diff options
Diffstat (limited to 'net/sunrpc/xprtrdma/svc_rdma_sendto.c')
| -rw-r--r-- | net/sunrpc/xprtrdma/svc_rdma_sendto.c | 1611 |
1 files changed, 987 insertions, 624 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c index c1d124dc772b..914cd263c2f1 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c @@ -1,4 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause /* + * Copyright (c) 2016-2018 Oracle. All rights reserved. + * Copyright (c) 2014 Open Grid Computing, Inc. All rights reserved. * Copyright (c) 2005-2006 Network Appliance, Inc. All rights reserved. * * This software is available to you under a choice of one of two @@ -39,709 +42,1069 @@ * Author: Tom Tucker <tom@opengridcomputing.com> */ -#include <linux/sunrpc/debug.h> -#include <linux/sunrpc/rpc_rdma.h> +/* Operation + * + * The main entry point is svc_rdma_sendto. This is called by the + * RPC server when an RPC Reply is ready to be transmitted to a client. + * + * The passed-in svc_rqst contains a struct xdr_buf which holds an + * XDR-encoded RPC Reply message. sendto must construct the RPC-over-RDMA + * transport header, post all Write WRs needed for this Reply, then post + * a Send WR conveying the transport header and the RPC message itself to + * the client. + * + * svc_rdma_sendto must fully transmit the Reply before returning, as + * the svc_rqst will be recycled as soon as sendto returns. Remaining + * resources referred to by the svc_rqst are also recycled at that time. + * Therefore any resources that must remain longer must be detached + * from the svc_rqst and released later. + * + * Page Management + * + * The I/O that performs Reply transmission is asynchronous, and may + * complete well after sendto returns. Thus pages under I/O must be + * removed from the svc_rqst before sendto returns. + * + * The logic here depends on Send Queue and completion ordering. Since + * the Send WR is always posted last, it will always complete last. Thus + * when it completes, it is guaranteed that all previous Write WRs have + * also completed. + * + * Write WRs are constructed and posted. Each Write segment gets its own + * svc_rdma_rw_ctxt, allowing the Write completion handler to find and + * DMA-unmap the pages under I/O for that Write segment. The Write + * completion handler does not release any pages. + * + * When the Send WR is constructed, it also gets its own svc_rdma_send_ctxt. + * The ownership of all of the Reply's pages are transferred into that + * ctxt, the Send WR is posted, and sendto returns. + * + * The svc_rdma_send_ctxt is presented when the Send WR completes. The + * Send completion handler finally releases the Reply's pages. + * + * This mechanism also assumes that completions on the transport's Send + * Completion Queue do not run in parallel. Otherwise a Write completion + * and Send completion running at the same time could release pages that + * are still DMA-mapped. + * + * Error Handling + * + * - If the Send WR is posted successfully, it will either complete + * successfully, or get flushed. Either way, the Send completion + * handler releases the Reply's pages. + * - If the Send WR cannot be not posted, the forward path releases + * the Reply's pages. + * + * This handles the case, without the use of page reference counting, + * where two different Write segments send portions of the same page. + */ + #include <linux/spinlock.h> -#include <asm/unaligned.h> +#include <linux/unaligned.h> + #include <rdma/ib_verbs.h> #include <rdma/rdma_cm.h> + +#include <linux/sunrpc/debug.h> #include <linux/sunrpc/svc_rdma.h> -#define RPCDBG_FACILITY RPCDBG_SVCXPRT +#include "xprt_rdma.h" +#include <trace/events/rpcrdma.h> + +static void svc_rdma_wc_send(struct ib_cq *cq, struct ib_wc *wc); + +static struct svc_rdma_send_ctxt * +svc_rdma_send_ctxt_alloc(struct svcxprt_rdma *rdma) +{ + int node = ibdev_to_node(rdma->sc_cm_id->device); + struct svc_rdma_send_ctxt *ctxt; + unsigned long pages; + dma_addr_t addr; + void *buffer; + int i; + + ctxt = kzalloc_node(struct_size(ctxt, sc_sges, rdma->sc_max_send_sges), + GFP_KERNEL, node); + if (!ctxt) + goto fail0; + pages = svc_serv_maxpages(rdma->sc_xprt.xpt_server); + ctxt->sc_pages = kcalloc_node(pages, sizeof(struct page *), + GFP_KERNEL, node); + if (!ctxt->sc_pages) + goto fail1; + ctxt->sc_maxpages = pages; + buffer = kmalloc_node(rdma->sc_max_req_size, GFP_KERNEL, node); + if (!buffer) + goto fail2; + addr = ib_dma_map_single(rdma->sc_pd->device, buffer, + rdma->sc_max_req_size, DMA_TO_DEVICE); + if (ib_dma_mapping_error(rdma->sc_pd->device, addr)) + goto fail3; + + svc_rdma_send_cid_init(rdma, &ctxt->sc_cid); + + ctxt->sc_rdma = rdma; + ctxt->sc_send_wr.next = NULL; + ctxt->sc_send_wr.wr_cqe = &ctxt->sc_cqe; + ctxt->sc_send_wr.sg_list = ctxt->sc_sges; + ctxt->sc_send_wr.send_flags = IB_SEND_SIGNALED; + ctxt->sc_cqe.done = svc_rdma_wc_send; + ctxt->sc_xprt_buf = buffer; + xdr_buf_init(&ctxt->sc_hdrbuf, ctxt->sc_xprt_buf, + rdma->sc_max_req_size); + ctxt->sc_sges[0].addr = addr; + + for (i = 0; i < rdma->sc_max_send_sges; i++) + ctxt->sc_sges[i].lkey = rdma->sc_pd->local_dma_lkey; + return ctxt; + +fail3: + kfree(buffer); +fail2: + kfree(ctxt->sc_pages); +fail1: + kfree(ctxt); +fail0: + return NULL; +} -/* Encode an XDR as an array of IB SGE +/** + * svc_rdma_send_ctxts_destroy - Release all send_ctxt's for an xprt + * @rdma: svcxprt_rdma being torn down * - * Assumptions: - * - head[0] is physically contiguous. - * - tail[0] is physically contiguous. - * - pages[] is not physically or virtually contiguous and consists of - * PAGE_SIZE elements. - * - * Output: - * SGE[0] reserved for RCPRDMA header - * SGE[1] data from xdr->head[] - * SGE[2..sge_count-2] data from xdr->pages[] - * SGE[sge_count-1] data from xdr->tail. - * - * The max SGE we need is the length of the XDR / pagesize + one for - * head + one for tail + one for RPCRDMA header. Since RPCSVC_MAXPAGES - * reserves a page for both the request and the reply header, and this - * array is only concerned with the reply we are assured that we have - * on extra page for the RPCRMDA header. */ -static int fast_reg_xdr(struct svcxprt_rdma *xprt, - struct xdr_buf *xdr, - struct svc_rdma_req_map *vec) +void svc_rdma_send_ctxts_destroy(struct svcxprt_rdma *rdma) { - int sge_no; - u32 sge_bytes; - u32 page_bytes; - u32 page_off; - int page_no = 0; - u8 *frva; - struct svc_rdma_fastreg_mr *frmr; - - frmr = svc_rdma_get_frmr(xprt); - if (IS_ERR(frmr)) - return -ENOMEM; - vec->frmr = frmr; - - /* Skip the RPCRDMA header */ - sge_no = 1; - - /* Map the head. */ - frva = (void *)((unsigned long)(xdr->head[0].iov_base) & PAGE_MASK); - vec->sge[sge_no].iov_base = xdr->head[0].iov_base; - vec->sge[sge_no].iov_len = xdr->head[0].iov_len; - vec->count = 2; - sge_no++; - - /* Map the XDR head */ - frmr->kva = frva; - frmr->direction = DMA_TO_DEVICE; - frmr->access_flags = 0; - frmr->map_len = PAGE_SIZE; - frmr->page_list_len = 1; - page_off = (unsigned long)xdr->head[0].iov_base & ~PAGE_MASK; - frmr->page_list->page_list[page_no] = - ib_dma_map_page(xprt->sc_cm_id->device, - virt_to_page(xdr->head[0].iov_base), - page_off, - PAGE_SIZE - page_off, - DMA_TO_DEVICE); - if (ib_dma_mapping_error(xprt->sc_cm_id->device, - frmr->page_list->page_list[page_no])) - goto fatal_err; - atomic_inc(&xprt->sc_dma_used); - - /* Map the XDR page list */ - page_off = xdr->page_base; - page_bytes = xdr->page_len + page_off; - if (!page_bytes) - goto encode_tail; - - /* Map the pages */ - vec->sge[sge_no].iov_base = frva + frmr->map_len + page_off; - vec->sge[sge_no].iov_len = page_bytes; - sge_no++; - while (page_bytes) { - struct page *page; - - page = xdr->pages[page_no++]; - sge_bytes = min_t(u32, page_bytes, (PAGE_SIZE - page_off)); - page_bytes -= sge_bytes; - - frmr->page_list->page_list[page_no] = - ib_dma_map_page(xprt->sc_cm_id->device, - page, page_off, - sge_bytes, DMA_TO_DEVICE); - if (ib_dma_mapping_error(xprt->sc_cm_id->device, - frmr->page_list->page_list[page_no])) - goto fatal_err; - - atomic_inc(&xprt->sc_dma_used); - page_off = 0; /* reset for next time through loop */ - frmr->map_len += PAGE_SIZE; - frmr->page_list_len++; + struct svc_rdma_send_ctxt *ctxt; + struct llist_node *node; + + while ((node = llist_del_first(&rdma->sc_send_ctxts)) != NULL) { + ctxt = llist_entry(node, struct svc_rdma_send_ctxt, sc_node); + ib_dma_unmap_single(rdma->sc_pd->device, + ctxt->sc_sges[0].addr, + rdma->sc_max_req_size, + DMA_TO_DEVICE); + kfree(ctxt->sc_xprt_buf); + kfree(ctxt->sc_pages); + kfree(ctxt); } - vec->count++; - - encode_tail: - /* Map tail */ - if (0 == xdr->tail[0].iov_len) - goto done; - - vec->count++; - vec->sge[sge_no].iov_len = xdr->tail[0].iov_len; - - if (((unsigned long)xdr->tail[0].iov_base & PAGE_MASK) == - ((unsigned long)xdr->head[0].iov_base & PAGE_MASK)) { - /* - * If head and tail use the same page, we don't need - * to map it again. - */ - vec->sge[sge_no].iov_base = xdr->tail[0].iov_base; - } else { - void *va; +} - /* Map another page for the tail */ - page_off = (unsigned long)xdr->tail[0].iov_base & ~PAGE_MASK; - va = (void *)((unsigned long)xdr->tail[0].iov_base & PAGE_MASK); - vec->sge[sge_no].iov_base = frva + frmr->map_len + page_off; +/** + * svc_rdma_send_ctxt_get - Get a free send_ctxt + * @rdma: controlling svcxprt_rdma + * + * Returns a ready-to-use send_ctxt, or NULL if none are + * available and a fresh one cannot be allocated. + */ +struct svc_rdma_send_ctxt *svc_rdma_send_ctxt_get(struct svcxprt_rdma *rdma) +{ + struct svc_rdma_send_ctxt *ctxt; + struct llist_node *node; + + spin_lock(&rdma->sc_send_lock); + node = llist_del_first(&rdma->sc_send_ctxts); + spin_unlock(&rdma->sc_send_lock); + if (!node) + goto out_empty; + + ctxt = llist_entry(node, struct svc_rdma_send_ctxt, sc_node); + +out: + rpcrdma_set_xdrlen(&ctxt->sc_hdrbuf, 0); + xdr_init_encode(&ctxt->sc_stream, &ctxt->sc_hdrbuf, + ctxt->sc_xprt_buf, NULL); + + svc_rdma_cc_init(rdma, &ctxt->sc_reply_info.wi_cc); + ctxt->sc_send_wr.num_sge = 0; + ctxt->sc_cur_sge_no = 0; + ctxt->sc_page_count = 0; + ctxt->sc_wr_chain = &ctxt->sc_send_wr; + ctxt->sc_sqecount = 1; + + return ctxt; + +out_empty: + ctxt = svc_rdma_send_ctxt_alloc(rdma); + if (!ctxt) + return NULL; + goto out; +} - frmr->page_list->page_list[page_no] = - ib_dma_map_page(xprt->sc_cm_id->device, virt_to_page(va), - page_off, - PAGE_SIZE, - DMA_TO_DEVICE); - if (ib_dma_mapping_error(xprt->sc_cm_id->device, - frmr->page_list->page_list[page_no])) - goto fatal_err; - atomic_inc(&xprt->sc_dma_used); - frmr->map_len += PAGE_SIZE; - frmr->page_list_len++; +static void svc_rdma_send_ctxt_release(struct svcxprt_rdma *rdma, + struct svc_rdma_send_ctxt *ctxt) +{ + struct ib_device *device = rdma->sc_cm_id->device; + unsigned int i; + + svc_rdma_reply_chunk_release(rdma, ctxt); + + if (ctxt->sc_page_count) + release_pages(ctxt->sc_pages, ctxt->sc_page_count); + + /* The first SGE contains the transport header, which + * remains mapped until @ctxt is destroyed. + */ + for (i = 1; i < ctxt->sc_send_wr.num_sge; i++) { + trace_svcrdma_dma_unmap_page(&ctxt->sc_cid, + ctxt->sc_sges[i].addr, + ctxt->sc_sges[i].length); + ib_dma_unmap_page(device, + ctxt->sc_sges[i].addr, + ctxt->sc_sges[i].length, + DMA_TO_DEVICE); } - done: - if (svc_rdma_fastreg(xprt, frmr)) - goto fatal_err; + llist_add(&ctxt->sc_node, &rdma->sc_send_ctxts); +} - return 0; +static void svc_rdma_send_ctxt_put_async(struct work_struct *work) +{ + struct svc_rdma_send_ctxt *ctxt; - fatal_err: - printk("svcrdma: Error fast registering memory for xprt %p\n", xprt); - vec->frmr = NULL; - svc_rdma_put_frmr(xprt, frmr); - return -EIO; + ctxt = container_of(work, struct svc_rdma_send_ctxt, sc_work); + svc_rdma_send_ctxt_release(ctxt->sc_rdma, ctxt); } -static int map_xdr(struct svcxprt_rdma *xprt, - struct xdr_buf *xdr, - struct svc_rdma_req_map *vec) +/** + * svc_rdma_send_ctxt_put - Return send_ctxt to free list + * @rdma: controlling svcxprt_rdma + * @ctxt: object to return to the free list + * + * Pages left in sc_pages are DMA unmapped and released. + */ +void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma, + struct svc_rdma_send_ctxt *ctxt) { - int sge_no; - u32 sge_bytes; - u32 page_bytes; - u32 page_off; - int page_no; - - BUG_ON(xdr->len != - (xdr->head[0].iov_len + xdr->page_len + xdr->tail[0].iov_len)); - - if (xprt->sc_frmr_pg_list_len) - return fast_reg_xdr(xprt, xdr, vec); - - /* Skip the first sge, this is for the RPCRDMA header */ - sge_no = 1; - - /* Head SGE */ - vec->sge[sge_no].iov_base = xdr->head[0].iov_base; - vec->sge[sge_no].iov_len = xdr->head[0].iov_len; - sge_no++; - - /* pages SGE */ - page_no = 0; - page_bytes = xdr->page_len; - page_off = xdr->page_base; - while (page_bytes) { - vec->sge[sge_no].iov_base = - page_address(xdr->pages[page_no]) + page_off; - sge_bytes = min_t(u32, page_bytes, (PAGE_SIZE - page_off)); - page_bytes -= sge_bytes; - vec->sge[sge_no].iov_len = sge_bytes; - - sge_no++; - page_no++; - page_off = 0; /* reset for next time through loop */ - } + INIT_WORK(&ctxt->sc_work, svc_rdma_send_ctxt_put_async); + queue_work(svcrdma_wq, &ctxt->sc_work); +} - /* Tail SGE */ - if (xdr->tail[0].iov_len) { - vec->sge[sge_no].iov_base = xdr->tail[0].iov_base; - vec->sge[sge_no].iov_len = xdr->tail[0].iov_len; - sge_no++; - } +/** + * svc_rdma_wake_send_waiters - manage Send Queue accounting + * @rdma: controlling transport + * @avail: Number of additional SQEs that are now available + * + */ +void svc_rdma_wake_send_waiters(struct svcxprt_rdma *rdma, int avail) +{ + atomic_add(avail, &rdma->sc_sq_avail); + smp_mb__after_atomic(); + if (unlikely(waitqueue_active(&rdma->sc_send_wait))) + wake_up(&rdma->sc_send_wait); +} - dprintk("svcrdma: map_xdr: sge_no %d page_no %d " - "page_base %u page_len %u head_len %zu tail_len %zu\n", - sge_no, page_no, xdr->page_base, xdr->page_len, - xdr->head[0].iov_len, xdr->tail[0].iov_len); +/** + * svc_rdma_wc_send - Invoked by RDMA provider for each polled Send WC + * @cq: Completion Queue context + * @wc: Work Completion object + * + * NB: The svc_xprt/svcxprt_rdma is pinned whenever it's possible that + * the Send completion handler could be running. + */ +static void svc_rdma_wc_send(struct ib_cq *cq, struct ib_wc *wc) +{ + struct svcxprt_rdma *rdma = cq->cq_context; + struct ib_cqe *cqe = wc->wr_cqe; + struct svc_rdma_send_ctxt *ctxt = + container_of(cqe, struct svc_rdma_send_ctxt, sc_cqe); - vec->count = sge_no; - return 0; + svc_rdma_wake_send_waiters(rdma, ctxt->sc_sqecount); + + if (unlikely(wc->status != IB_WC_SUCCESS)) + goto flushed; + + trace_svcrdma_wc_send(&ctxt->sc_cid); + svc_rdma_send_ctxt_put(rdma, ctxt); + return; + +flushed: + if (wc->status != IB_WC_WR_FLUSH_ERR) + trace_svcrdma_wc_send_err(wc, &ctxt->sc_cid); + else + trace_svcrdma_wc_send_flush(wc, &ctxt->sc_cid); + svc_rdma_send_ctxt_put(rdma, ctxt); + svc_xprt_deferred_close(&rdma->sc_xprt); } -static dma_addr_t dma_map_xdr(struct svcxprt_rdma *xprt, - struct xdr_buf *xdr, - u32 xdr_off, size_t len, int dir) +/** + * svc_rdma_post_send - Post a WR chain to the Send Queue + * @rdma: transport context + * @ctxt: WR chain to post + * + * Copy fields in @ctxt to stack variables in order to guarantee + * that these values remain available after the ib_post_send() call. + * In some error flow cases, svc_rdma_wc_send() releases @ctxt. + * + * Note there is potential for starvation when the Send Queue is + * full because there is no order to when waiting threads are + * awoken. The transport is typically provisioned with a deep + * enough Send Queue that SQ exhaustion should be a rare event. + * + * Return values: + * %0: @ctxt's WR chain was posted successfully + * %-ENOTCONN: The connection was lost + */ +int svc_rdma_post_send(struct svcxprt_rdma *rdma, + struct svc_rdma_send_ctxt *ctxt) { - struct page *page; - dma_addr_t dma_addr; - if (xdr_off < xdr->head[0].iov_len) { - /* This offset is in the head */ - xdr_off += (unsigned long)xdr->head[0].iov_base & ~PAGE_MASK; - page = virt_to_page(xdr->head[0].iov_base); - } else { - xdr_off -= xdr->head[0].iov_len; - if (xdr_off < xdr->page_len) { - /* This offset is in the page list */ - page = xdr->pages[xdr_off >> PAGE_SHIFT]; - xdr_off &= ~PAGE_MASK; - } else { - /* This offset is in the tail */ - xdr_off -= xdr->page_len; - xdr_off += (unsigned long) - xdr->tail[0].iov_base & ~PAGE_MASK; - page = virt_to_page(xdr->tail[0].iov_base); + struct ib_send_wr *first_wr = ctxt->sc_wr_chain; + struct ib_send_wr *send_wr = &ctxt->sc_send_wr; + const struct ib_send_wr *bad_wr = first_wr; + struct rpc_rdma_cid cid = ctxt->sc_cid; + int ret, sqecount = ctxt->sc_sqecount; + + might_sleep(); + + /* Sync the transport header buffer */ + ib_dma_sync_single_for_device(rdma->sc_pd->device, + send_wr->sg_list[0].addr, + send_wr->sg_list[0].length, + DMA_TO_DEVICE); + + /* If the SQ is full, wait until an SQ entry is available */ + while (!test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags)) { + if (atomic_sub_return(sqecount, &rdma->sc_sq_avail) < 0) { + svc_rdma_wake_send_waiters(rdma, sqecount); + + /* When the transport is torn down, assume + * ib_drain_sq() will trigger enough Send + * completions to wake us. The XPT_CLOSE test + * above should then cause the while loop to + * exit. + */ + percpu_counter_inc(&svcrdma_stat_sq_starve); + trace_svcrdma_sq_full(rdma, &cid); + wait_event(rdma->sc_send_wait, + atomic_read(&rdma->sc_sq_avail) > 0); + trace_svcrdma_sq_retry(rdma, &cid); + continue; } + + trace_svcrdma_post_send(ctxt); + ret = ib_post_send(rdma->sc_qp, first_wr, &bad_wr); + if (ret) { + trace_svcrdma_sq_post_err(rdma, &cid, ret); + svc_xprt_deferred_close(&rdma->sc_xprt); + + /* If even one WR was posted, there will be a + * Send completion that bumps sc_sq_avail. + */ + if (bad_wr == first_wr) { + svc_rdma_wake_send_waiters(rdma, sqecount); + break; + } + } + return 0; } - dma_addr = ib_dma_map_page(xprt->sc_cm_id->device, page, xdr_off, - min_t(size_t, PAGE_SIZE, len), dir); - return dma_addr; + return -ENOTCONN; } -/* Assumptions: - * - We are using FRMR - * - or - - * - The specified write_len can be represented in sc_max_sge * PAGE_SIZE +/** + * svc_rdma_encode_read_list - Encode RPC Reply's Read chunk list + * @sctxt: Send context for the RPC Reply + * + * Return values: + * On success, returns length in bytes of the Reply XDR buffer + * that was consumed by the Reply Read list + * %-EMSGSIZE on XDR buffer overflow + */ +static ssize_t svc_rdma_encode_read_list(struct svc_rdma_send_ctxt *sctxt) +{ + /* RPC-over-RDMA version 1 replies never have a Read list. */ + return xdr_stream_encode_item_absent(&sctxt->sc_stream); +} + +/** + * svc_rdma_encode_write_segment - Encode one Write segment + * @sctxt: Send context for the RPC Reply + * @chunk: Write chunk to push + * @remaining: remaining bytes of the payload left in the Write chunk + * @segno: which segment in the chunk + * + * Return values: + * On success, returns length in bytes of the Reply XDR buffer + * that was consumed by the Write segment, and updates @remaining + * %-EMSGSIZE on XDR buffer overflow + */ +static ssize_t svc_rdma_encode_write_segment(struct svc_rdma_send_ctxt *sctxt, + const struct svc_rdma_chunk *chunk, + u32 *remaining, unsigned int segno) +{ + const struct svc_rdma_segment *segment = &chunk->ch_segments[segno]; + const size_t len = rpcrdma_segment_maxsz * sizeof(__be32); + u32 length; + __be32 *p; + + p = xdr_reserve_space(&sctxt->sc_stream, len); + if (!p) + return -EMSGSIZE; + + length = min_t(u32, *remaining, segment->rs_length); + *remaining -= length; + xdr_encode_rdma_segment(p, segment->rs_handle, length, + segment->rs_offset); + trace_svcrdma_encode_wseg(sctxt, segno, segment->rs_handle, length, + segment->rs_offset); + return len; +} + +/** + * svc_rdma_encode_write_chunk - Encode one Write chunk + * @sctxt: Send context for the RPC Reply + * @chunk: Write chunk to push + * + * Copy a Write chunk from the Call transport header to the + * Reply transport header. Update each segment's length field + * to reflect the number of bytes written in that segment. + * + * Return values: + * On success, returns length in bytes of the Reply XDR buffer + * that was consumed by the Write chunk + * %-EMSGSIZE on XDR buffer overflow */ -static int send_write(struct svcxprt_rdma *xprt, struct svc_rqst *rqstp, - u32 rmr, u64 to, - u32 xdr_off, int write_len, - struct svc_rdma_req_map *vec) +static ssize_t svc_rdma_encode_write_chunk(struct svc_rdma_send_ctxt *sctxt, + const struct svc_rdma_chunk *chunk) { - struct ib_send_wr write_wr; - struct ib_sge *sge; - int xdr_sge_no; - int sge_no; - int sge_bytes; - int sge_off; - int bc; - struct svc_rdma_op_ctxt *ctxt; - - BUG_ON(vec->count > RPCSVC_MAXPAGES); - dprintk("svcrdma: RDMA_WRITE rmr=%x, to=%llx, xdr_off=%d, " - "write_len=%d, vec->sge=%p, vec->count=%lu\n", - rmr, (unsigned long long)to, xdr_off, - write_len, vec->sge, vec->count); - - ctxt = svc_rdma_get_context(xprt); - ctxt->direction = DMA_TO_DEVICE; - sge = ctxt->sge; - - /* Find the SGE associated with xdr_off */ - for (bc = xdr_off, xdr_sge_no = 1; bc && xdr_sge_no < vec->count; - xdr_sge_no++) { - if (vec->sge[xdr_sge_no].iov_len > bc) - break; - bc -= vec->sge[xdr_sge_no].iov_len; + u32 remaining = chunk->ch_payload_length; + unsigned int segno; + ssize_t len, ret; + + len = 0; + ret = xdr_stream_encode_item_present(&sctxt->sc_stream); + if (ret < 0) + return ret; + len += ret; + + ret = xdr_stream_encode_u32(&sctxt->sc_stream, chunk->ch_segcount); + if (ret < 0) + return ret; + len += ret; + + for (segno = 0; segno < chunk->ch_segcount; segno++) { + ret = svc_rdma_encode_write_segment(sctxt, chunk, &remaining, segno); + if (ret < 0) + return ret; + len += ret; } - sge_off = bc; - bc = write_len; - sge_no = 0; - - /* Copy the remaining SGE */ - while (bc != 0) { - sge_bytes = min_t(size_t, - bc, vec->sge[xdr_sge_no].iov_len-sge_off); - sge[sge_no].length = sge_bytes; - if (!vec->frmr) { - sge[sge_no].addr = - dma_map_xdr(xprt, &rqstp->rq_res, xdr_off, - sge_bytes, DMA_TO_DEVICE); - xdr_off += sge_bytes; - if (ib_dma_mapping_error(xprt->sc_cm_id->device, - sge[sge_no].addr)) - goto err; - atomic_inc(&xprt->sc_dma_used); - sge[sge_no].lkey = xprt->sc_dma_lkey; - } else { - sge[sge_no].addr = (unsigned long) - vec->sge[xdr_sge_no].iov_base + sge_off; - sge[sge_no].lkey = vec->frmr->mr->lkey; - } - ctxt->count++; - ctxt->frmr = vec->frmr; - sge_off = 0; - sge_no++; - xdr_sge_no++; - BUG_ON(xdr_sge_no > vec->count); - bc -= sge_bytes; + return len; +} + +/** + * svc_rdma_encode_write_list - Encode RPC Reply's Write chunk list + * @rctxt: Reply context with information about the RPC Call + * @sctxt: Send context for the RPC Reply + * + * Return values: + * On success, returns length in bytes of the Reply XDR buffer + * that was consumed by the Reply's Write list + * %-EMSGSIZE on XDR buffer overflow + */ +static ssize_t svc_rdma_encode_write_list(struct svc_rdma_recv_ctxt *rctxt, + struct svc_rdma_send_ctxt *sctxt) +{ + struct svc_rdma_chunk *chunk; + ssize_t len, ret; + + len = 0; + pcl_for_each_chunk(chunk, &rctxt->rc_write_pcl) { + ret = svc_rdma_encode_write_chunk(sctxt, chunk); + if (ret < 0) + return ret; + len += ret; } - /* Prepare WRITE WR */ - memset(&write_wr, 0, sizeof write_wr); - ctxt->wr_op = IB_WR_RDMA_WRITE; - write_wr.wr_id = (unsigned long)ctxt; - write_wr.sg_list = &sge[0]; - write_wr.num_sge = sge_no; - write_wr.opcode = IB_WR_RDMA_WRITE; - write_wr.send_flags = IB_SEND_SIGNALED; - write_wr.wr.rdma.rkey = rmr; - write_wr.wr.rdma.remote_addr = to; - - /* Post It */ - atomic_inc(&rdma_stat_write); - if (svc_rdma_send(xprt, &write_wr)) - goto err; + /* Terminate the Write list */ + ret = xdr_stream_encode_item_absent(&sctxt->sc_stream); + if (ret < 0) + return ret; + + return len + ret; +} + +/** + * svc_rdma_encode_reply_chunk - Encode RPC Reply's Reply chunk + * @rctxt: Reply context with information about the RPC Call + * @sctxt: Send context for the RPC Reply + * @length: size in bytes of the payload in the Reply chunk + * + * Return values: + * On success, returns length in bytes of the Reply XDR buffer + * that was consumed by the Reply's Reply chunk + * %-EMSGSIZE on XDR buffer overflow + * %-E2BIG if the RPC message is larger than the Reply chunk + */ +static ssize_t +svc_rdma_encode_reply_chunk(struct svc_rdma_recv_ctxt *rctxt, + struct svc_rdma_send_ctxt *sctxt, + unsigned int length) +{ + struct svc_rdma_chunk *chunk; + + if (pcl_is_empty(&rctxt->rc_reply_pcl)) + return xdr_stream_encode_item_absent(&sctxt->sc_stream); + + chunk = pcl_first_chunk(&rctxt->rc_reply_pcl); + if (length > chunk->ch_length) + return -E2BIG; + + chunk->ch_payload_length = length; + return svc_rdma_encode_write_chunk(sctxt, chunk); +} + +struct svc_rdma_map_data { + struct svcxprt_rdma *md_rdma; + struct svc_rdma_send_ctxt *md_ctxt; +}; + +/** + * svc_rdma_page_dma_map - DMA map one page + * @data: pointer to arguments + * @page: struct page to DMA map + * @offset: offset into the page + * @len: number of bytes to map + * + * Returns: + * %0 if DMA mapping was successful + * %-EIO if the page cannot be DMA mapped + */ +static int svc_rdma_page_dma_map(void *data, struct page *page, + unsigned long offset, unsigned int len) +{ + struct svc_rdma_map_data *args = data; + struct svcxprt_rdma *rdma = args->md_rdma; + struct svc_rdma_send_ctxt *ctxt = args->md_ctxt; + struct ib_device *dev = rdma->sc_cm_id->device; + dma_addr_t dma_addr; + + ++ctxt->sc_cur_sge_no; + + dma_addr = ib_dma_map_page(dev, page, offset, len, DMA_TO_DEVICE); + if (ib_dma_mapping_error(dev, dma_addr)) + goto out_maperr; + + trace_svcrdma_dma_map_page(&ctxt->sc_cid, dma_addr, len); + ctxt->sc_sges[ctxt->sc_cur_sge_no].addr = dma_addr; + ctxt->sc_sges[ctxt->sc_cur_sge_no].length = len; + ctxt->sc_send_wr.num_sge++; return 0; - err: - svc_rdma_unmap_dma(ctxt); - svc_rdma_put_frmr(xprt, vec->frmr); - svc_rdma_put_context(ctxt, 0); - /* Fatal error, close transport */ + +out_maperr: + trace_svcrdma_dma_map_err(&ctxt->sc_cid, dma_addr, len); return -EIO; } -static int send_write_chunks(struct svcxprt_rdma *xprt, - struct rpcrdma_msg *rdma_argp, - struct rpcrdma_msg *rdma_resp, - struct svc_rqst *rqstp, - struct svc_rdma_req_map *vec) +/** + * svc_rdma_iov_dma_map - DMA map an iovec + * @data: pointer to arguments + * @iov: kvec to DMA map + * + * ib_dma_map_page() is used here because svc_rdma_dma_unmap() + * handles DMA-unmap and it uses ib_dma_unmap_page() exclusively. + * + * Returns: + * %0 if DMA mapping was successful + * %-EIO if the iovec cannot be DMA mapped + */ +static int svc_rdma_iov_dma_map(void *data, const struct kvec *iov) { - u32 xfer_len = rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len; - int write_len; - int max_write; - u32 xdr_off; - int chunk_off; - int chunk_no; - struct rpcrdma_write_array *arg_ary; - struct rpcrdma_write_array *res_ary; + if (!iov->iov_len) + return 0; + return svc_rdma_page_dma_map(data, virt_to_page(iov->iov_base), + offset_in_page(iov->iov_base), + iov->iov_len); +} + +/** + * svc_rdma_xb_dma_map - DMA map all segments of an xdr_buf + * @xdr: xdr_buf containing portion of an RPC message to transmit + * @data: pointer to arguments + * + * Returns: + * %0 if DMA mapping was successful + * %-EIO if DMA mapping failed + * + * On failure, any DMA mappings that have been already done must be + * unmapped by the caller. + */ +static int svc_rdma_xb_dma_map(const struct xdr_buf *xdr, void *data) +{ + unsigned int len, remaining; + unsigned long pageoff; + struct page **ppages; int ret; - arg_ary = svc_rdma_get_write_array(rdma_argp); - if (!arg_ary) - return 0; - res_ary = (struct rpcrdma_write_array *) - &rdma_resp->rm_body.rm_chunks[1]; + ret = svc_rdma_iov_dma_map(data, &xdr->head[0]); + if (ret < 0) + return ret; - if (vec->frmr) - max_write = vec->frmr->map_len; - else - max_write = xprt->sc_max_sge * PAGE_SIZE; - - /* Write chunks start at the pagelist */ - for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0; - xfer_len && chunk_no < arg_ary->wc_nchunks; - chunk_no++) { - struct rpcrdma_segment *arg_ch; - u64 rs_offset; - - arg_ch = &arg_ary->wc_array[chunk_no].wc_target; - write_len = min(xfer_len, ntohl(arg_ch->rs_length)); - - /* Prepare the response chunk given the length actually - * written */ - xdr_decode_hyper((__be32 *)&arg_ch->rs_offset, &rs_offset); - svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no, - arg_ch->rs_handle, - arg_ch->rs_offset, - write_len); - chunk_off = 0; - while (write_len) { - int this_write; - this_write = min(write_len, max_write); - ret = send_write(xprt, rqstp, - ntohl(arg_ch->rs_handle), - rs_offset + chunk_off, - xdr_off, - this_write, - vec); - if (ret) { - dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n", - ret); - return -EIO; - } - chunk_off += this_write; - xdr_off += this_write; - xfer_len -= this_write; - write_len -= this_write; - } + ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT); + pageoff = offset_in_page(xdr->page_base); + remaining = xdr->page_len; + while (remaining) { + len = min_t(u32, PAGE_SIZE - pageoff, remaining); + + ret = svc_rdma_page_dma_map(data, *ppages++, pageoff, len); + if (ret < 0) + return ret; + + remaining -= len; + pageoff = 0; } - /* Update the req with the number of chunks actually used */ - svc_rdma_xdr_encode_write_list(rdma_resp, chunk_no); - return rqstp->rq_res.page_len + rqstp->rq_res.tail[0].iov_len; -} + ret = svc_rdma_iov_dma_map(data, &xdr->tail[0]); + if (ret < 0) + return ret; -static int send_reply_chunks(struct svcxprt_rdma *xprt, - struct rpcrdma_msg *rdma_argp, - struct rpcrdma_msg *rdma_resp, - struct svc_rqst *rqstp, - struct svc_rdma_req_map *vec) -{ - u32 xfer_len = rqstp->rq_res.len; - int write_len; - int max_write; - u32 xdr_off; - int chunk_no; - int chunk_off; - int nchunks; - struct rpcrdma_segment *ch; - struct rpcrdma_write_array *arg_ary; - struct rpcrdma_write_array *res_ary; - int ret; + return xdr->len; +} - arg_ary = svc_rdma_get_reply_array(rdma_argp); - if (!arg_ary) - return 0; - /* XXX: need to fix when reply lists occur with read-list and or - * write-list */ - res_ary = (struct rpcrdma_write_array *) - &rdma_resp->rm_body.rm_chunks[2]; +struct svc_rdma_pullup_data { + u8 *pd_dest; + unsigned int pd_length; + unsigned int pd_num_sges; +}; - if (vec->frmr) - max_write = vec->frmr->map_len; - else - max_write = xprt->sc_max_sge * PAGE_SIZE; - - /* xdr offset starts at RPC message */ - nchunks = ntohl(arg_ary->wc_nchunks); - for (xdr_off = 0, chunk_no = 0; - xfer_len && chunk_no < nchunks; - chunk_no++) { - u64 rs_offset; - ch = &arg_ary->wc_array[chunk_no].wc_target; - write_len = min(xfer_len, htonl(ch->rs_length)); - - /* Prepare the reply chunk given the length actually - * written */ - xdr_decode_hyper((__be32 *)&ch->rs_offset, &rs_offset); - svc_rdma_xdr_encode_array_chunk(res_ary, chunk_no, - ch->rs_handle, ch->rs_offset, - write_len); - chunk_off = 0; - while (write_len) { - int this_write; - - this_write = min(write_len, max_write); - ret = send_write(xprt, rqstp, - ntohl(ch->rs_handle), - rs_offset + chunk_off, - xdr_off, - this_write, - vec); - if (ret) { - dprintk("svcrdma: RDMA_WRITE failed, ret=%d\n", - ret); - return -EIO; - } - chunk_off += this_write; - xdr_off += this_write; - xfer_len -= this_write; - write_len -= this_write; - } +/** + * svc_rdma_xb_count_sges - Count how many SGEs will be needed + * @xdr: xdr_buf containing portion of an RPC message to transmit + * @data: pointer to arguments + * + * Returns: + * Number of SGEs needed to Send the contents of @xdr inline + */ +static int svc_rdma_xb_count_sges(const struct xdr_buf *xdr, + void *data) +{ + struct svc_rdma_pullup_data *args = data; + unsigned int remaining; + unsigned long offset; + + if (xdr->head[0].iov_len) + ++args->pd_num_sges; + + offset = offset_in_page(xdr->page_base); + remaining = xdr->page_len; + while (remaining) { + ++args->pd_num_sges; + remaining -= min_t(u32, PAGE_SIZE - offset, remaining); + offset = 0; } - /* Update the req with the number of chunks actually used */ - svc_rdma_xdr_encode_reply_array(res_ary, chunk_no); - return rqstp->rq_res.len; + if (xdr->tail[0].iov_len) + ++args->pd_num_sges; + + args->pd_length += xdr->len; + return 0; } -/* This function prepares the portion of the RPCRDMA message to be - * sent in the RDMA_SEND. This function is called after data sent via - * RDMA has already been transmitted. There are three cases: - * - The RPCRDMA header, RPC header, and payload are all sent in a - * single RDMA_SEND. This is the "inline" case. - * - The RPCRDMA header and some portion of the RPC header and data - * are sent via this RDMA_SEND and another portion of the data is - * sent via RDMA. - * - The RPCRDMA header [NOMSG] is sent in this RDMA_SEND and the RPC - * header and data are all transmitted via RDMA. - * In all three cases, this function prepares the RPCRDMA header in - * sge[0], the 'type' parameter indicates the type to place in the - * RPCRDMA header, and the 'byte_count' field indicates how much of - * the XDR to include in this RDMA_SEND. NB: The offset of the payload - * to send is zero in the XDR. +/** + * svc_rdma_pull_up_needed - Determine whether to use pull-up + * @rdma: controlling transport + * @sctxt: send_ctxt for the Send WR + * @write_pcl: Write chunk list provided by client + * @xdr: xdr_buf containing RPC message to transmit + * + * Returns: + * %true if pull-up must be used + * %false otherwise */ -static int send_reply(struct svcxprt_rdma *rdma, - struct svc_rqst *rqstp, - struct page *page, - struct rpcrdma_msg *rdma_resp, - struct svc_rdma_op_ctxt *ctxt, - struct svc_rdma_req_map *vec, - int byte_count) +static bool svc_rdma_pull_up_needed(const struct svcxprt_rdma *rdma, + const struct svc_rdma_send_ctxt *sctxt, + const struct svc_rdma_pcl *write_pcl, + const struct xdr_buf *xdr) { - struct ib_send_wr send_wr; - struct ib_send_wr inv_wr; - int sge_no; - int sge_bytes; - int page_no; - int pages; + /* Resources needed for the transport header */ + struct svc_rdma_pullup_data args = { + .pd_length = sctxt->sc_hdrbuf.len, + .pd_num_sges = 1, + }; int ret; - /* Post a recv buffer to handle another request. */ - ret = svc_rdma_post_recv(rdma); - if (ret) { - printk(KERN_INFO - "svcrdma: could not post a receive buffer, err=%d." - "Closing transport %p.\n", ret, rdma); - set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags); - svc_rdma_put_frmr(rdma, vec->frmr); - svc_rdma_put_context(ctxt, 0); - return -ENOTCONN; - } + ret = pcl_process_nonpayloads(write_pcl, xdr, + svc_rdma_xb_count_sges, &args); + if (ret < 0) + return false; - /* Prepare the context */ - ctxt->pages[0] = page; - ctxt->count = 1; - ctxt->frmr = vec->frmr; - if (vec->frmr) - set_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags); - else - clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags); - - /* Prepare the SGE for the RPCRDMA Header */ - ctxt->sge[0].lkey = rdma->sc_dma_lkey; - ctxt->sge[0].length = svc_rdma_xdr_get_reply_hdr_len(rdma_resp); - ctxt->sge[0].addr = - ib_dma_map_page(rdma->sc_cm_id->device, page, 0, - ctxt->sge[0].length, DMA_TO_DEVICE); - if (ib_dma_mapping_error(rdma->sc_cm_id->device, ctxt->sge[0].addr)) - goto err; - atomic_inc(&rdma->sc_dma_used); - - ctxt->direction = DMA_TO_DEVICE; - - /* Map the payload indicated by 'byte_count' */ - for (sge_no = 1; byte_count && sge_no < vec->count; sge_no++) { - int xdr_off = 0; - sge_bytes = min_t(size_t, vec->sge[sge_no].iov_len, byte_count); - byte_count -= sge_bytes; - if (!vec->frmr) { - ctxt->sge[sge_no].addr = - dma_map_xdr(rdma, &rqstp->rq_res, xdr_off, - sge_bytes, DMA_TO_DEVICE); - xdr_off += sge_bytes; - if (ib_dma_mapping_error(rdma->sc_cm_id->device, - ctxt->sge[sge_no].addr)) - goto err; - atomic_inc(&rdma->sc_dma_used); - ctxt->sge[sge_no].lkey = rdma->sc_dma_lkey; - } else { - ctxt->sge[sge_no].addr = (unsigned long) - vec->sge[sge_no].iov_base; - ctxt->sge[sge_no].lkey = vec->frmr->mr->lkey; - } - ctxt->sge[sge_no].length = sge_bytes; + if (args.pd_length < RPCRDMA_PULLUP_THRESH) + return true; + return args.pd_num_sges >= rdma->sc_max_send_sges; +} + +/** + * svc_rdma_xb_linearize - Copy region of xdr_buf to flat buffer + * @xdr: xdr_buf containing portion of an RPC message to copy + * @data: pointer to arguments + * + * Returns: + * Always zero. + */ +static int svc_rdma_xb_linearize(const struct xdr_buf *xdr, + void *data) +{ + struct svc_rdma_pullup_data *args = data; + unsigned int len, remaining; + unsigned long pageoff; + struct page **ppages; + + if (xdr->head[0].iov_len) { + memcpy(args->pd_dest, xdr->head[0].iov_base, xdr->head[0].iov_len); + args->pd_dest += xdr->head[0].iov_len; } - BUG_ON(byte_count != 0); - /* Save all respages in the ctxt and remove them from the - * respages array. They are our pages until the I/O - * completes. - */ - pages = rqstp->rq_next_page - rqstp->rq_respages; - for (page_no = 0; page_no < pages; page_no++) { - ctxt->pages[page_no+1] = rqstp->rq_respages[page_no]; - ctxt->count++; - rqstp->rq_respages[page_no] = NULL; - /* - * If there are more pages than SGE, terminate SGE - * list so that svc_rdma_unmap_dma doesn't attempt to - * unmap garbage. - */ - if (page_no+1 >= sge_no) - ctxt->sge[page_no+1].length = 0; + ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT); + pageoff = offset_in_page(xdr->page_base); + remaining = xdr->page_len; + while (remaining) { + len = min_t(u32, PAGE_SIZE - pageoff, remaining); + memcpy(args->pd_dest, page_address(*ppages) + pageoff, len); + remaining -= len; + args->pd_dest += len; + pageoff = 0; + ppages++; } - BUG_ON(sge_no > rdma->sc_max_sge); - memset(&send_wr, 0, sizeof send_wr); - ctxt->wr_op = IB_WR_SEND; - send_wr.wr_id = (unsigned long)ctxt; - send_wr.sg_list = ctxt->sge; - send_wr.num_sge = sge_no; - send_wr.opcode = IB_WR_SEND; - send_wr.send_flags = IB_SEND_SIGNALED; - if (vec->frmr) { - /* Prepare INVALIDATE WR */ - memset(&inv_wr, 0, sizeof inv_wr); - inv_wr.opcode = IB_WR_LOCAL_INV; - inv_wr.send_flags = IB_SEND_SIGNALED; - inv_wr.ex.invalidate_rkey = - vec->frmr->mr->lkey; - send_wr.next = &inv_wr; + + if (xdr->tail[0].iov_len) { + memcpy(args->pd_dest, xdr->tail[0].iov_base, xdr->tail[0].iov_len); + args->pd_dest += xdr->tail[0].iov_len; } - ret = svc_rdma_send(rdma, &send_wr); - if (ret) - goto err; + args->pd_length += xdr->len; + return 0; +} +/** + * svc_rdma_pull_up_reply_msg - Copy Reply into a single buffer + * @rdma: controlling transport + * @sctxt: send_ctxt for the Send WR; xprt hdr is already prepared + * @write_pcl: Write chunk list provided by client + * @xdr: prepared xdr_buf containing RPC message + * + * The device is not capable of sending the reply directly. + * Assemble the elements of @xdr into the transport header buffer. + * + * Assumptions: + * pull_up_needed has determined that @xdr will fit in the buffer. + * + * Returns: + * %0 if pull-up was successful + * %-EMSGSIZE if a buffer manipulation problem occurred + */ +static int svc_rdma_pull_up_reply_msg(const struct svcxprt_rdma *rdma, + struct svc_rdma_send_ctxt *sctxt, + const struct svc_rdma_pcl *write_pcl, + const struct xdr_buf *xdr) +{ + struct svc_rdma_pullup_data args = { + .pd_dest = sctxt->sc_xprt_buf + sctxt->sc_hdrbuf.len, + }; + int ret; + + ret = pcl_process_nonpayloads(write_pcl, xdr, + svc_rdma_xb_linearize, &args); + if (ret < 0) + return ret; + + sctxt->sc_sges[0].length = sctxt->sc_hdrbuf.len + args.pd_length; + trace_svcrdma_send_pullup(sctxt, args.pd_length); return 0; +} - err: - svc_rdma_unmap_dma(ctxt); - svc_rdma_put_frmr(rdma, vec->frmr); - svc_rdma_put_context(ctxt, 1); - return -EIO; +/* svc_rdma_map_reply_msg - DMA map the buffer holding RPC message + * @rdma: controlling transport + * @sctxt: send_ctxt for the Send WR + * @write_pcl: Write chunk list provided by client + * @reply_pcl: Reply chunk provided by client + * @xdr: prepared xdr_buf containing RPC message + * + * Returns: + * %0 if DMA mapping was successful. + * %-EMSGSIZE if a buffer manipulation problem occurred + * %-EIO if DMA mapping failed + * + * The Send WR's num_sge field is set in all cases. + */ +int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma, + struct svc_rdma_send_ctxt *sctxt, + const struct svc_rdma_pcl *write_pcl, + const struct svc_rdma_pcl *reply_pcl, + const struct xdr_buf *xdr) +{ + struct svc_rdma_map_data args = { + .md_rdma = rdma, + .md_ctxt = sctxt, + }; + + /* Set up the (persistently-mapped) transport header SGE. */ + sctxt->sc_send_wr.num_sge = 1; + sctxt->sc_sges[0].length = sctxt->sc_hdrbuf.len; + + /* If there is a Reply chunk, nothing follows the transport + * header, so there is nothing to map. + */ + if (!pcl_is_empty(reply_pcl)) + return 0; + + /* For pull-up, svc_rdma_send() will sync the transport header. + * No additional DMA mapping is necessary. + */ + if (svc_rdma_pull_up_needed(rdma, sctxt, write_pcl, xdr)) + return svc_rdma_pull_up_reply_msg(rdma, sctxt, write_pcl, xdr); + + return pcl_process_nonpayloads(write_pcl, xdr, + svc_rdma_xb_dma_map, &args); } -void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp) +/* The svc_rqst and all resources it owns are released as soon as + * svc_rdma_sendto returns. Transfer pages under I/O to the ctxt + * so they are released by the Send completion handler. + */ +static void svc_rdma_save_io_pages(struct svc_rqst *rqstp, + struct svc_rdma_send_ctxt *ctxt) { + int i, pages = rqstp->rq_next_page - rqstp->rq_respages; + + ctxt->sc_page_count += pages; + for (i = 0; i < pages; i++) { + ctxt->sc_pages[i] = rqstp->rq_respages[i]; + rqstp->rq_respages[i] = NULL; + } + + /* Prevent svc_xprt_release from releasing pages in rq_pages */ + rqstp->rq_next_page = rqstp->rq_respages; } -/* - * Return the start of an xdr buffer. +/* Prepare the portion of the RPC Reply that will be transmitted + * via RDMA Send. The RPC-over-RDMA transport header is prepared + * in sc_sges[0], and the RPC xdr_buf is prepared in following sges. + * + * Depending on whether a Write list or Reply chunk is present, + * the server may Send all, a portion of, or none of the xdr_buf. + * In the latter case, only the transport header (sc_sges[0]) is + * transmitted. + * + * Assumptions: + * - The Reply's transport header will never be larger than a page. + */ +static int svc_rdma_send_reply_msg(struct svcxprt_rdma *rdma, + struct svc_rdma_send_ctxt *sctxt, + const struct svc_rdma_recv_ctxt *rctxt, + struct svc_rqst *rqstp) +{ + struct ib_send_wr *send_wr = &sctxt->sc_send_wr; + int ret; + + ret = svc_rdma_map_reply_msg(rdma, sctxt, &rctxt->rc_write_pcl, + &rctxt->rc_reply_pcl, &rqstp->rq_res); + if (ret < 0) + return ret; + + /* Transfer pages involved in RDMA Writes to the sctxt's + * page array. Completion handling releases these pages. + */ + svc_rdma_save_io_pages(rqstp, sctxt); + + if (rctxt->rc_inv_rkey) { + send_wr->opcode = IB_WR_SEND_WITH_INV; + send_wr->ex.invalidate_rkey = rctxt->rc_inv_rkey; + } else { + send_wr->opcode = IB_WR_SEND; + } + + return svc_rdma_post_send(rdma, sctxt); +} + +/** + * svc_rdma_send_error_msg - Send an RPC/RDMA v1 error response + * @rdma: controlling transport context + * @sctxt: Send context for the response + * @rctxt: Receive context for incoming bad message + * @status: negative errno indicating error that occurred + * + * Given the client-provided Read, Write, and Reply chunks, the + * server was not able to parse the Call or form a complete Reply. + * Return an RDMA_ERROR message so the client can retire the RPC + * transaction. + * + * The caller does not have to release @sctxt. It is released by + * Send completion, or by this function on error. */ -static void *xdr_start(struct xdr_buf *xdr) +void svc_rdma_send_error_msg(struct svcxprt_rdma *rdma, + struct svc_rdma_send_ctxt *sctxt, + struct svc_rdma_recv_ctxt *rctxt, + int status) { - return xdr->head[0].iov_base - - (xdr->len - - xdr->page_len - - xdr->tail[0].iov_len - - xdr->head[0].iov_len); + __be32 *rdma_argp = rctxt->rc_recv_buf; + __be32 *p; + + rpcrdma_set_xdrlen(&sctxt->sc_hdrbuf, 0); + xdr_init_encode(&sctxt->sc_stream, &sctxt->sc_hdrbuf, + sctxt->sc_xprt_buf, NULL); + + p = xdr_reserve_space(&sctxt->sc_stream, + rpcrdma_fixed_maxsz * sizeof(*p)); + if (!p) + goto put_ctxt; + + *p++ = *rdma_argp; + *p++ = *(rdma_argp + 1); + *p++ = rdma->sc_fc_credits; + *p = rdma_error; + + switch (status) { + case -EPROTONOSUPPORT: + p = xdr_reserve_space(&sctxt->sc_stream, 3 * sizeof(*p)); + if (!p) + goto put_ctxt; + + *p++ = err_vers; + *p++ = rpcrdma_version; + *p = rpcrdma_version; + trace_svcrdma_err_vers(*rdma_argp); + break; + default: + p = xdr_reserve_space(&sctxt->sc_stream, sizeof(*p)); + if (!p) + goto put_ctxt; + + *p = err_chunk; + trace_svcrdma_err_chunk(*rdma_argp); + } + + /* Remote Invalidation is skipped for simplicity. */ + sctxt->sc_send_wr.num_sge = 1; + sctxt->sc_send_wr.opcode = IB_WR_SEND; + sctxt->sc_sges[0].length = sctxt->sc_hdrbuf.len; + if (svc_rdma_post_send(rdma, sctxt)) + goto put_ctxt; + return; + +put_ctxt: + svc_rdma_send_ctxt_put(rdma, sctxt); } +/** + * svc_rdma_sendto - Transmit an RPC reply + * @rqstp: processed RPC request, reply XDR already in ::rq_res + * + * Any resources still associated with @rqstp are released upon return. + * If no reply message was possible, the connection is closed. + * + * Returns: + * %0 if an RPC reply has been successfully posted, + * %-ENOMEM if a resource shortage occurred (connection is lost), + * %-ENOTCONN if posting failed (connection is lost). + */ int svc_rdma_sendto(struct svc_rqst *rqstp) { struct svc_xprt *xprt = rqstp->rq_xprt; struct svcxprt_rdma *rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt); - struct rpcrdma_msg *rdma_argp; - struct rpcrdma_msg *rdma_resp; - struct rpcrdma_write_array *reply_ary; - enum rpcrdma_proc reply_type; + struct svc_rdma_recv_ctxt *rctxt = rqstp->rq_xprt_ctxt; + __be32 *rdma_argp = rctxt->rc_recv_buf; + struct svc_rdma_send_ctxt *sctxt; + unsigned int rc_size; + __be32 *p; int ret; - int inline_bytes; - struct page *res_page; - struct svc_rdma_op_ctxt *ctxt; - struct svc_rdma_req_map *vec; - - dprintk("svcrdma: sending response for rqstp=%p\n", rqstp); - - /* Get the RDMA request header. */ - rdma_argp = xdr_start(&rqstp->rq_arg); - - /* Build an req vec for the XDR */ - ctxt = svc_rdma_get_context(rdma); - ctxt->direction = DMA_TO_DEVICE; - vec = svc_rdma_get_req_map(); - ret = map_xdr(rdma, &rqstp->rq_res, vec); - if (ret) - goto err0; - inline_bytes = rqstp->rq_res.len; - - /* Create the RDMA response header */ - res_page = svc_rdma_get_page(); - rdma_resp = page_address(res_page); - reply_ary = svc_rdma_get_reply_array(rdma_argp); - if (reply_ary) - reply_type = RDMA_NOMSG; - else - reply_type = RDMA_MSG; - svc_rdma_xdr_encode_reply_header(rdma, rdma_argp, - rdma_resp, reply_type); - - /* Send any write-chunk data and build resp write-list */ - ret = send_write_chunks(rdma, rdma_argp, rdma_resp, - rqstp, vec); - if (ret < 0) { - printk(KERN_ERR "svcrdma: failed to send write chunks, rc=%d\n", - ret); - goto err1; - } - inline_bytes -= ret; - - /* Send any reply-list data and update resp reply-list */ - ret = send_reply_chunks(rdma, rdma_argp, rdma_resp, - rqstp, vec); - if (ret < 0) { - printk(KERN_ERR "svcrdma: failed to send reply chunks, rc=%d\n", - ret); - goto err1; + + ret = -ENOTCONN; + if (svc_xprt_is_dead(xprt)) + goto drop_connection; + + ret = -ENOMEM; + sctxt = svc_rdma_send_ctxt_get(rdma); + if (!sctxt) + goto drop_connection; + + ret = -EMSGSIZE; + p = xdr_reserve_space(&sctxt->sc_stream, + rpcrdma_fixed_maxsz * sizeof(*p)); + if (!p) + goto put_ctxt; + + ret = svc_rdma_send_write_list(rdma, rctxt, &rqstp->rq_res); + if (ret < 0) + goto put_ctxt; + + rc_size = 0; + if (!pcl_is_empty(&rctxt->rc_reply_pcl)) { + ret = svc_rdma_prepare_reply_chunk(rdma, &rctxt->rc_write_pcl, + &rctxt->rc_reply_pcl, sctxt, + &rqstp->rq_res); + if (ret < 0) + goto reply_chunk; + rc_size = ret; } - inline_bytes -= ret; - - ret = send_reply(rdma, rqstp, res_page, rdma_resp, ctxt, vec, - inline_bytes); - svc_rdma_put_req_map(vec); - dprintk("svcrdma: send_reply returns %d\n", ret); - return ret; - - err1: - put_page(res_page); - err0: - svc_rdma_put_req_map(vec); - svc_rdma_put_context(ctxt, 0); - return ret; + + *p++ = *rdma_argp; + *p++ = *(rdma_argp + 1); + *p++ = rdma->sc_fc_credits; + *p = pcl_is_empty(&rctxt->rc_reply_pcl) ? rdma_msg : rdma_nomsg; + + ret = svc_rdma_encode_read_list(sctxt); + if (ret < 0) + goto put_ctxt; + ret = svc_rdma_encode_write_list(rctxt, sctxt); + if (ret < 0) + goto put_ctxt; + ret = svc_rdma_encode_reply_chunk(rctxt, sctxt, rc_size); + if (ret < 0) + goto put_ctxt; + + ret = svc_rdma_send_reply_msg(rdma, sctxt, rctxt, rqstp); + if (ret < 0) + goto put_ctxt; + return 0; + +reply_chunk: + if (ret != -E2BIG && ret != -EINVAL) + goto put_ctxt; + + /* Send completion releases payload pages that were part + * of previously posted RDMA Writes. + */ + svc_rdma_save_io_pages(rqstp, sctxt); + svc_rdma_send_error_msg(rdma, sctxt, rctxt, ret); + return 0; + +put_ctxt: + svc_rdma_send_ctxt_put(rdma, sctxt); +drop_connection: + trace_svcrdma_send_err(rqstp, ret); + svc_xprt_deferred_close(&rdma->sc_xprt); + return -ENOTCONN; +} + +/** + * svc_rdma_result_payload - special processing for a result payload + * @rqstp: RPC transaction context + * @offset: payload's byte offset in @rqstp->rq_res + * @length: size of payload, in bytes + * + * Assign the passed-in result payload to the current Write chunk, + * and advance to cur_result_payload to the next Write chunk, if + * there is one. + * + * Return values: + * %0 if successful or nothing needed to be done + * %-E2BIG if the payload was larger than the Write chunk + */ +int svc_rdma_result_payload(struct svc_rqst *rqstp, unsigned int offset, + unsigned int length) +{ + struct svc_rdma_recv_ctxt *rctxt = rqstp->rq_xprt_ctxt; + struct svc_rdma_chunk *chunk; + + chunk = rctxt->rc_cur_result_payload; + if (!length || !chunk) + return 0; + rctxt->rc_cur_result_payload = + pcl_next_chunk(&rctxt->rc_write_pcl, chunk); + + if (length > chunk->ch_length) + return -E2BIG; + chunk->ch_position = offset; + chunk->ch_payload_length = length; + return 0; } |