/* * 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 "xprt_rdma.h" #include #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) # define RPCDBG_FACILITY RPCDBG_TRANS #endif static const char transfertypes[][12] = { "inline", /* no chunks */ "read list", /* some argument via rdma read */ "*read list", /* entire request via rdma read */ "write list", /* some result via rdma write */ "reply chunk" /* entire reply via rdma write */ }; /* 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 */ maxsegs += 2; /* segment for head and tail buffers */ 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 */ dprintk("RPC: %s: max call header size = %u\n", __func__, size); 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 */ maxsegs += 2; /* segment for head and tail buffers */ size = sizeof(__be32); /* segment count */ size += maxsegs * rpcrdma_segment_maxsz * sizeof(__be32); size += sizeof(__be32); /* list discriminator */ dprintk("RPC: %s: max reply header size = %u\n", __func__, size); return size; } void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data; struct rpcrdma_ia *ia = &r_xprt->rx_ia; unsigned int maxsegs = ia->ri_max_segs; ia->ri_max_inline_write = cdata->inline_wsize - rpcrdma_max_call_header_size(maxsegs); ia->ri_max_inline_read = cdata->inline_rsize - 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; unsigned int count, remaining, offset; if (xdr->len > r_xprt->rx_ia.ri_max_inline_write) 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 > r_xprt->rx_ia.ri_max_send_sges) 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) { struct rpcrdma_ia *ia = &r_xprt->rx_ia; return rqst->rq_rcv_buf.buflen <= ia->ri_max_inline_read; } /* 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) { if (unlikely(!*ppages)) { /* XXX: Certain upper layer operations do * not provide receive buffer pages. */ *ppages = alloc_page(GFP_ATOMIC); if (!*ppages) return -EAGAIN; } 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_ia.ri_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_ia.ri_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 inline int encode_item_present(struct xdr_stream *xdr) { __be32 *p; p = xdr_reserve_space(xdr, sizeof(*p)); if (unlikely(!p)) return -EMSGSIZE; *p = xdr_one; return 0; } static inline int encode_item_not_present(struct xdr_stream *xdr) { __be32 *p; p = xdr_reserve_space(xdr, sizeof(*p)); if (unlikely(!p)) return -EMSGSIZE; *p = xdr_zero; return 0; } static void xdr_encode_rdma_segment(__be32 *iptr, struct rpcrdma_mr *mr) { *iptr++ = cpu_to_be32(mr->mr_handle); *iptr++ = cpu_to_be32(mr->mr_length); xdr_encode_hyper(iptr, mr->mr_offset); } 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); 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 */ *p++ = cpu_to_be32(position); xdr_encode_rdma_segment(p, mr); return 0; } /* 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 noinline 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; 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 = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs, false, &mr); if (IS_ERR(seg)) goto out_maperr; rpcrdma_mr_push(mr, &req->rl_registered); if (encode_read_segment(xdr, mr, pos) < 0) return -EMSGSIZE; trace_xprtrdma_read_chunk(rqst->rq_task, pos, mr, nsegs); r_xprt->rx_stats.read_chunk_count++; nsegs -= mr->mr_nents; } while (nsegs); return 0; out_maperr: if (PTR_ERR(seg) == -EAGAIN) xprt_wait_for_buffer_space(rqst->rq_task, NULL); return PTR_ERR(seg); } /* 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 noinline 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; 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 (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 = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs, true, &mr); if (IS_ERR(seg)) goto out_maperr; rpcrdma_mr_push(mr, &req->rl_registered); if (encode_rdma_segment(xdr, mr) < 0) return -EMSGSIZE; trace_xprtrdma_write_chunk(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); return 0; out_maperr: if (PTR_ERR(seg) == -EAGAIN) xprt_wait_for_buffer_space(rqst->rq_task, NULL); return PTR_ERR(seg); } /* 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 noinline 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; seg = req->rl_segments; nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf, 0, wtype, seg); if (nsegs < 0) return nsegs; if (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 = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs, true, &mr); if (IS_ERR(seg)) goto out_maperr; rpcrdma_mr_push(mr, &req->rl_registered); if (encode_rdma_segment(xdr, mr) < 0) return -EMSGSIZE; trace_xprtrdma_reply_chunk(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; out_maperr: if (PTR_ERR(seg) == -EAGAIN) xprt_wait_for_buffer_space(rqst->rq_task, NULL); return PTR_ERR(seg); } /** * rpcrdma_unmap_sendctx - DMA-unmap Send buffers * @sc: sendctx containing SGEs to unmap * */ void rpcrdma_unmap_sendctx(struct rpcrdma_sendctx *sc) { struct rpcrdma_ia *ia = &sc->sc_xprt->rx_ia; struct ib_sge *sge; unsigned int count; /* The first two SGEs contain the transport header and * the inline buffer. These are always left mapped so * they can be cheaply re-used. */ sge = &sc->sc_sges[2]; for (count = sc->sc_unmap_count; count; ++sge, --count) ib_dma_unmap_page(ia->ri_device, sge->addr, sge->length, DMA_TO_DEVICE); if (test_and_clear_bit(RPCRDMA_REQ_F_TX_RESOURCES, &sc->sc_req->rl_flags)) { smp_mb__after_atomic(); wake_up_bit(&sc->sc_req->rl_flags, RPCRDMA_REQ_F_TX_RESOURCES); } } /* Prepare an SGE for the RPC-over-RDMA transport header. */ static bool rpcrdma_prepare_hdr_sge(struct rpcrdma_ia *ia, 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; if (!rpcrdma_dma_map_regbuf(ia, rb)) goto out_regbuf; 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); sc->sc_wr.num_sge++; return true; out_regbuf: pr_err("rpcrdma: failed to DMA map a Send buffer\n"); return false; } /* Prepare the Send SGEs. The head and tail iovec, and each entry * in the page list, gets its own SGE. */ static bool rpcrdma_prepare_msg_sges(struct rpcrdma_ia *ia, struct rpcrdma_req *req, struct xdr_buf *xdr, enum rpcrdma_chunktype rtype) { struct rpcrdma_sendctx *sc = req->rl_sendctx; unsigned int sge_no, page_base, len, remaining; struct rpcrdma_regbuf *rb = req->rl_sendbuf; struct ib_device *device = ia->ri_device; struct ib_sge *sge = sc->sc_sges; u32 lkey = ia->ri_pd->local_dma_lkey; struct page *page, **ppages; /* The head iovec is straightforward, as it is already * DMA-mapped. Sync the content that has changed. */ if (!rpcrdma_dma_map_regbuf(ia, rb)) goto out_regbuf; sge_no = 1; sge[sge_no].addr = rdmab_addr(rb); sge[sge_no].length = xdr->head[0].iov_len; sge[sge_no].lkey = rdmab_lkey(rb); ib_dma_sync_single_for_device(rdmab_device(rb), sge[sge_no].addr, sge[sge_no].length, DMA_TO_DEVICE); /* If there is a Read chunk, the page list is being handled * via explicit RDMA, and thus is skipped here. However, 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. */ if (rtype == rpcrdma_readch) { len = xdr->tail[0].iov_len; /* Do not include the tail if it is only an XDR pad */ if (len < 4) goto out; page = virt_to_page(xdr->tail[0].iov_base); page_base = offset_in_page(xdr->tail[0].iov_base); /* If the content in the page list is an odd length, * xdr_write_pages() has added 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 += len & 3; len -= len & 3; goto map_tail; } /* If there is a page list present, temporarily DMA map * and prepare an SGE for each page to be sent. */ if (xdr->page_len) { ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT); page_base = offset_in_page(xdr->page_base); remaining = xdr->page_len; while (remaining) { sge_no++; if (sge_no > RPCRDMA_MAX_SEND_SGES - 2) goto out_mapping_overflow; len = min_t(u32, PAGE_SIZE - page_base, remaining); sge[sge_no].addr = ib_dma_map_page(device, *ppages, page_base, len, DMA_TO_DEVICE); if (ib_dma_mapping_error(device, sge[sge_no].addr)) goto out_mapping_err; sge[sge_no].length = len; sge[sge_no].lkey = lkey; sc->sc_unmap_count++; ppages++; remaining -= len; page_base = 0; } } /* The tail iovec is not always constructed in the same * page where the head iovec resides (see, for example, * gss_wrap_req_priv). To neatly accommodate that case, * DMA map it separately. */ if (xdr->tail[0].iov_len) { page = virt_to_page(xdr->tail[0].iov_base); page_base = offset_in_page(xdr->tail[0].iov_base); len = xdr->tail[0].iov_len; map_tail: sge_no++; sge[sge_no].addr = ib_dma_map_page(device, page, page_base, len, DMA_TO_DEVICE); if (ib_dma_mapping_error(device, sge[sge_no].addr)) goto out_mapping_err; sge[sge_no].length = len; sge[sge_no].lkey = lkey; sc->sc_unmap_count++; } out: sc->sc_wr.num_sge += sge_no; if (sc->sc_unmap_count) __set_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags); return true; out_regbuf: pr_err("rpcrdma: failed to DMA map a Send buffer\n"); return false; out_mapping_overflow: rpcrdma_unmap_sendctx(sc); pr_err("rpcrdma: too many Send SGEs (%u)\n", sge_no); return false; out_mapping_err: rpcrdma_unmap_sendctx(sc); pr_err("rpcrdma: Send mapping error\n"); return false; } /** * 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. */ int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, u32 hdrlen, struct xdr_buf *xdr, enum rpcrdma_chunktype rtype) { req->rl_sendctx = rpcrdma_sendctx_get_locked(&r_xprt->rx_buf); if (!req->rl_sendctx) return -ENOBUFS; req->rl_sendctx->sc_wr.num_sge = 0; req->rl_sendctx->sc_unmap_count = 0; req->rl_sendctx->sc_req = req; __clear_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags); if (!rpcrdma_prepare_hdr_sge(&r_xprt->rx_ia, req, hdrlen)) return -EIO; if (rtype != rpcrdma_areadch) if (!rpcrdma_prepare_msg_sges(&r_xprt->rx_ia, req, xdr, rtype)) return -EIO; return 0; } /** * 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; bool ddp_allowed; __be32 *p; int ret; rpcrdma_set_xdrlen(&req->rl_hdrbuf, 0); xdr_init_encode(xdr, &req->rl_hdrbuf, req->rl_rdmabuf->rg_base); /* 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++ = cpu_to_be32(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 = !(rqst->rq_cred->cr_auth->au_flags & RPCAUTH_AUTH_DATATOUCH); /* * 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) 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 = rpcrdma_noch; } else if (ddp_allowed && rqst->rq_snd_buf.flags & XDRBUF_WRITE) { *p++ = rdma_msg; rtype = rpcrdma_readch; } else { r_xprt->rx_stats.nomsg_call_count++; *p++ = rdma_nomsg; rtype = rpcrdma_areadch; } /* If this is a retransmit, discard previously registered * chunks. Very likely the connection has been replaced, * so these registrations are invalid and unusable. */ while (unlikely(!list_empty(&req->rl_registered))) { struct rpcrdma_mr *mr; mr = rpcrdma_mr_pop(&req->rl_registered); rpcrdma_mr_defer_recovery(mr); } /* 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. */ if (rtype != rpcrdma_noch) { ret = rpcrdma_encode_read_list(r_xprt, req, rqst, rtype); if (ret) goto out_err; } ret = encode_item_not_present(xdr); if (ret) goto out_err; if (wtype == rpcrdma_writech) { ret = rpcrdma_encode_write_list(r_xprt, req, rqst, wtype); if (ret) goto out_err; } ret = encode_item_not_present(xdr); if (ret) goto out_err; if (wtype != rpcrdma_replych) ret = encode_item_not_present(xdr); else ret = rpcrdma_encode_reply_chunk(r_xprt, req, rqst, wtype); if (ret) goto out_err; trace_xprtrdma_marshal(rqst, xdr_stream_pos(xdr), rtype, wtype); ret = rpcrdma_prepare_send_sges(r_xprt, req, xdr_stream_pos(xdr), &rqst->rq_snd_buf, rtype); if (ret) goto out_err; return 0; out_err: r_xprt->rx_stats.failed_marshal_count++; return ret; } /** * 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; trace_xprtrdma_fixup(rqst, copy_len, curlen); 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; trace_xprtrdma_fixup_pg(rqst, i, srcp, copy_len, curlen); 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; } 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 (*p++ != xdr_zero) return false; if (*p++ != xdr_zero) return false; if (*p++ != xdr_zero) 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"); if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, rep)) xprt_disconnect_done(&r_xprt->rx_xprt); 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; handle = be32_to_cpup(p++); *length = be32_to_cpup(p++); xdr_decode_hyper(p, &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(*p != xdr_zero)) 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 (*p == xdr_zero) 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 (*p != xdr_zero) 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: %5u: %s: server reports version error (%u-%u)\n", rqst->rq_task->tk_pid, __func__, be32_to_cpup(p), be32_to_cpu(*(p + 1))); break; case err_chunk: dprintk("RPC: %5u: %s: server reports header decoding error\n", rqst->rq_task->tk_pid, __func__); break; default: dprintk("RPC: %5u: %s: server reports unrecognized error %d\n", rqst->rq_task->tk_pid, __func__, be32_to_cpup(p)); } r_xprt->rx_stats.bad_reply_count++; return -EREMOTEIO; } /* 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; unsigned long cwnd; int status; xprt->reestablish_timeout = 0; 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->recv_lock); cwnd = xprt->cwnd; xprt->cwnd = r_xprt->rx_buf.rb_credits << RPC_CWNDSHIFT; if (xprt->cwnd > cwnd) xprt_release_rqst_cong(rqst->rq_task); xprt_complete_rqst(rqst->rq_task, status); xprt_unpin_rqst(rqst); spin_unlock(&xprt->recv_lock); return; /* If the incoming reply terminated a pending RPC, the next * RPC call will post a replacement receive buffer as it is * being marshaled. */ out_badheader: trace_xprtrdma_reply_hdr(rep); r_xprt->rx_stats.bad_reply_count++; status = -EIO; goto out; } void rpcrdma_release_rqst(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req) { /* Invalidate and unmap the data payloads before waking * the waiting application. This guarantees the memory * regions are properly fenced from the server before the * application accesses the data. It also ensures proper * send flow control: waking the next RPC waits until this * RPC has relinquished all its Send Queue entries. */ if (!list_empty(&req->rl_registered)) r_xprt->rx_ia.ri_ops->ro_unmap_sync(r_xprt, &req->rl_registered); /* Ensure that any DMA mapped pages associated with * the Send of the RPC Call have been unmapped before * allowing the RPC to complete. This protects argument * memory not controlled by the RPC client from being * re-used before we're done with it. */ if (test_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags)) { r_xprt->rx_stats.reply_waits_for_send++; out_of_line_wait_on_bit(&req->rl_flags, RPCRDMA_REQ_F_TX_RESOURCES, bit_wait, TASK_UNINTERRUPTIBLE); } } /* Reply handling runs in the poll worker thread. Anything that * might wait is deferred to a separate workqueue. */ void rpcrdma_deferred_completion(struct work_struct *work) { struct rpcrdma_rep *rep = container_of(work, struct rpcrdma_rep, rr_work); struct rpcrdma_req *req = rpcr_to_rdmar(rep->rr_rqst); struct rpcrdma_xprt *r_xprt = rep->rr_rxprt; trace_xprtrdma_defer_cmp(rep); if (rep->rr_wc_flags & IB_WC_WITH_INVALIDATE) r_xprt->rx_ia.ri_ops->ro_reminv(rep, &req->rl_registered); rpcrdma_release_rqst(r_xprt, req); rpcrdma_complete_rqst(rep); } /* Process received RPC/RDMA messages. * * 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; if (rep->rr_hdrbuf.head[0].iov_len == 0) goto out_badstatus; xdr_init_decode(&rep->rr_stream, &rep->rr_hdrbuf, rep->rr_hdrbuf.head[0].iov_base); /* Fixed transport header fields */ 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->recv_lock); rqst = xprt_lookup_rqst(xprt, rep->rr_xid); if (!rqst) goto out_norqst; xprt_pin_rqst(rqst); if (credits == 0) credits = 1; /* don't deadlock */ else if (credits > buf->rb_max_requests) credits = buf->rb_max_requests; buf->rb_credits = credits; spin_unlock(&xprt->recv_lock); req = rpcr_to_rdmar(rqst); req->rl_reply = rep; rep->rr_rqst = rqst; clear_bit(RPCRDMA_REQ_F_PENDING, &req->rl_flags); trace_xprtrdma_reply(rqst->rq_task, rep, req, credits); queue_work(rpcrdma_receive_wq, &rep->rr_work); return; out_badstatus: rpcrdma_recv_buffer_put(rep); if (r_xprt->rx_ep.rep_connected == 1) { r_xprt->rx_ep.rep_connected = -EIO; rpcrdma_conn_func(&r_xprt->rx_ep); } return; out_badversion: trace_xprtrdma_reply_vers(rep); goto repost; /* The RPC transaction has already been terminated, or the header * is corrupt. */ out_norqst: spin_unlock(&xprt->recv_lock); trace_xprtrdma_reply_rqst(rep); goto repost; out_shortreply: trace_xprtrdma_reply_short(rep); /* If no pending RPC transaction was matched, post a replacement * receive buffer before returning. */ repost: r_xprt->rx_stats.bad_reply_count++; if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, rep)) rpcrdma_recv_buffer_put(rep); }