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 */ 94 95 #include <linux/slab.h> 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 static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc); 110 111 static inline struct svc_rdma_recv_ctxt * 112 svc_rdma_next_recv_ctxt(struct list_head *list) 113 { 114 return list_first_entry_or_null(list, struct svc_rdma_recv_ctxt, 115 rc_list); 116 } 117 118 static void svc_rdma_recv_cid_init(struct svcxprt_rdma *rdma, 119 struct rpc_rdma_cid *cid) 120 { 121 cid->ci_queue_id = rdma->sc_rq_cq->res.id; 122 cid->ci_completion_id = atomic_inc_return(&rdma->sc_completion_ids); 123 } 124 125 static struct svc_rdma_recv_ctxt * 126 svc_rdma_recv_ctxt_alloc(struct svcxprt_rdma *rdma) 127 { 128 struct svc_rdma_recv_ctxt *ctxt; 129 dma_addr_t addr; 130 void *buffer; 131 132 ctxt = kmalloc(sizeof(*ctxt), GFP_KERNEL); 133 if (!ctxt) 134 goto fail0; 135 buffer = kmalloc(rdma->sc_max_req_size, GFP_KERNEL); 136 if (!buffer) 137 goto fail1; 138 addr = ib_dma_map_single(rdma->sc_pd->device, buffer, 139 rdma->sc_max_req_size, DMA_FROM_DEVICE); 140 if (ib_dma_mapping_error(rdma->sc_pd->device, addr)) 141 goto fail2; 142 143 svc_rdma_recv_cid_init(rdma, &ctxt->rc_cid); 144 pcl_init(&ctxt->rc_call_pcl); 145 pcl_init(&ctxt->rc_read_pcl); 146 pcl_init(&ctxt->rc_write_pcl); 147 pcl_init(&ctxt->rc_reply_pcl); 148 149 ctxt->rc_recv_wr.next = NULL; 150 ctxt->rc_recv_wr.wr_cqe = &ctxt->rc_cqe; 151 ctxt->rc_recv_wr.sg_list = &ctxt->rc_recv_sge; 152 ctxt->rc_recv_wr.num_sge = 1; 153 ctxt->rc_cqe.done = svc_rdma_wc_receive; 154 ctxt->rc_recv_sge.addr = addr; 155 ctxt->rc_recv_sge.length = rdma->sc_max_req_size; 156 ctxt->rc_recv_sge.lkey = rdma->sc_pd->local_dma_lkey; 157 ctxt->rc_recv_buf = buffer; 158 ctxt->rc_temp = false; 159 return ctxt; 160 161 fail2: 162 kfree(buffer); 163 fail1: 164 kfree(ctxt); 165 fail0: 166 return NULL; 167 } 168 169 static void svc_rdma_recv_ctxt_destroy(struct svcxprt_rdma *rdma, 170 struct svc_rdma_recv_ctxt *ctxt) 171 { 172 ib_dma_unmap_single(rdma->sc_pd->device, ctxt->rc_recv_sge.addr, 173 ctxt->rc_recv_sge.length, DMA_FROM_DEVICE); 174 kfree(ctxt->rc_recv_buf); 175 kfree(ctxt); 176 } 177 178 /** 179 * svc_rdma_recv_ctxts_destroy - Release all recv_ctxt's for an xprt 180 * @rdma: svcxprt_rdma being torn down 181 * 182 */ 183 void svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma *rdma) 184 { 185 struct svc_rdma_recv_ctxt *ctxt; 186 struct llist_node *node; 187 188 while ((node = llist_del_first(&rdma->sc_recv_ctxts))) { 189 ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node); 190 svc_rdma_recv_ctxt_destroy(rdma, ctxt); 191 } 192 } 193 194 /** 195 * svc_rdma_recv_ctxt_get - Allocate a recv_ctxt 196 * @rdma: controlling svcxprt_rdma 197 * 198 * Returns a recv_ctxt or (rarely) NULL if none are available. 199 */ 200 struct svc_rdma_recv_ctxt *svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma) 201 { 202 struct svc_rdma_recv_ctxt *ctxt; 203 struct llist_node *node; 204 205 node = llist_del_first(&rdma->sc_recv_ctxts); 206 if (!node) 207 goto out_empty; 208 ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node); 209 210 out: 211 ctxt->rc_page_count = 0; 212 return ctxt; 213 214 out_empty: 215 ctxt = svc_rdma_recv_ctxt_alloc(rdma); 216 if (!ctxt) 217 return NULL; 218 goto out; 219 } 220 221 /** 222 * svc_rdma_recv_ctxt_put - Return recv_ctxt to free list 223 * @rdma: controlling svcxprt_rdma 224 * @ctxt: object to return to the free list 225 * 226 */ 227 void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma, 228 struct svc_rdma_recv_ctxt *ctxt) 229 { 230 pcl_free(&ctxt->rc_call_pcl); 231 pcl_free(&ctxt->rc_read_pcl); 232 pcl_free(&ctxt->rc_write_pcl); 233 pcl_free(&ctxt->rc_reply_pcl); 234 235 if (!ctxt->rc_temp) 236 llist_add(&ctxt->rc_node, &rdma->sc_recv_ctxts); 237 else 238 svc_rdma_recv_ctxt_destroy(rdma, ctxt); 239 } 240 241 /** 242 * svc_rdma_release_ctxt - Release transport-specific per-rqst resources 243 * @xprt: the transport which owned the context 244 * @vctxt: the context from rqstp->rq_xprt_ctxt or dr->xprt_ctxt 245 * 246 * Ensure that the recv_ctxt is released whether or not a Reply 247 * was sent. For example, the client could close the connection, 248 * or svc_process could drop an RPC, before the Reply is sent. 249 */ 250 void svc_rdma_release_ctxt(struct svc_xprt *xprt, void *vctxt) 251 { 252 struct svc_rdma_recv_ctxt *ctxt = vctxt; 253 struct svcxprt_rdma *rdma = 254 container_of(xprt, struct svcxprt_rdma, sc_xprt); 255 256 if (ctxt) 257 svc_rdma_recv_ctxt_put(rdma, ctxt); 258 } 259 260 static bool svc_rdma_refresh_recvs(struct svcxprt_rdma *rdma, 261 unsigned int wanted, bool temp) 262 { 263 const struct ib_recv_wr *bad_wr = NULL; 264 struct svc_rdma_recv_ctxt *ctxt; 265 struct ib_recv_wr *recv_chain; 266 int ret; 267 268 if (test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags)) 269 return false; 270 271 recv_chain = NULL; 272 while (wanted--) { 273 ctxt = svc_rdma_recv_ctxt_get(rdma); 274 if (!ctxt) 275 break; 276 277 trace_svcrdma_post_recv(ctxt); 278 ctxt->rc_temp = temp; 279 ctxt->rc_recv_wr.next = recv_chain; 280 recv_chain = &ctxt->rc_recv_wr; 281 rdma->sc_pending_recvs++; 282 } 283 if (!recv_chain) 284 return false; 285 286 ret = ib_post_recv(rdma->sc_qp, recv_chain, &bad_wr); 287 if (ret) 288 goto err_free; 289 return true; 290 291 err_free: 292 trace_svcrdma_rq_post_err(rdma, ret); 293 while (bad_wr) { 294 ctxt = container_of(bad_wr, struct svc_rdma_recv_ctxt, 295 rc_recv_wr); 296 bad_wr = bad_wr->next; 297 svc_rdma_recv_ctxt_put(rdma, ctxt); 298 } 299 /* Since we're destroying the xprt, no need to reset 300 * sc_pending_recvs. */ 301 return false; 302 } 303 304 /** 305 * svc_rdma_post_recvs - Post initial set of Recv WRs 306 * @rdma: fresh svcxprt_rdma 307 * 308 * Returns true if successful, otherwise false. 309 */ 310 bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma) 311 { 312 return svc_rdma_refresh_recvs(rdma, rdma->sc_max_requests, true); 313 } 314 315 /** 316 * svc_rdma_wc_receive - Invoked by RDMA provider for each polled Receive WC 317 * @cq: Completion Queue context 318 * @wc: Work Completion object 319 * 320 */ 321 static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc) 322 { 323 struct svcxprt_rdma *rdma = cq->cq_context; 324 struct ib_cqe *cqe = wc->wr_cqe; 325 struct svc_rdma_recv_ctxt *ctxt; 326 327 rdma->sc_pending_recvs--; 328 329 /* WARNING: Only wc->wr_cqe and wc->status are reliable */ 330 ctxt = container_of(cqe, struct svc_rdma_recv_ctxt, rc_cqe); 331 332 if (wc->status != IB_WC_SUCCESS) 333 goto flushed; 334 trace_svcrdma_wc_recv(wc, &ctxt->rc_cid); 335 336 /* If receive posting fails, the connection is about to be 337 * lost anyway. The server will not be able to send a reply 338 * for this RPC, and the client will retransmit this RPC 339 * anyway when it reconnects. 340 * 341 * Therefore we drop the Receive, even if status was SUCCESS 342 * to reduce the likelihood of replayed requests once the 343 * client reconnects. 344 */ 345 if (rdma->sc_pending_recvs < rdma->sc_max_requests) 346 if (!svc_rdma_refresh_recvs(rdma, rdma->sc_recv_batch, false)) 347 goto dropped; 348 349 /* All wc fields are now known to be valid */ 350 ctxt->rc_byte_len = wc->byte_len; 351 352 spin_lock(&rdma->sc_rq_dto_lock); 353 list_add_tail(&ctxt->rc_list, &rdma->sc_rq_dto_q); 354 /* Note the unlock pairs with the smp_rmb in svc_xprt_ready: */ 355 set_bit(XPT_DATA, &rdma->sc_xprt.xpt_flags); 356 spin_unlock(&rdma->sc_rq_dto_lock); 357 if (!test_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags)) 358 svc_xprt_enqueue(&rdma->sc_xprt); 359 return; 360 361 flushed: 362 if (wc->status == IB_WC_WR_FLUSH_ERR) 363 trace_svcrdma_wc_recv_flush(wc, &ctxt->rc_cid); 364 else 365 trace_svcrdma_wc_recv_err(wc, &ctxt->rc_cid); 366 dropped: 367 svc_rdma_recv_ctxt_put(rdma, ctxt); 368 svc_xprt_deferred_close(&rdma->sc_xprt); 369 } 370 371 /** 372 * svc_rdma_flush_recv_queues - Drain pending Receive work 373 * @rdma: svcxprt_rdma being shut down 374 * 375 */ 376 void svc_rdma_flush_recv_queues(struct svcxprt_rdma *rdma) 377 { 378 struct svc_rdma_recv_ctxt *ctxt; 379 380 while ((ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_rq_dto_q))) { 381 list_del(&ctxt->rc_list); 382 svc_rdma_recv_ctxt_put(rdma, ctxt); 383 } 384 } 385 386 static void svc_rdma_build_arg_xdr(struct svc_rqst *rqstp, 387 struct svc_rdma_recv_ctxt *ctxt) 388 { 389 struct xdr_buf *arg = &rqstp->rq_arg; 390 391 arg->head[0].iov_base = ctxt->rc_recv_buf; 392 arg->head[0].iov_len = ctxt->rc_byte_len; 393 arg->tail[0].iov_base = NULL; 394 arg->tail[0].iov_len = 0; 395 arg->page_len = 0; 396 arg->page_base = 0; 397 arg->buflen = ctxt->rc_byte_len; 398 arg->len = ctxt->rc_byte_len; 399 } 400 401 /** 402 * xdr_count_read_segments - Count number of Read segments in Read list 403 * @rctxt: Ingress receive context 404 * @p: Start of an un-decoded Read list 405 * 406 * Before allocating anything, ensure the ingress Read list is safe 407 * to use. 408 * 409 * The segment count is limited to how many segments can fit in the 410 * transport header without overflowing the buffer. That's about 40 411 * Read segments for a 1KB inline threshold. 412 * 413 * Return values: 414 * %true: Read list is valid. @rctxt's xdr_stream is updated to point 415 * to the first byte past the Read list. rc_read_pcl and 416 * rc_call_pcl cl_count fields are set to the number of 417 * Read segments in the list. 418 * %false: Read list is corrupt. @rctxt's xdr_stream is left in an 419 * unknown state. 420 */ 421 static bool xdr_count_read_segments(struct svc_rdma_recv_ctxt *rctxt, __be32 *p) 422 { 423 rctxt->rc_call_pcl.cl_count = 0; 424 rctxt->rc_read_pcl.cl_count = 0; 425 while (xdr_item_is_present(p)) { 426 u32 position, handle, length; 427 u64 offset; 428 429 p = xdr_inline_decode(&rctxt->rc_stream, 430 rpcrdma_readseg_maxsz * sizeof(*p)); 431 if (!p) 432 return false; 433 434 xdr_decode_read_segment(p, &position, &handle, 435 &length, &offset); 436 if (position) { 437 if (position & 3) 438 return false; 439 ++rctxt->rc_read_pcl.cl_count; 440 } else { 441 ++rctxt->rc_call_pcl.cl_count; 442 } 443 444 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p)); 445 if (!p) 446 return false; 447 } 448 return true; 449 } 450 451 /* Sanity check the Read list. 452 * 453 * Sanity checks: 454 * - Read list does not overflow Receive buffer. 455 * - Chunk size limited by largest NFS data payload. 456 * 457 * Return values: 458 * %true: Read list is valid. @rctxt's xdr_stream is updated 459 * to point to the first byte past the Read list. 460 * %false: Read list is corrupt. @rctxt's xdr_stream is left 461 * in an unknown state. 462 */ 463 static bool xdr_check_read_list(struct svc_rdma_recv_ctxt *rctxt) 464 { 465 __be32 *p; 466 467 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p)); 468 if (!p) 469 return false; 470 if (!xdr_count_read_segments(rctxt, p)) 471 return false; 472 if (!pcl_alloc_call(rctxt, p)) 473 return false; 474 return pcl_alloc_read(rctxt, p); 475 } 476 477 static bool xdr_check_write_chunk(struct svc_rdma_recv_ctxt *rctxt) 478 { 479 u32 segcount; 480 __be32 *p; 481 482 if (xdr_stream_decode_u32(&rctxt->rc_stream, &segcount)) 483 return false; 484 485 /* A bogus segcount causes this buffer overflow check to fail. */ 486 p = xdr_inline_decode(&rctxt->rc_stream, 487 segcount * rpcrdma_segment_maxsz * sizeof(*p)); 488 return p != NULL; 489 } 490 491 /** 492 * xdr_count_write_chunks - Count number of Write chunks in Write list 493 * @rctxt: Received header and decoding state 494 * @p: start of an un-decoded Write list 495 * 496 * Before allocating anything, ensure the ingress Write list is 497 * safe to use. 498 * 499 * Return values: 500 * %true: Write list is valid. @rctxt's xdr_stream is updated 501 * to point to the first byte past the Write list, and 502 * the number of Write chunks is in rc_write_pcl.cl_count. 503 * %false: Write list is corrupt. @rctxt's xdr_stream is left 504 * in an indeterminate state. 505 */ 506 static bool xdr_count_write_chunks(struct svc_rdma_recv_ctxt *rctxt, __be32 *p) 507 { 508 rctxt->rc_write_pcl.cl_count = 0; 509 while (xdr_item_is_present(p)) { 510 if (!xdr_check_write_chunk(rctxt)) 511 return false; 512 ++rctxt->rc_write_pcl.cl_count; 513 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p)); 514 if (!p) 515 return false; 516 } 517 return true; 518 } 519 520 /* Sanity check the Write list. 521 * 522 * Implementation limits: 523 * - This implementation currently supports only one Write chunk. 524 * 525 * Sanity checks: 526 * - Write list does not overflow Receive buffer. 527 * - Chunk size limited by largest NFS data payload. 528 * 529 * Return values: 530 * %true: Write list is valid. @rctxt's xdr_stream is updated 531 * to point to the first byte past the Write list. 532 * %false: Write list is corrupt. @rctxt's xdr_stream is left 533 * in an unknown state. 534 */ 535 static bool xdr_check_write_list(struct svc_rdma_recv_ctxt *rctxt) 536 { 537 __be32 *p; 538 539 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p)); 540 if (!p) 541 return false; 542 if (!xdr_count_write_chunks(rctxt, p)) 543 return false; 544 if (!pcl_alloc_write(rctxt, &rctxt->rc_write_pcl, p)) 545 return false; 546 547 rctxt->rc_cur_result_payload = pcl_first_chunk(&rctxt->rc_write_pcl); 548 return true; 549 } 550 551 /* Sanity check the Reply chunk. 552 * 553 * Sanity checks: 554 * - Reply chunk does not overflow Receive buffer. 555 * - Chunk size limited by largest NFS data payload. 556 * 557 * Return values: 558 * %true: Reply chunk is valid. @rctxt's xdr_stream is updated 559 * to point to the first byte past the Reply chunk. 560 * %false: Reply chunk is corrupt. @rctxt's xdr_stream is left 561 * in an unknown state. 562 */ 563 static bool xdr_check_reply_chunk(struct svc_rdma_recv_ctxt *rctxt) 564 { 565 __be32 *p; 566 567 p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p)); 568 if (!p) 569 return false; 570 571 if (!xdr_item_is_present(p)) 572 return true; 573 if (!xdr_check_write_chunk(rctxt)) 574 return false; 575 576 rctxt->rc_reply_pcl.cl_count = 1; 577 return pcl_alloc_write(rctxt, &rctxt->rc_reply_pcl, p); 578 } 579 580 /* RPC-over-RDMA Version One private extension: Remote Invalidation. 581 * Responder's choice: requester signals it can handle Send With 582 * Invalidate, and responder chooses one R_key to invalidate. 583 * 584 * If there is exactly one distinct R_key in the received transport 585 * header, set rc_inv_rkey to that R_key. Otherwise, set it to zero. 586 */ 587 static void svc_rdma_get_inv_rkey(struct svcxprt_rdma *rdma, 588 struct svc_rdma_recv_ctxt *ctxt) 589 { 590 struct svc_rdma_segment *segment; 591 struct svc_rdma_chunk *chunk; 592 u32 inv_rkey; 593 594 ctxt->rc_inv_rkey = 0; 595 596 if (!rdma->sc_snd_w_inv) 597 return; 598 599 inv_rkey = 0; 600 pcl_for_each_chunk(chunk, &ctxt->rc_call_pcl) { 601 pcl_for_each_segment(segment, chunk) { 602 if (inv_rkey == 0) 603 inv_rkey = segment->rs_handle; 604 else if (inv_rkey != segment->rs_handle) 605 return; 606 } 607 } 608 pcl_for_each_chunk(chunk, &ctxt->rc_read_pcl) { 609 pcl_for_each_segment(segment, chunk) { 610 if (inv_rkey == 0) 611 inv_rkey = segment->rs_handle; 612 else if (inv_rkey != segment->rs_handle) 613 return; 614 } 615 } 616 pcl_for_each_chunk(chunk, &ctxt->rc_write_pcl) { 617 pcl_for_each_segment(segment, chunk) { 618 if (inv_rkey == 0) 619 inv_rkey = segment->rs_handle; 620 else if (inv_rkey != segment->rs_handle) 621 return; 622 } 623 } 624 pcl_for_each_chunk(chunk, &ctxt->rc_reply_pcl) { 625 pcl_for_each_segment(segment, chunk) { 626 if (inv_rkey == 0) 627 inv_rkey = segment->rs_handle; 628 else if (inv_rkey != segment->rs_handle) 629 return; 630 } 631 } 632 ctxt->rc_inv_rkey = inv_rkey; 633 } 634 635 /** 636 * svc_rdma_xdr_decode_req - Decode the transport header 637 * @rq_arg: xdr_buf containing ingress RPC/RDMA message 638 * @rctxt: state of decoding 639 * 640 * On entry, xdr->head[0].iov_base points to first byte of the 641 * RPC-over-RDMA transport header. 642 * 643 * On successful exit, head[0] points to first byte past the 644 * RPC-over-RDMA header. For RDMA_MSG, this is the RPC message. 645 * 646 * The length of the RPC-over-RDMA header is returned. 647 * 648 * Assumptions: 649 * - The transport header is entirely contained in the head iovec. 650 */ 651 static int svc_rdma_xdr_decode_req(struct xdr_buf *rq_arg, 652 struct svc_rdma_recv_ctxt *rctxt) 653 { 654 __be32 *p, *rdma_argp; 655 unsigned int hdr_len; 656 657 rdma_argp = rq_arg->head[0].iov_base; 658 xdr_init_decode(&rctxt->rc_stream, rq_arg, rdma_argp, NULL); 659 660 p = xdr_inline_decode(&rctxt->rc_stream, 661 rpcrdma_fixed_maxsz * sizeof(*p)); 662 if (unlikely(!p)) 663 goto out_short; 664 p++; 665 if (*p != rpcrdma_version) 666 goto out_version; 667 p += 2; 668 rctxt->rc_msgtype = *p; 669 switch (rctxt->rc_msgtype) { 670 case rdma_msg: 671 break; 672 case rdma_nomsg: 673 break; 674 case rdma_done: 675 goto out_drop; 676 case rdma_error: 677 goto out_drop; 678 default: 679 goto out_proc; 680 } 681 682 if (!xdr_check_read_list(rctxt)) 683 goto out_inval; 684 if (!xdr_check_write_list(rctxt)) 685 goto out_inval; 686 if (!xdr_check_reply_chunk(rctxt)) 687 goto out_inval; 688 689 rq_arg->head[0].iov_base = rctxt->rc_stream.p; 690 hdr_len = xdr_stream_pos(&rctxt->rc_stream); 691 rq_arg->head[0].iov_len -= hdr_len; 692 rq_arg->len -= hdr_len; 693 trace_svcrdma_decode_rqst(rctxt, rdma_argp, hdr_len); 694 return hdr_len; 695 696 out_short: 697 trace_svcrdma_decode_short_err(rctxt, rq_arg->len); 698 return -EINVAL; 699 700 out_version: 701 trace_svcrdma_decode_badvers_err(rctxt, rdma_argp); 702 return -EPROTONOSUPPORT; 703 704 out_drop: 705 trace_svcrdma_decode_drop_err(rctxt, rdma_argp); 706 return 0; 707 708 out_proc: 709 trace_svcrdma_decode_badproc_err(rctxt, rdma_argp); 710 return -EINVAL; 711 712 out_inval: 713 trace_svcrdma_decode_parse_err(rctxt, rdma_argp); 714 return -EINVAL; 715 } 716 717 static void svc_rdma_send_error(struct svcxprt_rdma *rdma, 718 struct svc_rdma_recv_ctxt *rctxt, 719 int status) 720 { 721 struct svc_rdma_send_ctxt *sctxt; 722 723 sctxt = svc_rdma_send_ctxt_get(rdma); 724 if (!sctxt) 725 return; 726 svc_rdma_send_error_msg(rdma, sctxt, rctxt, status); 727 } 728 729 /* By convention, backchannel calls arrive via rdma_msg type 730 * messages, and never populate the chunk lists. This makes 731 * the RPC/RDMA header small and fixed in size, so it is 732 * straightforward to check the RPC header's direction field. 733 */ 734 static bool svc_rdma_is_reverse_direction_reply(struct svc_xprt *xprt, 735 struct svc_rdma_recv_ctxt *rctxt) 736 { 737 __be32 *p = rctxt->rc_recv_buf; 738 739 if (!xprt->xpt_bc_xprt) 740 return false; 741 742 if (rctxt->rc_msgtype != rdma_msg) 743 return false; 744 745 if (!pcl_is_empty(&rctxt->rc_call_pcl)) 746 return false; 747 if (!pcl_is_empty(&rctxt->rc_read_pcl)) 748 return false; 749 if (!pcl_is_empty(&rctxt->rc_write_pcl)) 750 return false; 751 if (!pcl_is_empty(&rctxt->rc_reply_pcl)) 752 return false; 753 754 /* RPC call direction */ 755 if (*(p + 8) == cpu_to_be32(RPC_CALL)) 756 return false; 757 758 return true; 759 } 760 761 /** 762 * svc_rdma_recvfrom - Receive an RPC call 763 * @rqstp: request structure into which to receive an RPC Call 764 * 765 * Returns: 766 * The positive number of bytes in the RPC Call message, 767 * %0 if there were no Calls ready to return, 768 * %-EINVAL if the Read chunk data is too large, 769 * %-ENOMEM if rdma_rw context pool was exhausted, 770 * %-ENOTCONN if posting failed (connection is lost), 771 * %-EIO if rdma_rw initialization failed (DMA mapping, etc). 772 * 773 * Called in a loop when XPT_DATA is set. XPT_DATA is cleared only 774 * when there are no remaining ctxt's to process. 775 * 776 * The next ctxt is removed from the "receive" lists. 777 * 778 * - If the ctxt completes a Read, then finish assembling the Call 779 * message and return the number of bytes in the message. 780 * 781 * - If the ctxt completes a Receive, then construct the Call 782 * message from the contents of the Receive buffer. 783 * 784 * - If there are no Read chunks in this message, then finish 785 * assembling the Call message and return the number of bytes 786 * in the message. 787 * 788 * - If there are Read chunks in this message, post Read WRs to 789 * pull that payload and return 0. 790 */ 791 int svc_rdma_recvfrom(struct svc_rqst *rqstp) 792 { 793 struct svc_xprt *xprt = rqstp->rq_xprt; 794 struct svcxprt_rdma *rdma_xprt = 795 container_of(xprt, struct svcxprt_rdma, sc_xprt); 796 struct svc_rdma_recv_ctxt *ctxt; 797 int ret; 798 799 rqstp->rq_xprt_ctxt = NULL; 800 801 ctxt = NULL; 802 spin_lock(&rdma_xprt->sc_rq_dto_lock); 803 ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_rq_dto_q); 804 if (ctxt) 805 list_del(&ctxt->rc_list); 806 else 807 /* No new incoming requests, terminate the loop */ 808 clear_bit(XPT_DATA, &xprt->xpt_flags); 809 spin_unlock(&rdma_xprt->sc_rq_dto_lock); 810 811 /* Unblock the transport for the next receive */ 812 svc_xprt_received(xprt); 813 if (!ctxt) 814 return 0; 815 816 percpu_counter_inc(&svcrdma_stat_recv); 817 ib_dma_sync_single_for_cpu(rdma_xprt->sc_pd->device, 818 ctxt->rc_recv_sge.addr, ctxt->rc_byte_len, 819 DMA_FROM_DEVICE); 820 svc_rdma_build_arg_xdr(rqstp, ctxt); 821 822 /* Prevent svc_xprt_release from releasing pages in rq_pages 823 * if we return 0 or an error. 824 */ 825 rqstp->rq_respages = rqstp->rq_pages; 826 rqstp->rq_next_page = rqstp->rq_respages; 827 828 ret = svc_rdma_xdr_decode_req(&rqstp->rq_arg, ctxt); 829 if (ret < 0) 830 goto out_err; 831 if (ret == 0) 832 goto out_drop; 833 834 if (svc_rdma_is_reverse_direction_reply(xprt, ctxt)) 835 goto out_backchannel; 836 837 svc_rdma_get_inv_rkey(rdma_xprt, ctxt); 838 839 if (!pcl_is_empty(&ctxt->rc_read_pcl) || 840 !pcl_is_empty(&ctxt->rc_call_pcl)) { 841 ret = svc_rdma_process_read_list(rdma_xprt, rqstp, ctxt); 842 if (ret < 0) 843 goto out_readfail; 844 } 845 846 rqstp->rq_xprt_ctxt = ctxt; 847 rqstp->rq_prot = IPPROTO_MAX; 848 svc_xprt_copy_addrs(rqstp, xprt); 849 set_bit(RQ_SECURE, &rqstp->rq_flags); 850 return rqstp->rq_arg.len; 851 852 out_err: 853 svc_rdma_send_error(rdma_xprt, ctxt, ret); 854 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); 855 return 0; 856 857 out_readfail: 858 if (ret == -EINVAL) 859 svc_rdma_send_error(rdma_xprt, ctxt, ret); 860 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); 861 return ret; 862 863 out_backchannel: 864 svc_rdma_handle_bc_reply(rqstp, ctxt); 865 out_drop: 866 svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); 867 return 0; 868 } 869