diff options
Diffstat (limited to 'net/sunrpc/xprtrdma/frwr_ops.c')
| -rw-r--r-- | net/sunrpc/xprtrdma/frwr_ops.c | 615 |
1 files changed, 615 insertions, 0 deletions
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c new file mode 100644 index 000000000..1bb00dd6c --- /dev/null +++ b/net/sunrpc/xprtrdma/frwr_ops.c @@ -0,0 +1,615 @@ +// 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_op_map). When the RDMA operation is finished, this + * Memory Region is invalidated using a LOCAL_INV Work Request + * (frwr_op_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_op_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_op_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_op_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_op_map allocates another MR for the current RPC while + * the broken MR is reset. + * + * To ensure that frwr_op_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 <linux/sunrpc/rpc_rdma.h> +#include <linux/sunrpc/svc_rdma.h> + +#include "xprt_rdma.h" +#include <trace/events/rpcrdma.h> + +#if IS_ENABLED(CONFIG_SUNRPC_DEBUG) +# define RPCDBG_FACILITY RPCDBG_TRANS +#endif + +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; +} + +static int +frwr_op_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr) +{ + unsigned int depth = ia->ri_max_frwr_depth; + struct rpcrdma_frwr *frwr = &mr->frwr; + int rc; + + frwr->fr_mr = ib_alloc_mr(ia->ri_pd, ia->ri_mrtype, depth); + if (IS_ERR(frwr->fr_mr)) + goto out_mr_err; + + mr->mr_sg = kcalloc(depth, sizeof(*mr->mr_sg), GFP_KERNEL); + if (!mr->mr_sg) + goto out_list_err; + + INIT_LIST_HEAD(&mr->mr_list); + sg_init_table(mr->mr_sg, depth); + init_completion(&frwr->fr_linv_done); + return 0; + +out_mr_err: + rc = PTR_ERR(frwr->fr_mr); + dprintk("RPC: %s: ib_alloc_mr status %i\n", + __func__, rc); + return rc; + +out_list_err: + rc = -ENOMEM; + dprintk("RPC: %s: sg allocation failure\n", + __func__); + ib_dereg_mr(frwr->fr_mr); + return rc; +} + +static void +frwr_op_release_mr(struct rpcrdma_mr *mr) +{ + int rc; + + rc = ib_dereg_mr(mr->frwr.fr_mr); + if (rc) + pr_err("rpcrdma: final ib_dereg_mr for %p returned %i\n", + mr, rc); + kfree(mr->mr_sg); + kfree(mr); +} + +static int +__frwr_mr_reset(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr) +{ + struct rpcrdma_frwr *frwr = &mr->frwr; + int rc; + + rc = ib_dereg_mr(frwr->fr_mr); + if (rc) { + pr_warn("rpcrdma: ib_dereg_mr status %d, frwr %p orphaned\n", + rc, mr); + return rc; + } + + frwr->fr_mr = ib_alloc_mr(ia->ri_pd, ia->ri_mrtype, + ia->ri_max_frwr_depth); + if (IS_ERR(frwr->fr_mr)) { + pr_warn("rpcrdma: ib_alloc_mr status %ld, frwr %p orphaned\n", + PTR_ERR(frwr->fr_mr), mr); + return PTR_ERR(frwr->fr_mr); + } + + dprintk("RPC: %s: recovered FRWR %p\n", __func__, frwr); + frwr->fr_state = FRWR_IS_INVALID; + return 0; +} + +/* Reset of a single FRWR. Generate a fresh rkey by replacing the MR. + */ +static void +frwr_op_recover_mr(struct rpcrdma_mr *mr) +{ + enum rpcrdma_frwr_state state = mr->frwr.fr_state; + struct rpcrdma_xprt *r_xprt = mr->mr_xprt; + struct rpcrdma_ia *ia = &r_xprt->rx_ia; + int rc; + + rc = __frwr_mr_reset(ia, mr); + if (state != FRWR_FLUSHED_LI) { + trace_xprtrdma_dma_unmap(mr); + ib_dma_unmap_sg(ia->ri_device, + mr->mr_sg, mr->mr_nents, mr->mr_dir); + } + if (rc) + goto out_release; + + rpcrdma_mr_put(mr); + r_xprt->rx_stats.mrs_recovered++; + return; + +out_release: + pr_err("rpcrdma: FRWR reset failed %d, %p released\n", rc, mr); + r_xprt->rx_stats.mrs_orphaned++; + + spin_lock(&r_xprt->rx_buf.rb_mrlock); + list_del(&mr->mr_all); + spin_unlock(&r_xprt->rx_buf.rb_mrlock); + + frwr_op_release_mr(mr); +} + +/* 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 + */ +static int +frwr_op_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; + + ia->ri_max_frwr_depth = + min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS, + attrs->max_fast_reg_page_list_len); + dprintk("RPC: %s: device's max FR page list len = %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); + return 0; +} + +/* FRWR mode conveys a list of pages per chunk segment. The + * maximum length of that list is the FRWR page list depth. + */ +static size_t +frwr_op_maxpages(struct rpcrdma_xprt *r_xprt) +{ + struct rpcrdma_ia *ia = &r_xprt->rx_ia; + + return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS, + RPCRDMA_MAX_HDR_SEGS * 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); +} + +/* Post a REG_MR Work Request to register a memory region + * for remote access via RDMA READ or RDMA WRITE. + */ +static struct rpcrdma_mr_seg * +frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg, + int nsegs, bool writing, 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_defer_recovery(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; + trace_xprtrdma_dma_map(mr); + + 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; + + 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; + + *out = mr; + return seg; + +out_dmamap_err: + pr_err("rpcrdma: failed to DMA map sg %p sg_nents %d\n", + mr->mr_sg, i); + frwr->fr_state = FRWR_IS_INVALID; + rpcrdma_mr_put(mr); + return ERR_PTR(-EIO); + +out_mapmr_err: + pr_err("rpcrdma: failed to map mr %p (%d/%d)\n", + frwr->fr_mr, n, mr->mr_nents); + rpcrdma_mr_defer_recovery(mr); + return ERR_PTR(-EIO); +} + +/* Post Send WR containing the RPC Call message. + * + * For FRMR, 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. + */ +static int +frwr_op_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 MWs for recovery. + */ + return ib_post_send(ia->ri_id->qp, post_wr, NULL); +} + +/* Handle a remotely invalidated mr on the @mrs list + */ +static void +frwr_op_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_remoteinv(mr); + mr->frwr.fr_state = FRWR_IS_INVALID; + rpcrdma_mr_unmap_and_put(mr); + break; /* only one invalidated MR per RPC */ + } +} + +/* Invalidate all memory regions that were registered for "req". + * + * 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. + */ +static void +frwr_op_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_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 reset_mrs; + + /* 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; + +reset_mrs: + pr_err("rpcrdma: FRWR invalidate ib_post_send returned %i\n", rc); + + /* Find and reset 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); + + __frwr_mr_reset(ia, mr); + + bad_wr = bad_wr->next; + } + goto unmap; +} + +const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops = { + .ro_map = frwr_op_map, + .ro_send = frwr_op_send, + .ro_reminv = frwr_op_reminv, + .ro_unmap_sync = frwr_op_unmap_sync, + .ro_recover_mr = frwr_op_recover_mr, + .ro_open = frwr_op_open, + .ro_maxpages = frwr_op_maxpages, + .ro_init_mr = frwr_op_init_mr, + .ro_release_mr = frwr_op_release_mr, + .ro_displayname = "frwr", + .ro_send_w_inv_ok = RPCRDMA_CMP_F_SND_W_INV_OK, +}; |