1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause 2 /* 3 * Copyright (c) 2016-2018 Oracle. All rights reserved. 4 * Copyright (c) 2014 Open Grid Computing, Inc. All rights reserved. 5 * Copyright (c) 2005-2006 Network Appliance, Inc. All rights reserved. 6 * 7 * This software is available to you under a choice of one of two 8 * licenses. You may choose to be licensed under the terms of the GNU 9 * General Public License (GPL) Version 2, available from the file 10 * COPYING in the main directory of this source tree, or the BSD-type 11 * license below: 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 17 * Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 20 * Redistributions in binary form must reproduce the above 21 * copyright notice, this list of conditions and the following 22 * disclaimer in the documentation and/or other materials provided 23 * with the distribution. 24 * 25 * Neither the name of the Network Appliance, Inc. nor the names of 26 * its contributors may be used to endorse or promote products 27 * derived from this software without specific prior written 28 * permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 31 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 32 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 33 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 34 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 36 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 40 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 41 * 42 * Author: Tom Tucker <tom@opengridcomputing.com> 43 */ 44 45 /* Operation 46 * 47 * The main entry point is svc_rdma_recvfrom. This is called from 48 * svc_recv when the transport indicates there is incoming data to 49 * be read. "Data Ready" is signaled when an RDMA Receive completes, 50 * or when a set of RDMA Reads complete. 51 * 52 * An svc_rqst is passed in. This structure contains an array of 53 * free pages (rq_pages) that will contain the incoming RPC message. 54 * 55 * Short messages are moved directly into svc_rqst::rq_arg, and 56 * the RPC Call is ready to be processed by the Upper Layer. 57 * svc_rdma_recvfrom returns the length of the RPC Call message, 58 * completing the reception of the RPC Call. 59 * 60 * However, when an incoming message has Read chunks, 61 * svc_rdma_recvfrom must post RDMA Reads to pull the RPC Call's 62 * data payload from the client. svc_rdma_recvfrom sets up the 63 * RDMA Reads using pages in svc_rqst::rq_pages, which are 64 * transferred to an svc_rdma_recv_ctxt for the duration of the 65 * I/O. svc_rdma_recvfrom then returns zero, since the RPC message 66 * is still not yet ready. 67 * 68 * When the Read chunk payloads have become available on the 69 * server, "Data Ready" is raised again, and svc_recv calls 70 * svc_rdma_recvfrom again. This second call may use a different 71 * svc_rqst than the first one, thus any information that needs 72 * to be preserved across these two calls is kept in an 73 * svc_rdma_recv_ctxt. 74 * 75 * The second call to svc_rdma_recvfrom performs final assembly 76 * of the RPC Call message, using the RDMA Read sink pages kept in 77 * the svc_rdma_recv_ctxt. The xdr_buf is copied from the 78 * svc_rdma_recv_ctxt to the second svc_rqst. The second call returns 79 * the length of the completed RPC Call message. 80 * 81 * Page Management 82 * 83 * Pages under I/O must be transferred from the first svc_rqst to an 84 * svc_rdma_recv_ctxt before the first svc_rdma_recvfrom call returns. 85 * 86 * The first svc_rqst supplies pages for RDMA Reads. These are moved 87 * from rqstp::rq_pages into ctxt::pages. The consumed elements of 88 * the rq_pages array are set to NULL and refilled with the first 89 * svc_rdma_recvfrom call returns. 90 * 91 * During the second svc_rdma_recvfrom call, RDMA Read sink pages 92 * are transferred from the svc_rdma_recv_ctxt to the second svc_rqst 93 * (see rdma_read_complete() below). 94 */ 95 96 #include <linux/spinlock.h> 97 #include <asm/unaligned.h> 98 #include <rdma/ib_verbs.h> 99 #include <rdma/rdma_cm.h> 100 101 #include <linux/sunrpc/xdr.h> 102 #include <linux/sunrpc/debug.h> 103 #include <linux/sunrpc/rpc_rdma.h> 104 #include <linux/sunrpc/svc_rdma.h> 105 106 #include "xprt_rdma.h" 107 #include <trace/events/rpcrdma.h> 108 109 #define RPCDBG_FACILITY RPCDBG_SVCXPRT 110 111 static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc); 112 113 static inline struct svc_rdma_recv_ctxt * 114 svc_rdma_next_recv_ctxt(struct list_head *list) 115 { 116 return list_first_entry_or_null(list, struct svc_rdma_recv_ctxt, 117 rc_list); 118 } 119 120 static struct svc_rdma_recv_ctxt * 121 svc_rdma_recv_ctxt_alloc(struct svcxprt_rdma *rdma) 122 { 123 struct svc_rdma_recv_ctxt *ctxt; 124 dma_addr_t addr; 125 void *buffer; 126 127 ctxt = kmalloc(sizeof(*ctxt), GFP_KERNEL); 128 if (!ctxt) 129 goto fail0; 130 buffer = kmalloc(rdma->sc_max_req_size, GFP_KERNEL); 131 if (!buffer) 132 goto fail1; 133 addr = ib_dma_map_single(rdma->sc_pd->device, buffer, 134 rdma->sc_max_req_size, DMA_FROM_DEVICE); 135 if (ib_dma_mapping_error(rdma->sc_pd->device, addr)) 136 goto fail2; 137 138 ctxt->rc_recv_wr.next = NULL; 139 ctxt->rc_recv_wr.wr_cqe = &ctxt->rc_cqe; 140 ctxt->rc_recv_wr.sg_list = &ctxt->rc_recv_sge; 141 ctxt->rc_recv_wr.num_sge = 1; 142 ctxt->rc_cqe.done = svc_rdma_wc_receive; 143 ctxt->rc_recv_sge.addr = addr; 144 ctxt->rc_recv_sge.length = rdma->sc_max_req_size; 145 ctxt->rc_recv_sge.lkey = rdma->sc_pd->local_dma_lkey; 146 ctxt->rc_recv_buf = buffer; 147 ctxt->rc_temp = false; 148 return ctxt; 149 150 fail2: 151 kfree(buffer); 152 fail1: 153 kfree(ctxt); 154 fail0: 155 return NULL; 156 } 157 158 static void svc_rdma_recv_ctxt_destroy(struct svcxprt_rdma *rdma, 159 struct svc_rdma_recv_ctxt *ctxt) 160 { 161 ib_dma_unmap_single(rdma->sc_pd->device, ctxt->rc_recv_sge.addr, 162 ctxt->rc_recv_sge.length, DMA_FROM_DEVICE); 163 kfree(ctxt->rc_recv_buf); 164 kfree(ctxt); 165 } 166 167 /** 168 * svc_rdma_recv_ctxts_destroy - Release all recv_ctxt's for an xprt 169 * @rdma: svcxprt_rdma being torn down 170 * 171 */ 172 void svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma *rdma) 173 { 174 struct svc_rdma_recv_ctxt *ctxt; 175 struct llist_node *node; 176 177 while ((node = llist_del_first(&rdma->sc_recv_ctxts))) { 178 ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node); 179 svc_rdma_recv_ctxt_destroy(rdma, ctxt); 180 } 181 } 182 183 static struct svc_rdma_recv_ctxt * 184 svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma) 185 { 186 struct svc_rdma_recv_ctxt *ctxt; 187 struct llist_node *node; 188 189 node = llist_del_first(&rdma->sc_recv_ctxts); 190 if (!node) 191 goto out_empty; 192 ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node); 193 194 out: 195 ctxt->rc_page_count = 0; 196 return ctxt; 197 198 out_empty: 199 ctxt = svc_rdma_recv_ctxt_alloc(rdma); 200 if (!ctxt) 201 return NULL; 202 goto out; 203 } 204 205 /** 206 * svc_rdma_recv_ctxt_put - Return recv_ctxt to free list 207 * @rdma: controlling svcxprt_rdma 208 * @ctxt: object to return to the free list 209 * 210 */ 211 void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma, 212 struct svc_rdma_recv_ctxt *ctxt) 213 { 214 unsigned int i; 215 216 for (i = 0; i < ctxt->rc_page_count; i++) 217 put_page(ctxt->rc_pages[i]); 218 219 if (!ctxt->rc_temp) 220 llist_add(&ctxt->rc_node, &rdma->sc_recv_ctxts); 221 else 222 svc_rdma_recv_ctxt_destroy(rdma, ctxt); 223 } 224 225 static int __svc_rdma_post_recv(struct svcxprt_rdma *rdma, 226 struct svc_rdma_recv_ctxt *ctxt) 227 { 228 int ret; 229 230 svc_xprt_get(&rdma->sc_xprt); 231 ret = ib_post_recv(rdma->sc_qp, &ctxt->rc_recv_wr, NULL); 232 trace_svcrdma_post_recv(&ctxt->rc_recv_wr, ret); 233 if (ret) 234 goto err_post; 235 return 0; 236 237 err_post: 238 svc_rdma_recv_ctxt_put(rdma, ctxt); 239 svc_xprt_put(&rdma->sc_xprt); 240 return ret; 241 } 242 243 static int svc_rdma_post_recv(struct svcxprt_rdma *rdma) 244 { 245 struct svc_rdma_recv_ctxt *ctxt; 246 247 ctxt = svc_rdma_recv_ctxt_get(rdma); 248 if (!ctxt) 249 return -ENOMEM; 250 return __svc_rdma_post_recv(rdma, ctxt); 251 } 252 253 /** 254 * svc_rdma_post_recvs - Post initial set of Recv WRs 255 * @rdma: fresh svcxprt_rdma 256 * 257 * Returns true if successful, otherwise false. 258 */ 259 bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma) 260 { 261 struct svc_rdma_recv_ctxt *ctxt; 262 unsigned int i; 263 int ret; 264 265 for (i = 0; i < rdma->sc_max_requests; i++) { 266 ctxt = svc_rdma_recv_ctxt_get(rdma); 267 if (!ctxt) 268 return false; 269 ctxt->rc_temp = true; 270 ret = __svc_rdma_post_recv(rdma, ctxt); 271 if (ret) 272 return false; 273 } 274 return true; 275 } 276 277 /** 278 * svc_rdma_wc_receive - Invoked by RDMA provider for each polled Receive WC 279 * @cq: Completion Queue context 280 * @wc: Work Completion object 281 * 282 * NB: The svc_xprt/svcxprt_rdma is pinned whenever it's possible that 283 * the Receive completion handler could be running. 284 */ 285 static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc) 286 { 287 struct svcxprt_rdma *rdma = cq->cq_context; 288 struct ib_cqe *cqe = wc->wr_cqe; 289 struct svc_rdma_recv_ctxt *ctxt; 290 291 trace_svcrdma_wc_receive(wc); 292 293 /* WARNING: Only wc->wr_cqe and wc->status are reliable */ 294 ctxt = container_of(cqe, struct svc_rdma_recv_ctxt, rc_cqe); 295 296 if (wc->status != IB_WC_SUCCESS) 297 goto flushed; 298 299 if (svc_rdma_post_recv(rdma)) 300 goto post_err; 301 302 /* All wc fields are now known to be valid */ 303 ctxt->rc_byte_len = wc->byte_len; 304 ib_dma_sync_single_for_cpu(rdma->sc_pd->device, 305 ctxt->rc_recv_sge.addr, 306 wc->byte_len, DMA_FROM_DEVICE); 307 308 spin_lock(&rdma->sc_rq_dto_lock); 309 list_add_tail(&ctxt->rc_list, &rdma->sc_rq_dto_q); 310 /* Note the unlock pairs with the smp_rmb in svc_xprt_ready: */ 311 set_bit(XPT_DATA, &rdma->sc_xprt.xpt_flags); 312 spin_unlock(&rdma->sc_rq_dto_lock); 313 if (!test_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags)) 314 svc_xprt_enqueue(&rdma->sc_xprt); 315 goto out; 316 317 flushed: 318 post_err: 319 svc_rdma_recv_ctxt_put(rdma, ctxt); 320 set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags); 321 svc_xprt_enqueue(&rdma->sc_xprt); 322 out: 323 svc_xprt_put(&rdma->sc_xprt); 324 } 325 326 /** 327 * svc_rdma_flush_recv_queues - Drain pending Receive work 328 * @rdma: svcxprt_rdma being shut down 329 * 330 */ 331 void svc_rdma_flush_recv_queues(struct svcxprt_rdma *rdma) 332 { 333 struct svc_rdma_recv_ctxt *ctxt; 334 335 while ((ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_read_complete_q))) { 336 list_del(&ctxt->rc_list); 337 svc_rdma_recv_ctxt_put(rdma, ctxt); 338 } 339 while ((ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_rq_dto_q))) { 340 list_del(&ctxt->rc_list); 341 svc_rdma_recv_ctxt_put(rdma, ctxt); 342 } 343 } 344 345 static void svc_rdma_build_arg_xdr(struct svc_rqst *rqstp, 346 struct svc_rdma_recv_ctxt *ctxt) 347 { 348 struct xdr_buf *arg = &rqstp->rq_arg; 349 350 arg->head[0].iov_base = ctxt->rc_recv_buf; 351 arg->head[0].iov_len = ctxt->rc_byte_len; 352 arg->tail[0].iov_base = NULL; 353 arg->tail[0].iov_len = 0; 354 arg->page_len = 0; 355 arg->page_base = 0; 356 arg->buflen = ctxt->rc_byte_len; 357 arg->len = ctxt->rc_byte_len; 358 } 359 360 /* This accommodates the largest possible Write chunk, 361 * in one segment. 362 */ 363 #define MAX_BYTES_WRITE_SEG ((u32)(RPCSVC_MAXPAGES << PAGE_SHIFT)) 364 365 /* This accommodates the largest possible Position-Zero 366 * Read chunk or Reply chunk, in one segment. 367 */ 368 #define MAX_BYTES_SPECIAL_SEG ((u32)((RPCSVC_MAXPAGES + 2) << PAGE_SHIFT)) 369 370 /* Sanity check the Read list. 371 * 372 * Implementation limits: 373 * - This implementation supports only one Read chunk. 374 * 375 * Sanity checks: 376 * - Read list does not overflow buffer. 377 * - Segment size limited by largest NFS data payload. 378 * 379 * The segment count is limited to how many segments can 380 * fit in the transport header without overflowing the 381 * buffer. That's about 40 Read segments for a 1KB inline 382 * threshold. 383 * 384 * Returns pointer to the following Write list. 385 */ 386 static __be32 *xdr_check_read_list(__be32 *p, const __be32 *end) 387 { 388 u32 position; 389 bool first; 390 391 first = true; 392 while (*p++ != xdr_zero) { 393 if (first) { 394 position = be32_to_cpup(p++); 395 first = false; 396 } else if (be32_to_cpup(p++) != position) { 397 return NULL; 398 } 399 p++; /* handle */ 400 if (be32_to_cpup(p++) > MAX_BYTES_SPECIAL_SEG) 401 return NULL; 402 p += 2; /* offset */ 403 404 if (p > end) 405 return NULL; 406 } 407 return p; 408 } 409 410 /* The segment count is limited to how many segments can 411 * fit in the transport header without overflowing the 412 * buffer. That's about 60 Write segments for a 1KB inline 413 * threshold. 414 */ 415 static __be32 *xdr_check_write_chunk(__be32 *p, const __be32 *end, 416 u32 maxlen) 417 { 418 u32 i, segcount; 419 420 segcount = be32_to_cpup(p++); 421 for (i = 0; i < segcount; i++) { 422 p++; /* handle */ 423 if (be32_to_cpup(p++) > maxlen) 424 return NULL; 425 p += 2; /* offset */ 426 427 if (p > end) 428 return NULL; 429 } 430 431 return p; 432 } 433 434 /* Sanity check the Write list. 435 * 436 * Implementation limits: 437 * - This implementation supports only one Write chunk. 438 * 439 * Sanity checks: 440 * - Write list does not overflow buffer. 441 * - Segment size limited by largest NFS data payload. 442 * 443 * Returns pointer to the following Reply chunk. 444 */ 445 static __be32 *xdr_check_write_list(__be32 *p, const __be32 *end) 446 { 447 u32 chcount; 448 449 chcount = 0; 450 while (*p++ != xdr_zero) { 451 p = xdr_check_write_chunk(p, end, MAX_BYTES_WRITE_SEG); 452 if (!p) 453 return NULL; 454 if (chcount++ > 1) 455 return NULL; 456 } 457 return p; 458 } 459 460 /* Sanity check the Reply chunk. 461 * 462 * Sanity checks: 463 * - Reply chunk does not overflow buffer. 464 * - Segment size limited by largest NFS data payload. 465 * 466 * Returns pointer to the following RPC header. 467 */ 468 static __be32 *xdr_check_reply_chunk(__be32 *p, const __be32 *end) 469 { 470 if (*p++ != xdr_zero) { 471 p = xdr_check_write_chunk(p, end, MAX_BYTES_SPECIAL_SEG); 472 if (!p) 473 return NULL; 474 } 475 return p; 476 } 477 478 /* RPC-over-RDMA Version One private extension: Remote Invalidation. 479 * Responder's choice: requester signals it can handle Send With 480 * Invalidate, and responder chooses one R_key to invalidate. 481 * 482 * If there is exactly one distinct R_key in the received transport 483 * header, set rc_inv_rkey to that R_key. Otherwise, set it to zero. 484 * 485 * Perform this operation while the received transport header is 486 * still in the CPU cache. 487 */ 488 static void svc_rdma_get_inv_rkey(struct svcxprt_rdma *rdma, 489 struct svc_rdma_recv_ctxt *ctxt) 490 { 491 __be32 inv_rkey, *p; 492 u32 i, segcount; 493 494 ctxt->rc_inv_rkey = 0; 495 496 if (!rdma->sc_snd_w_inv) 497 return; 498 499 inv_rkey = xdr_zero; 500 p = ctxt->rc_recv_buf; 501 p += rpcrdma_fixed_maxsz; 502 503 /* Read list */ 504 while (*p++ != xdr_zero) { 505 p++; /* position */ 506 if (inv_rkey == xdr_zero) 507 inv_rkey = *p; 508 else if (inv_rkey != *p) 509 return; 510 p += 4; 511 } 512 513 /* Write list */ 514 while (*p++ != xdr_zero) { 515 segcount = be32_to_cpup(p++); 516 for (i = 0; i < segcount; i++) { 517 if (inv_rkey == xdr_zero) 518 inv_rkey = *p; 519 else if (inv_rkey != *p) 520 return; 521 p += 4; 522 } 523 } 524 525 /* Reply chunk */ 526 if (*p++ != xdr_zero) { 527 segcount = be32_to_cpup(p++); 528 for (i = 0; i < segcount; i++) { 529 if (inv_rkey == xdr_zero) 530 inv_rkey = *p; 531 else if (inv_rkey != *p) 532 return; 533 p += 4; 534 } 535 } 536 537 ctxt->rc_inv_rkey = be32_to_cpu(inv_rkey); 538 } 539 540 /* On entry, xdr->head[0].iov_base points to first byte in the 541 * RPC-over-RDMA header. 542 * 543 * On successful exit, head[0] points to first byte past the 544 * RPC-over-RDMA header. For RDMA_MSG, this is the RPC message. 545 * The length of the RPC-over-RDMA header is returned. 546 * 547 * Assumptions: 548 * - The transport header is entirely contained in the head iovec. 549 */ 550 static int svc_rdma_xdr_decode_req(struct xdr_buf *rq_arg) 551 { 552 __be32 *p, *end, *rdma_argp; 553 unsigned int hdr_len; 554 555 /* Verify that there's enough bytes for header + something */ 556 if (rq_arg->len <= RPCRDMA_HDRLEN_ERR) 557 goto out_short; 558 559 rdma_argp = rq_arg->head[0].iov_base; 560 if (*(rdma_argp + 1) != rpcrdma_version) 561 goto out_version; 562 563 switch (*(rdma_argp + 3)) { 564 case rdma_msg: 565 break; 566 case rdma_nomsg: 567 break; 568 569 case rdma_done: 570 goto out_drop; 571 572 case rdma_error: 573 goto out_drop; 574 575 default: 576 goto out_proc; 577 } 578 579 end = (__be32 *)((unsigned long)rdma_argp + rq_arg->len); 580 p = xdr_check_read_list(rdma_argp + 4, end); 581 if (!p) 582 goto out_inval; 583 p = xdr_check_write_list(p, end); 584 if (!p) 585 goto out_inval; 586 p = xdr_check_reply_chunk(p, end); 587 if (!p) 588 goto out_inval; 589 if (p > end) 590 goto out_inval; 591 592 rq_arg->head[0].iov_base = p; 593 hdr_len = (unsigned long)p - (unsigned long)rdma_argp; 594 rq_arg->head[0].iov_len -= hdr_len; 595 rq_arg->len -= hdr_len; 596 trace_svcrdma_decode_rqst(rdma_argp, hdr_len); 597 return hdr_len; 598 599 out_short: 600 trace_svcrdma_decode_short(rq_arg->len); 601 return -EINVAL; 602 603 out_version: 604 trace_svcrdma_decode_badvers(rdma_argp); 605 return -EPROTONOSUPPORT; 606 607 out_drop: 608 trace_svcrdma_decode_drop(rdma_argp); 609 return 0; 610 611 out_proc: 612 trace_svcrdma_decode_badproc(rdma_argp); 613 return -EINVAL; 614 615 out_inval: 616 trace_svcrdma_decode_parse(rdma_argp); 617 return -EINVAL; 618 } 619 620 static void rdma_read_complete(struct svc_rqst *rqstp, 621 struct svc_rdma_recv_ctxt *head) 622 { 623 int page_no; 624 625 /* Move Read chunk pages to rqstp so that they will be released 626 * when svc_process is done with them. 627 */ 628 for (page_no = 0; page_no < head->rc_page_count; page_no++) { 629 put_page(rqstp->rq_pages[page_no]); 630 rqstp->rq_pages[page_no] = head->rc_pages[page_no]; 631 } 632 head->rc_page_count = 0; 633 634 /* Point rq_arg.pages past header */ 635 rqstp->rq_arg.pages = &rqstp->rq_pages[head->rc_hdr_count]; 636 rqstp->rq_arg.page_len = head->rc_arg.page_len; 637 638 /* rq_respages starts after the last arg page */ 639 rqstp->rq_respages = &rqstp->rq_pages[page_no]; 640 rqstp->rq_next_page = rqstp->rq_respages + 1; 641 642 /* Rebuild rq_arg head and tail. */ 643 rqstp->rq_arg.head[0] = head->rc_arg.head[0]; 644 rqstp->rq_arg.tail[0] = head->rc_arg.tail[0]; 645 rqstp->rq_arg.len = head->rc_arg.len; 646 rqstp->rq_arg.buflen = head->rc_arg.buflen; 647 } 648 649 static void svc_rdma_send_error(struct svcxprt_rdma *xprt, 650 __be32 *rdma_argp, int status) 651 { 652 struct svc_rdma_send_ctxt *ctxt; 653 unsigned int length; 654 __be32 *p; 655 int ret; 656 657 ctxt = svc_rdma_send_ctxt_get(xprt); 658 if (!ctxt) 659 return; 660 661 p = ctxt->sc_xprt_buf; 662 *p++ = *rdma_argp; 663 *p++ = *(rdma_argp + 1); 664 *p++ = xprt->sc_fc_credits; 665 *p++ = rdma_error; 666 switch (status) { 667 case -EPROTONOSUPPORT: 668 *p++ = err_vers; 669 *p++ = rpcrdma_version; 670 *p++ = rpcrdma_version; 671 trace_svcrdma_err_vers(*rdma_argp); 672 break; 673 default: 674 *p++ = err_chunk; 675 trace_svcrdma_err_chunk(*rdma_argp); 676 } 677 length = (unsigned long)p - (unsigned long)ctxt->sc_xprt_buf; 678 svc_rdma_sync_reply_hdr(xprt, ctxt, length); 679 680 ctxt->sc_send_wr.opcode = IB_WR_SEND; 681 ret = svc_rdma_send(xprt, &ctxt->sc_send_wr); 682 if (ret) 683 svc_rdma_send_ctxt_put(xprt, ctxt); 684 } 685 686 /* By convention, backchannel calls arrive via rdma_msg type 687 * messages, and never populate the chunk lists. This makes 688 * the RPC/RDMA header small and fixed in size, so it is 689 * straightforward to check the RPC header's direction field. 690 */ 691 static bool svc_rdma_is_backchannel_reply(struct svc_xprt *xprt, 692 __be32 *rdma_resp) 693 { 694 __be32 *p; 695 696 if (!xprt->xpt_bc_xprt) 697 return false; 698 699 p = rdma_resp + 3; 700 if (*p++ != rdma_msg) 701 return false; 702 703 if (*p++ != xdr_zero) 704 return false; 705 if (*p++ != xdr_zero) 706 return false; 707 if (*p++ != xdr_zero) 708 return false; 709 710 /* XID sanity */ 711 if (*p++ != *rdma_resp) 712 return false; 713 /* call direction */ 714 if (*p == cpu_to_be32(RPC_CALL)) 715 return false; 716 717 return true; 718 } 719 720 /** 721 * svc_rdma_recvfrom - Receive an RPC call 722 * @rqstp: request structure into which to receive an RPC Call 723 * 724 * Returns: 725 * The positive number of bytes in the RPC Call message, 726 * %0 if there were no Calls ready to return, 727 * %-EINVAL if the Read chunk data is too large, 728 * %-ENOMEM if rdma_rw context pool was exhausted, 729 * %-ENOTCONN if posting failed (connection is lost), 730 * %-EIO if rdma_rw initialization failed (DMA mapping, etc). 731 * 732 * Called in a loop when XPT_DATA is set. XPT_DATA is cleared only 733 * when there are no remaining ctxt's to process. 734 * 735 * The next ctxt is removed from the "receive" lists. 736 * 737 * - If the ctxt completes a Read, then finish assembling the Call 738 * message and return the number of bytes in the message. 739 * 740 * - If the ctxt completes a Receive, then construct the Call 741 * message from the contents of the Receive buffer. 742 * 743 * - If there are no Read chunks in this message, then finish 744 * assembling the Call message and return the number of bytes 745 * in the message. 746 * 747 * - If there are Read chunks in this message, post Read WRs to 748 * pull that payload and return 0. 749 */ 750 int svc_rdma_recvfrom(struct svc_rqst *rqstp) 751 { 752 struct svc_xprt *xprt = rqstp->rq_xprt; 753 struct svcxprt_rdma *rdma_xprt = 754 container_of(xprt, struct svcxprt_rdma, sc_xprt); 755 struct svc_rdma_recv_ctxt *ctxt; 756 __be32 *p; 757 int ret; 758 759 spin_lock(&rdma_xprt->sc_rq_dto_lock); 760 ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_read_complete_q); 761 if (ctxt) { 762 list_del(&ctxt->rc_list); 763 spin_unlock(&rdma_xprt->sc_rq_dto_lock); 764 rdma_read_complete(rqstp, ctxt); 765 goto complete; 766 } 767 ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_rq_dto_q); 768 if (!ctxt) { 769 /* No new incoming requests, terminate the loop */ 770 clear_bit(XPT_DATA, &xprt->xpt_flags); 771 spin_unlock(&rdma_xprt->sc_rq_dto_lock); 772 return 0; 773 } 774 list_del(&ctxt->rc_list); 775 spin_unlock(&rdma_xprt->sc_rq_dto_lock); 776 777 atomic_inc(&rdma_stat_recv); 778 779 svc_rdma_build_arg_xdr(rqstp, ctxt); 780 781 /* Prevent svc_xprt_release from releasing pages in rq_pages 782 * if we return 0 or an error. 783 */ 784 rqstp->rq_respages = rqstp->rq_pages; 785 rqstp->rq_next_page = rqstp->rq_respages; 786 787 p = (__be32 *)rqstp->rq_arg.head[0].iov_base; 788 ret = svc_rdma_xdr_decode_req(&rqstp->rq_arg); 789 if (ret < 0) 790 goto out_err; 791 if (ret == 0) 792 goto out_drop; 793 rqstp->rq_xprt_hlen = ret; 794 795 if (svc_rdma_is_backchannel_reply(xprt, p)) { 796 ret = svc_rdma_handle_bc_reply(xprt->xpt_bc_xprt, p, 797 &rqstp->rq_arg); 798 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); 799 return ret; 800 } 801 svc_rdma_get_inv_rkey(rdma_xprt, ctxt); 802 803 p += rpcrdma_fixed_maxsz; 804 if (*p != xdr_zero) 805 goto out_readchunk; 806 807 complete: 808 rqstp->rq_xprt_ctxt = ctxt; 809 rqstp->rq_prot = IPPROTO_MAX; 810 svc_xprt_copy_addrs(rqstp, xprt); 811 return rqstp->rq_arg.len; 812 813 out_readchunk: 814 ret = svc_rdma_recv_read_chunk(rdma_xprt, rqstp, ctxt, p); 815 if (ret < 0) 816 goto out_postfail; 817 return 0; 818 819 out_err: 820 svc_rdma_send_error(rdma_xprt, p, ret); 821 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); 822 return 0; 823 824 out_postfail: 825 if (ret == -EINVAL) 826 svc_rdma_send_error(rdma_xprt, p, ret); 827 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); 828 return ret; 829 830 out_drop: 831 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); 832 return 0; 833 } 834