// SPDX-License-Identifier: GPL-2.0 /* * Copyright (c) 2016-2018 Oracle. All rights reserved. * * Use the core R/W API to move RPC-over-RDMA Read and Write chunks. */ #include #include #include #include #include "xprt_rdma.h" #include static void svc_rdma_write_done(struct ib_cq *cq, struct ib_wc *wc); static void svc_rdma_wc_read_done(struct ib_cq *cq, struct ib_wc *wc); /* Each R/W context contains state for one chain of RDMA Read or * Write Work Requests. * * Each WR chain handles a single contiguous server-side buffer, * because scatterlist entries after the first have to start on * page alignment. xdr_buf iovecs cannot guarantee alignment. * * Each WR chain handles only one R_key. Each RPC-over-RDMA segment * from a client may contain a unique R_key, so each WR chain moves * up to one segment at a time. * * The scatterlist makes this data structure over 4KB in size. To * make it less likely to fail, and to handle the allocation for * smaller I/O requests without disabling bottom-halves, these * contexts are created on demand, but cached and reused until the * controlling svcxprt_rdma is destroyed. */ struct svc_rdma_rw_ctxt { struct list_head rw_list; struct rdma_rw_ctx rw_ctx; unsigned int rw_nents; struct sg_table rw_sg_table; struct scatterlist rw_first_sgl[]; }; static inline struct svc_rdma_rw_ctxt * svc_rdma_next_ctxt(struct list_head *list) { return list_first_entry_or_null(list, struct svc_rdma_rw_ctxt, rw_list); } static struct svc_rdma_rw_ctxt * svc_rdma_get_rw_ctxt(struct svcxprt_rdma *rdma, unsigned int sges) { struct svc_rdma_rw_ctxt *ctxt; spin_lock(&rdma->sc_rw_ctxt_lock); ctxt = svc_rdma_next_ctxt(&rdma->sc_rw_ctxts); if (ctxt) { list_del(&ctxt->rw_list); spin_unlock(&rdma->sc_rw_ctxt_lock); } else { spin_unlock(&rdma->sc_rw_ctxt_lock); ctxt = kmalloc(struct_size(ctxt, rw_first_sgl, SG_CHUNK_SIZE), GFP_KERNEL); if (!ctxt) goto out_noctx; INIT_LIST_HEAD(&ctxt->rw_list); } ctxt->rw_sg_table.sgl = ctxt->rw_first_sgl; if (sg_alloc_table_chained(&ctxt->rw_sg_table, sges, ctxt->rw_sg_table.sgl, SG_CHUNK_SIZE)) goto out_free; return ctxt; out_free: kfree(ctxt); out_noctx: trace_svcrdma_no_rwctx_err(rdma, sges); return NULL; } static void svc_rdma_put_rw_ctxt(struct svcxprt_rdma *rdma, struct svc_rdma_rw_ctxt *ctxt) { sg_free_table_chained(&ctxt->rw_sg_table, SG_CHUNK_SIZE); spin_lock(&rdma->sc_rw_ctxt_lock); list_add(&ctxt->rw_list, &rdma->sc_rw_ctxts); spin_unlock(&rdma->sc_rw_ctxt_lock); } /** * svc_rdma_destroy_rw_ctxts - Free accumulated R/W contexts * @rdma: transport about to be destroyed * */ void svc_rdma_destroy_rw_ctxts(struct svcxprt_rdma *rdma) { struct svc_rdma_rw_ctxt *ctxt; while ((ctxt = svc_rdma_next_ctxt(&rdma->sc_rw_ctxts)) != NULL) { list_del(&ctxt->rw_list); kfree(ctxt); } } /** * svc_rdma_rw_ctx_init - Prepare a R/W context for I/O * @rdma: controlling transport instance * @ctxt: R/W context to prepare * @offset: RDMA offset * @handle: RDMA tag/handle * @direction: I/O direction * * Returns on success, the number of WQEs that will be needed * on the workqueue, or a negative errno. */ static int svc_rdma_rw_ctx_init(struct svcxprt_rdma *rdma, struct svc_rdma_rw_ctxt *ctxt, u64 offset, u32 handle, enum dma_data_direction direction) { int ret; ret = rdma_rw_ctx_init(&ctxt->rw_ctx, rdma->sc_qp, rdma->sc_port_num, ctxt->rw_sg_table.sgl, ctxt->rw_nents, 0, offset, handle, direction); if (unlikely(ret < 0)) { svc_rdma_put_rw_ctxt(rdma, ctxt); trace_svcrdma_dma_map_rw_err(rdma, ctxt->rw_nents, ret); } return ret; } /* A chunk context tracks all I/O for moving one Read or Write * chunk. This is a set of rdma_rw's that handle data movement * for all segments of one chunk. * * These are small, acquired with a single allocator call, and * no more than one is needed per chunk. They are allocated on * demand, and not cached. */ struct svc_rdma_chunk_ctxt { struct rpc_rdma_cid cc_cid; struct ib_cqe cc_cqe; struct svcxprt_rdma *cc_rdma; struct list_head cc_rwctxts; int cc_sqecount; enum ib_wc_status cc_status; struct completion cc_done; }; static void svc_rdma_cc_cid_init(struct svcxprt_rdma *rdma, struct rpc_rdma_cid *cid) { cid->ci_queue_id = rdma->sc_sq_cq->res.id; cid->ci_completion_id = atomic_inc_return(&rdma->sc_completion_ids); } static void svc_rdma_cc_init(struct svcxprt_rdma *rdma, struct svc_rdma_chunk_ctxt *cc) { svc_rdma_cc_cid_init(rdma, &cc->cc_cid); cc->cc_rdma = rdma; INIT_LIST_HEAD(&cc->cc_rwctxts); cc->cc_sqecount = 0; } static void svc_rdma_cc_release(struct svc_rdma_chunk_ctxt *cc, enum dma_data_direction dir) { struct svcxprt_rdma *rdma = cc->cc_rdma; struct svc_rdma_rw_ctxt *ctxt; while ((ctxt = svc_rdma_next_ctxt(&cc->cc_rwctxts)) != NULL) { list_del(&ctxt->rw_list); rdma_rw_ctx_destroy(&ctxt->rw_ctx, rdma->sc_qp, rdma->sc_port_num, ctxt->rw_sg_table.sgl, ctxt->rw_nents, dir); svc_rdma_put_rw_ctxt(rdma, ctxt); } } /* State for sending a Write or Reply chunk. * - Tracks progress of writing one chunk over all its segments * - Stores arguments for the SGL constructor functions */ struct svc_rdma_write_info { const struct svc_rdma_chunk *wi_chunk; /* write state of this chunk */ unsigned int wi_seg_off; unsigned int wi_seg_no; /* SGL constructor arguments */ const struct xdr_buf *wi_xdr; unsigned char *wi_base; unsigned int wi_next_off; struct svc_rdma_chunk_ctxt wi_cc; }; static struct svc_rdma_write_info * svc_rdma_write_info_alloc(struct svcxprt_rdma *rdma, const struct svc_rdma_chunk *chunk) { struct svc_rdma_write_info *info; info = kmalloc(sizeof(*info), GFP_KERNEL); if (!info) return info; info->wi_chunk = chunk; info->wi_seg_off = 0; info->wi_seg_no = 0; svc_rdma_cc_init(rdma, &info->wi_cc); info->wi_cc.cc_cqe.done = svc_rdma_write_done; return info; } static void svc_rdma_write_info_free(struct svc_rdma_write_info *info) { svc_rdma_cc_release(&info->wi_cc, DMA_TO_DEVICE); kfree(info); } /** * svc_rdma_write_done - Write chunk completion * @cq: controlling Completion Queue * @wc: Work Completion * * Pages under I/O are freed by a subsequent Send completion. */ static void svc_rdma_write_done(struct ib_cq *cq, struct ib_wc *wc) { struct ib_cqe *cqe = wc->wr_cqe; struct svc_rdma_chunk_ctxt *cc = container_of(cqe, struct svc_rdma_chunk_ctxt, cc_cqe); struct svcxprt_rdma *rdma = cc->cc_rdma; struct svc_rdma_write_info *info = container_of(cc, struct svc_rdma_write_info, wi_cc); trace_svcrdma_wc_write(wc, &cc->cc_cid); atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail); wake_up(&rdma->sc_send_wait); if (unlikely(wc->status != IB_WC_SUCCESS)) svc_xprt_deferred_close(&rdma->sc_xprt); svc_rdma_write_info_free(info); } /* State for pulling a Read chunk. */ struct svc_rdma_read_info { struct svc_rqst *ri_rqst; struct svc_rdma_recv_ctxt *ri_readctxt; unsigned int ri_pageno; unsigned int ri_pageoff; unsigned int ri_totalbytes; struct svc_rdma_chunk_ctxt ri_cc; }; static struct svc_rdma_read_info * svc_rdma_read_info_alloc(struct svcxprt_rdma *rdma) { struct svc_rdma_read_info *info; info = kmalloc(sizeof(*info), GFP_KERNEL); if (!info) return info; svc_rdma_cc_init(rdma, &info->ri_cc); info->ri_cc.cc_cqe.done = svc_rdma_wc_read_done; return info; } static void svc_rdma_read_info_free(struct svc_rdma_read_info *info) { svc_rdma_cc_release(&info->ri_cc, DMA_FROM_DEVICE); kfree(info); } /** * svc_rdma_wc_read_done - Handle completion of an RDMA Read ctx * @cq: controlling Completion Queue * @wc: Work Completion * */ static void svc_rdma_wc_read_done(struct ib_cq *cq, struct ib_wc *wc) { struct ib_cqe *cqe = wc->wr_cqe; struct svc_rdma_chunk_ctxt *cc = container_of(cqe, struct svc_rdma_chunk_ctxt, cc_cqe); struct svcxprt_rdma *rdma = cc->cc_rdma; trace_svcrdma_wc_read(wc, &cc->cc_cid); atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail); wake_up(&rdma->sc_send_wait); cc->cc_status = wc->status; complete(&cc->cc_done); return; } /* This function sleeps when the transport's Send Queue is congested. * * Assumptions: * - If ib_post_send() succeeds, only one completion is expected, * even if one or more WRs are flushed. This is true when posting * an rdma_rw_ctx or when posting a single signaled WR. */ static int svc_rdma_post_chunk_ctxt(struct svc_rdma_chunk_ctxt *cc) { struct svcxprt_rdma *rdma = cc->cc_rdma; struct ib_send_wr *first_wr; const struct ib_send_wr *bad_wr; struct list_head *tmp; struct ib_cqe *cqe; int ret; if (cc->cc_sqecount > rdma->sc_sq_depth) return -EINVAL; first_wr = NULL; cqe = &cc->cc_cqe; list_for_each(tmp, &cc->cc_rwctxts) { struct svc_rdma_rw_ctxt *ctxt; ctxt = list_entry(tmp, struct svc_rdma_rw_ctxt, rw_list); first_wr = rdma_rw_ctx_wrs(&ctxt->rw_ctx, rdma->sc_qp, rdma->sc_port_num, cqe, first_wr); cqe = NULL; } do { if (atomic_sub_return(cc->cc_sqecount, &rdma->sc_sq_avail) > 0) { ret = ib_post_send(rdma->sc_qp, first_wr, &bad_wr); if (ret) break; return 0; } percpu_counter_inc(&svcrdma_stat_sq_starve); trace_svcrdma_sq_full(rdma); atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail); wait_event(rdma->sc_send_wait, atomic_read(&rdma->sc_sq_avail) > cc->cc_sqecount); trace_svcrdma_sq_retry(rdma); } while (1); trace_svcrdma_sq_post_err(rdma, ret); svc_xprt_deferred_close(&rdma->sc_xprt); /* If even one was posted, there will be a completion. */ if (bad_wr != first_wr) return 0; atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail); wake_up(&rdma->sc_send_wait); return -ENOTCONN; } /* Build and DMA-map an SGL that covers one kvec in an xdr_buf */ static void svc_rdma_vec_to_sg(struct svc_rdma_write_info *info, unsigned int len, struct svc_rdma_rw_ctxt *ctxt) { struct scatterlist *sg = ctxt->rw_sg_table.sgl; sg_set_buf(&sg[0], info->wi_base, len); info->wi_base += len; ctxt->rw_nents = 1; } /* Build and DMA-map an SGL that covers part of an xdr_buf's pagelist. */ static void svc_rdma_pagelist_to_sg(struct svc_rdma_write_info *info, unsigned int remaining, struct svc_rdma_rw_ctxt *ctxt) { unsigned int sge_no, sge_bytes, page_off, page_no; const struct xdr_buf *xdr = info->wi_xdr; struct scatterlist *sg; struct page **page; page_off = info->wi_next_off + xdr->page_base; page_no = page_off >> PAGE_SHIFT; page_off = offset_in_page(page_off); page = xdr->pages + page_no; info->wi_next_off += remaining; sg = ctxt->rw_sg_table.sgl; sge_no = 0; do { sge_bytes = min_t(unsigned int, remaining, PAGE_SIZE - page_off); sg_set_page(sg, *page, sge_bytes, page_off); remaining -= sge_bytes; sg = sg_next(sg); page_off = 0; sge_no++; page++; } while (remaining); ctxt->rw_nents = sge_no; } /* Construct RDMA Write WRs to send a portion of an xdr_buf containing * an RPC Reply. */ static int svc_rdma_build_writes(struct svc_rdma_write_info *info, void (*constructor)(struct svc_rdma_write_info *info, unsigned int len, struct svc_rdma_rw_ctxt *ctxt), unsigned int remaining) { struct svc_rdma_chunk_ctxt *cc = &info->wi_cc; struct svcxprt_rdma *rdma = cc->cc_rdma; const struct svc_rdma_segment *seg; struct svc_rdma_rw_ctxt *ctxt; int ret; do { unsigned int write_len; u64 offset; seg = &info->wi_chunk->ch_segments[info->wi_seg_no]; if (!seg) goto out_overflow; write_len = min(remaining, seg->rs_length - info->wi_seg_off); if (!write_len) goto out_overflow; ctxt = svc_rdma_get_rw_ctxt(rdma, (write_len >> PAGE_SHIFT) + 2); if (!ctxt) return -ENOMEM; constructor(info, write_len, ctxt); offset = seg->rs_offset + info->wi_seg_off; ret = svc_rdma_rw_ctx_init(rdma, ctxt, offset, seg->rs_handle, DMA_TO_DEVICE); if (ret < 0) return -EIO; percpu_counter_inc(&svcrdma_stat_write); list_add(&ctxt->rw_list, &cc->cc_rwctxts); cc->cc_sqecount += ret; if (write_len == seg->rs_length - info->wi_seg_off) { info->wi_seg_no++; info->wi_seg_off = 0; } else { info->wi_seg_off += write_len; } remaining -= write_len; } while (remaining); return 0; out_overflow: trace_svcrdma_small_wrch_err(rdma, remaining, info->wi_seg_no, info->wi_chunk->ch_segcount); return -E2BIG; } /** * svc_rdma_iov_write - Construct RDMA Writes from an iov * @info: pointer to write arguments * @iov: kvec to write * * Returns: * On success, returns zero * %-E2BIG if the client-provided Write chunk is too small * %-ENOMEM if a resource has been exhausted * %-EIO if an rdma-rw error occurred */ static int svc_rdma_iov_write(struct svc_rdma_write_info *info, const struct kvec *iov) { info->wi_base = iov->iov_base; return svc_rdma_build_writes(info, svc_rdma_vec_to_sg, iov->iov_len); } /** * svc_rdma_pages_write - Construct RDMA Writes from pages * @info: pointer to write arguments * @xdr: xdr_buf with pages to write * @offset: offset into the content of @xdr * @length: number of bytes to write * * Returns: * On success, returns zero * %-E2BIG if the client-provided Write chunk is too small * %-ENOMEM if a resource has been exhausted * %-EIO if an rdma-rw error occurred */ static int svc_rdma_pages_write(struct svc_rdma_write_info *info, const struct xdr_buf *xdr, unsigned int offset, unsigned long length) { info->wi_xdr = xdr; info->wi_next_off = offset - xdr->head[0].iov_len; return svc_rdma_build_writes(info, svc_rdma_pagelist_to_sg, length); } /** * svc_rdma_xb_write - Construct RDMA Writes to write an xdr_buf * @xdr: xdr_buf to write * @data: pointer to write arguments * * Returns: * On success, returns zero * %-E2BIG if the client-provided Write chunk is too small * %-ENOMEM if a resource has been exhausted * %-EIO if an rdma-rw error occurred */ static int svc_rdma_xb_write(const struct xdr_buf *xdr, void *data) { struct svc_rdma_write_info *info = data; int ret; if (xdr->head[0].iov_len) { ret = svc_rdma_iov_write(info, &xdr->head[0]); if (ret < 0) return ret; } if (xdr->page_len) { ret = svc_rdma_pages_write(info, xdr, xdr->head[0].iov_len, xdr->page_len); if (ret < 0) return ret; } if (xdr->tail[0].iov_len) { ret = svc_rdma_iov_write(info, &xdr->tail[0]); if (ret < 0) return ret; } return xdr->len; } /** * svc_rdma_send_write_chunk - Write all segments in a Write chunk * @rdma: controlling RDMA transport * @chunk: Write chunk provided by the client * @xdr: xdr_buf containing the data payload * * Returns a non-negative number of bytes the chunk consumed, or * %-E2BIG if the payload was larger than the Write chunk, * %-EINVAL if client provided too many segments, * %-ENOMEM if rdma_rw context pool was exhausted, * %-ENOTCONN if posting failed (connection is lost), * %-EIO if rdma_rw initialization failed (DMA mapping, etc). */ int svc_rdma_send_write_chunk(struct svcxprt_rdma *rdma, const struct svc_rdma_chunk *chunk, const struct xdr_buf *xdr) { struct svc_rdma_write_info *info; struct svc_rdma_chunk_ctxt *cc; int ret; info = svc_rdma_write_info_alloc(rdma, chunk); if (!info) return -ENOMEM; cc = &info->wi_cc; ret = svc_rdma_xb_write(xdr, info); if (ret != xdr->len) goto out_err; trace_svcrdma_post_write_chunk(&cc->cc_cid, cc->cc_sqecount); ret = svc_rdma_post_chunk_ctxt(cc); if (ret < 0) goto out_err; return xdr->len; out_err: svc_rdma_write_info_free(info); return ret; } /** * svc_rdma_send_reply_chunk - Write all segments in the Reply chunk * @rdma: controlling RDMA transport * @rctxt: Write and Reply chunks from client * @xdr: xdr_buf containing an RPC Reply * * Returns a non-negative number of bytes the chunk consumed, or * %-E2BIG if the payload was larger than the Reply chunk, * %-EINVAL if client provided too many segments, * %-ENOMEM if rdma_rw context pool was exhausted, * %-ENOTCONN if posting failed (connection is lost), * %-EIO if rdma_rw initialization failed (DMA mapping, etc). */ int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma, const struct svc_rdma_recv_ctxt *rctxt, const struct xdr_buf *xdr) { struct svc_rdma_write_info *info; struct svc_rdma_chunk_ctxt *cc; struct svc_rdma_chunk *chunk; int ret; if (pcl_is_empty(&rctxt->rc_reply_pcl)) return 0; chunk = pcl_first_chunk(&rctxt->rc_reply_pcl); info = svc_rdma_write_info_alloc(rdma, chunk); if (!info) return -ENOMEM; cc = &info->wi_cc; ret = pcl_process_nonpayloads(&rctxt->rc_write_pcl, xdr, svc_rdma_xb_write, info); if (ret < 0) goto out_err; trace_svcrdma_post_reply_chunk(&cc->cc_cid, cc->cc_sqecount); ret = svc_rdma_post_chunk_ctxt(cc); if (ret < 0) goto out_err; return xdr->len; out_err: svc_rdma_write_info_free(info); return ret; } /** * svc_rdma_build_read_segment - Build RDMA Read WQEs to pull one RDMA segment * @info: context for ongoing I/O * @segment: co-ordinates of remote memory to be read * * Returns: * %0: the Read WR chain was constructed successfully * %-EINVAL: there were not enough rq_pages to finish * %-ENOMEM: allocating a local resources failed * %-EIO: a DMA mapping error occurred */ static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info, const struct svc_rdma_segment *segment) { struct svc_rdma_recv_ctxt *head = info->ri_readctxt; struct svc_rdma_chunk_ctxt *cc = &info->ri_cc; struct svc_rqst *rqstp = info->ri_rqst; unsigned int sge_no, seg_len, len; struct svc_rdma_rw_ctxt *ctxt; struct scatterlist *sg; int ret; len = segment->rs_length; sge_no = PAGE_ALIGN(info->ri_pageoff + len) >> PAGE_SHIFT; ctxt = svc_rdma_get_rw_ctxt(cc->cc_rdma, sge_no); if (!ctxt) return -ENOMEM; ctxt->rw_nents = sge_no; sg = ctxt->rw_sg_table.sgl; for (sge_no = 0; sge_no < ctxt->rw_nents; sge_no++) { seg_len = min_t(unsigned int, len, PAGE_SIZE - info->ri_pageoff); if (!info->ri_pageoff) head->rc_page_count++; sg_set_page(sg, rqstp->rq_pages[info->ri_pageno], seg_len, info->ri_pageoff); sg = sg_next(sg); info->ri_pageoff += seg_len; if (info->ri_pageoff == PAGE_SIZE) { info->ri_pageno++; info->ri_pageoff = 0; } len -= seg_len; /* Safety check */ if (len && &rqstp->rq_pages[info->ri_pageno + 1] > rqstp->rq_page_end) goto out_overrun; } ret = svc_rdma_rw_ctx_init(cc->cc_rdma, ctxt, segment->rs_offset, segment->rs_handle, DMA_FROM_DEVICE); if (ret < 0) return -EIO; percpu_counter_inc(&svcrdma_stat_read); list_add(&ctxt->rw_list, &cc->cc_rwctxts); cc->cc_sqecount += ret; return 0; out_overrun: trace_svcrdma_page_overrun_err(cc->cc_rdma, rqstp, info->ri_pageno); return -EINVAL; } /** * svc_rdma_build_read_chunk - Build RDMA Read WQEs to pull one RDMA chunk * @info: context for ongoing I/O * @chunk: Read chunk to pull * * Return values: * %0: the Read WR chain was constructed successfully * %-EINVAL: there were not enough resources to finish * %-ENOMEM: allocating a local resources failed * %-EIO: a DMA mapping error occurred */ static int svc_rdma_build_read_chunk(struct svc_rdma_read_info *info, const struct svc_rdma_chunk *chunk) { const struct svc_rdma_segment *segment; int ret; ret = -EINVAL; pcl_for_each_segment(segment, chunk) { ret = svc_rdma_build_read_segment(info, segment); if (ret < 0) break; info->ri_totalbytes += segment->rs_length; } return ret; } /** * svc_rdma_copy_inline_range - Copy part of the inline content into pages * @info: context for RDMA Reads * @offset: offset into the Receive buffer of region to copy * @remaining: length of region to copy * * Take a page at a time from rqstp->rq_pages and copy the inline * content from the Receive buffer into that page. Update * info->ri_pageno and info->ri_pageoff so that the next RDMA Read * result will land contiguously with the copied content. * * Return values: * %0: Inline content was successfully copied * %-EINVAL: offset or length was incorrect */ static int svc_rdma_copy_inline_range(struct svc_rdma_read_info *info, unsigned int offset, unsigned int remaining) { struct svc_rdma_recv_ctxt *head = info->ri_readctxt; unsigned char *dst, *src = head->rc_recv_buf; struct svc_rqst *rqstp = info->ri_rqst; unsigned int page_no, numpages; numpages = PAGE_ALIGN(info->ri_pageoff + remaining) >> PAGE_SHIFT; for (page_no = 0; page_no < numpages; page_no++) { unsigned int page_len; page_len = min_t(unsigned int, remaining, PAGE_SIZE - info->ri_pageoff); if (!info->ri_pageoff) head->rc_page_count++; dst = page_address(rqstp->rq_pages[info->ri_pageno]); memcpy(dst + info->ri_pageno, src + offset, page_len); info->ri_totalbytes += page_len; info->ri_pageoff += page_len; if (info->ri_pageoff == PAGE_SIZE) { info->ri_pageno++; info->ri_pageoff = 0; } remaining -= page_len; offset += page_len; } return -EINVAL; } /** * svc_rdma_read_multiple_chunks - Construct RDMA Reads to pull data item Read chunks * @info: context for RDMA Reads * * The chunk data lands in rqstp->rq_arg as a series of contiguous pages, * like an incoming TCP call. * * Return values: * %0: RDMA Read WQEs were successfully built * %-EINVAL: client provided too many chunks or segments, * %-ENOMEM: rdma_rw context pool was exhausted, * %-ENOTCONN: posting failed (connection is lost), * %-EIO: rdma_rw initialization failed (DMA mapping, etc). */ static noinline int svc_rdma_read_multiple_chunks(struct svc_rdma_read_info *info) { struct svc_rdma_recv_ctxt *head = info->ri_readctxt; const struct svc_rdma_pcl *pcl = &head->rc_read_pcl; struct xdr_buf *buf = &info->ri_rqst->rq_arg; struct svc_rdma_chunk *chunk, *next; unsigned int start, length; int ret; start = 0; chunk = pcl_first_chunk(pcl); length = chunk->ch_position; ret = svc_rdma_copy_inline_range(info, start, length); if (ret < 0) return ret; pcl_for_each_chunk(chunk, pcl) { ret = svc_rdma_build_read_chunk(info, chunk); if (ret < 0) return ret; next = pcl_next_chunk(pcl, chunk); if (!next) break; start += length; length = next->ch_position - info->ri_totalbytes; ret = svc_rdma_copy_inline_range(info, start, length); if (ret < 0) return ret; } start += length; length = head->rc_byte_len - start; ret = svc_rdma_copy_inline_range(info, start, length); if (ret < 0) return ret; buf->len += info->ri_totalbytes; buf->buflen += info->ri_totalbytes; buf->head[0].iov_base = page_address(info->ri_rqst->rq_pages[0]); buf->head[0].iov_len = min_t(size_t, PAGE_SIZE, info->ri_totalbytes); buf->pages = &info->ri_rqst->rq_pages[1]; buf->page_len = info->ri_totalbytes - buf->head[0].iov_len; return 0; } /** * svc_rdma_read_data_item - Construct RDMA Reads to pull data item Read chunks * @info: context for RDMA Reads * * The chunk data lands in the page list of rqstp->rq_arg.pages. * * Currently NFSD does not look at the rqstp->rq_arg.tail[0] kvec. * Therefore, XDR round-up of the Read chunk and trailing * inline content must both be added at the end of the pagelist. * * Return values: * %0: RDMA Read WQEs were successfully built * %-EINVAL: client provided too many chunks or segments, * %-ENOMEM: rdma_rw context pool was exhausted, * %-ENOTCONN: posting failed (connection is lost), * %-EIO: rdma_rw initialization failed (DMA mapping, etc). */ static int svc_rdma_read_data_item(struct svc_rdma_read_info *info) { struct svc_rdma_recv_ctxt *head = info->ri_readctxt; struct xdr_buf *buf = &info->ri_rqst->rq_arg; struct svc_rdma_chunk *chunk; unsigned int length; int ret; chunk = pcl_first_chunk(&head->rc_read_pcl); ret = svc_rdma_build_read_chunk(info, chunk); if (ret < 0) goto out; /* Split the Receive buffer between the head and tail * buffers at Read chunk's position. XDR roundup of the * chunk is not included in either the pagelist or in * the tail. */ buf->tail[0].iov_base = buf->head[0].iov_base + chunk->ch_position; buf->tail[0].iov_len = buf->head[0].iov_len - chunk->ch_position; buf->head[0].iov_len = chunk->ch_position; /* Read chunk may need XDR roundup (see RFC 8166, s. 3.4.5.2). * * If the client already rounded up the chunk length, the * length does not change. Otherwise, the length of the page * list is increased to include XDR round-up. * * Currently these chunks always start at page offset 0, * thus the rounded-up length never crosses a page boundary. */ buf->pages = &info->ri_rqst->rq_pages[0]; length = xdr_align_size(chunk->ch_length); buf->page_len = length; buf->len += length; buf->buflen += length; out: return ret; } /** * svc_rdma_read_chunk_range - Build RDMA Read WQEs for portion of a chunk * @info: context for RDMA Reads * @chunk: parsed Call chunk to pull * @offset: offset of region to pull * @length: length of region to pull * * Return values: * %0: RDMA Read WQEs were successfully built * %-EINVAL: there were not enough resources to finish * %-ENOMEM: rdma_rw context pool was exhausted, * %-ENOTCONN: posting failed (connection is lost), * %-EIO: rdma_rw initialization failed (DMA mapping, etc). */ static int svc_rdma_read_chunk_range(struct svc_rdma_read_info *info, const struct svc_rdma_chunk *chunk, unsigned int offset, unsigned int length) { const struct svc_rdma_segment *segment; int ret; ret = -EINVAL; pcl_for_each_segment(segment, chunk) { struct svc_rdma_segment dummy; if (offset > segment->rs_length) { offset -= segment->rs_length; continue; } dummy.rs_handle = segment->rs_handle; dummy.rs_length = min_t(u32, length, segment->rs_length) - offset; dummy.rs_offset = segment->rs_offset + offset; ret = svc_rdma_build_read_segment(info, &dummy); if (ret < 0) break; info->ri_totalbytes += dummy.rs_length; length -= dummy.rs_length; offset = 0; } return ret; } /** * svc_rdma_read_call_chunk - Build RDMA Read WQEs to pull a Long Message * @info: context for RDMA Reads * * Return values: * %0: RDMA Read WQEs were successfully built * %-EINVAL: there were not enough resources to finish * %-ENOMEM: rdma_rw context pool was exhausted, * %-ENOTCONN: posting failed (connection is lost), * %-EIO: rdma_rw initialization failed (DMA mapping, etc). */ static int svc_rdma_read_call_chunk(struct svc_rdma_read_info *info) { struct svc_rdma_recv_ctxt *head = info->ri_readctxt; const struct svc_rdma_chunk *call_chunk = pcl_first_chunk(&head->rc_call_pcl); const struct svc_rdma_pcl *pcl = &head->rc_read_pcl; struct svc_rdma_chunk *chunk, *next; unsigned int start, length; int ret; if (pcl_is_empty(pcl)) return svc_rdma_build_read_chunk(info, call_chunk); start = 0; chunk = pcl_first_chunk(pcl); length = chunk->ch_position; ret = svc_rdma_read_chunk_range(info, call_chunk, start, length); if (ret < 0) return ret; pcl_for_each_chunk(chunk, pcl) { ret = svc_rdma_build_read_chunk(info, chunk); if (ret < 0) return ret; next = pcl_next_chunk(pcl, chunk); if (!next) break; start += length; length = next->ch_position - info->ri_totalbytes; ret = svc_rdma_read_chunk_range(info, call_chunk, start, length); if (ret < 0) return ret; } start += length; length = call_chunk->ch_length - start; return svc_rdma_read_chunk_range(info, call_chunk, start, length); } /** * svc_rdma_read_special - Build RDMA Read WQEs to pull a Long Message * @info: context for RDMA Reads * * The start of the data lands in the first page just after the * Transport header, and the rest lands in rqstp->rq_arg.pages. * * Assumptions: * - A PZRC is never sent in an RDMA_MSG message, though it's * allowed by spec. * * Return values: * %0: RDMA Read WQEs were successfully built * %-EINVAL: client provided too many chunks or segments, * %-ENOMEM: rdma_rw context pool was exhausted, * %-ENOTCONN: posting failed (connection is lost), * %-EIO: rdma_rw initialization failed (DMA mapping, etc). */ static noinline int svc_rdma_read_special(struct svc_rdma_read_info *info) { struct xdr_buf *buf = &info->ri_rqst->rq_arg; int ret; ret = svc_rdma_read_call_chunk(info); if (ret < 0) goto out; buf->len += info->ri_totalbytes; buf->buflen += info->ri_totalbytes; buf->head[0].iov_base = page_address(info->ri_rqst->rq_pages[0]); buf->head[0].iov_len = min_t(size_t, PAGE_SIZE, info->ri_totalbytes); buf->pages = &info->ri_rqst->rq_pages[1]; buf->page_len = info->ri_totalbytes - buf->head[0].iov_len; out: return ret; } /** * svc_rdma_process_read_list - Pull list of Read chunks from the client * @rdma: controlling RDMA transport * @rqstp: set of pages to use as Read sink buffers * @head: pages under I/O collect here * * The RPC/RDMA protocol assumes that the upper layer's XDR decoders * pull each Read chunk as they decode an incoming RPC message. * * On Linux, however, the server needs to have a fully-constructed RPC * message in rqstp->rq_arg when there is a positive return code from * ->xpo_recvfrom. So the Read list is safety-checked immediately when * it is received, then here the whole Read list is pulled all at once. * The ingress RPC message is fully reconstructed once all associated * RDMA Reads have completed. * * Return values: * %1: all needed RDMA Reads were posted successfully, * %-EINVAL: client provided too many chunks or segments, * %-ENOMEM: rdma_rw context pool was exhausted, * %-ENOTCONN: posting failed (connection is lost), * %-EIO: rdma_rw initialization failed (DMA mapping, etc). */ int svc_rdma_process_read_list(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp, struct svc_rdma_recv_ctxt *head) { struct svc_rdma_read_info *info; struct svc_rdma_chunk_ctxt *cc; int ret; info = svc_rdma_read_info_alloc(rdma); if (!info) return -ENOMEM; cc = &info->ri_cc; info->ri_rqst = rqstp; info->ri_readctxt = head; info->ri_pageno = 0; info->ri_pageoff = 0; info->ri_totalbytes = 0; if (pcl_is_empty(&head->rc_call_pcl)) { if (head->rc_read_pcl.cl_count == 1) ret = svc_rdma_read_data_item(info); else ret = svc_rdma_read_multiple_chunks(info); } else ret = svc_rdma_read_special(info); if (ret < 0) goto out_err; trace_svcrdma_post_read_chunk(&cc->cc_cid, cc->cc_sqecount); init_completion(&cc->cc_done); ret = svc_rdma_post_chunk_ctxt(cc); if (ret < 0) goto out_err; ret = 1; wait_for_completion(&cc->cc_done); if (cc->cc_status != IB_WC_SUCCESS) ret = -EIO; /* rq_respages starts after the last arg page */ rqstp->rq_respages = &rqstp->rq_pages[head->rc_page_count]; rqstp->rq_next_page = rqstp->rq_respages + 1; /* Ensure svc_rdma_recv_ctxt_put() does not try to release pages */ head->rc_page_count = 0; out_err: svc_rdma_read_info_free(info); return ret; }