// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2016-2018 Oracle. All rights reserved.
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*
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* Use the core R/W API to move RPC-over-RDMA Read and Write chunks.
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*/
|
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#include <rdma/rw.h>
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#include <linux/sunrpc/xdr.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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static void svc_rdma_write_done(struct ib_cq *cq, struct ib_wc *wc);
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static void svc_rdma_wc_read_done(struct ib_cq *cq, struct ib_wc *wc);
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/* Each R/W context contains state for one chain of RDMA Read or
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* Write Work Requests.
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*
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* Each WR chain handles a single contiguous server-side buffer,
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* because scatterlist entries after the first have to start on
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* page alignment. xdr_buf iovecs cannot guarantee alignment.
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*
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* Each WR chain handles only one R_key. Each RPC-over-RDMA segment
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* from a client may contain a unique R_key, so each WR chain moves
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* up to one segment at a time.
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*
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* The scatterlist makes this data structure over 4KB in size. To
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* make it less likely to fail, and to handle the allocation for
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* smaller I/O requests without disabling bottom-halves, these
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* contexts are created on demand, but cached and reused until the
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* controlling svcxprt_rdma is destroyed.
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*/
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struct svc_rdma_rw_ctxt {
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struct list_head rw_list;
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struct rdma_rw_ctx rw_ctx;
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unsigned int rw_nents;
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struct sg_table rw_sg_table;
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struct scatterlist rw_first_sgl[];
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};
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static inline struct svc_rdma_rw_ctxt *
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svc_rdma_next_ctxt(struct list_head *list)
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{
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return list_first_entry_or_null(list, struct svc_rdma_rw_ctxt,
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rw_list);
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}
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static struct svc_rdma_rw_ctxt *
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svc_rdma_get_rw_ctxt(struct svcxprt_rdma *rdma, unsigned int sges)
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{
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struct svc_rdma_rw_ctxt *ctxt;
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spin_lock(&rdma->sc_rw_ctxt_lock);
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ctxt = svc_rdma_next_ctxt(&rdma->sc_rw_ctxts);
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if (ctxt) {
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list_del(&ctxt->rw_list);
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spin_unlock(&rdma->sc_rw_ctxt_lock);
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} else {
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spin_unlock(&rdma->sc_rw_ctxt_lock);
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ctxt = kmalloc(struct_size(ctxt, rw_first_sgl, SG_CHUNK_SIZE),
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GFP_KERNEL);
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if (!ctxt)
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goto out_noctx;
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INIT_LIST_HEAD(&ctxt->rw_list);
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}
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ctxt->rw_sg_table.sgl = ctxt->rw_first_sgl;
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if (sg_alloc_table_chained(&ctxt->rw_sg_table, sges,
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ctxt->rw_sg_table.sgl,
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SG_CHUNK_SIZE))
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goto out_free;
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return ctxt;
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out_free:
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kfree(ctxt);
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out_noctx:
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trace_svcrdma_no_rwctx_err(rdma, sges);
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return NULL;
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}
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static void svc_rdma_put_rw_ctxt(struct svcxprt_rdma *rdma,
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struct svc_rdma_rw_ctxt *ctxt)
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{
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sg_free_table_chained(&ctxt->rw_sg_table, SG_CHUNK_SIZE);
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spin_lock(&rdma->sc_rw_ctxt_lock);
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list_add(&ctxt->rw_list, &rdma->sc_rw_ctxts);
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spin_unlock(&rdma->sc_rw_ctxt_lock);
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}
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/**
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* svc_rdma_destroy_rw_ctxts - Free accumulated R/W contexts
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* @rdma: transport about to be destroyed
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*
|
*/
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void svc_rdma_destroy_rw_ctxts(struct svcxprt_rdma *rdma)
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{
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struct svc_rdma_rw_ctxt *ctxt;
|
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while ((ctxt = svc_rdma_next_ctxt(&rdma->sc_rw_ctxts)) != NULL) {
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list_del(&ctxt->rw_list);
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kfree(ctxt);
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}
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}
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/**
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* svc_rdma_rw_ctx_init - Prepare a R/W context for I/O
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* @rdma: controlling transport instance
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* @ctxt: R/W context to prepare
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* @offset: RDMA offset
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* @handle: RDMA tag/handle
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* @direction: I/O direction
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*
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* Returns on success, the number of WQEs that will be needed
|
* on the workqueue, or a negative errno.
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*/
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static int svc_rdma_rw_ctx_init(struct svcxprt_rdma *rdma,
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struct svc_rdma_rw_ctxt *ctxt,
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u64 offset, u32 handle,
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enum dma_data_direction direction)
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{
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int ret;
|
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ret = rdma_rw_ctx_init(&ctxt->rw_ctx, rdma->sc_qp, rdma->sc_port_num,
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ctxt->rw_sg_table.sgl, ctxt->rw_nents,
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0, offset, handle, direction);
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if (unlikely(ret < 0)) {
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svc_rdma_put_rw_ctxt(rdma, ctxt);
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trace_svcrdma_dma_map_rw_err(rdma, ctxt->rw_nents, ret);
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}
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return ret;
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}
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/* A chunk context tracks all I/O for moving one Read or Write
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* chunk. This is a set of rdma_rw's that handle data movement
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* for all segments of one chunk.
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*
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* These are small, acquired with a single allocator call, and
|
* no more than one is needed per chunk. They are allocated on
|
* demand, and not cached.
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*/
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struct svc_rdma_chunk_ctxt {
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struct rpc_rdma_cid cc_cid;
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struct ib_cqe cc_cqe;
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struct svcxprt_rdma *cc_rdma;
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struct list_head cc_rwctxts;
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int cc_sqecount;
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};
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static void svc_rdma_cc_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 void svc_rdma_cc_init(struct svcxprt_rdma *rdma,
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struct svc_rdma_chunk_ctxt *cc)
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{
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svc_rdma_cc_cid_init(rdma, &cc->cc_cid);
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cc->cc_rdma = rdma;
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INIT_LIST_HEAD(&cc->cc_rwctxts);
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cc->cc_sqecount = 0;
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}
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static void svc_rdma_cc_release(struct svc_rdma_chunk_ctxt *cc,
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enum dma_data_direction dir)
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{
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struct svcxprt_rdma *rdma = cc->cc_rdma;
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struct svc_rdma_rw_ctxt *ctxt;
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while ((ctxt = svc_rdma_next_ctxt(&cc->cc_rwctxts)) != NULL) {
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list_del(&ctxt->rw_list);
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rdma_rw_ctx_destroy(&ctxt->rw_ctx, rdma->sc_qp,
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rdma->sc_port_num, ctxt->rw_sg_table.sgl,
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ctxt->rw_nents, dir);
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svc_rdma_put_rw_ctxt(rdma, ctxt);
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}
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}
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/* State for sending a Write or Reply chunk.
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* - Tracks progress of writing one chunk over all its segments
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* - Stores arguments for the SGL constructor functions
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*/
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struct svc_rdma_write_info {
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/* write state of this chunk */
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unsigned int wi_seg_off;
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unsigned int wi_seg_no;
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unsigned int wi_nsegs;
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__be32 *wi_segs;
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/* SGL constructor arguments */
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struct xdr_buf *wi_xdr;
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unsigned char *wi_base;
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unsigned int wi_next_off;
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struct svc_rdma_chunk_ctxt wi_cc;
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};
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static struct svc_rdma_write_info *
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svc_rdma_write_info_alloc(struct svcxprt_rdma *rdma, __be32 *chunk)
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{
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struct svc_rdma_write_info *info;
|
|
info = kmalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return info;
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info->wi_seg_off = 0;
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info->wi_seg_no = 0;
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info->wi_nsegs = be32_to_cpup(++chunk);
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info->wi_segs = ++chunk;
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svc_rdma_cc_init(rdma, &info->wi_cc);
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info->wi_cc.cc_cqe.done = svc_rdma_write_done;
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return info;
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}
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static void svc_rdma_write_info_free(struct svc_rdma_write_info *info)
|
{
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svc_rdma_cc_release(&info->wi_cc, DMA_TO_DEVICE);
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kfree(info);
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}
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/**
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* svc_rdma_write_done - Write chunk completion
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* @cq: controlling Completion Queue
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* @wc: Work Completion
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*
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* Pages under I/O are freed by a subsequent Send completion.
|
*/
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static void svc_rdma_write_done(struct ib_cq *cq, struct ib_wc *wc)
|
{
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struct ib_cqe *cqe = wc->wr_cqe;
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struct svc_rdma_chunk_ctxt *cc =
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container_of(cqe, struct svc_rdma_chunk_ctxt, cc_cqe);
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struct svcxprt_rdma *rdma = cc->cc_rdma;
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struct svc_rdma_write_info *info =
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container_of(cc, struct svc_rdma_write_info, wi_cc);
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trace_svcrdma_wc_write(wc, &cc->cc_cid);
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atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail);
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wake_up(&rdma->sc_send_wait);
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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_rdma_write_info_free(info);
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}
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/* State for pulling a Read chunk.
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*/
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struct svc_rdma_read_info {
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struct svc_rdma_recv_ctxt *ri_readctxt;
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unsigned int ri_position;
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unsigned int ri_pageno;
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unsigned int ri_pageoff;
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unsigned int ri_chunklen;
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struct svc_rdma_chunk_ctxt ri_cc;
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};
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static struct svc_rdma_read_info *
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svc_rdma_read_info_alloc(struct svcxprt_rdma *rdma)
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{
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struct svc_rdma_read_info *info;
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|
info = kmalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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return info;
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svc_rdma_cc_init(rdma, &info->ri_cc);
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info->ri_cc.cc_cqe.done = svc_rdma_wc_read_done;
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return info;
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}
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static void svc_rdma_read_info_free(struct svc_rdma_read_info *info)
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{
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svc_rdma_cc_release(&info->ri_cc, DMA_FROM_DEVICE);
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kfree(info);
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}
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/**
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* svc_rdma_wc_read_done - Handle completion of an RDMA Read ctx
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* @cq: controlling Completion Queue
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* @wc: Work Completion
|
*
|
*/
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static void svc_rdma_wc_read_done(struct ib_cq *cq, struct ib_wc *wc)
|
{
|
struct ib_cqe *cqe = wc->wr_cqe;
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struct svc_rdma_chunk_ctxt *cc =
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container_of(cqe, struct svc_rdma_chunk_ctxt, cc_cqe);
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struct svcxprt_rdma *rdma = cc->cc_rdma;
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struct svc_rdma_read_info *info =
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container_of(cc, struct svc_rdma_read_info, ri_cc);
|
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trace_svcrdma_wc_read(wc, &cc->cc_cid);
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atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail);
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wake_up(&rdma->sc_send_wait);
|
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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_rdma_recv_ctxt_put(rdma, info->ri_readctxt);
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} else {
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spin_lock(&rdma->sc_rq_dto_lock);
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list_add_tail(&info->ri_readctxt->rc_list,
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&rdma->sc_read_complete_q);
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/* Note the unlock pairs with the smp_rmb in svc_xprt_ready: */
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set_bit(XPT_DATA, &rdma->sc_xprt.xpt_flags);
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spin_unlock(&rdma->sc_rq_dto_lock);
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|
svc_xprt_enqueue(&rdma->sc_xprt);
|
}
|
|
svc_rdma_read_info_free(info);
|
}
|
|
/* This function sleeps when the transport's Send Queue is congested.
|
*
|
* Assumptions:
|
* - If ib_post_send() succeeds, only one completion is expected,
|
* even if one or more WRs are flushed. This is true when posting
|
* an rdma_rw_ctx or when posting a single signaled WR.
|
*/
|
static int svc_rdma_post_chunk_ctxt(struct svc_rdma_chunk_ctxt *cc)
|
{
|
struct svcxprt_rdma *rdma = cc->cc_rdma;
|
struct svc_xprt *xprt = &rdma->sc_xprt;
|
struct ib_send_wr *first_wr;
|
const struct ib_send_wr *bad_wr;
|
struct list_head *tmp;
|
struct ib_cqe *cqe;
|
int ret;
|
|
if (cc->cc_sqecount > rdma->sc_sq_depth)
|
return -EINVAL;
|
|
first_wr = NULL;
|
cqe = &cc->cc_cqe;
|
list_for_each(tmp, &cc->cc_rwctxts) {
|
struct svc_rdma_rw_ctxt *ctxt;
|
|
ctxt = list_entry(tmp, struct svc_rdma_rw_ctxt, rw_list);
|
first_wr = rdma_rw_ctx_wrs(&ctxt->rw_ctx, rdma->sc_qp,
|
rdma->sc_port_num, cqe, first_wr);
|
cqe = NULL;
|
}
|
|
do {
|
if (atomic_sub_return(cc->cc_sqecount,
|
&rdma->sc_sq_avail) > 0) {
|
trace_svcrdma_post_chunk(&cc->cc_cid, cc->cc_sqecount);
|
ret = ib_post_send(rdma->sc_qp, first_wr, &bad_wr);
|
if (ret)
|
break;
|
return 0;
|
}
|
|
trace_svcrdma_sq_full(rdma);
|
atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail);
|
wait_event(rdma->sc_send_wait,
|
atomic_read(&rdma->sc_sq_avail) > cc->cc_sqecount);
|
trace_svcrdma_sq_retry(rdma);
|
} while (1);
|
|
trace_svcrdma_sq_post_err(rdma, ret);
|
set_bit(XPT_CLOSE, &xprt->xpt_flags);
|
|
/* If even one was posted, there will be a completion. */
|
if (bad_wr != first_wr)
|
return 0;
|
|
atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail);
|
wake_up(&rdma->sc_send_wait);
|
return -ENOTCONN;
|
}
|
|
/* Build and DMA-map an SGL that covers one kvec in an xdr_buf
|
*/
|
static void svc_rdma_vec_to_sg(struct svc_rdma_write_info *info,
|
unsigned int len,
|
struct svc_rdma_rw_ctxt *ctxt)
|
{
|
struct scatterlist *sg = ctxt->rw_sg_table.sgl;
|
|
sg_set_buf(&sg[0], info->wi_base, len);
|
info->wi_base += len;
|
|
ctxt->rw_nents = 1;
|
}
|
|
/* Build and DMA-map an SGL that covers part of an xdr_buf's pagelist.
|
*/
|
static void svc_rdma_pagelist_to_sg(struct svc_rdma_write_info *info,
|
unsigned int remaining,
|
struct svc_rdma_rw_ctxt *ctxt)
|
{
|
unsigned int sge_no, sge_bytes, page_off, page_no;
|
struct xdr_buf *xdr = info->wi_xdr;
|
struct scatterlist *sg;
|
struct page **page;
|
|
page_off = info->wi_next_off + xdr->page_base;
|
page_no = page_off >> PAGE_SHIFT;
|
page_off = offset_in_page(page_off);
|
page = xdr->pages + page_no;
|
info->wi_next_off += remaining;
|
sg = ctxt->rw_sg_table.sgl;
|
sge_no = 0;
|
do {
|
sge_bytes = min_t(unsigned int, remaining,
|
PAGE_SIZE - page_off);
|
sg_set_page(sg, *page, sge_bytes, page_off);
|
|
remaining -= sge_bytes;
|
sg = sg_next(sg);
|
page_off = 0;
|
sge_no++;
|
page++;
|
} while (remaining);
|
|
ctxt->rw_nents = sge_no;
|
}
|
|
/* Construct RDMA Write WRs to send a portion of an xdr_buf containing
|
* an RPC Reply.
|
*/
|
static int
|
svc_rdma_build_writes(struct svc_rdma_write_info *info,
|
void (*constructor)(struct svc_rdma_write_info *info,
|
unsigned int len,
|
struct svc_rdma_rw_ctxt *ctxt),
|
unsigned int remaining)
|
{
|
struct svc_rdma_chunk_ctxt *cc = &info->wi_cc;
|
struct svcxprt_rdma *rdma = cc->cc_rdma;
|
struct svc_rdma_rw_ctxt *ctxt;
|
__be32 *seg;
|
int ret;
|
|
seg = info->wi_segs + info->wi_seg_no * rpcrdma_segment_maxsz;
|
do {
|
unsigned int write_len;
|
u32 handle, length;
|
u64 offset;
|
|
if (info->wi_seg_no >= info->wi_nsegs)
|
goto out_overflow;
|
|
xdr_decode_rdma_segment(seg, &handle, &length, &offset);
|
offset += info->wi_seg_off;
|
|
write_len = min(remaining, length - info->wi_seg_off);
|
ctxt = svc_rdma_get_rw_ctxt(rdma,
|
(write_len >> PAGE_SHIFT) + 2);
|
if (!ctxt)
|
return -ENOMEM;
|
|
constructor(info, write_len, ctxt);
|
ret = svc_rdma_rw_ctx_init(rdma, ctxt, offset, handle,
|
DMA_TO_DEVICE);
|
if (ret < 0)
|
return -EIO;
|
|
trace_svcrdma_send_wseg(handle, write_len, offset);
|
|
list_add(&ctxt->rw_list, &cc->cc_rwctxts);
|
cc->cc_sqecount += ret;
|
if (write_len == length - info->wi_seg_off) {
|
seg += 4;
|
info->wi_seg_no++;
|
info->wi_seg_off = 0;
|
} else {
|
info->wi_seg_off += write_len;
|
}
|
remaining -= write_len;
|
} while (remaining);
|
|
return 0;
|
|
out_overflow:
|
trace_svcrdma_small_wrch_err(rdma, remaining, info->wi_seg_no,
|
info->wi_nsegs);
|
return -E2BIG;
|
}
|
|
/* Send one of an xdr_buf's kvecs by itself. To send a Reply
|
* chunk, the whole RPC Reply is written back to the client.
|
* This function writes either the head or tail of the xdr_buf
|
* containing the Reply.
|
*/
|
static int svc_rdma_send_xdr_kvec(struct svc_rdma_write_info *info,
|
struct kvec *vec)
|
{
|
info->wi_base = vec->iov_base;
|
return svc_rdma_build_writes(info, svc_rdma_vec_to_sg,
|
vec->iov_len);
|
}
|
|
/* Send an xdr_buf's page list by itself. A Write chunk is just
|
* the page list. A Reply chunk is @xdr's head, page list, and
|
* tail. This function is shared between the two types of chunk.
|
*/
|
static int svc_rdma_send_xdr_pagelist(struct svc_rdma_write_info *info,
|
struct xdr_buf *xdr,
|
unsigned int offset,
|
unsigned long length)
|
{
|
info->wi_xdr = xdr;
|
info->wi_next_off = offset - xdr->head[0].iov_len;
|
return svc_rdma_build_writes(info, svc_rdma_pagelist_to_sg,
|
length);
|
}
|
|
/**
|
* svc_rdma_send_write_chunk - Write all segments in a Write chunk
|
* @rdma: controlling RDMA transport
|
* @wr_ch: Write chunk provided by client
|
* @xdr: xdr_buf containing the data payload
|
* @offset: payload's byte offset in @xdr
|
* @length: size of payload, in bytes
|
*
|
* Returns a non-negative number of bytes the chunk consumed, or
|
* %-E2BIG if the payload was larger than the Write chunk,
|
* %-EINVAL if client provided too many segments,
|
* %-ENOMEM if rdma_rw context pool was exhausted,
|
* %-ENOTCONN if posting failed (connection is lost),
|
* %-EIO if rdma_rw initialization failed (DMA mapping, etc).
|
*/
|
int svc_rdma_send_write_chunk(struct svcxprt_rdma *rdma, __be32 *wr_ch,
|
struct xdr_buf *xdr,
|
unsigned int offset, unsigned long length)
|
{
|
struct svc_rdma_write_info *info;
|
int ret;
|
|
if (!length)
|
return 0;
|
|
info = svc_rdma_write_info_alloc(rdma, wr_ch);
|
if (!info)
|
return -ENOMEM;
|
|
ret = svc_rdma_send_xdr_pagelist(info, xdr, offset, length);
|
if (ret < 0)
|
goto out_err;
|
|
ret = svc_rdma_post_chunk_ctxt(&info->wi_cc);
|
if (ret < 0)
|
goto out_err;
|
|
trace_svcrdma_send_write_chunk(xdr->page_len);
|
return length;
|
|
out_err:
|
svc_rdma_write_info_free(info);
|
return ret;
|
}
|
|
/**
|
* svc_rdma_send_reply_chunk - Write all segments in the Reply chunk
|
* @rdma: controlling RDMA transport
|
* @rctxt: Write and Reply chunks from client
|
* @xdr: xdr_buf containing an RPC Reply
|
*
|
* Returns a non-negative number of bytes the chunk consumed, or
|
* %-E2BIG if the payload was larger than the Reply chunk,
|
* %-EINVAL if client provided too many segments,
|
* %-ENOMEM if rdma_rw context pool was exhausted,
|
* %-ENOTCONN if posting failed (connection is lost),
|
* %-EIO if rdma_rw initialization failed (DMA mapping, etc).
|
*/
|
int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma,
|
const struct svc_rdma_recv_ctxt *rctxt,
|
struct xdr_buf *xdr)
|
{
|
struct svc_rdma_write_info *info;
|
int consumed, ret;
|
|
info = svc_rdma_write_info_alloc(rdma, rctxt->rc_reply_chunk);
|
if (!info)
|
return -ENOMEM;
|
|
ret = svc_rdma_send_xdr_kvec(info, &xdr->head[0]);
|
if (ret < 0)
|
goto out_err;
|
consumed = xdr->head[0].iov_len;
|
|
/* Send the page list in the Reply chunk only if the
|
* client did not provide Write chunks.
|
*/
|
if (!rctxt->rc_write_list && xdr->page_len) {
|
ret = svc_rdma_send_xdr_pagelist(info, xdr,
|
xdr->head[0].iov_len,
|
xdr->page_len);
|
if (ret < 0)
|
goto out_err;
|
consumed += xdr->page_len;
|
}
|
|
if (xdr->tail[0].iov_len) {
|
ret = svc_rdma_send_xdr_kvec(info, &xdr->tail[0]);
|
if (ret < 0)
|
goto out_err;
|
consumed += xdr->tail[0].iov_len;
|
}
|
|
ret = svc_rdma_post_chunk_ctxt(&info->wi_cc);
|
if (ret < 0)
|
goto out_err;
|
|
trace_svcrdma_send_reply_chunk(consumed);
|
return consumed;
|
|
out_err:
|
svc_rdma_write_info_free(info);
|
return ret;
|
}
|
|
static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info,
|
struct svc_rqst *rqstp,
|
u32 rkey, u32 len, u64 offset)
|
{
|
struct svc_rdma_recv_ctxt *head = info->ri_readctxt;
|
struct svc_rdma_chunk_ctxt *cc = &info->ri_cc;
|
struct svc_rdma_rw_ctxt *ctxt;
|
unsigned int sge_no, seg_len;
|
struct scatterlist *sg;
|
int ret;
|
|
sge_no = PAGE_ALIGN(info->ri_pageoff + len) >> PAGE_SHIFT;
|
ctxt = svc_rdma_get_rw_ctxt(cc->cc_rdma, sge_no);
|
if (!ctxt)
|
return -ENOMEM;
|
ctxt->rw_nents = sge_no;
|
|
sg = ctxt->rw_sg_table.sgl;
|
for (sge_no = 0; sge_no < ctxt->rw_nents; sge_no++) {
|
seg_len = min_t(unsigned int, len,
|
PAGE_SIZE - info->ri_pageoff);
|
|
head->rc_arg.pages[info->ri_pageno] =
|
rqstp->rq_pages[info->ri_pageno];
|
if (!info->ri_pageoff)
|
head->rc_page_count++;
|
|
sg_set_page(sg, rqstp->rq_pages[info->ri_pageno],
|
seg_len, info->ri_pageoff);
|
sg = sg_next(sg);
|
|
info->ri_pageoff += seg_len;
|
if (info->ri_pageoff == PAGE_SIZE) {
|
info->ri_pageno++;
|
info->ri_pageoff = 0;
|
}
|
len -= seg_len;
|
|
/* Safety check */
|
if (len &&
|
&rqstp->rq_pages[info->ri_pageno + 1] > rqstp->rq_page_end)
|
goto out_overrun;
|
}
|
|
ret = svc_rdma_rw_ctx_init(cc->cc_rdma, ctxt, offset, rkey,
|
DMA_FROM_DEVICE);
|
if (ret < 0)
|
return -EIO;
|
|
list_add(&ctxt->rw_list, &cc->cc_rwctxts);
|
cc->cc_sqecount += ret;
|
return 0;
|
|
out_overrun:
|
trace_svcrdma_page_overrun_err(cc->cc_rdma, rqstp, info->ri_pageno);
|
return -EINVAL;
|
}
|
|
/* Walk the segments in the Read chunk starting at @p and construct
|
* RDMA Read operations to pull the chunk to the server.
|
*/
|
static int svc_rdma_build_read_chunk(struct svc_rqst *rqstp,
|
struct svc_rdma_read_info *info,
|
__be32 *p)
|
{
|
int ret;
|
|
ret = -EINVAL;
|
info->ri_chunklen = 0;
|
while (*p++ != xdr_zero && be32_to_cpup(p++) == info->ri_position) {
|
u32 handle, length;
|
u64 offset;
|
|
p = xdr_decode_rdma_segment(p, &handle, &length, &offset);
|
ret = svc_rdma_build_read_segment(info, rqstp, handle, length,
|
offset);
|
if (ret < 0)
|
break;
|
|
trace_svcrdma_send_rseg(handle, length, offset);
|
info->ri_chunklen += length;
|
}
|
|
return ret;
|
}
|
|
/* Construct RDMA Reads to pull over a normal Read chunk. The chunk
|
* data lands in the page list of head->rc_arg.pages.
|
*
|
* Currently NFSD does not look at the head->rc_arg.tail[0] iovec.
|
* Therefore, XDR round-up of the Read chunk and trailing
|
* inline content must both be added at the end of the pagelist.
|
*/
|
static int svc_rdma_build_normal_read_chunk(struct svc_rqst *rqstp,
|
struct svc_rdma_read_info *info,
|
__be32 *p)
|
{
|
struct svc_rdma_recv_ctxt *head = info->ri_readctxt;
|
int ret;
|
|
ret = svc_rdma_build_read_chunk(rqstp, info, p);
|
if (ret < 0)
|
goto out;
|
|
trace_svcrdma_send_read_chunk(info->ri_chunklen, info->ri_position);
|
|
head->rc_hdr_count = 0;
|
|
/* Split the Receive buffer between the head and tail
|
* buffers at Read chunk's position. XDR roundup of the
|
* chunk is not included in either the pagelist or in
|
* the tail.
|
*/
|
head->rc_arg.tail[0].iov_base =
|
head->rc_arg.head[0].iov_base + info->ri_position;
|
head->rc_arg.tail[0].iov_len =
|
head->rc_arg.head[0].iov_len - info->ri_position;
|
head->rc_arg.head[0].iov_len = info->ri_position;
|
|
/* Read chunk may need XDR roundup (see RFC 8166, s. 3.4.5.2).
|
*
|
* If the client already rounded up the chunk length, the
|
* length does not change. Otherwise, the length of the page
|
* list is increased to include XDR round-up.
|
*
|
* Currently these chunks always start at page offset 0,
|
* thus the rounded-up length never crosses a page boundary.
|
*/
|
info->ri_chunklen = XDR_QUADLEN(info->ri_chunklen) << 2;
|
|
head->rc_arg.page_len = info->ri_chunklen;
|
head->rc_arg.len += info->ri_chunklen;
|
head->rc_arg.buflen += info->ri_chunklen;
|
|
out:
|
return ret;
|
}
|
|
/* Construct RDMA Reads to pull over a Position Zero Read chunk.
|
* The start of the data lands in the first page just after
|
* the Transport header, and the rest lands in the page list of
|
* head->rc_arg.pages.
|
*
|
* Assumptions:
|
* - A PZRC has an XDR-aligned length (no implicit round-up).
|
* - There can be no trailing inline content (IOW, we assume
|
* a PZRC is never sent in an RDMA_MSG message, though it's
|
* allowed by spec).
|
*/
|
static int svc_rdma_build_pz_read_chunk(struct svc_rqst *rqstp,
|
struct svc_rdma_read_info *info,
|
__be32 *p)
|
{
|
struct svc_rdma_recv_ctxt *head = info->ri_readctxt;
|
int ret;
|
|
ret = svc_rdma_build_read_chunk(rqstp, info, p);
|
if (ret < 0)
|
goto out;
|
|
trace_svcrdma_send_pzr(info->ri_chunklen);
|
|
head->rc_arg.len += info->ri_chunklen;
|
head->rc_arg.buflen += info->ri_chunklen;
|
|
head->rc_hdr_count = 1;
|
head->rc_arg.head[0].iov_base = page_address(head->rc_pages[0]);
|
head->rc_arg.head[0].iov_len = min_t(size_t, PAGE_SIZE,
|
info->ri_chunklen);
|
|
head->rc_arg.page_len = info->ri_chunklen -
|
head->rc_arg.head[0].iov_len;
|
|
out:
|
return ret;
|
}
|
|
/* Pages under I/O have been copied to head->rc_pages. Ensure they
|
* are not released by svc_xprt_release() until the I/O is complete.
|
*
|
* This has to be done after all Read WRs are constructed to properly
|
* handle a page that is part of I/O on behalf of two different RDMA
|
* segments.
|
*
|
* Do this only if I/O has been posted. Otherwise, we do indeed want
|
* svc_xprt_release() to clean things up properly.
|
*/
|
static void svc_rdma_save_io_pages(struct svc_rqst *rqstp,
|
const unsigned int start,
|
const unsigned int num_pages)
|
{
|
unsigned int i;
|
|
for (i = start; i < num_pages + start; i++)
|
rqstp->rq_pages[i] = NULL;
|
}
|
|
/**
|
* svc_rdma_recv_read_chunk - Pull a Read chunk from the client
|
* @rdma: controlling RDMA transport
|
* @rqstp: set of pages to use as Read sink buffers
|
* @head: pages under I/O collect here
|
* @p: pointer to start of Read chunk
|
*
|
* Returns:
|
* %0 if all needed RDMA Reads were posted successfully,
|
* %-EINVAL if client provided too many segments,
|
* %-ENOMEM if rdma_rw context pool was exhausted,
|
* %-ENOTCONN if posting failed (connection is lost),
|
* %-EIO if rdma_rw initialization failed (DMA mapping, etc).
|
*
|
* Assumptions:
|
* - All Read segments in @p have the same Position value.
|
*/
|
int svc_rdma_recv_read_chunk(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp,
|
struct svc_rdma_recv_ctxt *head, __be32 *p)
|
{
|
struct svc_rdma_read_info *info;
|
int ret;
|
|
/* The request (with page list) is constructed in
|
* head->rc_arg. Pages involved with RDMA Read I/O are
|
* transferred there.
|
*/
|
head->rc_arg.head[0] = rqstp->rq_arg.head[0];
|
head->rc_arg.tail[0] = rqstp->rq_arg.tail[0];
|
head->rc_arg.pages = head->rc_pages;
|
head->rc_arg.page_base = 0;
|
head->rc_arg.page_len = 0;
|
head->rc_arg.len = rqstp->rq_arg.len;
|
head->rc_arg.buflen = rqstp->rq_arg.buflen;
|
|
info = svc_rdma_read_info_alloc(rdma);
|
if (!info)
|
return -ENOMEM;
|
info->ri_readctxt = head;
|
info->ri_pageno = 0;
|
info->ri_pageoff = 0;
|
|
info->ri_position = be32_to_cpup(p + 1);
|
if (info->ri_position)
|
ret = svc_rdma_build_normal_read_chunk(rqstp, info, p);
|
else
|
ret = svc_rdma_build_pz_read_chunk(rqstp, info, p);
|
if (ret < 0)
|
goto out_err;
|
|
ret = svc_rdma_post_chunk_ctxt(&info->ri_cc);
|
if (ret < 0)
|
goto out_err;
|
svc_rdma_save_io_pages(rqstp, 0, head->rc_page_count);
|
return 0;
|
|
out_err:
|
svc_rdma_read_info_free(info);
|
return ret;
|
}
|
