diff options
Diffstat (limited to 'net/sunrpc/xprtrdma/frwr_ops.c')
| -rw-r--r-- | net/sunrpc/xprtrdma/frwr_ops.c | 696 |
1 files changed, 696 insertions, 0 deletions
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c new file mode 100644 index 0000000000..ffbf998949 --- /dev/null +++ b/net/sunrpc/xprtrdma/frwr_ops.c @@ -0,0 +1,696 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2015, 2017 Oracle. All rights reserved. + * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved. + */ + +/* Lightweight memory registration using Fast Registration Work + * Requests (FRWR). + * + * FRWR features ordered asynchronous registration and invalidation + * of arbitrarily-sized memory regions. This is the fastest and safest + * but most complex memory registration mode. + */ + +/* Normal operation + * + * A Memory Region is prepared for RDMA Read or Write using a FAST_REG + * Work Request (frwr_map). When the RDMA operation is finished, this + * Memory Region is invalidated using a LOCAL_INV Work Request + * (frwr_unmap_async and frwr_unmap_sync). + * + * Typically FAST_REG Work Requests are not signaled, and neither are + * RDMA Send Work Requests (with the exception of signaling occasionally + * to prevent provider work queue overflows). This greatly reduces HCA + * interrupt workload. + */ + +/* Transport recovery + * + * frwr_map and frwr_unmap_* cannot run at the same time the transport + * connect worker is running. The connect worker holds the transport + * send lock, just as ->send_request does. This prevents frwr_map and + * the connect worker from running concurrently. When a connection is + * closed, the Receive completion queue is drained before the allowing + * the connect worker to get control. This prevents frwr_unmap and the + * connect worker from running concurrently. + * + * When the underlying transport disconnects, MRs that are in flight + * are flushed and are likely unusable. Thus all MRs are destroyed. + * New MRs are created on demand. + */ + +#include <linux/sunrpc/svc_rdma.h> + +#include "xprt_rdma.h" +#include <trace/events/rpcrdma.h> + +static void frwr_cid_init(struct rpcrdma_ep *ep, + struct rpcrdma_mr *mr) +{ + struct rpc_rdma_cid *cid = &mr->mr_cid; + + cid->ci_queue_id = ep->re_attr.send_cq->res.id; + cid->ci_completion_id = mr->mr_ibmr->res.id; +} + +static void frwr_mr_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr) +{ + if (mr->mr_device) { + trace_xprtrdma_mr_unmap(mr); + ib_dma_unmap_sg(mr->mr_device, mr->mr_sg, mr->mr_nents, + mr->mr_dir); + mr->mr_device = NULL; + } +} + +/** + * frwr_mr_release - Destroy one MR + * @mr: MR allocated by frwr_mr_init + * + */ +void frwr_mr_release(struct rpcrdma_mr *mr) +{ + int rc; + + frwr_mr_unmap(mr->mr_xprt, mr); + + rc = ib_dereg_mr(mr->mr_ibmr); + if (rc) + trace_xprtrdma_frwr_dereg(mr, rc); + kfree(mr->mr_sg); + kfree(mr); +} + +static void frwr_mr_put(struct rpcrdma_mr *mr) +{ + frwr_mr_unmap(mr->mr_xprt, mr); + + /* The MR is returned to the req's MR free list instead + * of to the xprt's MR free list. No spinlock is needed. + */ + rpcrdma_mr_push(mr, &mr->mr_req->rl_free_mrs); +} + +/* frwr_reset - Place MRs back on the free list + * @req: request to reset + * + * Used after a failed marshal. For FRWR, this means the MRs + * don't have to be fully released and recreated. + * + * NB: This is safe only as long as none of @req's MRs are + * involved with an ongoing asynchronous FAST_REG or LOCAL_INV + * Work Request. + */ +void frwr_reset(struct rpcrdma_req *req) +{ + struct rpcrdma_mr *mr; + + while ((mr = rpcrdma_mr_pop(&req->rl_registered))) + frwr_mr_put(mr); +} + +/** + * frwr_mr_init - Initialize one MR + * @r_xprt: controlling transport instance + * @mr: generic MR to prepare for FRWR + * + * Returns zero if successful. Otherwise a negative errno + * is returned. + */ +int frwr_mr_init(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr) +{ + struct rpcrdma_ep *ep = r_xprt->rx_ep; + unsigned int depth = ep->re_max_fr_depth; + struct scatterlist *sg; + struct ib_mr *frmr; + + sg = kcalloc_node(depth, sizeof(*sg), XPRTRDMA_GFP_FLAGS, + ibdev_to_node(ep->re_id->device)); + if (!sg) + return -ENOMEM; + + frmr = ib_alloc_mr(ep->re_pd, ep->re_mrtype, depth); + if (IS_ERR(frmr)) + goto out_mr_err; + + mr->mr_xprt = r_xprt; + mr->mr_ibmr = frmr; + mr->mr_device = NULL; + INIT_LIST_HEAD(&mr->mr_list); + init_completion(&mr->mr_linv_done); + frwr_cid_init(ep, mr); + + sg_init_table(sg, depth); + mr->mr_sg = sg; + return 0; + +out_mr_err: + kfree(sg); + trace_xprtrdma_frwr_alloc(mr, PTR_ERR(frmr)); + return PTR_ERR(frmr); +} + +/** + * frwr_query_device - Prepare a transport for use with FRWR + * @ep: endpoint to fill in + * @device: RDMA device to query + * + * On success, sets: + * ep->re_attr + * ep->re_max_requests + * ep->re_max_rdma_segs + * ep->re_max_fr_depth + * ep->re_mrtype + * + * Return values: + * On success, returns zero. + * %-EINVAL - the device does not support FRWR memory registration + * %-ENOMEM - the device is not sufficiently capable for NFS/RDMA + */ +int frwr_query_device(struct rpcrdma_ep *ep, const struct ib_device *device) +{ + const struct ib_device_attr *attrs = &device->attrs; + int max_qp_wr, depth, delta; + unsigned int max_sge; + + if (!(attrs->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) || + attrs->max_fast_reg_page_list_len == 0) { + pr_err("rpcrdma: 'frwr' mode is not supported by device %s\n", + device->name); + return -EINVAL; + } + + max_sge = min_t(unsigned int, attrs->max_send_sge, + RPCRDMA_MAX_SEND_SGES); + if (max_sge < RPCRDMA_MIN_SEND_SGES) { + pr_err("rpcrdma: HCA provides only %u send SGEs\n", max_sge); + return -ENOMEM; + } + ep->re_attr.cap.max_send_sge = max_sge; + ep->re_attr.cap.max_recv_sge = 1; + + ep->re_mrtype = IB_MR_TYPE_MEM_REG; + if (attrs->kernel_cap_flags & IBK_SG_GAPS_REG) + ep->re_mrtype = IB_MR_TYPE_SG_GAPS; + + /* Quirk: Some devices advertise a large max_fast_reg_page_list_len + * capability, but perform optimally when the MRs are not larger + * than a page. + */ + if (attrs->max_sge_rd > RPCRDMA_MAX_HDR_SEGS) + ep->re_max_fr_depth = attrs->max_sge_rd; + else + ep->re_max_fr_depth = attrs->max_fast_reg_page_list_len; + if (ep->re_max_fr_depth > RPCRDMA_MAX_DATA_SEGS) + ep->re_max_fr_depth = RPCRDMA_MAX_DATA_SEGS; + + /* Add room for frwr register and invalidate WRs. + * 1. FRWR reg WR for head + * 2. FRWR invalidate WR for head + * 3. N FRWR reg WRs for pagelist + * 4. N FRWR invalidate WRs for pagelist + * 5. FRWR reg WR for tail + * 6. FRWR invalidate WR for tail + * 7. The RDMA_SEND WR + */ + depth = 7; + + /* Calculate N if the device max FRWR depth is smaller than + * RPCRDMA_MAX_DATA_SEGS. + */ + if (ep->re_max_fr_depth < RPCRDMA_MAX_DATA_SEGS) { + delta = RPCRDMA_MAX_DATA_SEGS - ep->re_max_fr_depth; + do { + depth += 2; /* FRWR reg + invalidate */ + delta -= ep->re_max_fr_depth; + } while (delta > 0); + } + + max_qp_wr = attrs->max_qp_wr; + max_qp_wr -= RPCRDMA_BACKWARD_WRS; + max_qp_wr -= 1; + if (max_qp_wr < RPCRDMA_MIN_SLOT_TABLE) + return -ENOMEM; + if (ep->re_max_requests > max_qp_wr) + ep->re_max_requests = max_qp_wr; + ep->re_attr.cap.max_send_wr = ep->re_max_requests * depth; + if (ep->re_attr.cap.max_send_wr > max_qp_wr) { + ep->re_max_requests = max_qp_wr / depth; + if (!ep->re_max_requests) + return -ENOMEM; + ep->re_attr.cap.max_send_wr = ep->re_max_requests * depth; + } + ep->re_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS; + ep->re_attr.cap.max_send_wr += 1; /* for ib_drain_sq */ + ep->re_attr.cap.max_recv_wr = ep->re_max_requests; + ep->re_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS; + ep->re_attr.cap.max_recv_wr += RPCRDMA_MAX_RECV_BATCH; + ep->re_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */ + + ep->re_max_rdma_segs = + DIV_ROUND_UP(RPCRDMA_MAX_DATA_SEGS, ep->re_max_fr_depth); + /* Reply chunks require segments for head and tail buffers */ + ep->re_max_rdma_segs += 2; + if (ep->re_max_rdma_segs > RPCRDMA_MAX_HDR_SEGS) + ep->re_max_rdma_segs = RPCRDMA_MAX_HDR_SEGS; + + /* Ensure the underlying device is capable of conveying the + * largest r/wsize NFS will ask for. This guarantees that + * failing over from one RDMA device to another will not + * break NFS I/O. + */ + if ((ep->re_max_rdma_segs * ep->re_max_fr_depth) < RPCRDMA_MAX_SEGS) + return -ENOMEM; + + return 0; +} + +/** + * frwr_map - Register a memory region + * @r_xprt: controlling transport + * @seg: memory region co-ordinates + * @nsegs: number of segments remaining + * @writing: true when RDMA Write will be used + * @xid: XID of RPC using the registered memory + * @mr: MR to fill in + * + * Prepare a REG_MR Work Request to register a memory region + * for remote access via RDMA READ or RDMA WRITE. + * + * Returns the next segment or a negative errno pointer. + * On success, @mr is filled in. + */ +struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt, + struct rpcrdma_mr_seg *seg, + int nsegs, bool writing, __be32 xid, + struct rpcrdma_mr *mr) +{ + struct rpcrdma_ep *ep = r_xprt->rx_ep; + struct ib_reg_wr *reg_wr; + int i, n, dma_nents; + struct ib_mr *ibmr; + u8 key; + + if (nsegs > ep->re_max_fr_depth) + nsegs = ep->re_max_fr_depth; + for (i = 0; i < nsegs;) { + sg_set_page(&mr->mr_sg[i], seg->mr_page, + seg->mr_len, seg->mr_offset); + + ++seg; + ++i; + if (ep->re_mrtype == IB_MR_TYPE_SG_GAPS) + continue; + if ((i < nsegs && seg->mr_offset) || + offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len)) + break; + } + mr->mr_dir = rpcrdma_data_dir(writing); + mr->mr_nents = i; + + dma_nents = ib_dma_map_sg(ep->re_id->device, mr->mr_sg, mr->mr_nents, + mr->mr_dir); + if (!dma_nents) + goto out_dmamap_err; + mr->mr_device = ep->re_id->device; + + ibmr = mr->mr_ibmr; + n = ib_map_mr_sg(ibmr, mr->mr_sg, dma_nents, NULL, PAGE_SIZE); + if (n != dma_nents) + goto out_mapmr_err; + + ibmr->iova &= 0x00000000ffffffff; + ibmr->iova |= ((u64)be32_to_cpu(xid)) << 32; + key = (u8)(ibmr->rkey & 0x000000FF); + ib_update_fast_reg_key(ibmr, ++key); + + reg_wr = &mr->mr_regwr; + reg_wr->mr = ibmr; + reg_wr->key = ibmr->rkey; + reg_wr->access = writing ? + IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE : + IB_ACCESS_REMOTE_READ; + + mr->mr_handle = ibmr->rkey; + mr->mr_length = ibmr->length; + mr->mr_offset = ibmr->iova; + trace_xprtrdma_mr_map(mr); + + return seg; + +out_dmamap_err: + trace_xprtrdma_frwr_sgerr(mr, i); + return ERR_PTR(-EIO); + +out_mapmr_err: + trace_xprtrdma_frwr_maperr(mr, n); + return ERR_PTR(-EIO); +} + +/** + * frwr_wc_fastreg - Invoked by RDMA provider for a flushed FastReg WC + * @cq: completion queue + * @wc: WCE for a completed FastReg WR + * + * Each flushed MR gets destroyed after the QP has drained. + */ +static void frwr_wc_fastreg(struct ib_cq *cq, struct ib_wc *wc) +{ + struct ib_cqe *cqe = wc->wr_cqe; + struct rpcrdma_mr *mr = container_of(cqe, struct rpcrdma_mr, mr_cqe); + + /* WARNING: Only wr_cqe and status are reliable at this point */ + trace_xprtrdma_wc_fastreg(wc, &mr->mr_cid); + + rpcrdma_flush_disconnect(cq->cq_context, wc); +} + +/** + * frwr_send - post Send WRs containing the RPC Call message + * @r_xprt: controlling transport instance + * @req: prepared RPC Call + * + * For FRWR, chain any FastReg WRs to the Send WR. Only a + * single ib_post_send call is needed to register memory + * and then post the Send WR. + * + * Returns the return code from ib_post_send. + * + * Caller must hold the transport send lock to ensure that the + * pointers to the transport's rdma_cm_id and QP are stable. + */ +int frwr_send(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req) +{ + struct ib_send_wr *post_wr, *send_wr = &req->rl_wr; + struct rpcrdma_ep *ep = r_xprt->rx_ep; + struct rpcrdma_mr *mr; + unsigned int num_wrs; + int ret; + + num_wrs = 1; + post_wr = send_wr; + list_for_each_entry(mr, &req->rl_registered, mr_list) { + trace_xprtrdma_mr_fastreg(mr); + + mr->mr_cqe.done = frwr_wc_fastreg; + mr->mr_regwr.wr.next = post_wr; + mr->mr_regwr.wr.wr_cqe = &mr->mr_cqe; + mr->mr_regwr.wr.num_sge = 0; + mr->mr_regwr.wr.opcode = IB_WR_REG_MR; + mr->mr_regwr.wr.send_flags = 0; + post_wr = &mr->mr_regwr.wr; + ++num_wrs; + } + + if ((kref_read(&req->rl_kref) > 1) || num_wrs > ep->re_send_count) { + send_wr->send_flags |= IB_SEND_SIGNALED; + ep->re_send_count = min_t(unsigned int, ep->re_send_batch, + num_wrs - ep->re_send_count); + } else { + send_wr->send_flags &= ~IB_SEND_SIGNALED; + ep->re_send_count -= num_wrs; + } + + trace_xprtrdma_post_send(req); + ret = ib_post_send(ep->re_id->qp, post_wr, NULL); + if (ret) + trace_xprtrdma_post_send_err(r_xprt, req, ret); + return ret; +} + +/** + * frwr_reminv - handle a remotely invalidated mr on the @mrs list + * @rep: Received reply + * @mrs: list of MRs to check + * + */ +void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs) +{ + struct rpcrdma_mr *mr; + + list_for_each_entry(mr, mrs, mr_list) + if (mr->mr_handle == rep->rr_inv_rkey) { + list_del_init(&mr->mr_list); + trace_xprtrdma_mr_reminv(mr); + frwr_mr_put(mr); + break; /* only one invalidated MR per RPC */ + } +} + +static void frwr_mr_done(struct ib_wc *wc, struct rpcrdma_mr *mr) +{ + if (likely(wc->status == IB_WC_SUCCESS)) + frwr_mr_put(mr); +} + +/** + * frwr_wc_localinv - Invoked by RDMA provider for a LOCAL_INV WC + * @cq: completion queue + * @wc: WCE for a completed LocalInv WR + * + */ +static void frwr_wc_localinv(struct ib_cq *cq, struct ib_wc *wc) +{ + struct ib_cqe *cqe = wc->wr_cqe; + struct rpcrdma_mr *mr = container_of(cqe, struct rpcrdma_mr, mr_cqe); + + /* WARNING: Only wr_cqe and status are reliable at this point */ + trace_xprtrdma_wc_li(wc, &mr->mr_cid); + frwr_mr_done(wc, mr); + + rpcrdma_flush_disconnect(cq->cq_context, wc); +} + +/** + * frwr_wc_localinv_wake - Invoked by RDMA provider for a LOCAL_INV WC + * @cq: completion queue + * @wc: WCE for a completed LocalInv WR + * + * Awaken anyone waiting for an MR to finish being fenced. + */ +static void frwr_wc_localinv_wake(struct ib_cq *cq, struct ib_wc *wc) +{ + struct ib_cqe *cqe = wc->wr_cqe; + struct rpcrdma_mr *mr = container_of(cqe, struct rpcrdma_mr, mr_cqe); + + /* WARNING: Only wr_cqe and status are reliable at this point */ + trace_xprtrdma_wc_li_wake(wc, &mr->mr_cid); + frwr_mr_done(wc, mr); + complete(&mr->mr_linv_done); + + rpcrdma_flush_disconnect(cq->cq_context, wc); +} + +/** + * frwr_unmap_sync - invalidate memory regions that were registered for @req + * @r_xprt: controlling transport instance + * @req: rpcrdma_req with a non-empty list of MRs to process + * + * Sleeps until it is safe for the host CPU to access the previously mapped + * memory regions. This guarantees that registered MRs are properly fenced + * from the server before the RPC consumer accesses the data in them. It + * also ensures proper Send flow control: waking the next RPC waits until + * this RPC has relinquished all its Send Queue entries. + */ +void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req) +{ + struct ib_send_wr *first, **prev, *last; + struct rpcrdma_ep *ep = r_xprt->rx_ep; + const struct ib_send_wr *bad_wr; + struct rpcrdma_mr *mr; + int rc; + + /* ORDER: Invalidate all of the MRs first + * + * Chain the LOCAL_INV Work Requests and post them with + * a single ib_post_send() call. + */ + prev = &first; + mr = rpcrdma_mr_pop(&req->rl_registered); + do { + trace_xprtrdma_mr_localinv(mr); + r_xprt->rx_stats.local_inv_needed++; + + last = &mr->mr_invwr; + last->next = NULL; + last->wr_cqe = &mr->mr_cqe; + last->sg_list = NULL; + last->num_sge = 0; + last->opcode = IB_WR_LOCAL_INV; + last->send_flags = IB_SEND_SIGNALED; + last->ex.invalidate_rkey = mr->mr_handle; + + last->wr_cqe->done = frwr_wc_localinv; + + *prev = last; + prev = &last->next; + } while ((mr = rpcrdma_mr_pop(&req->rl_registered))); + + mr = container_of(last, struct rpcrdma_mr, mr_invwr); + + /* Strong send queue ordering guarantees that when the + * last WR in the chain completes, all WRs in the chain + * are complete. + */ + last->wr_cqe->done = frwr_wc_localinv_wake; + reinit_completion(&mr->mr_linv_done); + + /* Transport disconnect drains the receive CQ before it + * replaces the QP. The RPC reply handler won't call us + * unless re_id->qp is a valid pointer. + */ + bad_wr = NULL; + rc = ib_post_send(ep->re_id->qp, first, &bad_wr); + + /* The final LOCAL_INV WR in the chain is supposed to + * do the wake. If it was never posted, the wake will + * not happen, so don't wait in that case. + */ + if (bad_wr != first) + wait_for_completion(&mr->mr_linv_done); + if (!rc) + return; + + /* On error, the MRs get destroyed once the QP has drained. */ + trace_xprtrdma_post_linv_err(req, rc); + + /* Force a connection loss to ensure complete recovery. + */ + rpcrdma_force_disconnect(ep); +} + +/** + * frwr_wc_localinv_done - Invoked by RDMA provider for a signaled LOCAL_INV WC + * @cq: completion queue + * @wc: WCE for a completed LocalInv WR + * + */ +static void frwr_wc_localinv_done(struct ib_cq *cq, struct ib_wc *wc) +{ + struct ib_cqe *cqe = wc->wr_cqe; + struct rpcrdma_mr *mr = container_of(cqe, struct rpcrdma_mr, mr_cqe); + struct rpcrdma_rep *rep; + + /* WARNING: Only wr_cqe and status are reliable at this point */ + trace_xprtrdma_wc_li_done(wc, &mr->mr_cid); + + /* Ensure that @rep is generated before the MR is released */ + rep = mr->mr_req->rl_reply; + smp_rmb(); + + if (wc->status != IB_WC_SUCCESS) { + if (rep) + rpcrdma_unpin_rqst(rep); + rpcrdma_flush_disconnect(cq->cq_context, wc); + return; + } + frwr_mr_put(mr); + rpcrdma_complete_rqst(rep); +} + +/** + * frwr_unmap_async - invalidate memory regions that were registered for @req + * @r_xprt: controlling transport instance + * @req: rpcrdma_req with a non-empty list of MRs to process + * + * This guarantees that registered MRs are properly fenced from the + * server before the RPC consumer accesses the data in them. It also + * ensures proper Send flow control: waking the next RPC waits until + * this RPC has relinquished all its Send Queue entries. + */ +void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req) +{ + struct ib_send_wr *first, *last, **prev; + struct rpcrdma_ep *ep = r_xprt->rx_ep; + struct rpcrdma_mr *mr; + int rc; + + /* Chain the LOCAL_INV Work Requests and post them with + * a single ib_post_send() call. + */ + prev = &first; + mr = rpcrdma_mr_pop(&req->rl_registered); + do { + trace_xprtrdma_mr_localinv(mr); + r_xprt->rx_stats.local_inv_needed++; + + last = &mr->mr_invwr; + last->next = NULL; + last->wr_cqe = &mr->mr_cqe; + last->sg_list = NULL; + last->num_sge = 0; + last->opcode = IB_WR_LOCAL_INV; + last->send_flags = IB_SEND_SIGNALED; + last->ex.invalidate_rkey = mr->mr_handle; + + last->wr_cqe->done = frwr_wc_localinv; + + *prev = last; + prev = &last->next; + } while ((mr = rpcrdma_mr_pop(&req->rl_registered))); + + /* Strong send queue ordering guarantees that when the + * last WR in the chain completes, all WRs in the chain + * are complete. The last completion will wake up the + * RPC waiter. + */ + last->wr_cqe->done = frwr_wc_localinv_done; + + /* Transport disconnect drains the receive CQ before it + * replaces the QP. The RPC reply handler won't call us + * unless re_id->qp is a valid pointer. + */ + rc = ib_post_send(ep->re_id->qp, first, NULL); + if (!rc) + return; + + /* On error, the MRs get destroyed once the QP has drained. */ + trace_xprtrdma_post_linv_err(req, rc); + + /* The final LOCAL_INV WR in the chain is supposed to + * do the wake. If it was never posted, the wake does + * not happen. Unpin the rqst in preparation for its + * retransmission. + */ + rpcrdma_unpin_rqst(req->rl_reply); + + /* Force a connection loss to ensure complete recovery. + */ + rpcrdma_force_disconnect(ep); +} + +/** + * frwr_wp_create - Create an MR for padding Write chunks + * @r_xprt: transport resources to use + * + * Return 0 on success, negative errno on failure. + */ +int frwr_wp_create(struct rpcrdma_xprt *r_xprt) +{ + struct rpcrdma_ep *ep = r_xprt->rx_ep; + struct rpcrdma_mr_seg seg; + struct rpcrdma_mr *mr; + + mr = rpcrdma_mr_get(r_xprt); + if (!mr) + return -EAGAIN; + mr->mr_req = NULL; + ep->re_write_pad_mr = mr; + + seg.mr_len = XDR_UNIT; + seg.mr_page = virt_to_page(ep->re_write_pad); + seg.mr_offset = offset_in_page(ep->re_write_pad); + if (IS_ERR(frwr_map(r_xprt, &seg, 1, true, xdr_zero, mr))) + return -EIO; + trace_xprtrdma_mr_fastreg(mr); + + mr->mr_cqe.done = frwr_wc_fastreg; + mr->mr_regwr.wr.next = NULL; + mr->mr_regwr.wr.wr_cqe = &mr->mr_cqe; + mr->mr_regwr.wr.num_sge = 0; + mr->mr_regwr.wr.opcode = IB_WR_REG_MR; + mr->mr_regwr.wr.send_flags = 0; + + return ib_post_send(ep->re_id->qp, &mr->mr_regwr.wr, NULL); +} |