// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
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/*
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* Copyright (c) 2016-2018 Oracle. All rights reserved.
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* Copyright (c) 2014 Open Grid Computing, Inc. All rights reserved.
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* Copyright (c) 2005-2006 Network Appliance, Inc. All rights reserved.
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*
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* This software is available to you under a choice of one of two
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* licenses. You may choose to be licensed under the terms of the GNU
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* General Public License (GPL) Version 2, available from the file
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* COPYING in the main directory of this source tree, or the BSD-type
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* license below:
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*
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* Neither the name of the Network Appliance, Inc. nor the names of
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* its contributors may be used to endorse or promote products
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* derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Author: Tom Tucker <tom@opengridcomputing.com>
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*/
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/* Operation
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*
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* The main entry point is svc_rdma_sendto. This is called by the
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* RPC server when an RPC Reply is ready to be transmitted to a client.
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*
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* The passed-in svc_rqst contains a struct xdr_buf which holds an
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* XDR-encoded RPC Reply message. sendto must construct the RPC-over-RDMA
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* transport header, post all Write WRs needed for this Reply, then post
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* a Send WR conveying the transport header and the RPC message itself to
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* the client.
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*
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* svc_rdma_sendto must fully transmit the Reply before returning, as
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* the svc_rqst will be recycled as soon as sendto returns. Remaining
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* resources referred to by the svc_rqst are also recycled at that time.
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* Therefore any resources that must remain longer must be detached
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* from the svc_rqst and released later.
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*
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* Page Management
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*
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* The I/O that performs Reply transmission is asynchronous, and may
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* complete well after sendto returns. Thus pages under I/O must be
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* removed from the svc_rqst before sendto returns.
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*
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* The logic here depends on Send Queue and completion ordering. Since
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* the Send WR is always posted last, it will always complete last. Thus
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* when it completes, it is guaranteed that all previous Write WRs have
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* also completed.
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*
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* Write WRs are constructed and posted. Each Write segment gets its own
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* svc_rdma_rw_ctxt, allowing the Write completion handler to find and
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* DMA-unmap the pages under I/O for that Write segment. The Write
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* completion handler does not release any pages.
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*
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* When the Send WR is constructed, it also gets its own svc_rdma_send_ctxt.
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* The ownership of all of the Reply's pages are transferred into that
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* ctxt, the Send WR is posted, and sendto returns.
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*
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* The svc_rdma_send_ctxt is presented when the Send WR completes. The
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* Send completion handler finally releases the Reply's pages.
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*
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* This mechanism also assumes that completions on the transport's Send
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* Completion Queue do not run in parallel. Otherwise a Write completion
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* and Send completion running at the same time could release pages that
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* are still DMA-mapped.
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*
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* Error Handling
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*
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* - If the Send WR is posted successfully, it will either complete
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* successfully, or get flushed. Either way, the Send completion
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* handler releases the Reply's pages.
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* - If the Send WR cannot be not posted, the forward path releases
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* the Reply's pages.
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*
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* This handles the case, without the use of page reference counting,
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* where two different Write segments send portions of the same page.
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*/
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#include <linux/spinlock.h>
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#include <asm/unaligned.h>
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#include <rdma/ib_verbs.h>
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#include <rdma/rdma_cm.h>
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#include <linux/sunrpc/debug.h>
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#include <linux/sunrpc/svc_rdma.h>
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#include "xprt_rdma.h"
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#include <trace/events/rpcrdma.h>
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#define RPCDBG_FACILITY RPCDBG_SVCXPRT
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static void svc_rdma_wc_send(struct ib_cq *cq, struct ib_wc *wc);
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static inline struct svc_rdma_send_ctxt *
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svc_rdma_next_send_ctxt(struct list_head *list)
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{
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return list_first_entry_or_null(list, struct svc_rdma_send_ctxt,
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sc_list);
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}
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static void svc_rdma_send_cid_init(struct svcxprt_rdma *rdma,
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struct rpc_rdma_cid *cid)
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{
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cid->ci_queue_id = rdma->sc_sq_cq->res.id;
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cid->ci_completion_id = atomic_inc_return(&rdma->sc_completion_ids);
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}
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static struct svc_rdma_send_ctxt *
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svc_rdma_send_ctxt_alloc(struct svcxprt_rdma *rdma)
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{
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struct svc_rdma_send_ctxt *ctxt;
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dma_addr_t addr;
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void *buffer;
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size_t size;
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int i;
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size = sizeof(*ctxt);
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size += rdma->sc_max_send_sges * sizeof(struct ib_sge);
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ctxt = kmalloc(size, GFP_KERNEL);
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if (!ctxt)
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goto fail0;
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buffer = kmalloc(rdma->sc_max_req_size, GFP_KERNEL);
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if (!buffer)
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goto fail1;
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addr = ib_dma_map_single(rdma->sc_pd->device, buffer,
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rdma->sc_max_req_size, DMA_TO_DEVICE);
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if (ib_dma_mapping_error(rdma->sc_pd->device, addr))
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goto fail2;
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svc_rdma_send_cid_init(rdma, &ctxt->sc_cid);
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ctxt->sc_send_wr.next = NULL;
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ctxt->sc_send_wr.wr_cqe = &ctxt->sc_cqe;
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ctxt->sc_send_wr.sg_list = ctxt->sc_sges;
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ctxt->sc_send_wr.send_flags = IB_SEND_SIGNALED;
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ctxt->sc_cqe.done = svc_rdma_wc_send;
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ctxt->sc_xprt_buf = buffer;
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xdr_buf_init(&ctxt->sc_hdrbuf, ctxt->sc_xprt_buf,
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rdma->sc_max_req_size);
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ctxt->sc_sges[0].addr = addr;
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for (i = 0; i < rdma->sc_max_send_sges; i++)
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ctxt->sc_sges[i].lkey = rdma->sc_pd->local_dma_lkey;
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return ctxt;
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fail2:
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kfree(buffer);
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fail1:
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kfree(ctxt);
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fail0:
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return NULL;
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}
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/**
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* svc_rdma_send_ctxts_destroy - Release all send_ctxt's for an xprt
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* @rdma: svcxprt_rdma being torn down
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*
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*/
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void svc_rdma_send_ctxts_destroy(struct svcxprt_rdma *rdma)
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{
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struct svc_rdma_send_ctxt *ctxt;
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while ((ctxt = svc_rdma_next_send_ctxt(&rdma->sc_send_ctxts))) {
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list_del(&ctxt->sc_list);
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ib_dma_unmap_single(rdma->sc_pd->device,
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ctxt->sc_sges[0].addr,
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rdma->sc_max_req_size,
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DMA_TO_DEVICE);
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kfree(ctxt->sc_xprt_buf);
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kfree(ctxt);
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}
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}
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/**
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* svc_rdma_send_ctxt_get - Get a free send_ctxt
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* @rdma: controlling svcxprt_rdma
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*
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* Returns a ready-to-use send_ctxt, or NULL if none are
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* available and a fresh one cannot be allocated.
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*/
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struct svc_rdma_send_ctxt *svc_rdma_send_ctxt_get(struct svcxprt_rdma *rdma)
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{
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struct svc_rdma_send_ctxt *ctxt;
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spin_lock(&rdma->sc_send_lock);
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ctxt = svc_rdma_next_send_ctxt(&rdma->sc_send_ctxts);
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if (!ctxt)
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goto out_empty;
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list_del(&ctxt->sc_list);
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spin_unlock(&rdma->sc_send_lock);
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out:
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rpcrdma_set_xdrlen(&ctxt->sc_hdrbuf, 0);
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xdr_init_encode(&ctxt->sc_stream, &ctxt->sc_hdrbuf,
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ctxt->sc_xprt_buf, NULL);
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ctxt->sc_send_wr.num_sge = 0;
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ctxt->sc_cur_sge_no = 0;
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ctxt->sc_page_count = 0;
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return ctxt;
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out_empty:
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spin_unlock(&rdma->sc_send_lock);
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ctxt = svc_rdma_send_ctxt_alloc(rdma);
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if (!ctxt)
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return NULL;
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goto out;
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}
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/**
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* svc_rdma_send_ctxt_put - Return send_ctxt to free list
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* @rdma: controlling svcxprt_rdma
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* @ctxt: object to return to the free list
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*
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* Pages left in sc_pages are DMA unmapped and released.
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*/
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void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma,
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struct svc_rdma_send_ctxt *ctxt)
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{
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struct ib_device *device = rdma->sc_cm_id->device;
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unsigned int i;
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/* The first SGE contains the transport header, which
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* remains mapped until @ctxt is destroyed.
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*/
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for (i = 1; i < ctxt->sc_send_wr.num_sge; i++) {
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ib_dma_unmap_page(device,
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ctxt->sc_sges[i].addr,
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ctxt->sc_sges[i].length,
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DMA_TO_DEVICE);
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trace_svcrdma_dma_unmap_page(rdma,
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ctxt->sc_sges[i].addr,
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ctxt->sc_sges[i].length);
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}
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for (i = 0; i < ctxt->sc_page_count; ++i)
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put_page(ctxt->sc_pages[i]);
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spin_lock(&rdma->sc_send_lock);
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list_add(&ctxt->sc_list, &rdma->sc_send_ctxts);
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spin_unlock(&rdma->sc_send_lock);
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}
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/**
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* svc_rdma_wc_send - Invoked by RDMA provider for each polled Send WC
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* @cq: Completion Queue context
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* @wc: Work Completion object
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*
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* NB: The svc_xprt/svcxprt_rdma is pinned whenever it's possible that
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* the Send completion handler could be running.
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*/
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static void svc_rdma_wc_send(struct ib_cq *cq, struct ib_wc *wc)
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{
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struct svcxprt_rdma *rdma = cq->cq_context;
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struct ib_cqe *cqe = wc->wr_cqe;
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struct svc_rdma_send_ctxt *ctxt =
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container_of(cqe, struct svc_rdma_send_ctxt, sc_cqe);
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trace_svcrdma_wc_send(wc, &ctxt->sc_cid);
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atomic_inc(&rdma->sc_sq_avail);
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wake_up(&rdma->sc_send_wait);
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svc_rdma_send_ctxt_put(rdma, ctxt);
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if (unlikely(wc->status != IB_WC_SUCCESS)) {
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set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
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svc_xprt_enqueue(&rdma->sc_xprt);
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}
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}
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/**
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* svc_rdma_send - Post a single Send WR
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* @rdma: transport on which to post the WR
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* @ctxt: send ctxt with a Send WR ready to post
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*
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* Returns zero the Send WR was posted successfully. Otherwise, a
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* negative errno is returned.
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*/
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int svc_rdma_send(struct svcxprt_rdma *rdma, struct svc_rdma_send_ctxt *ctxt)
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{
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struct ib_send_wr *wr = &ctxt->sc_send_wr;
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int ret;
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might_sleep();
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/* Sync the transport header buffer */
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ib_dma_sync_single_for_device(rdma->sc_pd->device,
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wr->sg_list[0].addr,
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wr->sg_list[0].length,
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DMA_TO_DEVICE);
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/* If the SQ is full, wait until an SQ entry is available */
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while (1) {
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if ((atomic_dec_return(&rdma->sc_sq_avail) < 0)) {
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atomic_inc(&rdma_stat_sq_starve);
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trace_svcrdma_sq_full(rdma);
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atomic_inc(&rdma->sc_sq_avail);
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wait_event(rdma->sc_send_wait,
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atomic_read(&rdma->sc_sq_avail) > 1);
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if (test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags))
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return -ENOTCONN;
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trace_svcrdma_sq_retry(rdma);
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continue;
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}
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trace_svcrdma_post_send(ctxt);
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ret = ib_post_send(rdma->sc_qp, wr, NULL);
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if (ret)
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break;
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return 0;
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}
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trace_svcrdma_sq_post_err(rdma, ret);
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set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
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wake_up(&rdma->sc_send_wait);
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return ret;
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}
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/**
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* svc_rdma_encode_read_list - Encode RPC Reply's Read chunk list
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* @sctxt: Send context for the RPC Reply
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*
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* Return values:
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* On success, returns length in bytes of the Reply XDR buffer
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* that was consumed by the Reply Read list
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* %-EMSGSIZE on XDR buffer overflow
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*/
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static ssize_t svc_rdma_encode_read_list(struct svc_rdma_send_ctxt *sctxt)
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{
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/* RPC-over-RDMA version 1 replies never have a Read list. */
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return xdr_stream_encode_item_absent(&sctxt->sc_stream);
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}
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/**
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* svc_rdma_encode_write_segment - Encode one Write segment
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* @src: matching Write chunk in the RPC Call header
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* @sctxt: Send context for the RPC Reply
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* @remaining: remaining bytes of the payload left in the Write chunk
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*
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* Return values:
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* On success, returns length in bytes of the Reply XDR buffer
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* that was consumed by the Write segment
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* %-EMSGSIZE on XDR buffer overflow
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*/
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static ssize_t svc_rdma_encode_write_segment(__be32 *src,
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struct svc_rdma_send_ctxt *sctxt,
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unsigned int *remaining)
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{
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__be32 *p;
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const size_t len = rpcrdma_segment_maxsz * sizeof(*p);
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u32 handle, length;
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u64 offset;
|
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p = xdr_reserve_space(&sctxt->sc_stream, len);
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if (!p)
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return -EMSGSIZE;
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xdr_decode_rdma_segment(src, &handle, &length, &offset);
|
|
if (*remaining < length) {
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/* segment only partly filled */
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length = *remaining;
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*remaining = 0;
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} else {
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/* entire segment was consumed */
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*remaining -= length;
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}
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xdr_encode_rdma_segment(p, handle, length, offset);
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|
trace_svcrdma_encode_wseg(handle, length, offset);
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return len;
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}
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|
/**
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* svc_rdma_encode_write_chunk - Encode one Write chunk
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* @src: matching Write chunk in the RPC Call header
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* @sctxt: Send context for the RPC Reply
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* @remaining: size in bytes of the payload in the Write chunk
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*
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* Copy a Write chunk from the Call transport header to the
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* Reply transport header. Update each segment's length field
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* to reflect the number of bytes written in that segment.
|
*
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* Return values:
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* On success, returns length in bytes of the Reply XDR buffer
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* that was consumed by the Write chunk
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* %-EMSGSIZE on XDR buffer overflow
|
*/
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static ssize_t svc_rdma_encode_write_chunk(__be32 *src,
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struct svc_rdma_send_ctxt *sctxt,
|
unsigned int remaining)
|
{
|
unsigned int i, nsegs;
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ssize_t len, ret;
|
|
len = 0;
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trace_svcrdma_encode_write_chunk(remaining);
|
|
src++;
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ret = xdr_stream_encode_item_present(&sctxt->sc_stream);
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if (ret < 0)
|
return -EMSGSIZE;
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len += ret;
|
|
nsegs = be32_to_cpup(src++);
|
ret = xdr_stream_encode_u32(&sctxt->sc_stream, nsegs);
|
if (ret < 0)
|
return -EMSGSIZE;
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len += ret;
|
|
for (i = nsegs; i; i--) {
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ret = svc_rdma_encode_write_segment(src, sctxt, &remaining);
|
if (ret < 0)
|
return -EMSGSIZE;
|
src += rpcrdma_segment_maxsz;
|
len += ret;
|
}
|
|
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
|
* @length: size in bytes of the payload in the first Write chunk
|
*
|
* The client provides a Write chunk list in the Call message. Fill
|
* in the segments in the first Write chunk in the Reply's transport
|
* header with the number of bytes consumed in each segment.
|
* Remaining chunks are returned unused.
|
*
|
* Assumptions:
|
* - Client has provided only one Write chunk
|
*
|
* 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(const struct svc_rdma_recv_ctxt *rctxt,
|
struct svc_rdma_send_ctxt *sctxt,
|
unsigned int length)
|
{
|
ssize_t len, ret;
|
|
ret = svc_rdma_encode_write_chunk(rctxt->rc_write_list, sctxt, length);
|
if (ret < 0)
|
return ret;
|
len = ret;
|
|
/* 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
|
*
|
* Assumptions:
|
* - Reply can always fit in the client-provided 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
|
*/
|
static ssize_t
|
svc_rdma_encode_reply_chunk(const struct svc_rdma_recv_ctxt *rctxt,
|
struct svc_rdma_send_ctxt *sctxt,
|
unsigned int length)
|
{
|
return svc_rdma_encode_write_chunk(rctxt->rc_reply_chunk, sctxt,
|
length);
|
}
|
|
static int svc_rdma_dma_map_page(struct svcxprt_rdma *rdma,
|
struct svc_rdma_send_ctxt *ctxt,
|
struct page *page,
|
unsigned long offset,
|
unsigned int len)
|
{
|
struct ib_device *dev = rdma->sc_cm_id->device;
|
dma_addr_t dma_addr;
|
|
dma_addr = ib_dma_map_page(dev, page, offset, len, DMA_TO_DEVICE);
|
trace_svcrdma_dma_map_page(rdma, dma_addr, len);
|
if (ib_dma_mapping_error(dev, dma_addr))
|
goto out_maperr;
|
|
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;
|
|
out_maperr:
|
return -EIO;
|
}
|
|
/* ib_dma_map_page() is used here because svc_rdma_dma_unmap()
|
* handles DMA-unmap and it uses ib_dma_unmap_page() exclusively.
|
*/
|
static int svc_rdma_dma_map_buf(struct svcxprt_rdma *rdma,
|
struct svc_rdma_send_ctxt *ctxt,
|
unsigned char *base,
|
unsigned int len)
|
{
|
return svc_rdma_dma_map_page(rdma, ctxt, virt_to_page(base),
|
offset_in_page(base), len);
|
}
|
|
/**
|
* svc_rdma_pull_up_needed - Determine whether to use pull-up
|
* @rdma: controlling transport
|
* @sctxt: send_ctxt for the Send WR
|
* @rctxt: Write and Reply chunks provided by client
|
* @xdr: xdr_buf containing RPC message to transmit
|
*
|
* Returns:
|
* %true if pull-up must be used
|
* %false otherwise
|
*/
|
static bool svc_rdma_pull_up_needed(struct svcxprt_rdma *rdma,
|
struct svc_rdma_send_ctxt *sctxt,
|
const struct svc_rdma_recv_ctxt *rctxt,
|
struct xdr_buf *xdr)
|
{
|
int elements;
|
|
/* For small messages, copying bytes is cheaper than DMA mapping.
|
*/
|
if (sctxt->sc_hdrbuf.len + xdr->len < RPCRDMA_PULLUP_THRESH)
|
return true;
|
|
/* Check whether the xdr_buf has more elements than can
|
* fit in a single RDMA Send.
|
*/
|
/* xdr->head */
|
elements = 1;
|
|
/* xdr->pages */
|
if (!rctxt || !rctxt->rc_write_list) {
|
unsigned int remaining;
|
unsigned long pageoff;
|
|
pageoff = xdr->page_base & ~PAGE_MASK;
|
remaining = xdr->page_len;
|
while (remaining) {
|
++elements;
|
remaining -= min_t(u32, PAGE_SIZE - pageoff,
|
remaining);
|
pageoff = 0;
|
}
|
}
|
|
/* xdr->tail */
|
if (xdr->tail[0].iov_len)
|
++elements;
|
|
/* assume 1 SGE is needed for the transport header */
|
return elements >= rdma->sc_max_send_sges;
|
}
|
|
/**
|
* 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
|
* @rctxt: Write and Reply chunks 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.
|
*
|
* Returns zero on success, or a negative errno on failure.
|
*/
|
static int svc_rdma_pull_up_reply_msg(struct svcxprt_rdma *rdma,
|
struct svc_rdma_send_ctxt *sctxt,
|
const struct svc_rdma_recv_ctxt *rctxt,
|
const struct xdr_buf *xdr)
|
{
|
unsigned char *dst, *tailbase;
|
unsigned int taillen;
|
|
dst = sctxt->sc_xprt_buf + sctxt->sc_hdrbuf.len;
|
memcpy(dst, xdr->head[0].iov_base, xdr->head[0].iov_len);
|
dst += xdr->head[0].iov_len;
|
|
tailbase = xdr->tail[0].iov_base;
|
taillen = xdr->tail[0].iov_len;
|
if (rctxt && rctxt->rc_write_list) {
|
u32 xdrpad;
|
|
xdrpad = xdr_pad_size(xdr->page_len);
|
if (taillen && xdrpad) {
|
tailbase += xdrpad;
|
taillen -= xdrpad;
|
}
|
} else {
|
unsigned int len, remaining;
|
unsigned long pageoff;
|
struct page **ppages;
|
|
ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
|
pageoff = xdr->page_base & ~PAGE_MASK;
|
remaining = xdr->page_len;
|
while (remaining) {
|
len = min_t(u32, PAGE_SIZE - pageoff, remaining);
|
|
memcpy(dst, page_address(*ppages) + pageoff, len);
|
remaining -= len;
|
dst += len;
|
pageoff = 0;
|
ppages++;
|
}
|
}
|
|
if (taillen)
|
memcpy(dst, tailbase, taillen);
|
|
sctxt->sc_sges[0].length += xdr->len;
|
trace_svcrdma_send_pullup(sctxt->sc_sges[0].length);
|
return 0;
|
}
|
|
/* svc_rdma_map_reply_msg - DMA map the buffer holding RPC message
|
* @rdma: controlling transport
|
* @sctxt: send_ctxt for the Send WR
|
* @rctxt: Write and Reply chunks provided by client
|
* @xdr: prepared xdr_buf containing RPC message
|
*
|
* Load the xdr_buf into the ctxt's sge array, and DMA map each
|
* element as it is added. The Send WR's num_sge field is set.
|
*
|
* Returns zero on success, or a negative errno on failure.
|
*/
|
int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
|
struct svc_rdma_send_ctxt *sctxt,
|
const struct svc_rdma_recv_ctxt *rctxt,
|
struct xdr_buf *xdr)
|
{
|
unsigned int len, remaining;
|
unsigned long page_off;
|
struct page **ppages;
|
unsigned char *base;
|
u32 xdr_pad;
|
int ret;
|
|
/* 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, and we're done here.
|
*/
|
if (rctxt && rctxt->rc_reply_chunk)
|
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, rctxt, xdr))
|
return svc_rdma_pull_up_reply_msg(rdma, sctxt, rctxt, xdr);
|
|
++sctxt->sc_cur_sge_no;
|
ret = svc_rdma_dma_map_buf(rdma, sctxt,
|
xdr->head[0].iov_base,
|
xdr->head[0].iov_len);
|
if (ret < 0)
|
return ret;
|
|
/* If a Write chunk is present, the xdr_buf's page list
|
* is not included inline. However the Upper Layer may
|
* have added XDR padding in the tail buffer, and that
|
* should not be included inline.
|
*/
|
if (rctxt && rctxt->rc_write_list) {
|
base = xdr->tail[0].iov_base;
|
len = xdr->tail[0].iov_len;
|
xdr_pad = xdr_pad_size(xdr->page_len);
|
|
if (len && xdr_pad) {
|
base += xdr_pad;
|
len -= xdr_pad;
|
}
|
|
goto tail;
|
}
|
|
ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
|
page_off = xdr->page_base & ~PAGE_MASK;
|
remaining = xdr->page_len;
|
while (remaining) {
|
len = min_t(u32, PAGE_SIZE - page_off, remaining);
|
|
++sctxt->sc_cur_sge_no;
|
ret = svc_rdma_dma_map_page(rdma, sctxt, *ppages++,
|
page_off, len);
|
if (ret < 0)
|
return ret;
|
|
remaining -= len;
|
page_off = 0;
|
}
|
|
base = xdr->tail[0].iov_base;
|
len = xdr->tail[0].iov_len;
|
tail:
|
if (len) {
|
++sctxt->sc_cur_sge_no;
|
ret = svc_rdma_dma_map_buf(rdma, sctxt, base, len);
|
if (ret < 0)
|
return ret;
|
}
|
|
return 0;
|
}
|
|
/* 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;
|
}
|
|
/* 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.
|
*
|
* RDMA Send is the last step of transmitting an RPC reply. Pages
|
* involved in the earlier RDMA Writes are here transferred out
|
* of the rqstp and into the sctxt's page array. These pages are
|
* DMA unmapped by each Write completion, but the subsequent Send
|
* completion finally releases these pages.
|
*
|
* 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)
|
{
|
int ret;
|
|
ret = svc_rdma_map_reply_msg(rdma, sctxt, rctxt, &rqstp->rq_res);
|
if (ret < 0)
|
return ret;
|
|
svc_rdma_save_io_pages(rqstp, sctxt);
|
|
if (rctxt->rc_inv_rkey) {
|
sctxt->sc_send_wr.opcode = IB_WR_SEND_WITH_INV;
|
sctxt->sc_send_wr.ex.invalidate_rkey = rctxt->rc_inv_rkey;
|
} else {
|
sctxt->sc_send_wr.opcode = IB_WR_SEND;
|
}
|
return svc_rdma_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.
|
*/
|
void svc_rdma_send_error_msg(struct svcxprt_rdma *rdma,
|
struct svc_rdma_send_ctxt *sctxt,
|
struct svc_rdma_recv_ctxt *rctxt,
|
int status)
|
{
|
__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_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 svc_rdma_recv_ctxt *rctxt = rqstp->rq_xprt_ctxt;
|
__be32 *rdma_argp = rctxt->rc_recv_buf;
|
__be32 *wr_lst = rctxt->rc_write_list;
|
__be32 *rp_ch = rctxt->rc_reply_chunk;
|
struct xdr_buf *xdr = &rqstp->rq_res;
|
struct svc_rdma_send_ctxt *sctxt;
|
__be32 *p;
|
int ret;
|
|
ret = -ENOTCONN;
|
if (svc_xprt_is_dead(xprt))
|
goto err0;
|
|
ret = -ENOMEM;
|
sctxt = svc_rdma_send_ctxt_get(rdma);
|
if (!sctxt)
|
goto err0;
|
|
p = xdr_reserve_space(&sctxt->sc_stream,
|
rpcrdma_fixed_maxsz * sizeof(*p));
|
if (!p)
|
goto err0;
|
*p++ = *rdma_argp;
|
*p++ = *(rdma_argp + 1);
|
*p++ = rdma->sc_fc_credits;
|
*p = rp_ch ? rdma_nomsg : rdma_msg;
|
|
if (svc_rdma_encode_read_list(sctxt) < 0)
|
goto err0;
|
if (wr_lst) {
|
/* XXX: Presume the client sent only one Write chunk */
|
unsigned long offset;
|
unsigned int length;
|
|
if (rctxt->rc_read_payload_length) {
|
offset = rctxt->rc_read_payload_offset;
|
length = rctxt->rc_read_payload_length;
|
} else {
|
offset = xdr->head[0].iov_len;
|
length = xdr->page_len;
|
}
|
ret = svc_rdma_send_write_chunk(rdma, wr_lst, xdr, offset,
|
length);
|
if (ret < 0)
|
goto err2;
|
if (svc_rdma_encode_write_list(rctxt, sctxt, length) < 0)
|
goto err0;
|
} else {
|
if (xdr_stream_encode_item_absent(&sctxt->sc_stream) < 0)
|
goto err0;
|
}
|
if (rp_ch) {
|
ret = svc_rdma_send_reply_chunk(rdma, rctxt, &rqstp->rq_res);
|
if (ret < 0)
|
goto err2;
|
if (svc_rdma_encode_reply_chunk(rctxt, sctxt, ret) < 0)
|
goto err0;
|
} else {
|
if (xdr_stream_encode_item_absent(&sctxt->sc_stream) < 0)
|
goto err0;
|
}
|
|
ret = svc_rdma_send_reply_msg(rdma, sctxt, rctxt, rqstp);
|
if (ret < 0)
|
goto err1;
|
return 0;
|
|
err2:
|
if (ret != -E2BIG && ret != -EINVAL)
|
goto err1;
|
|
/* 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;
|
|
err1:
|
svc_rdma_send_ctxt_put(rdma, sctxt);
|
err0:
|
trace_svcrdma_send_err(rqstp, ret);
|
set_bit(XPT_CLOSE, &xprt->xpt_flags);
|
return -ENOTCONN;
|
}
|
|
/**
|
* svc_rdma_read_payload - special processing for a READ payload
|
* @rqstp: svc_rqst to operate on
|
* @offset: payload's byte offset in @xdr
|
* @length: size of payload, in bytes
|
*
|
* Returns zero on success.
|
*
|
* For the moment, just record the xdr_buf location of the READ
|
* payload. svc_rdma_sendto will use that location later when
|
* we actually send the payload.
|
*/
|
int svc_rdma_read_payload(struct svc_rqst *rqstp, unsigned int offset,
|
unsigned int length)
|
{
|
struct svc_rdma_recv_ctxt *rctxt = rqstp->rq_xprt_ctxt;
|
|
/* XXX: Just one READ payload slot for now, since our
|
* transport implementation currently supports only one
|
* Write chunk.
|
*/
|
rctxt->rc_read_payload_offset = offset;
|
rctxt->rc_read_payload_length = length;
|
|
return 0;
|
}
|
