1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (c) 2015, 2017 Oracle. All rights reserved.
4 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
7 /* Lightweight memory registration using Fast Registration Work
10 * FRWR features ordered asynchronous registration and invalidation
11 * of arbitrarily-sized memory regions. This is the fastest and safest
12 * but most complex memory registration mode.
17 * A Memory Region is prepared for RDMA Read or Write using a FAST_REG
18 * Work Request (frwr_map). When the RDMA operation is finished, this
19 * Memory Region is invalidated using a LOCAL_INV Work Request
20 * (frwr_unmap_async and frwr_unmap_sync).
22 * Typically FAST_REG Work Requests are not signaled, and neither are
23 * RDMA Send Work Requests (with the exception of signaling occasionally
24 * to prevent provider work queue overflows). This greatly reduces HCA
30 * frwr_map and frwr_unmap_* cannot run at the same time the transport
31 * connect worker is running. The connect worker holds the transport
32 * send lock, just as ->send_request does. This prevents frwr_map and
33 * the connect worker from running concurrently. When a connection is
34 * closed, the Receive completion queue is drained before the allowing
35 * the connect worker to get control. This prevents frwr_unmap and the
36 * connect worker from running concurrently.
38 * When the underlying transport disconnects, MRs that are in flight
39 * are flushed and are likely unusable. Thus all MRs are destroyed.
40 * New MRs are created on demand.
43 #include <linux/sunrpc/svc_rdma.h>
45 #include "xprt_rdma.h"
46 #include <trace/events/rpcrdma.h>
48 static void frwr_cid_init(struct rpcrdma_ep *ep,
49 struct rpcrdma_mr *mr)
51 struct rpc_rdma_cid *cid = &mr->mr_cid;
53 cid->ci_queue_id = ep->re_attr.send_cq->res.id;
54 cid->ci_completion_id = mr->mr_ibmr->res.id;
57 static void frwr_mr_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr)
60 trace_xprtrdma_mr_unmap(mr);
61 ib_dma_unmap_sg(mr->mr_device, mr->mr_sg, mr->mr_nents,
68 * frwr_mr_release - Destroy one MR
69 * @mr: MR allocated by frwr_mr_init
72 void frwr_mr_release(struct rpcrdma_mr *mr)
76 frwr_mr_unmap(mr->mr_xprt, mr);
78 rc = ib_dereg_mr(mr->mr_ibmr);
80 trace_xprtrdma_frwr_dereg(mr, rc);
85 static void frwr_mr_put(struct rpcrdma_mr *mr)
87 frwr_mr_unmap(mr->mr_xprt, mr);
89 /* The MR is returned to the req's MR free list instead
90 * of to the xprt's MR free list. No spinlock is needed.
92 rpcrdma_mr_push(mr, &mr->mr_req->rl_free_mrs);
95 /* frwr_reset - Place MRs back on the free list
96 * @req: request to reset
98 * Used after a failed marshal. For FRWR, this means the MRs
99 * don't have to be fully released and recreated.
101 * NB: This is safe only as long as none of @req's MRs are
102 * involved with an ongoing asynchronous FAST_REG or LOCAL_INV
105 void frwr_reset(struct rpcrdma_req *req)
107 struct rpcrdma_mr *mr;
109 while ((mr = rpcrdma_mr_pop(&req->rl_registered)))
114 * frwr_mr_init - Initialize one MR
115 * @r_xprt: controlling transport instance
116 * @mr: generic MR to prepare for FRWR
118 * Returns zero if successful. Otherwise a negative errno
121 int frwr_mr_init(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr)
123 struct rpcrdma_ep *ep = r_xprt->rx_ep;
124 unsigned int depth = ep->re_max_fr_depth;
125 struct scatterlist *sg;
128 sg = kcalloc_node(depth, sizeof(*sg), XPRTRDMA_GFP_FLAGS,
129 ibdev_to_node(ep->re_id->device));
133 frmr = ib_alloc_mr(ep->re_pd, ep->re_mrtype, depth);
137 mr->mr_xprt = r_xprt;
139 mr->mr_device = NULL;
140 INIT_LIST_HEAD(&mr->mr_list);
141 init_completion(&mr->mr_linv_done);
142 frwr_cid_init(ep, mr);
144 sg_init_table(sg, depth);
150 trace_xprtrdma_frwr_alloc(mr, PTR_ERR(frmr));
151 return PTR_ERR(frmr);
155 * frwr_query_device - Prepare a transport for use with FRWR
156 * @ep: endpoint to fill in
157 * @device: RDMA device to query
161 * ep->re_max_requests
162 * ep->re_max_rdma_segs
163 * ep->re_max_fr_depth
167 * On success, returns zero.
168 * %-EINVAL - the device does not support FRWR memory registration
169 * %-ENOMEM - the device is not sufficiently capable for NFS/RDMA
171 int frwr_query_device(struct rpcrdma_ep *ep, const struct ib_device *device)
173 const struct ib_device_attr *attrs = &device->attrs;
174 int max_qp_wr, depth, delta;
175 unsigned int max_sge;
177 if (!(attrs->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) ||
178 attrs->max_fast_reg_page_list_len == 0) {
179 pr_err("rpcrdma: 'frwr' mode is not supported by device %s\n",
184 max_sge = min_t(unsigned int, attrs->max_send_sge,
185 RPCRDMA_MAX_SEND_SGES);
186 if (max_sge < RPCRDMA_MIN_SEND_SGES) {
187 pr_err("rpcrdma: HCA provides only %u send SGEs\n", max_sge);
190 ep->re_attr.cap.max_send_sge = max_sge;
191 ep->re_attr.cap.max_recv_sge = 1;
193 ep->re_mrtype = IB_MR_TYPE_MEM_REG;
194 if (attrs->kernel_cap_flags & IBK_SG_GAPS_REG)
195 ep->re_mrtype = IB_MR_TYPE_SG_GAPS;
197 /* Quirk: Some devices advertise a large max_fast_reg_page_list_len
198 * capability, but perform optimally when the MRs are not larger
201 if (attrs->max_sge_rd > RPCRDMA_MAX_HDR_SEGS)
202 ep->re_max_fr_depth = attrs->max_sge_rd;
204 ep->re_max_fr_depth = attrs->max_fast_reg_page_list_len;
205 if (ep->re_max_fr_depth > RPCRDMA_MAX_DATA_SEGS)
206 ep->re_max_fr_depth = RPCRDMA_MAX_DATA_SEGS;
208 /* Add room for frwr register and invalidate WRs.
209 * 1. FRWR reg WR for head
210 * 2. FRWR invalidate WR for head
211 * 3. N FRWR reg WRs for pagelist
212 * 4. N FRWR invalidate WRs for pagelist
213 * 5. FRWR reg WR for tail
214 * 6. FRWR invalidate WR for tail
215 * 7. The RDMA_SEND WR
219 /* Calculate N if the device max FRWR depth is smaller than
220 * RPCRDMA_MAX_DATA_SEGS.
222 if (ep->re_max_fr_depth < RPCRDMA_MAX_DATA_SEGS) {
223 delta = RPCRDMA_MAX_DATA_SEGS - ep->re_max_fr_depth;
225 depth += 2; /* FRWR reg + invalidate */
226 delta -= ep->re_max_fr_depth;
230 max_qp_wr = attrs->max_qp_wr;
231 max_qp_wr -= RPCRDMA_BACKWARD_WRS;
233 if (max_qp_wr < RPCRDMA_MIN_SLOT_TABLE)
235 if (ep->re_max_requests > max_qp_wr)
236 ep->re_max_requests = max_qp_wr;
237 ep->re_attr.cap.max_send_wr = ep->re_max_requests * depth;
238 if (ep->re_attr.cap.max_send_wr > max_qp_wr) {
239 ep->re_max_requests = max_qp_wr / depth;
240 if (!ep->re_max_requests)
242 ep->re_attr.cap.max_send_wr = ep->re_max_requests * depth;
244 ep->re_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;
245 ep->re_attr.cap.max_send_wr += 1; /* for ib_drain_sq */
246 ep->re_attr.cap.max_recv_wr = ep->re_max_requests;
247 ep->re_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
248 ep->re_attr.cap.max_recv_wr += RPCRDMA_MAX_RECV_BATCH;
249 ep->re_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */
251 ep->re_max_rdma_segs =
252 DIV_ROUND_UP(RPCRDMA_MAX_DATA_SEGS, ep->re_max_fr_depth);
253 /* Reply chunks require segments for head and tail buffers */
254 ep->re_max_rdma_segs += 2;
255 if (ep->re_max_rdma_segs > RPCRDMA_MAX_HDR_SEGS)
256 ep->re_max_rdma_segs = RPCRDMA_MAX_HDR_SEGS;
258 /* Ensure the underlying device is capable of conveying the
259 * largest r/wsize NFS will ask for. This guarantees that
260 * failing over from one RDMA device to another will not
263 if ((ep->re_max_rdma_segs * ep->re_max_fr_depth) < RPCRDMA_MAX_SEGS)
270 * frwr_map - Register a memory region
271 * @r_xprt: controlling transport
272 * @seg: memory region co-ordinates
273 * @nsegs: number of segments remaining
274 * @writing: true when RDMA Write will be used
275 * @xid: XID of RPC using the registered memory
278 * Prepare a REG_MR Work Request to register a memory region
279 * for remote access via RDMA READ or RDMA WRITE.
281 * Returns the next segment or a negative errno pointer.
282 * On success, @mr is filled in.
284 struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
285 struct rpcrdma_mr_seg *seg,
286 int nsegs, bool writing, __be32 xid,
287 struct rpcrdma_mr *mr)
289 struct rpcrdma_ep *ep = r_xprt->rx_ep;
290 struct ib_reg_wr *reg_wr;
295 if (nsegs > ep->re_max_fr_depth)
296 nsegs = ep->re_max_fr_depth;
297 for (i = 0; i < nsegs;) {
298 sg_set_page(&mr->mr_sg[i], seg->mr_page,
299 seg->mr_len, seg->mr_offset);
303 if (ep->re_mrtype == IB_MR_TYPE_SG_GAPS)
305 if ((i < nsegs && seg->mr_offset) ||
306 offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
309 mr->mr_dir = rpcrdma_data_dir(writing);
312 dma_nents = ib_dma_map_sg(ep->re_id->device, mr->mr_sg, mr->mr_nents,
316 mr->mr_device = ep->re_id->device;
319 n = ib_map_mr_sg(ibmr, mr->mr_sg, dma_nents, NULL, PAGE_SIZE);
323 ibmr->iova &= 0x00000000ffffffff;
324 ibmr->iova |= ((u64)be32_to_cpu(xid)) << 32;
325 key = (u8)(ibmr->rkey & 0x000000FF);
326 ib_update_fast_reg_key(ibmr, ++key);
328 reg_wr = &mr->mr_regwr;
330 reg_wr->key = ibmr->rkey;
331 reg_wr->access = writing ?
332 IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE :
333 IB_ACCESS_REMOTE_READ;
335 mr->mr_handle = ibmr->rkey;
336 mr->mr_length = ibmr->length;
337 mr->mr_offset = ibmr->iova;
338 trace_xprtrdma_mr_map(mr);
343 trace_xprtrdma_frwr_sgerr(mr, i);
344 return ERR_PTR(-EIO);
347 trace_xprtrdma_frwr_maperr(mr, n);
348 return ERR_PTR(-EIO);
352 * frwr_wc_fastreg - Invoked by RDMA provider for a flushed FastReg WC
353 * @cq: completion queue
354 * @wc: WCE for a completed FastReg WR
356 * Each flushed MR gets destroyed after the QP has drained.
358 static void frwr_wc_fastreg(struct ib_cq *cq, struct ib_wc *wc)
360 struct ib_cqe *cqe = wc->wr_cqe;
361 struct rpcrdma_mr *mr = container_of(cqe, struct rpcrdma_mr, mr_cqe);
363 /* WARNING: Only wr_cqe and status are reliable at this point */
364 trace_xprtrdma_wc_fastreg(wc, &mr->mr_cid);
366 rpcrdma_flush_disconnect(cq->cq_context, wc);
370 * frwr_send - post Send WRs containing the RPC Call message
371 * @r_xprt: controlling transport instance
372 * @req: prepared RPC Call
374 * For FRWR, chain any FastReg WRs to the Send WR. Only a
375 * single ib_post_send call is needed to register memory
376 * and then post the Send WR.
378 * Returns the return code from ib_post_send.
380 * Caller must hold the transport send lock to ensure that the
381 * pointers to the transport's rdma_cm_id and QP are stable.
383 int frwr_send(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
385 struct ib_send_wr *post_wr, *send_wr = &req->rl_wr;
386 struct rpcrdma_ep *ep = r_xprt->rx_ep;
387 struct rpcrdma_mr *mr;
388 unsigned int num_wrs;
393 list_for_each_entry(mr, &req->rl_registered, mr_list) {
394 trace_xprtrdma_mr_fastreg(mr);
396 mr->mr_cqe.done = frwr_wc_fastreg;
397 mr->mr_regwr.wr.next = post_wr;
398 mr->mr_regwr.wr.wr_cqe = &mr->mr_cqe;
399 mr->mr_regwr.wr.num_sge = 0;
400 mr->mr_regwr.wr.opcode = IB_WR_REG_MR;
401 mr->mr_regwr.wr.send_flags = 0;
402 post_wr = &mr->mr_regwr.wr;
406 if ((kref_read(&req->rl_kref) > 1) || num_wrs > ep->re_send_count) {
407 send_wr->send_flags |= IB_SEND_SIGNALED;
408 ep->re_send_count = min_t(unsigned int, ep->re_send_batch,
409 num_wrs - ep->re_send_count);
411 send_wr->send_flags &= ~IB_SEND_SIGNALED;
412 ep->re_send_count -= num_wrs;
415 trace_xprtrdma_post_send(req);
416 ret = ib_post_send(ep->re_id->qp, post_wr, NULL);
418 trace_xprtrdma_post_send_err(r_xprt, req, ret);
423 * frwr_reminv - handle a remotely invalidated mr on the @mrs list
424 * @rep: Received reply
425 * @mrs: list of MRs to check
428 void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs)
430 struct rpcrdma_mr *mr;
432 list_for_each_entry(mr, mrs, mr_list)
433 if (mr->mr_handle == rep->rr_inv_rkey) {
434 list_del_init(&mr->mr_list);
435 trace_xprtrdma_mr_reminv(mr);
437 break; /* only one invalidated MR per RPC */
441 static void frwr_mr_done(struct ib_wc *wc, struct rpcrdma_mr *mr)
443 if (likely(wc->status == IB_WC_SUCCESS))
448 * frwr_wc_localinv - Invoked by RDMA provider for a LOCAL_INV WC
449 * @cq: completion queue
450 * @wc: WCE for a completed LocalInv WR
453 static void frwr_wc_localinv(struct ib_cq *cq, struct ib_wc *wc)
455 struct ib_cqe *cqe = wc->wr_cqe;
456 struct rpcrdma_mr *mr = container_of(cqe, struct rpcrdma_mr, mr_cqe);
458 /* WARNING: Only wr_cqe and status are reliable at this point */
459 trace_xprtrdma_wc_li(wc, &mr->mr_cid);
460 frwr_mr_done(wc, mr);
462 rpcrdma_flush_disconnect(cq->cq_context, wc);
466 * frwr_wc_localinv_wake - Invoked by RDMA provider for a LOCAL_INV WC
467 * @cq: completion queue
468 * @wc: WCE for a completed LocalInv WR
470 * Awaken anyone waiting for an MR to finish being fenced.
472 static void frwr_wc_localinv_wake(struct ib_cq *cq, struct ib_wc *wc)
474 struct ib_cqe *cqe = wc->wr_cqe;
475 struct rpcrdma_mr *mr = container_of(cqe, struct rpcrdma_mr, mr_cqe);
477 /* WARNING: Only wr_cqe and status are reliable at this point */
478 trace_xprtrdma_wc_li_wake(wc, &mr->mr_cid);
479 frwr_mr_done(wc, mr);
480 complete(&mr->mr_linv_done);
482 rpcrdma_flush_disconnect(cq->cq_context, wc);
486 * frwr_unmap_sync - invalidate memory regions that were registered for @req
487 * @r_xprt: controlling transport instance
488 * @req: rpcrdma_req with a non-empty list of MRs to process
490 * Sleeps until it is safe for the host CPU to access the previously mapped
491 * memory regions. This guarantees that registered MRs are properly fenced
492 * from the server before the RPC consumer accesses the data in them. It
493 * also ensures proper Send flow control: waking the next RPC waits until
494 * this RPC has relinquished all its Send Queue entries.
496 void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
498 struct ib_send_wr *first, **prev, *last;
499 struct rpcrdma_ep *ep = r_xprt->rx_ep;
500 const struct ib_send_wr *bad_wr;
501 struct rpcrdma_mr *mr;
504 /* ORDER: Invalidate all of the MRs first
506 * Chain the LOCAL_INV Work Requests and post them with
507 * a single ib_post_send() call.
510 mr = rpcrdma_mr_pop(&req->rl_registered);
512 trace_xprtrdma_mr_localinv(mr);
513 r_xprt->rx_stats.local_inv_needed++;
515 last = &mr->mr_invwr;
517 last->wr_cqe = &mr->mr_cqe;
518 last->sg_list = NULL;
520 last->opcode = IB_WR_LOCAL_INV;
521 last->send_flags = IB_SEND_SIGNALED;
522 last->ex.invalidate_rkey = mr->mr_handle;
524 last->wr_cqe->done = frwr_wc_localinv;
528 } while ((mr = rpcrdma_mr_pop(&req->rl_registered)));
530 mr = container_of(last, struct rpcrdma_mr, mr_invwr);
532 /* Strong send queue ordering guarantees that when the
533 * last WR in the chain completes, all WRs in the chain
536 last->wr_cqe->done = frwr_wc_localinv_wake;
537 reinit_completion(&mr->mr_linv_done);
539 /* Transport disconnect drains the receive CQ before it
540 * replaces the QP. The RPC reply handler won't call us
541 * unless re_id->qp is a valid pointer.
544 rc = ib_post_send(ep->re_id->qp, first, &bad_wr);
546 /* The final LOCAL_INV WR in the chain is supposed to
547 * do the wake. If it was never posted, the wake will
548 * not happen, so don't wait in that case.
551 wait_for_completion(&mr->mr_linv_done);
555 /* On error, the MRs get destroyed once the QP has drained. */
556 trace_xprtrdma_post_linv_err(req, rc);
558 /* Force a connection loss to ensure complete recovery.
560 rpcrdma_force_disconnect(ep);
564 * frwr_wc_localinv_done - Invoked by RDMA provider for a signaled LOCAL_INV WC
565 * @cq: completion queue
566 * @wc: WCE for a completed LocalInv WR
569 static void frwr_wc_localinv_done(struct ib_cq *cq, struct ib_wc *wc)
571 struct ib_cqe *cqe = wc->wr_cqe;
572 struct rpcrdma_mr *mr = container_of(cqe, struct rpcrdma_mr, mr_cqe);
573 struct rpcrdma_rep *rep;
575 /* WARNING: Only wr_cqe and status are reliable at this point */
576 trace_xprtrdma_wc_li_done(wc, &mr->mr_cid);
578 /* Ensure that @rep is generated before the MR is released */
579 rep = mr->mr_req->rl_reply;
582 if (wc->status != IB_WC_SUCCESS) {
584 rpcrdma_unpin_rqst(rep);
585 rpcrdma_flush_disconnect(cq->cq_context, wc);
589 rpcrdma_complete_rqst(rep);
593 * frwr_unmap_async - invalidate memory regions that were registered for @req
594 * @r_xprt: controlling transport instance
595 * @req: rpcrdma_req with a non-empty list of MRs to process
597 * This guarantees that registered MRs are properly fenced from the
598 * server before the RPC consumer accesses the data in them. It also
599 * ensures proper Send flow control: waking the next RPC waits until
600 * this RPC has relinquished all its Send Queue entries.
602 void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
604 struct ib_send_wr *first, *last, **prev;
605 struct rpcrdma_ep *ep = r_xprt->rx_ep;
606 struct rpcrdma_mr *mr;
609 /* Chain the LOCAL_INV Work Requests and post them with
610 * a single ib_post_send() call.
613 mr = rpcrdma_mr_pop(&req->rl_registered);
615 trace_xprtrdma_mr_localinv(mr);
616 r_xprt->rx_stats.local_inv_needed++;
618 last = &mr->mr_invwr;
620 last->wr_cqe = &mr->mr_cqe;
621 last->sg_list = NULL;
623 last->opcode = IB_WR_LOCAL_INV;
624 last->send_flags = IB_SEND_SIGNALED;
625 last->ex.invalidate_rkey = mr->mr_handle;
627 last->wr_cqe->done = frwr_wc_localinv;
631 } while ((mr = rpcrdma_mr_pop(&req->rl_registered)));
633 /* Strong send queue ordering guarantees that when the
634 * last WR in the chain completes, all WRs in the chain
635 * are complete. The last completion will wake up the
638 last->wr_cqe->done = frwr_wc_localinv_done;
640 /* Transport disconnect drains the receive CQ before it
641 * replaces the QP. The RPC reply handler won't call us
642 * unless re_id->qp is a valid pointer.
644 rc = ib_post_send(ep->re_id->qp, first, NULL);
648 /* On error, the MRs get destroyed once the QP has drained. */
649 trace_xprtrdma_post_linv_err(req, rc);
651 /* The final LOCAL_INV WR in the chain is supposed to
652 * do the wake. If it was never posted, the wake does
653 * not happen. Unpin the rqst in preparation for its
656 rpcrdma_unpin_rqst(req->rl_reply);
658 /* Force a connection loss to ensure complete recovery.
660 rpcrdma_force_disconnect(ep);
664 * frwr_wp_create - Create an MR for padding Write chunks
665 * @r_xprt: transport resources to use
667 * Return 0 on success, negative errno on failure.
669 int frwr_wp_create(struct rpcrdma_xprt *r_xprt)
671 struct rpcrdma_ep *ep = r_xprt->rx_ep;
672 struct rpcrdma_mr_seg seg;
673 struct rpcrdma_mr *mr;
675 mr = rpcrdma_mr_get(r_xprt);
679 ep->re_write_pad_mr = mr;
681 seg.mr_len = XDR_UNIT;
682 seg.mr_page = virt_to_page(ep->re_write_pad);
683 seg.mr_offset = offset_in_page(ep->re_write_pad);
684 if (IS_ERR(frwr_map(r_xprt, &seg, 1, true, xdr_zero, mr)))
686 trace_xprtrdma_mr_fastreg(mr);
688 mr->mr_cqe.done = frwr_wc_fastreg;
689 mr->mr_regwr.wr.next = NULL;
690 mr->mr_regwr.wr.wr_cqe = &mr->mr_cqe;
691 mr->mr_regwr.wr.num_sge = 0;
692 mr->mr_regwr.wr.opcode = IB_WR_REG_MR;
693 mr->mr_regwr.wr.send_flags = 0;
695 return ib_post_send(ep->re_id->qp, &mr->mr_regwr.wr, NULL);