// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause /* * Copyright (c) 2014-2017 Oracle. All rights reserved. * 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 #include #include "xprt_rdma.h" #include #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) # define RPCDBG_FACILITY RPCDBG_TRANS #endif /* 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; } /* Split @vec on page boundaries into SGEs. FMR registers pages, not * a byte range. Other modes coalesce these SGEs into a single MR * when they can. * * 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) { u32 remaining, page_offset; char *base; base = vec->iov_base; page_offset = offset_in_page(base); remaining = vec->iov_len; while (remaining) { seg->mr_page = NULL; seg->mr_offset = base; seg->mr_len = min_t(u32, PAGE_SIZE - page_offset, remaining); remaining -= seg->mr_len; base += seg->mr_len; ++seg; ++(*n); page_offset = 0; } 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 = (char *)page_base; seg->mr_len = min_t(u32, PAGE_SIZE - page_base, len); len -= seg->mr_len; ++ppages; ++seg; ++n; page_base = 0; } /* When encoding a Read chunk, the tail iovec contains an * XDR pad and may be omitted. */ if (type == rpcrdma_readch && r_xprt->rx_ep->re_implicit_roundup) goto out; /* When encoding a Write chunk, some servers need to see an * extra segment for non-XDR-aligned Write chunks. The upper * layer provides space in the tail iovec that may be used * for this purpose. */ if (type == rpcrdma_writech && r_xprt->rx_ep->re_implicit_roundup) goto out; if (xdrbuf->tail[0].iov_len) seg = 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; trace_xprtrdma_mr_get(req); (*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(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_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); /* 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 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; /* 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)) goto out_short; rpcrdma_bc_receive_call(r_xprt, rep); return true; out_short: pr_warn("RPC/RDMA short backward direction call\n"); 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; dprintk("RPC: %s: server reports " "version error (%u-%u), xid %08x\n", __func__, be32_to_cpup(p), be32_to_cpu(*(p + 1)), be32_to_cpu(rep->rr_xid)); break; case err_chunk: dprintk("RPC: %s: server reports " "header decoding error, xid %08x\n", __func__, be32_to_cpu(rep->rr_xid)); break; default: dprintk("RPC: %s: server reports " "unrecognized error %d, xid %08x\n", __func__, be32_to_cpup(p), be32_to_cpu(rep->rr_xid)); } return -EIO; } /* Perform XID lookup, reconstruction of the RPC reply, and * RPC completion while holding the transport lock 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(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; if (buf->rb_credits != credits) rpcrdma_update_cwnd(r_xprt, credits); rpcrdma_post_recvs(r_xprt, false); req = rpcr_to_rdmar(rqst); if (req->rl_reply) { trace_xprtrdma_leaked_rep(rqst, req->rl_reply); rpcrdma_recv_buffer_put(req->rl_reply); } req->rl_reply = rep; rep->rr_rqst = rqst; trace_xprtrdma_reply(rqst->rq_task, rep, req, 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(rep); goto out; out_norqst: spin_unlock(&xprt->queue_lock); trace_xprtrdma_reply_rqst(rep); goto out; out_shortreply: trace_xprtrdma_reply_short(rep); out: rpcrdma_recv_buffer_put(rep); }