1 /* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */ 2 /* 3 * Copyright (c) 2014-2017 Oracle. All rights reserved. 4 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved. 5 * 6 * This software is available to you under a choice of one of two 7 * licenses. You may choose to be licensed under the terms of the GNU 8 * General Public License (GPL) Version 2, available from the file 9 * COPYING in the main directory of this source tree, or the BSD-type 10 * license below: 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 16 * Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 19 * Redistributions in binary form must reproduce the above 20 * copyright notice, this list of conditions and the following 21 * disclaimer in the documentation and/or other materials provided 22 * with the distribution. 23 * 24 * Neither the name of the Network Appliance, Inc. nor the names of 25 * its contributors may be used to endorse or promote products 26 * derived from this software without specific prior written 27 * permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #ifndef _LINUX_SUNRPC_XPRT_RDMA_H 43 #define _LINUX_SUNRPC_XPRT_RDMA_H 44 45 #include <linux/wait.h> /* wait_queue_head_t, etc */ 46 #include <linux/spinlock.h> /* spinlock_t, etc */ 47 #include <linux/atomic.h> /* atomic_t, etc */ 48 #include <linux/kref.h> /* struct kref */ 49 #include <linux/workqueue.h> /* struct work_struct */ 50 #include <linux/llist.h> 51 52 #include <rdma/rdma_cm.h> /* RDMA connection api */ 53 #include <rdma/ib_verbs.h> /* RDMA verbs api */ 54 55 #include <linux/sunrpc/clnt.h> /* rpc_xprt */ 56 #include <linux/sunrpc/rpc_rdma.h> /* RPC/RDMA protocol */ 57 #include <linux/sunrpc/xprtrdma.h> /* xprt parameters */ 58 59 #define RDMA_RESOLVE_TIMEOUT (5000) /* 5 seconds */ 60 #define RDMA_CONNECT_RETRY_MAX (2) /* retries if no listener backlog */ 61 62 #define RPCRDMA_BIND_TO (60U * HZ) 63 #define RPCRDMA_INIT_REEST_TO (5U * HZ) 64 #define RPCRDMA_MAX_REEST_TO (30U * HZ) 65 #define RPCRDMA_IDLE_DISC_TO (5U * 60 * HZ) 66 67 /* 68 * RDMA Endpoint -- connection endpoint details 69 */ 70 struct rpcrdma_ep { 71 struct kref re_kref; 72 struct rdma_cm_id *re_id; 73 struct ib_pd *re_pd; 74 unsigned int re_max_rdma_segs; 75 unsigned int re_max_fr_depth; 76 bool re_implicit_roundup; 77 enum ib_mr_type re_mrtype; 78 struct completion re_done; 79 unsigned int re_send_count; 80 unsigned int re_send_batch; 81 unsigned int re_max_inline_send; 82 unsigned int re_max_inline_recv; 83 int re_async_rc; 84 int re_connect_status; 85 struct ib_qp_init_attr re_attr; 86 wait_queue_head_t re_connect_wait; 87 struct rpc_xprt *re_xprt; 88 struct rpcrdma_connect_private 89 re_cm_private; 90 struct rdma_conn_param re_remote_cma; 91 int re_receive_count; 92 unsigned int re_max_requests; /* depends on device */ 93 unsigned int re_inline_send; /* negotiated */ 94 unsigned int re_inline_recv; /* negotiated */ 95 }; 96 97 /* Pre-allocate extra Work Requests for handling backward receives 98 * and sends. This is a fixed value because the Work Queues are 99 * allocated when the forward channel is set up, long before the 100 * backchannel is provisioned. This value is two times 101 * NFS4_DEF_CB_SLOT_TABLE_SIZE. 102 */ 103 #if defined(CONFIG_SUNRPC_BACKCHANNEL) 104 #define RPCRDMA_BACKWARD_WRS (32) 105 #else 106 #define RPCRDMA_BACKWARD_WRS (0) 107 #endif 108 109 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV 110 */ 111 112 struct rpcrdma_regbuf { 113 struct ib_sge rg_iov; 114 struct ib_device *rg_device; 115 enum dma_data_direction rg_direction; 116 void *rg_data; 117 }; 118 119 static inline u64 rdmab_addr(struct rpcrdma_regbuf *rb) 120 { 121 return rb->rg_iov.addr; 122 } 123 124 static inline u32 rdmab_length(struct rpcrdma_regbuf *rb) 125 { 126 return rb->rg_iov.length; 127 } 128 129 static inline u32 rdmab_lkey(struct rpcrdma_regbuf *rb) 130 { 131 return rb->rg_iov.lkey; 132 } 133 134 static inline struct ib_device *rdmab_device(struct rpcrdma_regbuf *rb) 135 { 136 return rb->rg_device; 137 } 138 139 static inline void *rdmab_data(const struct rpcrdma_regbuf *rb) 140 { 141 return rb->rg_data; 142 } 143 144 #define RPCRDMA_DEF_GFP (GFP_NOIO | __GFP_NOWARN) 145 146 /* To ensure a transport can always make forward progress, 147 * the number of RDMA segments allowed in header chunk lists 148 * is capped at 16. This prevents less-capable devices from 149 * overrunning the Send buffer while building chunk lists. 150 * 151 * Elements of the Read list take up more room than the 152 * Write list or Reply chunk. 16 read segments means the 153 * chunk lists cannot consume more than 154 * 155 * ((16 + 2) * read segment size) + 1 XDR words, 156 * 157 * or about 400 bytes. The fixed part of the header is 158 * another 24 bytes. Thus when the inline threshold is 159 * 1024 bytes, at least 600 bytes are available for RPC 160 * message bodies. 161 */ 162 enum { 163 RPCRDMA_MAX_HDR_SEGS = 16, 164 }; 165 166 /* 167 * struct rpcrdma_rep -- this structure encapsulates state required 168 * to receive and complete an RPC Reply, asychronously. It needs 169 * several pieces of state: 170 * 171 * o receive buffer and ib_sge (donated to provider) 172 * o status of receive (success or not, length, inv rkey) 173 * o bookkeeping state to get run by reply handler (XDR stream) 174 * 175 * These structures are allocated during transport initialization. 176 * N of these are associated with a transport instance, managed by 177 * struct rpcrdma_buffer. N is the max number of outstanding RPCs. 178 */ 179 180 struct rpcrdma_rep { 181 struct ib_cqe rr_cqe; 182 __be32 rr_xid; 183 __be32 rr_vers; 184 __be32 rr_proc; 185 int rr_wc_flags; 186 u32 rr_inv_rkey; 187 bool rr_temp; 188 struct rpcrdma_regbuf *rr_rdmabuf; 189 struct rpcrdma_xprt *rr_rxprt; 190 struct rpc_rqst *rr_rqst; 191 struct xdr_buf rr_hdrbuf; 192 struct xdr_stream rr_stream; 193 struct llist_node rr_node; 194 struct ib_recv_wr rr_recv_wr; 195 struct list_head rr_all; 196 }; 197 198 /* To reduce the rate at which a transport invokes ib_post_recv 199 * (and thus the hardware doorbell rate), xprtrdma posts Receive 200 * WRs in batches. 201 * 202 * Setting this to zero disables Receive post batching. 203 */ 204 enum { 205 RPCRDMA_MAX_RECV_BATCH = 7, 206 }; 207 208 /* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes 209 */ 210 struct rpcrdma_req; 211 struct rpcrdma_sendctx { 212 struct ib_cqe sc_cqe; 213 struct rpcrdma_req *sc_req; 214 unsigned int sc_unmap_count; 215 struct ib_sge sc_sges[]; 216 }; 217 218 /* 219 * struct rpcrdma_mr - external memory region metadata 220 * 221 * An external memory region is any buffer or page that is registered 222 * on the fly (ie, not pre-registered). 223 */ 224 struct rpcrdma_frwr { 225 struct ib_mr *fr_mr; 226 struct ib_cqe fr_cqe; 227 struct completion fr_linv_done; 228 union { 229 struct ib_reg_wr fr_regwr; 230 struct ib_send_wr fr_invwr; 231 }; 232 }; 233 234 struct rpcrdma_req; 235 struct rpcrdma_mr { 236 struct list_head mr_list; 237 struct rpcrdma_req *mr_req; 238 struct scatterlist *mr_sg; 239 int mr_nents; 240 enum dma_data_direction mr_dir; 241 struct rpcrdma_frwr frwr; 242 struct rpcrdma_xprt *mr_xprt; 243 u32 mr_handle; 244 u32 mr_length; 245 u64 mr_offset; 246 struct list_head mr_all; 247 }; 248 249 /* 250 * struct rpcrdma_req -- structure central to the request/reply sequence. 251 * 252 * N of these are associated with a transport instance, and stored in 253 * struct rpcrdma_buffer. N is the max number of outstanding requests. 254 * 255 * It includes pre-registered buffer memory for send AND recv. 256 * The recv buffer, however, is not owned by this structure, and 257 * is "donated" to the hardware when a recv is posted. When a 258 * reply is handled, the recv buffer used is given back to the 259 * struct rpcrdma_req associated with the request. 260 * 261 * In addition to the basic memory, this structure includes an array 262 * of iovs for send operations. The reason is that the iovs passed to 263 * ib_post_{send,recv} must not be modified until the work request 264 * completes. 265 */ 266 267 /* Maximum number of page-sized "segments" per chunk list to be 268 * registered or invalidated. Must handle a Reply chunk: 269 */ 270 enum { 271 RPCRDMA_MAX_IOV_SEGS = 3, 272 RPCRDMA_MAX_DATA_SEGS = ((1 * 1024 * 1024) / PAGE_SIZE) + 1, 273 RPCRDMA_MAX_SEGS = RPCRDMA_MAX_DATA_SEGS + 274 RPCRDMA_MAX_IOV_SEGS, 275 }; 276 277 struct rpcrdma_mr_seg { /* chunk descriptors */ 278 u32 mr_len; /* length of chunk or segment */ 279 struct page *mr_page; /* owning page, if any */ 280 char *mr_offset; /* kva if no page, else offset */ 281 }; 282 283 /* The Send SGE array is provisioned to send a maximum size 284 * inline request: 285 * - RPC-over-RDMA header 286 * - xdr_buf head iovec 287 * - RPCRDMA_MAX_INLINE bytes, in pages 288 * - xdr_buf tail iovec 289 * 290 * The actual number of array elements consumed by each RPC 291 * depends on the device's max_sge limit. 292 */ 293 enum { 294 RPCRDMA_MIN_SEND_SGES = 3, 295 RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT, 296 RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1, 297 }; 298 299 struct rpcrdma_buffer; 300 struct rpcrdma_req { 301 struct list_head rl_list; 302 struct rpc_rqst rl_slot; 303 struct rpcrdma_rep *rl_reply; 304 struct xdr_stream rl_stream; 305 struct xdr_buf rl_hdrbuf; 306 struct ib_send_wr rl_wr; 307 struct rpcrdma_sendctx *rl_sendctx; 308 struct rpcrdma_regbuf *rl_rdmabuf; /* xprt header */ 309 struct rpcrdma_regbuf *rl_sendbuf; /* rq_snd_buf */ 310 struct rpcrdma_regbuf *rl_recvbuf; /* rq_rcv_buf */ 311 312 struct list_head rl_all; 313 struct kref rl_kref; 314 315 struct list_head rl_free_mrs; 316 struct list_head rl_registered; 317 struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS]; 318 }; 319 320 static inline struct rpcrdma_req * 321 rpcr_to_rdmar(const struct rpc_rqst *rqst) 322 { 323 return container_of(rqst, struct rpcrdma_req, rl_slot); 324 } 325 326 static inline void 327 rpcrdma_mr_push(struct rpcrdma_mr *mr, struct list_head *list) 328 { 329 list_add(&mr->mr_list, list); 330 } 331 332 static inline struct rpcrdma_mr * 333 rpcrdma_mr_pop(struct list_head *list) 334 { 335 struct rpcrdma_mr *mr; 336 337 mr = list_first_entry_or_null(list, struct rpcrdma_mr, mr_list); 338 if (mr) 339 list_del_init(&mr->mr_list); 340 return mr; 341 } 342 343 /* 344 * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for 345 * inline requests/replies, and client/server credits. 346 * 347 * One of these is associated with a transport instance 348 */ 349 struct rpcrdma_buffer { 350 spinlock_t rb_lock; 351 struct list_head rb_send_bufs; 352 struct list_head rb_mrs; 353 354 unsigned long rb_sc_head; 355 unsigned long rb_sc_tail; 356 unsigned long rb_sc_last; 357 struct rpcrdma_sendctx **rb_sc_ctxs; 358 359 struct list_head rb_allreqs; 360 struct list_head rb_all_mrs; 361 struct list_head rb_all_reps; 362 363 struct llist_head rb_free_reps; 364 365 __be32 rb_max_requests; 366 u32 rb_credits; /* most recent credit grant */ 367 368 u32 rb_bc_srv_max_requests; 369 u32 rb_bc_max_requests; 370 371 struct work_struct rb_refresh_worker; 372 }; 373 374 /* 375 * Statistics for RPCRDMA 376 */ 377 struct rpcrdma_stats { 378 /* accessed when sending a call */ 379 unsigned long read_chunk_count; 380 unsigned long write_chunk_count; 381 unsigned long reply_chunk_count; 382 unsigned long long total_rdma_request; 383 384 /* rarely accessed error counters */ 385 unsigned long long pullup_copy_count; 386 unsigned long hardway_register_count; 387 unsigned long failed_marshal_count; 388 unsigned long bad_reply_count; 389 unsigned long mrs_recycled; 390 unsigned long mrs_orphaned; 391 unsigned long mrs_allocated; 392 unsigned long empty_sendctx_q; 393 394 /* accessed when receiving a reply */ 395 unsigned long long total_rdma_reply; 396 unsigned long long fixup_copy_count; 397 unsigned long reply_waits_for_send; 398 unsigned long local_inv_needed; 399 unsigned long nomsg_call_count; 400 unsigned long bcall_count; 401 }; 402 403 /* 404 * RPCRDMA transport -- encapsulates the structures above for 405 * integration with RPC. 406 * 407 * The contained structures are embedded, not pointers, 408 * for convenience. This structure need not be visible externally. 409 * 410 * It is allocated and initialized during mount, and released 411 * during unmount. 412 */ 413 struct rpcrdma_xprt { 414 struct rpc_xprt rx_xprt; 415 struct rpcrdma_ep *rx_ep; 416 struct rpcrdma_buffer rx_buf; 417 struct delayed_work rx_connect_worker; 418 struct rpc_timeout rx_timeout; 419 struct rpcrdma_stats rx_stats; 420 }; 421 422 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt) 423 424 static inline const char * 425 rpcrdma_addrstr(const struct rpcrdma_xprt *r_xprt) 426 { 427 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_ADDR]; 428 } 429 430 static inline const char * 431 rpcrdma_portstr(const struct rpcrdma_xprt *r_xprt) 432 { 433 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_PORT]; 434 } 435 436 /* Setting this to 0 ensures interoperability with early servers. 437 * Setting this to 1 enhances certain unaligned read/write performance. 438 * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */ 439 extern int xprt_rdma_pad_optimize; 440 441 /* This setting controls the hunt for a supported memory 442 * registration strategy. 443 */ 444 extern unsigned int xprt_rdma_memreg_strategy; 445 446 /* 447 * Endpoint calls - xprtrdma/verbs.c 448 */ 449 void rpcrdma_flush_disconnect(struct ib_cq *cq, struct ib_wc *wc); 450 int rpcrdma_xprt_connect(struct rpcrdma_xprt *r_xprt); 451 void rpcrdma_xprt_disconnect(struct rpcrdma_xprt *r_xprt); 452 453 int rpcrdma_post_sends(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 454 void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp); 455 456 /* 457 * Buffer calls - xprtrdma/verbs.c 458 */ 459 struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, size_t size, 460 gfp_t flags); 461 int rpcrdma_req_setup(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 462 void rpcrdma_req_destroy(struct rpcrdma_req *req); 463 int rpcrdma_buffer_create(struct rpcrdma_xprt *); 464 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *); 465 struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt); 466 467 struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt); 468 void rpcrdma_mr_put(struct rpcrdma_mr *mr); 469 void rpcrdma_mrs_refresh(struct rpcrdma_xprt *r_xprt); 470 471 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *); 472 void rpcrdma_buffer_put(struct rpcrdma_buffer *buffers, 473 struct rpcrdma_req *req); 474 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *); 475 476 bool rpcrdma_regbuf_realloc(struct rpcrdma_regbuf *rb, size_t size, 477 gfp_t flags); 478 bool __rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt, 479 struct rpcrdma_regbuf *rb); 480 481 /** 482 * rpcrdma_regbuf_is_mapped - check if buffer is DMA mapped 483 * 484 * Returns true if the buffer is now mapped to rb->rg_device. 485 */ 486 static inline bool rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb) 487 { 488 return rb->rg_device != NULL; 489 } 490 491 /** 492 * rpcrdma_regbuf_dma_map - DMA-map a regbuf 493 * @r_xprt: controlling transport instance 494 * @rb: regbuf to be mapped 495 * 496 * Returns true if the buffer is currently DMA mapped. 497 */ 498 static inline bool rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt, 499 struct rpcrdma_regbuf *rb) 500 { 501 if (likely(rpcrdma_regbuf_is_mapped(rb))) 502 return true; 503 return __rpcrdma_regbuf_dma_map(r_xprt, rb); 504 } 505 506 /* 507 * Wrappers for chunk registration, shared by read/write chunk code. 508 */ 509 510 static inline enum dma_data_direction 511 rpcrdma_data_dir(bool writing) 512 { 513 return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE; 514 } 515 516 /* Memory registration calls xprtrdma/frwr_ops.c 517 */ 518 void frwr_reset(struct rpcrdma_req *req); 519 int frwr_query_device(struct rpcrdma_ep *ep, const struct ib_device *device); 520 int frwr_mr_init(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr); 521 void frwr_release_mr(struct rpcrdma_mr *mr); 522 struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt, 523 struct rpcrdma_mr_seg *seg, 524 int nsegs, bool writing, __be32 xid, 525 struct rpcrdma_mr *mr); 526 int frwr_send(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 527 void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs); 528 void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 529 void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 530 531 /* 532 * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c 533 */ 534 535 enum rpcrdma_chunktype { 536 rpcrdma_noch = 0, 537 rpcrdma_noch_pullup, 538 rpcrdma_noch_mapped, 539 rpcrdma_readch, 540 rpcrdma_areadch, 541 rpcrdma_writech, 542 rpcrdma_replych 543 }; 544 545 int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt, 546 struct rpcrdma_req *req, u32 hdrlen, 547 struct xdr_buf *xdr, 548 enum rpcrdma_chunktype rtype); 549 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc); 550 int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst); 551 void rpcrdma_set_max_header_sizes(struct rpcrdma_ep *ep); 552 void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt); 553 void rpcrdma_complete_rqst(struct rpcrdma_rep *rep); 554 void rpcrdma_reply_handler(struct rpcrdma_rep *rep); 555 556 static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len) 557 { 558 xdr->head[0].iov_len = len; 559 xdr->len = len; 560 } 561 562 /* RPC/RDMA module init - xprtrdma/transport.c 563 */ 564 extern unsigned int xprt_rdma_max_inline_read; 565 extern unsigned int xprt_rdma_max_inline_write; 566 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap); 567 void xprt_rdma_free_addresses(struct rpc_xprt *xprt); 568 void xprt_rdma_close(struct rpc_xprt *xprt); 569 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq); 570 int xprt_rdma_init(void); 571 void xprt_rdma_cleanup(void); 572 573 /* Backchannel calls - xprtrdma/backchannel.c 574 */ 575 #if defined(CONFIG_SUNRPC_BACKCHANNEL) 576 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int); 577 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *); 578 unsigned int xprt_rdma_bc_max_slots(struct rpc_xprt *); 579 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int); 580 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *); 581 int xprt_rdma_bc_send_reply(struct rpc_rqst *rqst); 582 void xprt_rdma_bc_free_rqst(struct rpc_rqst *); 583 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int); 584 #endif /* CONFIG_SUNRPC_BACKCHANNEL */ 585 586 extern struct xprt_class xprt_rdma_bc; 587 588 #endif /* _LINUX_SUNRPC_XPRT_RDMA_H */ 589