// 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 deregistration * 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_sync). * * Typically these 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. * * As an optimization, frwr_unmap marks MRs INVALID before the * LOCAL_INV WR is posted. If posting succeeds, the MR is placed on * rb_mrs immediately so that no work (like managing a linked list * under a spinlock) is needed in the completion upcall. * * But this means that frwr_map() can occasionally encounter an MR * that is INVALID but the LOCAL_INV WR has not completed. Work Queue * ordering prevents a subsequent FAST_REG WR from executing against * that MR while it is still being invalidated. */ /* Transport recovery * * ->op_map and the transport connect worker cannot run at the same * time, but ->op_unmap can fire while the transport connect worker * is running. Thus MR recovery is handled in ->op_map, to guarantee * that recovered MRs are owned by a sending RPC, and not one where * ->op_unmap could fire at the same time transport reconnect is * being done. * * When the underlying transport disconnects, MRs are left in one of * four states: * * INVALID: The MR was not in use before the QP entered ERROR state. * * VALID: The MR was registered before the QP entered ERROR state. * * FLUSHED_FR: The MR was being registered when the QP entered ERROR * state, and the pending WR was flushed. * * FLUSHED_LI: The MR was being invalidated when the QP entered ERROR * state, and the pending WR was flushed. * * When frwr_map encounters FLUSHED and VALID MRs, they are recovered * with ib_dereg_mr and then are re-initialized. Because MR recovery * allocates fresh resources, it is deferred to a workqueue, and the * recovered MRs are placed back on the rb_mrs list when recovery is * complete. frwr_map allocates another MR for the current RPC while * the broken MR is reset. * * To ensure that frwr_map doesn't encounter an MR that is marked * INVALID but that is about to be flushed due to a previous transport * disconnect, the transport connect worker attempts to drain all * pending send queue WRs before the transport is reconnected. */ #include #include #include "xprt_rdma.h" #include #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) # define RPCDBG_FACILITY RPCDBG_TRANS #endif /** * frwr_is_supported - Check if device supports FRWR * @ia: interface adapter to check * * Returns true if device supports FRWR, otherwise false */ bool frwr_is_supported(struct rpcrdma_ia *ia) { struct ib_device_attr *attrs = &ia->ri_device->attrs; if (!(attrs->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS)) goto out_not_supported; if (attrs->max_fast_reg_page_list_len == 0) goto out_not_supported; return true; out_not_supported: pr_info("rpcrdma: 'frwr' mode is not supported by device %s\n", ia->ri_device->name); return false; } /** * frwr_release_mr - Destroy one MR * @mr: MR allocated by frwr_init_mr * */ void frwr_release_mr(struct rpcrdma_mr *mr) { int rc; rc = ib_dereg_mr(mr->frwr.fr_mr); if (rc) trace_xprtrdma_frwr_dereg(mr, rc); kfree(mr->mr_sg); kfree(mr); } /* MRs are dynamically allocated, so simply clean up and release the MR. * A replacement MR will subsequently be allocated on demand. */ static void frwr_mr_recycle_worker(struct work_struct *work) { struct rpcrdma_mr *mr = container_of(work, struct rpcrdma_mr, mr_recycle); struct rpcrdma_xprt *r_xprt = mr->mr_xprt; trace_xprtrdma_mr_recycle(mr); if (mr->mr_dir != DMA_NONE) { trace_xprtrdma_mr_unmap(mr); ib_dma_unmap_sg(r_xprt->rx_ia.ri_device, mr->mr_sg, mr->mr_nents, mr->mr_dir); mr->mr_dir = DMA_NONE; } spin_lock(&r_xprt->rx_buf.rb_mrlock); list_del(&mr->mr_all); r_xprt->rx_stats.mrs_recycled++; spin_unlock(&r_xprt->rx_buf.rb_mrlock); frwr_release_mr(mr); } /** * frwr_init_mr - Initialize one MR * @ia: interface adapter * @mr: generic MR to prepare for FRWR * * Returns zero if successful. Otherwise a negative errno * is returned. */ int frwr_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr) { unsigned int depth = ia->ri_max_frwr_depth; struct scatterlist *sg; struct ib_mr *frmr; int rc; frmr = ib_alloc_mr(ia->ri_pd, ia->ri_mrtype, depth); if (IS_ERR(frmr)) goto out_mr_err; sg = kcalloc(depth, sizeof(*sg), GFP_KERNEL); if (!sg) goto out_list_err; mr->frwr.fr_mr = frmr; mr->frwr.fr_state = FRWR_IS_INVALID; mr->mr_dir = DMA_NONE; INIT_LIST_HEAD(&mr->mr_list); INIT_WORK(&mr->mr_recycle, frwr_mr_recycle_worker); init_completion(&mr->frwr.fr_linv_done); sg_init_table(sg, depth); mr->mr_sg = sg; return 0; out_mr_err: rc = PTR_ERR(frmr); trace_xprtrdma_frwr_alloc(mr, rc); return rc; out_list_err: dprintk("RPC: %s: sg allocation failure\n", __func__); ib_dereg_mr(frmr); return -ENOMEM; } /** * frwr_open - Prepare an endpoint for use with FRWR * @ia: interface adapter this endpoint will use * @ep: endpoint to prepare * @cdata: transport parameters * * On success, sets: * ep->rep_attr.cap.max_send_wr * ep->rep_attr.cap.max_recv_wr * cdata->max_requests * ia->ri_max_segs * * And these FRWR-related fields: * ia->ri_max_frwr_depth * ia->ri_mrtype * * On failure, a negative errno is returned. */ int frwr_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, struct rpcrdma_create_data_internal *cdata) { struct ib_device_attr *attrs = &ia->ri_device->attrs; int max_qp_wr, depth, delta; ia->ri_mrtype = IB_MR_TYPE_MEM_REG; if (attrs->device_cap_flags & IB_DEVICE_SG_GAPS_REG) ia->ri_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 > 1) ia->ri_max_frwr_depth = attrs->max_sge_rd; else ia->ri_max_frwr_depth = attrs->max_fast_reg_page_list_len; if (ia->ri_max_frwr_depth > RPCRDMA_MAX_DATA_SEGS) ia->ri_max_frwr_depth = RPCRDMA_MAX_DATA_SEGS; dprintk("RPC: %s: max FR page list depth = %u\n", __func__, ia->ri_max_frwr_depth); /* 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 (ia->ri_max_frwr_depth < RPCRDMA_MAX_DATA_SEGS) { delta = RPCRDMA_MAX_DATA_SEGS - ia->ri_max_frwr_depth; do { depth += 2; /* FRWR reg + invalidate */ delta -= ia->ri_max_frwr_depth; } while (delta > 0); } max_qp_wr = ia->ri_device->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 (cdata->max_requests > max_qp_wr) cdata->max_requests = max_qp_wr; ep->rep_attr.cap.max_send_wr = cdata->max_requests * depth; if (ep->rep_attr.cap.max_send_wr > max_qp_wr) { cdata->max_requests = max_qp_wr / depth; if (!cdata->max_requests) return -EINVAL; ep->rep_attr.cap.max_send_wr = cdata->max_requests * depth; } ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS; ep->rep_attr.cap.max_send_wr += 1; /* for ib_drain_sq */ ep->rep_attr.cap.max_recv_wr = cdata->max_requests; ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS; ep->rep_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */ ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS / ia->ri_max_frwr_depth); /* Reply chunks require segments for head and tail buffers */ ia->ri_max_segs += 2; if (ia->ri_max_segs > RPCRDMA_MAX_HDR_SEGS) ia->ri_max_segs = RPCRDMA_MAX_HDR_SEGS; return 0; } /** * frwr_maxpages - Compute size of largest payload * @r_xprt: transport * * Returns maximum size of an RPC message, in pages. * * FRWR mode conveys a list of pages per chunk segment. The * maximum length of that list is the FRWR page list depth. */ size_t frwr_maxpages(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_ia *ia = &r_xprt->rx_ia; return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS, (ia->ri_max_segs - 2) * ia->ri_max_frwr_depth); } static void __frwr_sendcompletion_flush(struct ib_wc *wc, const char *wr) { if (wc->status != IB_WC_WR_FLUSH_ERR) pr_err("rpcrdma: %s: %s (%u/0x%x)\n", wr, ib_wc_status_msg(wc->status), wc->status, wc->vendor_err); } /** * frwr_wc_fastreg - Invoked by RDMA provider for a flushed FastReg WC * @cq: completion queue (ignored) * @wc: completed WR * */ static void frwr_wc_fastreg(struct ib_cq *cq, struct ib_wc *wc) { struct ib_cqe *cqe = wc->wr_cqe; struct rpcrdma_frwr *frwr = container_of(cqe, struct rpcrdma_frwr, fr_cqe); /* WARNING: Only wr_cqe and status are reliable at this point */ if (wc->status != IB_WC_SUCCESS) { frwr->fr_state = FRWR_FLUSHED_FR; __frwr_sendcompletion_flush(wc, "fastreg"); } trace_xprtrdma_wc_fastreg(wc, frwr); } /** * frwr_wc_localinv - Invoked by RDMA provider for a flushed LocalInv WC * @cq: completion queue (ignored) * @wc: completed WR * */ static void frwr_wc_localinv(struct ib_cq *cq, struct ib_wc *wc) { struct ib_cqe *cqe = wc->wr_cqe; struct rpcrdma_frwr *frwr = container_of(cqe, struct rpcrdma_frwr, fr_cqe); /* WARNING: Only wr_cqe and status are reliable at this point */ if (wc->status != IB_WC_SUCCESS) { frwr->fr_state = FRWR_FLUSHED_LI; __frwr_sendcompletion_flush(wc, "localinv"); } trace_xprtrdma_wc_li(wc, frwr); } /** * frwr_wc_localinv_wake - Invoked by RDMA provider for a signaled LocalInv WC * @cq: completion queue (ignored) * @wc: completed 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_frwr *frwr = container_of(cqe, struct rpcrdma_frwr, fr_cqe); /* WARNING: Only wr_cqe and status are reliable at this point */ if (wc->status != IB_WC_SUCCESS) { frwr->fr_state = FRWR_FLUSHED_LI; __frwr_sendcompletion_flush(wc, "localinv"); } complete(&frwr->fr_linv_done); trace_xprtrdma_wc_li_wake(wc, frwr); } /** * 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 * @out: initialized MR * * 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, the prepared MR is planted in @out. */ struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg, int nsegs, bool writing, u32 xid, struct rpcrdma_mr **out) { struct rpcrdma_ia *ia = &r_xprt->rx_ia; bool holes_ok = ia->ri_mrtype == IB_MR_TYPE_SG_GAPS; struct rpcrdma_frwr *frwr; struct rpcrdma_mr *mr; struct ib_mr *ibmr; struct ib_reg_wr *reg_wr; int i, n; u8 key; mr = NULL; do { if (mr) rpcrdma_mr_recycle(mr); mr = rpcrdma_mr_get(r_xprt); if (!mr) return ERR_PTR(-EAGAIN); } while (mr->frwr.fr_state != FRWR_IS_INVALID); frwr = &mr->frwr; frwr->fr_state = FRWR_IS_VALID; if (nsegs > ia->ri_max_frwr_depth) nsegs = ia->ri_max_frwr_depth; for (i = 0; i < nsegs;) { if (seg->mr_page) sg_set_page(&mr->mr_sg[i], seg->mr_page, seg->mr_len, offset_in_page(seg->mr_offset)); else sg_set_buf(&mr->mr_sg[i], seg->mr_offset, seg->mr_len); ++seg; ++i; if (holes_ok) continue; if ((i < nsegs && offset_in_page(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 = ib_dma_map_sg(ia->ri_device, mr->mr_sg, i, mr->mr_dir); if (!mr->mr_nents) goto out_dmamap_err; ibmr = frwr->fr_mr; n = ib_map_mr_sg(ibmr, mr->mr_sg, mr->mr_nents, NULL, PAGE_SIZE); if (unlikely(n != mr->mr_nents)) goto out_mapmr_err; ibmr->iova &= 0x00000000ffffffff; ibmr->iova |= ((u64)cpu_to_be32(xid)) << 32; key = (u8)(ibmr->rkey & 0x000000FF); ib_update_fast_reg_key(ibmr, ++key); reg_wr = &frwr->fr_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); *out = mr; return seg; out_dmamap_err: frwr->fr_state = FRWR_IS_INVALID; trace_xprtrdma_frwr_sgerr(mr, i); rpcrdma_mr_put(mr); return ERR_PTR(-EIO); out_mapmr_err: trace_xprtrdma_frwr_maperr(mr, n); rpcrdma_mr_recycle(mr); return ERR_PTR(-EIO); } /** * frwr_send - post Send WR containing the RPC Call message * @ia: interface adapter * @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 result of ib_post_send. */ int frwr_send(struct rpcrdma_ia *ia, struct rpcrdma_req *req) { struct ib_send_wr *post_wr; struct rpcrdma_mr *mr; post_wr = &req->rl_sendctx->sc_wr; list_for_each_entry(mr, &req->rl_registered, mr_list) { struct rpcrdma_frwr *frwr; frwr = &mr->frwr; frwr->fr_cqe.done = frwr_wc_fastreg; frwr->fr_regwr.wr.next = post_wr; frwr->fr_regwr.wr.wr_cqe = &frwr->fr_cqe; frwr->fr_regwr.wr.num_sge = 0; frwr->fr_regwr.wr.opcode = IB_WR_REG_MR; frwr->fr_regwr.wr.send_flags = 0; post_wr = &frwr->fr_regwr.wr; } /* If ib_post_send fails, the next ->send_request for * @req will queue these MRs for recovery. */ return ib_post_send(ia->ri_id->qp, post_wr, NULL); } /** * 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_remoteinv(mr); mr->frwr.fr_state = FRWR_IS_INVALID; rpcrdma_mr_unmap_and_put(mr); break; /* only one invalidated MR per RPC */ } } /** * frwr_unmap_sync - invalidate memory regions that were registered for @req * @r_xprt: controlling transport * @mrs: list of MRs to process * * Sleeps until it is safe for the host CPU to access the * previously mapped memory regions. * * Caller ensures that @mrs is not empty before the call. This * function empties the list. */ void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct list_head *mrs) { struct ib_send_wr *first, **prev, *last; const struct ib_send_wr *bad_wr; struct rpcrdma_ia *ia = &r_xprt->rx_ia; struct rpcrdma_frwr *frwr; struct rpcrdma_mr *mr; int count, rc; /* ORDER: Invalidate all of the MRs first * * Chain the LOCAL_INV Work Requests and post them with * a single ib_post_send() call. */ frwr = NULL; count = 0; prev = &first; list_for_each_entry(mr, mrs, mr_list) { mr->frwr.fr_state = FRWR_IS_INVALID; frwr = &mr->frwr; trace_xprtrdma_mr_localinv(mr); frwr->fr_cqe.done = frwr_wc_localinv; last = &frwr->fr_invwr; memset(last, 0, sizeof(*last)); last->wr_cqe = &frwr->fr_cqe; last->opcode = IB_WR_LOCAL_INV; last->ex.invalidate_rkey = mr->mr_handle; count++; *prev = last; prev = &last->next; } if (!frwr) goto unmap; /* Strong send queue ordering guarantees that when the * last WR in the chain completes, all WRs in the chain * are complete. */ last->send_flags = IB_SEND_SIGNALED; frwr->fr_cqe.done = frwr_wc_localinv_wake; reinit_completion(&frwr->fr_linv_done); /* Transport disconnect drains the receive CQ before it * replaces the QP. The RPC reply handler won't call us * unless ri_id->qp is a valid pointer. */ r_xprt->rx_stats.local_inv_needed++; bad_wr = NULL; rc = ib_post_send(ia->ri_id->qp, first, &bad_wr); if (bad_wr != first) wait_for_completion(&frwr->fr_linv_done); if (rc) goto out_release; /* ORDER: Now DMA unmap all of the MRs, and return * them to the free MR list. */ unmap: while (!list_empty(mrs)) { mr = rpcrdma_mr_pop(mrs); rpcrdma_mr_unmap_and_put(mr); } return; out_release: pr_err("rpcrdma: FRWR invalidate ib_post_send returned %i\n", rc); /* Unmap and release the MRs in the LOCAL_INV WRs that did not * get posted. */ while (bad_wr) { frwr = container_of(bad_wr, struct rpcrdma_frwr, fr_invwr); mr = container_of(frwr, struct rpcrdma_mr, frwr); bad_wr = bad_wr->next; list_del_init(&mr->mr_list); rpcrdma_mr_recycle(mr); } }