mirror of https://gitee.com/openkylin/linux.git
840 lines
23 KiB
C
840 lines
23 KiB
C
// 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/rpc_rdma.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 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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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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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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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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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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trace_svcrdma_wc_send(wc);
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atomic_inc(&rdma->sc_sq_avail);
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wake_up(&rdma->sc_send_wait);
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ctxt = container_of(cqe, struct svc_rdma_send_ctxt, sc_cqe);
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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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if (wc->status != IB_WC_WR_FLUSH_ERR)
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pr_err("svcrdma: Send: %s (%u/0x%x)\n",
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ib_wc_status_msg(wc->status),
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wc->status, wc->vendor_err);
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}
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svc_xprt_put(&rdma->sc_xprt);
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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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* @wr: prepared Send WR 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 ib_send_wr *wr)
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{
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struct ib_send_wr *bad_wr;
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int ret;
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might_sleep();
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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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svc_xprt_get(&rdma->sc_xprt);
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ret = ib_post_send(rdma->sc_qp, wr, &bad_wr);
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trace_svcrdma_post_send(wr, ret);
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if (ret) {
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set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
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svc_xprt_put(&rdma->sc_xprt);
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wake_up(&rdma->sc_send_wait);
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}
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break;
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}
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return ret;
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}
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static u32 xdr_padsize(u32 len)
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{
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return (len & 3) ? (4 - (len & 3)) : 0;
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}
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/* Returns length of transport header, in bytes.
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*/
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static unsigned int svc_rdma_reply_hdr_len(__be32 *rdma_resp)
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{
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unsigned int nsegs;
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__be32 *p;
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p = rdma_resp;
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/* RPC-over-RDMA V1 replies never have a Read list. */
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p += rpcrdma_fixed_maxsz + 1;
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/* Skip Write list. */
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while (*p++ != xdr_zero) {
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nsegs = be32_to_cpup(p++);
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p += nsegs * rpcrdma_segment_maxsz;
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}
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/* Skip Reply chunk. */
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if (*p++ != xdr_zero) {
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nsegs = be32_to_cpup(p++);
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p += nsegs * rpcrdma_segment_maxsz;
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}
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return (unsigned long)p - (unsigned long)rdma_resp;
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}
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/* One Write chunk is copied from Call transport header to Reply
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* transport header. Each segment's length field is updated to
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* reflect number of bytes consumed in the segment.
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*
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* Returns number of segments in this chunk.
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*/
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static unsigned int xdr_encode_write_chunk(__be32 *dst, __be32 *src,
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unsigned int remaining)
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{
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unsigned int i, nsegs;
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u32 seg_len;
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/* Write list discriminator */
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*dst++ = *src++;
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/* number of segments in this chunk */
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nsegs = be32_to_cpup(src);
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*dst++ = *src++;
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for (i = nsegs; i; i--) {
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/* segment's RDMA handle */
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*dst++ = *src++;
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/* bytes returned in this segment */
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seg_len = be32_to_cpu(*src);
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if (remaining >= seg_len) {
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/* entire segment was consumed */
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*dst = *src;
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remaining -= seg_len;
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} else {
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/* segment only partly filled */
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*dst = cpu_to_be32(remaining);
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remaining = 0;
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}
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dst++; src++;
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/* segment's RDMA offset */
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*dst++ = *src++;
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*dst++ = *src++;
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}
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return nsegs;
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}
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/* The client provided a Write list in the Call message. Fill in
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* the segments in the first Write chunk in the Reply's transport
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* header with the number of bytes consumed in each segment.
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* Remaining chunks are returned unused.
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*
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* Assumptions:
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* - Client has provided only one Write chunk
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*/
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static void svc_rdma_xdr_encode_write_list(__be32 *rdma_resp, __be32 *wr_ch,
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unsigned int consumed)
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{
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unsigned int nsegs;
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__be32 *p, *q;
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/* RPC-over-RDMA V1 replies never have a Read list. */
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p = rdma_resp + rpcrdma_fixed_maxsz + 1;
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q = wr_ch;
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while (*q != xdr_zero) {
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nsegs = xdr_encode_write_chunk(p, q, consumed);
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q += 2 + nsegs * rpcrdma_segment_maxsz;
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p += 2 + nsegs * rpcrdma_segment_maxsz;
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consumed = 0;
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}
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/* Terminate Write list */
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*p++ = xdr_zero;
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/* Reply chunk discriminator; may be replaced later */
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*p = xdr_zero;
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}
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/* The client provided a Reply chunk in the Call message. Fill in
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* the segments in the Reply chunk in the Reply message with the
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* number of bytes consumed in each segment.
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*
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* Assumptions:
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* - Reply can always fit in the provided Reply chunk
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*/
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static void svc_rdma_xdr_encode_reply_chunk(__be32 *rdma_resp, __be32 *rp_ch,
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unsigned int consumed)
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{
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__be32 *p;
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/* Find the Reply chunk in the Reply's xprt header.
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* RPC-over-RDMA V1 replies never have a Read list.
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*/
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p = rdma_resp + rpcrdma_fixed_maxsz + 1;
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/* Skip past Write list */
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while (*p++ != xdr_zero)
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p += 1 + be32_to_cpup(p) * rpcrdma_segment_maxsz;
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xdr_encode_write_chunk(p, rp_ch, consumed);
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}
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/* Parse the RPC Call's transport header.
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*/
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static void svc_rdma_get_write_arrays(__be32 *rdma_argp,
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__be32 **write, __be32 **reply)
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{
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__be32 *p;
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p = rdma_argp + rpcrdma_fixed_maxsz;
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/* Read list */
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while (*p++ != xdr_zero)
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p += 5;
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/* Write list */
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if (*p != xdr_zero) {
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*write = p;
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while (*p++ != xdr_zero)
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p += 1 + be32_to_cpu(*p) * 4;
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} else {
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*write = NULL;
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p++;
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}
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/* Reply chunk */
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if (*p != xdr_zero)
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*reply = p;
|
|
else
|
|
*reply = NULL;
|
|
}
|
|
|
|
/* RPC-over-RDMA Version One private extension: Remote Invalidation.
|
|
* Responder's choice: requester signals it can handle Send With
|
|
* Invalidate, and responder chooses one rkey to invalidate.
|
|
*
|
|
* Find a candidate rkey to invalidate when sending a reply. Picks the
|
|
* first R_key it finds in the chunk lists.
|
|
*
|
|
* Returns zero if RPC's chunk lists are empty.
|
|
*/
|
|
static u32 svc_rdma_get_inv_rkey(__be32 *rdma_argp,
|
|
__be32 *wr_lst, __be32 *rp_ch)
|
|
{
|
|
__be32 *p;
|
|
|
|
p = rdma_argp + rpcrdma_fixed_maxsz;
|
|
if (*p != xdr_zero)
|
|
p += 2;
|
|
else if (wr_lst && be32_to_cpup(wr_lst + 1))
|
|
p = wr_lst + 2;
|
|
else if (rp_ch && be32_to_cpup(rp_ch + 1))
|
|
p = rp_ch + 2;
|
|
else
|
|
return 0;
|
|
return be32_to_cpup(p);
|
|
}
|
|
|
|
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);
|
|
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:
|
|
trace_svcrdma_dma_map_page(rdma, page);
|
|
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_sync_reply_hdr - DMA sync the transport header buffer
|
|
* @rdma: controlling transport
|
|
* @ctxt: send_ctxt for the Send WR
|
|
* @len: length of transport header
|
|
*
|
|
*/
|
|
void svc_rdma_sync_reply_hdr(struct svcxprt_rdma *rdma,
|
|
struct svc_rdma_send_ctxt *ctxt,
|
|
unsigned int len)
|
|
{
|
|
ctxt->sc_sges[0].length = len;
|
|
ctxt->sc_send_wr.num_sge++;
|
|
ib_dma_sync_single_for_device(rdma->sc_pd->device,
|
|
ctxt->sc_sges[0].addr, len,
|
|
DMA_TO_DEVICE);
|
|
}
|
|
|
|
/* svc_rdma_map_reply_msg - Map the buffer holding RPC message
|
|
* @rdma: controlling transport
|
|
* @ctxt: send_ctxt for the Send WR
|
|
* @xdr: prepared xdr_buf containing RPC message
|
|
* @wr_lst: pointer to Call header's Write list, or NULL
|
|
*
|
|
* Load the xdr_buf into the ctxt's sge array, and DMA map each
|
|
* element as it is added.
|
|
*
|
|
* 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 *ctxt,
|
|
struct xdr_buf *xdr, __be32 *wr_lst)
|
|
{
|
|
unsigned int len, remaining;
|
|
unsigned long page_off;
|
|
struct page **ppages;
|
|
unsigned char *base;
|
|
u32 xdr_pad;
|
|
int ret;
|
|
|
|
if (++ctxt->sc_cur_sge_no >= rdma->sc_max_send_sges)
|
|
return -EIO;
|
|
ret = svc_rdma_dma_map_buf(rdma, ctxt,
|
|
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 (wr_lst) {
|
|
base = xdr->tail[0].iov_base;
|
|
len = xdr->tail[0].iov_len;
|
|
xdr_pad = xdr_padsize(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);
|
|
|
|
if (++ctxt->sc_cur_sge_no >= rdma->sc_max_send_sges)
|
|
return -EIO;
|
|
ret = svc_rdma_dma_map_page(rdma, ctxt, *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) {
|
|
if (++ctxt->sc_cur_sge_no >= rdma->sc_max_send_sges)
|
|
return -EIO;
|
|
ret = svc_rdma_dma_map_buf(rdma, ctxt, 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;
|
|
}
|
|
rqstp->rq_next_page = rqstp->rq_respages + 1;
|
|
}
|
|
|
|
/* 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 ctxt'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 *ctxt,
|
|
__be32 *rdma_argp,
|
|
struct svc_rqst *rqstp,
|
|
__be32 *wr_lst, __be32 *rp_ch)
|
|
{
|
|
int ret;
|
|
|
|
if (!rp_ch) {
|
|
ret = svc_rdma_map_reply_msg(rdma, ctxt,
|
|
&rqstp->rq_res, wr_lst);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
svc_rdma_save_io_pages(rqstp, ctxt);
|
|
|
|
ctxt->sc_send_wr.opcode = IB_WR_SEND;
|
|
if (rdma->sc_snd_w_inv) {
|
|
ctxt->sc_send_wr.ex.invalidate_rkey =
|
|
svc_rdma_get_inv_rkey(rdma_argp, wr_lst, rp_ch);
|
|
if (ctxt->sc_send_wr.ex.invalidate_rkey)
|
|
ctxt->sc_send_wr.opcode = IB_WR_SEND_WITH_INV;
|
|
}
|
|
dprintk("svcrdma: posting Send WR with %u sge(s)\n",
|
|
ctxt->sc_send_wr.num_sge);
|
|
return svc_rdma_send(rdma, &ctxt->sc_send_wr);
|
|
}
|
|
|
|
/* Given the client-provided Write and Reply chunks, the server was not
|
|
* able to form a complete reply. Return an RDMA_ERROR message so the
|
|
* client can retire this RPC transaction. As above, the Send completion
|
|
* routine releases payload pages that were part of a previous RDMA Write.
|
|
*
|
|
* Remote Invalidation is skipped for simplicity.
|
|
*/
|
|
static int svc_rdma_send_error_msg(struct svcxprt_rdma *rdma,
|
|
struct svc_rdma_send_ctxt *ctxt,
|
|
struct svc_rqst *rqstp)
|
|
{
|
|
__be32 *p;
|
|
int ret;
|
|
|
|
p = ctxt->sc_xprt_buf;
|
|
trace_svcrdma_err_chunk(*p);
|
|
p += 3;
|
|
*p++ = rdma_error;
|
|
*p = err_chunk;
|
|
svc_rdma_sync_reply_hdr(rdma, ctxt, RPCRDMA_HDRLEN_ERR);
|
|
|
|
svc_rdma_save_io_pages(rqstp, ctxt);
|
|
|
|
ctxt->sc_send_wr.opcode = IB_WR_SEND;
|
|
ret = svc_rdma_send(rdma, &ctxt->sc_send_wr);
|
|
if (ret) {
|
|
svc_rdma_send_ctxt_put(rdma, ctxt);
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
|
|
{
|
|
}
|
|
|
|
/**
|
|
* 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 *p, *rdma_argp, *rdma_resp, *wr_lst, *rp_ch;
|
|
struct xdr_buf *xdr = &rqstp->rq_res;
|
|
struct svc_rdma_send_ctxt *sctxt;
|
|
int ret;
|
|
|
|
rdma_argp = rctxt->rc_recv_buf;
|
|
svc_rdma_get_write_arrays(rdma_argp, &wr_lst, &rp_ch);
|
|
|
|
/* Create the RDMA response header. xprt->xpt_mutex,
|
|
* acquired in svc_send(), serializes RPC replies. The
|
|
* code path below that inserts the credit grant value
|
|
* into each transport header runs only inside this
|
|
* critical section.
|
|
*/
|
|
ret = -ENOMEM;
|
|
sctxt = svc_rdma_send_ctxt_get(rdma);
|
|
if (!sctxt)
|
|
goto err0;
|
|
rdma_resp = sctxt->sc_xprt_buf;
|
|
|
|
p = rdma_resp;
|
|
*p++ = *rdma_argp;
|
|
*p++ = *(rdma_argp + 1);
|
|
*p++ = rdma->sc_fc_credits;
|
|
*p++ = rp_ch ? rdma_nomsg : rdma_msg;
|
|
|
|
/* Start with empty chunks */
|
|
*p++ = xdr_zero;
|
|
*p++ = xdr_zero;
|
|
*p = xdr_zero;
|
|
|
|
if (wr_lst) {
|
|
/* XXX: Presume the client sent only one Write chunk */
|
|
ret = svc_rdma_send_write_chunk(rdma, wr_lst, xdr);
|
|
if (ret < 0)
|
|
goto err2;
|
|
svc_rdma_xdr_encode_write_list(rdma_resp, wr_lst, ret);
|
|
}
|
|
if (rp_ch) {
|
|
ret = svc_rdma_send_reply_chunk(rdma, rp_ch, wr_lst, xdr);
|
|
if (ret < 0)
|
|
goto err2;
|
|
svc_rdma_xdr_encode_reply_chunk(rdma_resp, rp_ch, ret);
|
|
}
|
|
|
|
svc_rdma_sync_reply_hdr(rdma, sctxt, svc_rdma_reply_hdr_len(rdma_resp));
|
|
ret = svc_rdma_send_reply_msg(rdma, sctxt, rdma_argp, rqstp,
|
|
wr_lst, rp_ch);
|
|
if (ret < 0)
|
|
goto err1;
|
|
ret = 0;
|
|
|
|
out:
|
|
rqstp->rq_xprt_ctxt = NULL;
|
|
svc_rdma_recv_ctxt_put(rdma, rctxt);
|
|
return ret;
|
|
|
|
err2:
|
|
if (ret != -E2BIG && ret != -EINVAL)
|
|
goto err1;
|
|
|
|
ret = svc_rdma_send_error_msg(rdma, sctxt, rqstp);
|
|
if (ret < 0)
|
|
goto err1;
|
|
ret = 0;
|
|
goto out;
|
|
|
|
err1:
|
|
svc_rdma_send_ctxt_put(rdma, sctxt);
|
|
err0:
|
|
trace_svcrdma_send_failed(rqstp, ret);
|
|
set_bit(XPT_CLOSE, &xprt->xpt_flags);
|
|
ret = -ENOTCONN;
|
|
goto out;
|
|
}
|