpcrdma_rep *rep = req->rl_reply;
525 rpcrdma_complete_rqst(rep);
526 rep->rr_rxprt->rx_stats.reply_waits_for_send++;
530 * rpcrdma_sendctx_unmap - DMA-unmap Send buffer
531 * @sc: sendctx containing SGEs to unmap
534 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc)
536 struct rpcrdma_regbuf *rb = sc->sc_req->rl_sendbuf;
539 if (!sc->sc_unmap_count)
542 /* The first two SGEs contain the transport header and
543 * the inline buffer. These are always left mapped so
544 * they can be cheaply re-used.
546 for (sge = &sc->sc_sges[2]; sc->sc_unmap_count;
547 ++sge, --sc->sc_unmap_count)
548 ib_dma_unmap_page(rdmab_device(rb), sge->addr, sge->length,
551 kref_put(&sc->sc_req->rl_kref, rpcrdma_sendctx_done);
554 /* Prepare an SGE for the RPC-over-RDMA transport header.
556 static void rpcrdma_prepare_hdr_sge(struct rpcrdma_xprt *r_xprt,
557 struct rpcrdma_req *req, u32 len)
559 struct rpcrdma_sendctx *sc = req->rl_sendctx;
560 struct rpcrdma_regbuf *rb = req->rl_rdmabuf;
561 struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
563 sge->addr = rdmab_addr(rb);
565 sge->lkey = rdmab_lkey(rb);
567 ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
571 /* The head iovec is straightforward, as it is usually already
572 * DMA-mapped. Sync the content that has changed.
574 static bool rpcrdma_prepare_head_iov(struct rpcrdma_xprt *r_xprt,
575 struct rpcrdma_req *req, unsigned int len)
577 struct rpcrdma_sendctx *sc = req->rl_sendctx;
578 struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
579 struct rpcrdma_regbuf *rb = req->rl_sendbuf;
581 if (!rpcrdma_regbuf_dma_map(r_xprt, rb))
584 sge->addr = rdmab_addr(rb);
586 sge->lkey = rdmab_lkey(rb);
588 ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
593 /* If there is a page list present, DMA map and prepare an
594 * SGE for each page to be sent.
596 static bool rpcrdma_prepare_pagelist(struct rpcrdma_req *req,
599 struct rpcrdma_sendctx *sc = req->rl_sendctx;
600 struct rpcrdma_regbuf *rb = req->rl_sendbuf;
601 unsigned int page_base, len, remaining;
602 struct page **ppages;
605 ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
606 page_base = offset_in_page(xdr->page_base);
607 remaining = xdr->page_len;
609 sge = &sc->sc_sges[req->rl_wr.num_sge++];
610 len = min_t(unsigned int, PAGE_SIZE - page_base, remaining);
611 sge->addr = ib_dma_map_page(rdmab_device(rb), *ppages,
612 page_base, len, DMA_TO_DEVICE);
613 if (ib_dma_mapping_error(rdmab_device(rb), sge->addr))
614 goto out_mapping_err;
617 sge->lkey = rdmab_lkey(rb);
619 sc->sc_unmap_count++;
628 trace_xprtrdma_dma_maperr(sge->addr);
632 /* The tail iovec may include an XDR pad for the page list,
633 * as well as additional content, and may not reside in the
634 * same page as the head iovec.
636 static bool rpcrdma_prepare_tail_iov(struct rpcrdma_req *req,
638 unsigned int page_base, unsigned int len)
640 struct rpcrdma_sendctx *sc = req->rl_sendctx;
641 struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
642 struct rpcrdma_regbuf *rb = req->rl_sendbuf;
643 struct page *page = virt_to_page(xdr->tail[0].iov_base);
645 sge->addr = ib_dma_map_page(rdmab_device(rb), page, page_base, len,
647 if (ib_dma_mapping_error(rdmab_device(rb), sge->addr))
648 goto out_mapping_err;
651 sge->lkey = rdmab_lkey(rb);
652 ++sc->sc_unmap_count;
656 trace_xprtrdma_dma_maperr(sge->addr);
660 /* Copy the tail to the end of the head buffer.
662 static void rpcrdma_pullup_tail_iov(struct rpcrdma_xprt *r_xprt,
663 struct rpcrdma_req *req,
668 dst = (unsigned char *)xdr->head[0].iov_base;
669 dst += xdr->head[0].iov_len + xdr->page_len;
670 memmove(dst, xdr->tail[0].iov_base, xdr->tail[0].iov_len);
671 r_xprt->rx_stats.pullup_copy_count += xdr->tail[0].iov_len;
674 /* Copy pagelist content into the head buffer.
676 static void rpcrdma_pullup_pagelist(struct rpcrdma_xprt *r_xprt,
677 struct rpcrdma_req *req,
680 unsigned int len, page_base, remaining;
681 struct page **ppages;
682 unsigned char *src, *dst;
684 dst = (unsigned char *)xdr->head[0].iov_base;
685 dst += xdr->head[0].iov_len;
686 ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
687 page_base = offset_in_page(xdr->page_base);
688 remaining = xdr->page_len;
690 src = page_address(*ppages);
692 len = min_t(unsigned int, PAGE_SIZE - page_base, remaining);
693 memcpy(dst, src, len);
694 r_xprt->rx_stats.pullup_copy_count += len;
703 /* Copy the contents of @xdr into @rl_sendbuf and DMA sync it.
704 * When the head, pagelist, and tail are small, a pull-up copy
705 * is considerably less costly than DMA mapping the components
709 * - the caller has already verified that the total length
710 * of the RPC Call body will fit into @rl_sendbuf.
712 static bool rpcrdma_prepare_noch_pullup(struct rpcrdma_xprt *r_xprt,
713 struct rpcrdma_req *req,
716 if (unlikely(xdr->tail[0].iov_len))
717 rpcrdma_pullup_tail_iov(r_xprt, req, xdr);
719 if (unlikely(xdr->page_len))
720 rpcrdma_pullup_pagelist(r_xprt, req, xdr);
722 /* The whole RPC message resides in the head iovec now */
723 return rpcrdma_prepare_head_iov(r_xprt, req, xdr->len);
726 static bool rpcrdma_prepare_noch_mapped(struct rpcrdma_xprt *r_xprt,
727 struct rpcrdma_req *req,
730 struct kvec *tail = &xdr->tail[0];
732 if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len))
735 if (!rpcrdma_prepare_pagelist(req, xdr))
738 if (!rpcrdma_prepare_tail_iov(req, xdr,
739 offset_in_page(tail->iov_base),
743 if (req->rl_sendctx->sc_unmap_count)
744 kref_get(&req->rl_kref);
748 static bool rpcrdma_prepare_readch(struct rpcrdma_xprt *r_xprt,
749 struct rpcrdma_req *req,
752 if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len))
755 /* If there is a Read chunk, the page list is being handled
756 * via explicit RDMA, and thus is skipped here.
759 /* Do not include the tail if it is only an XDR pad */
760 if (xdr->tail[0].iov_len > 3) {
761 unsigned int page_base, len;
763 /* If the content in the page list is an odd length,
764 * xdr_write_pages() adds a pad at the beginning of
765 * the tail iovec. Force the tail's non-pad content to
766 * land at the next XDR position in the Send message.
768 page_base = offset_in_page(xdr->tail[0].iov_base);
769 len = xdr->tail[0].iov_len;
770 page_base += len & 3;
772 if (!rpcrdma_prepare_tail_iov(req, xdr, page_base, len))
774 kref_get(&req->rl_kref);
781 * rpcrdma_prepare_send_sges - Construct SGEs for a Send WR
782 * @r_xprt: controlling transport
783 * @req: context of RPC Call being marshalled
784 * @hdrlen: size of transport header, in bytes
785 * @xdr: xdr_buf containing RPC Call
786 * @rtype: chunk type being encoded
788 * Returns 0 on success; otherwise a negative errno is returned.
790 inline int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
791 struct rpcrdma_req *req, u32 hdrlen,
793 enum rpcrdma_chunktype rtype)
798 req->rl_sendctx = rpcrdma_sendctx_get_locked(r_xprt);
799 if (!req->rl_sendctx)
801 req->rl_sendctx->sc_unmap_count = 0;
802 req->rl_sendctx->sc_req = req;
803 kref_init(&req->rl_kref);
804 req->rl_wr.wr_cqe = &req->rl_sendctx->sc_cqe;
805 req->rl_wr.sg_list = req->rl_sendctx->sc_sges;
806 req->rl_wr.num_sge = 0;
807 req->rl_wr.opcode = IB_WR_SEND;
809 rpcrdma_prepare_hdr_sge(r_xprt, req, hdrlen);
813 case rpcrdma_noch_pullup:
814 if (!rpcrdma_prepare_noch_pullup(r_xprt, req, xdr))
817 case rpcrdma_noch_mapped:
818 if (!rpcrdma_prepare_noch_mapped(r_xprt, req, xdr))
822 if (!rpcrdma_prepare_readch(r_xprt, req, xdr))
825 case rpcrdma_areadch:
834 rpcrdma_sendctx_unmap(req->rl_sendctx);
836 trace_xprtrdma_prepsend_failed(&req->rl_slot, ret);
841 * rpcrdma_marshal_req - Marshal and send one RPC request
842 * @r_xprt: controlling transport
843 * @rqst: RPC request to be marshaled
845 * For the RPC in "rqst", this function:
846 * - Chooses the transfer mode (eg., RDMA_MSG or RDMA_NOMSG)
847 * - Registers Read, Write, and Reply chunks
848 * - Constructs the transport header
849 * - Posts a Send WR to send the transport header and request
852 * %0 if the RPC was sent successfully,
853 * %-ENOTCONN if the connection was lost,
854 * %-EAGAIN if the caller should call again with the same arguments,
855 * %-ENOBUFS if the caller should call again after a delay,
856 * %-EMSGSIZE if the transport header is too small,
857 * %-EIO if a permanent problem occurred while marshaling.
860 rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst)
862 struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
863 struct xdr_stream *xdr = &req->rl_stream;
864 enum rpcrdma_chunktype rtype, wtype;
865 struct xdr_buf *buf = &rqst->rq_snd_buf;
870 rpcrdma_set_xdrlen(&req->rl_hdrbuf, 0);
871 xdr_init_encode(xdr, &req->rl_hdrbuf, rdmab_data(req->rl_rdmabuf),
874 /* Fixed header fields */
876 p = xdr_reserve_space(xdr, 4 * sizeof(*p));
880 *p++ = rpcrdma_version;
881 *p++ = r_xprt->rx_buf.rb_max_requests;
883 /* When the ULP employs a GSS flavor that guarantees integrity
884 * or privacy, direct data placement of individual data items
887 ddp_allowed = !test_bit(RPCAUTH_AUTH_DATATOUCH,
888 &rqst->rq_cred->cr_auth->au_flags);
891 * Chunks needed for results?
893 * o If the expected result is under the inline threshold, all ops
895 * o Large read ops return data as write chunk(s), header as
897 * o Large non-read ops return as a single reply chunk.
899 if (rpcrdma_results_inline(r_xprt, rqst))
900 wtype = rpcrdma_noch;
901 else if ((ddp_allowed && rqst->rq_rcv_buf.flags & XDRBUF_READ) &&
902 rpcrdma_nonpayload_inline(r_xprt, rqst))
903 wtype = rpcrdma_writech;
905 wtype = rpcrdma_replych;
908 * Chunks needed for arguments?
910 * o If the total request is under the inline threshold, all ops
911 * are sent as inline.
912 * o Large write ops transmit data as read chunk(s), header as
914 * o Large non-write ops are sent with the entire message as a
915 * single read chunk (protocol 0-position special case).
917 * This assumes that the upper layer does not present a request
918 * that both has a data payload, and whose non-data arguments
919 * by themselves are larger than the inline threshold.
921 if (rpcrdma_args_inline(r_xprt, rqst)) {
923 rtype = buf->len < rdmab_length(req->rl_sendbuf) ?
924 rpcrdma_noch_pullup : rpcrdma_noch_mapped;
925 } else if (ddp_allowed && buf->flags & XDRBUF_WRITE) {
927 rtype = rpcrdma_readch;
929 r_xprt->rx_stats.nomsg_call_count++;
931 rtype = rpcrdma_areadch;
934 /* This implementation supports the following combinations
935 * of chunk lists in one RPC-over-RDMA Call message:
940 * - Read list + Reply chunk
942 * It might not yet support the following combinations:
944 * - Read list + Write list
946 * It does not support the following combinations:
948 * - Write list + Reply chunk
949 * - Read list + Write list + Reply chunk
951 * This implementation supports only a single chunk in each
952 * Read or Write list. Thus for example the client cannot
953 * send a Call message with a Position Zero Read chunk and a
954 * regular Read chunk at the same time.
956 ret = rpcrdma_encode_read_list(r_xprt, req, rqst, rtype);
959 ret = rpcrdma_encode_write_list(r_xprt, req, rqst, wtype);
962 ret = rpcrdma_encode_reply_chunk(r_xprt, req, rqst, wtype);
966 ret = rpcrdma_prepare_send_sges(r_xprt, req, req->rl_hdrbuf.len,
971 trace_xprtrdma_marshal(req, rtype, wtype);
975 trace_xprtrdma_marshal_failed(rqst, ret);
976 r_xprt->rx_stats.failed_marshal_count++;
981 static void __rpcrdma_update_cwnd_locked(struct rpc_xprt *xprt,
982 struct rpcrdma_buffer *buf,
985 buf->rb_credits = grant;
986 xprt->cwnd = grant << RPC_CWNDSHIFT;
989 static void rpcrdma_update_cwnd(struct rpcrdma_xprt *r_xprt, u32 grant)
991 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
993 spin_lock(&xprt->transport_lock);
994 __rpcrdma_update_cwnd_locked(xprt, &r_xprt->rx_buf, grant);
995 spin_unlock(&xprt->transport_lock);
999 * rpcrdma_reset_cwnd - Reset the xprt's congestion window
1000 * @r_xprt: controlling transport instance
1002 * Prepare @r_xprt for the next connection by reinitializing
1003 * its credit grant to one (see RFC 8166, Section 3.3.3).
1005 void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt)
1007 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
1009 spin_lock(&xprt->transport_lock);
1011 __rpcrdma_update_cwnd_locked(xprt, &r_xprt->rx_buf, 1);
1012 spin_unlock(&xprt->transport_lock);
1016 * rpcrdma_inline_fixup - Scatter inline received data into rqst's iovecs
1017 * @rqst: controlling RPC request
1018 * @srcp: points to RPC message payload in receive buffer
1019 * @copy_len: remaining length of receive buffer content
1020 * @pad: Write chunk pad bytes needed (zero for pure inline)
1022 * The upper layer has set the maximum number of bytes it can
1023 * receive in each component of rq_rcv_buf. These values are set in
1024 * the head.iov_len, page_len, tail.iov_len, and buflen fields.
1026 * Unlike the TCP equivalent (xdr_partial_copy_from_skb), in
1027 * many cases this function simply updates iov_base pointers in
1028 * rq_rcv_buf to point directly to the received reply data, to
1029 * avoid copying reply data.
1031 * Returns the count of bytes which had to be memcopied.
1033 static unsigned long
1034 rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
1036 unsigned long fixup_copy_count;
1037 int i, npages, curlen;
1039 struct page **ppages;
1042 /* The head iovec is redirected to the RPC reply message
1043 * in the receive buffer, to avoid a memcopy.
1045 rqst->rq_rcv_buf.head[0].iov_base = srcp;
1046 rqst->rq_private_buf.head[0].iov_base = srcp;
1048 /* The contents of the receive buffer that follow
1049 * head.iov_len bytes are copied into the page list.
1051 curlen = rqst->rq_rcv_buf.head[0].iov_len;
1052 if (curlen > copy_len)
1057 ppages = rqst->rq_rcv_buf.pages +
1058 (rqst->rq_rcv_buf.page_base >> PAGE_SHIFT);
1059 page_base = offset_in_page(rqst->rq_rcv_buf.page_base);
1060 fixup_copy_count = 0;
1061 if (copy_len && rqst->rq_rcv_buf.page_len) {
1064 pagelist_len = rqst->rq_rcv_buf.page_len;
1065 if (pagelist_len > copy_len)
1066 pagelist_len = copy_len;
1067 npages = PAGE_ALIGN(page_base + pagelist_len) >> PAGE_SHIFT;
1068 for (i = 0; i < npages; i++) {
1069 curlen = PAGE_SIZE - page_base;
1070 if (curlen > pagelist_len)
1071 curlen = pagelist_len;
1073 destp = kmap_atomic(ppages[i]);
1074 memcpy(destp + page_base, srcp, curlen);
1075 flush_dcache_page(ppages[i]);
1076 kunmap_atomic(destp);
1079 fixup_copy_count += curlen;
1080 pagelist_len -= curlen;
1086 /* Implicit padding for the last segment in a Write
1087 * chunk is inserted inline at the front of the tail
1088 * iovec. The upper layer ignores the content of
1089 * the pad. Simply ensure inline content in the tail
1090 * that follows the Write chunk is properly aligned.
1096 /* The tail iovec is redirected to the remaining data
1097 * in the receive buffer, to avoid a memcopy.
1099 if (copy_len || pad) {
1100 rqst->rq_rcv_buf.tail[0].iov_base = srcp;
1101 rqst->rq_private_buf.tail[0].iov_base = srcp;
1104 if (fixup_copy_count)
1105 trace_xprtrdma_fixup(rqst, fixup_copy_count);
1106 return fixup_copy_count;
1109 /* By convention, backchannel calls arrive via rdma_msg type
1110 * messages, and never populate the chunk lists. This makes
1111 * the RPC/RDMA header small and fixed in size, so it is
1112 * straightforward to check the RPC header's direction field.
1115 rpcrdma_is_bcall(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
1116 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1118 struct xdr_stream *xdr = &rep->rr_stream;
1121 if (rep->rr_proc != rdma_msg)
1124 /* Peek at stream contents without advancing. */
1125 p = xdr_inline_decode(xdr, 0);
1128 if (xdr_item_is_present(p++))
1130 if (xdr_item_is_present(p++))
1132 if (xdr_item_is_present(p++))
1136 if (*p++ != rep->rr_xid)
1138 if (*p != cpu_to_be32(RPC_CALL))
1141 /* Now that we are sure this is a backchannel call,
1142 * advance to the RPC header.
1144 p = xdr_inline_decode(xdr, 3 * sizeof(*p));
1148 rpcrdma_bc_receive_call(r_xprt, rep);
1152 pr_warn("RPC/RDMA short backward direction call\n");
1155 #else /* CONFIG_SUNRPC_BACKCHANNEL */
1159 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1161 static int decode_rdma_segment(struct xdr_stream *xdr, u32 *length)
1167 p = xdr_inline_decode(xdr, 4 * sizeof(*p));
1171 xdr_decode_rdma_segment(p, &handle, length, &offset);
1172 trace_xprtrdma_decode_seg(handle, *length, offset);
1176 static int decode_write_chunk(struct xdr_stream *xdr, u32 *length)
1178 u32 segcount, seglength;
1181 p = xdr_inline_decode(xdr, sizeof(*p));
1186 segcount = be32_to_cpup(p);
1187 while (segcount--) {
1188 if (decode_rdma_segment(xdr, &seglength))
1190 *length += seglength;
1196 /* In RPC-over-RDMA Version One replies, a Read list is never
1197 * expected. This decoder is a stub that returns an error if
1198 * a Read list is present.
1200 static int decode_read_list(struct xdr_stream *xdr)
1204 p = xdr_inline_decode(xdr, sizeof(*p));
1207 if (unlikely(xdr_item_is_present(p)))
1212 /* Supports only one Write chunk in the Write list
1214 static int decode_write_list(struct xdr_stream *xdr, u32 *length)
1223 p = xdr_inline_decode(xdr, sizeof(*p));
1226 if (xdr_item_is_absent(p))
1231 if (decode_write_chunk(xdr, &chunklen))
1233 *length += chunklen;
1239 static int decode_reply_chunk(struct xdr_stream *xdr, u32 *length)
1243 p = xdr_inline_decode(xdr, sizeof(*p));
1248 if (xdr_item_is_present(p))
1249 if (decode_write_chunk(xdr, length))
1255 rpcrdma_decode_msg(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
1256 struct rpc_rqst *rqst)
1258 struct xdr_stream *xdr = &rep->rr_stream;
1259 u32 writelist, replychunk, rpclen;
1262 /* Decode the chunk lists */
1263 if (decode_read_list(xdr))
1265 if (decode_write_list(xdr, &writelist))
1267 if (decode_reply_chunk(xdr, &replychunk))
1270 /* RDMA_MSG sanity checks */
1271 if (unlikely(replychunk))
1274 /* Build the RPC reply's Payload stream in rqst->rq_rcv_buf */
1275 base = (char *)xdr_inline_decode(xdr, 0);
1276 rpclen = xdr_stream_remaining(xdr);
1277 r_xprt->rx_stats.fixup_copy_count +=
1278 rpcrdma_inline_fixup(rqst, base, rpclen, writelist & 3);
1280 r_xprt->rx_stats.total_rdma_reply += writelist;
1281 return rpclen + xdr_align_size(writelist);
1285 rpcrdma_decode_nomsg(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
1287 struct xdr_stream *xdr = &rep->rr_stream;
1288 u32 writelist, replychunk;
1290 /* Decode the chunk lists */
1291 if (decode_read_list(xdr))
1293 if (decode_write_list(xdr, &writelist))
1295 if (decode_reply_chunk(xdr, &replychunk))
1298 /* RDMA_NOMSG sanity checks */
1299 if (unlikely(writelist))
1301 if (unlikely(!replychunk))
1304 /* Reply chunk buffer already is the reply vector */
1305 r_xprt->rx_stats.total_rdma_reply += replychunk;
1310 rpcrdma_decode_error(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
1311 struct rpc_rqst *rqst)
1313 struct xdr_stream *xdr = &rep->rr_stream;
1316 p = xdr_inline_decode(xdr, sizeof(*p));
1322 p = xdr_inline_decode(xdr, 2 * sizeof(*p));
1325 dprintk("RPC: %s: server reports "
1326 "version error (%u-%u), xid %08x\n", __func__,
1327 be32_to_cpup(p), be32_to_cpu(*(p + 1)),
1328 be32_to_cpu(rep->rr_xid));
1331 dprintk("RPC: %s: server reports "
1332 "header decoding error, xid %08x\n", __func__,
1333 be32_to_cpu(rep->rr_xid));
1336 dprintk("RPC: %s: server reports "
1337 "unrecognized error %d, xid %08x\n", __func__,
1338 be32_to_cpup(p), be32_to_cpu(rep->rr_xid));
1344 /* Perform XID lookup, reconstruction of the RPC reply, and
1345 * RPC completion while holding the transport lock to ensure
1346 * the rep, rqst, and rq_task pointers remain stable.
1348 void rpcrdma_complete_rqst(struct rpcrdma_rep *rep)
1350 struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
1351 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
1352 struct rpc_rqst *rqst = rep->rr_rqst;
1355 switch (rep->rr_proc) {
1357 status = rpcrdma_decode_msg(r_xprt, rep, rqst);
1360 status = rpcrdma_decode_nomsg(r_xprt, rep);
1363 status = rpcrdma_decode_error(r_xprt, rep, rqst);
1372 spin_lock(&xprt->queue_lock);
1373 xprt_complete_rqst(rqst->rq_task, status);
1374 xprt_unpin_rqst(rqst);
1375 spin_unlock(&xprt->queue_lock);
1379 trace_xprtrdma_reply_hdr(rep);
1380 r_xprt->rx_stats.bad_reply_count++;
1381 rqst->rq_task->tk_status = status;
1386 static void rpcrdma_reply_done(struct kref *kref)
1388 struct rpcrdma_req *req =
1389 container_of(kref, struct rpcrdma_req, rl_kref);
1391 rpcrdma_complete_rqst(req->rl_reply);
1395 * rpcrdma_reply_handler - Process received RPC/RDMA messages
1396 * @rep: Incoming rpcrdma_rep object to process
1398 * Errors must result in the RPC task either being awakened, or
1399 * allowed to timeout, to discover the errors at that time.
1401 void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
1403 struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
1404 struct rpc_xprt *xprt = &r_xprt->rx_xprt;
1405 struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
1406 struct rpcrdma_req *req;
1407 struct rpc_rqst *rqst;
1411 /* Any data means we had a useful conversation, so
1412 * then we don't need to delay the next reconnect.
1414 if (xprt->reestablish_timeout)
1415 xprt->reestablish_timeout = 0;
1417 /* Fixed transport header fields */
1418 xdr_init_decode(&rep->rr_stream, &rep->rr_hdrbuf,
1419 rep->rr_hdrbuf.head[0].iov_base, NULL);
1420 p = xdr_inline_decode(&rep->rr_stream, 4 * sizeof(*p));
1422 goto out_shortreply;
1424 rep->rr_vers = *p++;
1425 credits = be32_to_cpu(*p++);
1426 rep->rr_proc = *p++;
1428 if (rep->rr_vers != rpcrdma_version)
1429 goto out_badversion;
1431 if (rpcrdma_is_bcall(r_xprt, rep))
1434 /* Match incoming rpcrdma_rep to an rpcrdma_req to
1435 * get context for handling any incoming chunks.
1437 spin_lock(&xprt->queue_lock);
1438 rqst = xprt_lookup_rqst(xprt, rep->rr_xid);
1441 xprt_pin_rqst(rqst);
1442 spin_unlock(&xprt->queue_lock);
1445 credits = 1; /* don't deadlock */
1446 else if (credits > r_xprt->rx_ep->re_max_requests)
1447 credits = r_xprt->rx_ep->re_max_requests;
1448 if (buf->rb_credits != credits)
1449 rpcrdma_update_cwnd(r_xprt, credits);
1450 rpcrdma_post_recvs(r_xprt, false);
1452 req = rpcr_to_rdmar(rqst);
1453 if (req->rl_reply) {
1454 trace_xprtrdma_leaked_rep(rqst, req->rl_reply);
1455 rpcrdma_recv_buffer_put(req->rl_reply);
1457 req->rl_reply = rep;
1458 rep->rr_rqst = rqst;
1460 trace_xprtrdma_reply(rqst->rq_task, rep, req, credits);
1462 if (rep->rr_wc_flags & IB_WC_WITH_INVALIDATE)
1463 frwr_reminv(rep, &req->rl_registered);
1464 if (!list_empty(&req->rl_registered))
1465 frwr_unmap_async(r_xprt, req);
1466 /* LocalInv completion will complete the RPC */
1468 kref_put(&req->rl_kref, rpcrdma_reply_done);
1472 trace_xprtrdma_reply_vers(rep);
1476 spin_unlock(&xprt->queue_lock);
1477 trace_xprtrdma_reply_rqst(rep);
1481 trace_xprtrdma_reply_short(rep);
1484 rpcrdma_recv_buffer_put(rep);