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_cid.h> /* completion IDs */ 57 #include <linux/sunrpc/rpc_rdma.h> /* RPC/RDMA protocol */ 58 #include <linux/sunrpc/xprtrdma.h> /* xprt parameters */ 59 60 #define RDMA_RESOLVE_TIMEOUT (5000) /* 5 seconds */ 61 #define RDMA_CONNECT_RETRY_MAX (2) /* retries if no listener backlog */ 62 63 #define RPCRDMA_BIND_TO (60U * HZ) 64 #define RPCRDMA_INIT_REEST_TO (5U * HZ) 65 #define RPCRDMA_MAX_REEST_TO (30U * HZ) 66 #define RPCRDMA_IDLE_DISC_TO (5U * 60 * HZ) 67 68 /* 69 * RDMA Endpoint -- connection endpoint details 70 */ 71 struct rpcrdma_ep { 72 struct kref re_kref; 73 struct rdma_cm_id *re_id; 74 struct ib_pd *re_pd; 75 unsigned int re_max_rdma_segs; 76 unsigned int re_max_fr_depth; 77 bool re_implicit_roundup; 78 enum ib_mr_type re_mrtype; 79 struct completion re_done; 80 unsigned int re_send_count; 81 unsigned int re_send_batch; 82 unsigned int re_max_inline_send; 83 unsigned int re_max_inline_recv; 84 int re_async_rc; 85 int re_connect_status; 86 atomic_t re_force_disconnect; 87 struct ib_qp_init_attr re_attr; 88 wait_queue_head_t re_connect_wait; 89 struct rpc_xprt *re_xprt; 90 struct rpcrdma_connect_private 91 re_cm_private; 92 struct rdma_conn_param re_remote_cma; 93 int re_receive_count; 94 unsigned int re_max_requests; /* depends on device */ 95 unsigned int re_inline_send; /* negotiated */ 96 unsigned int re_inline_recv; /* negotiated */ 97 98 atomic_t re_completion_ids; 99 }; 100 101 /* Pre-allocate extra Work Requests for handling reverse-direction 102 * Receives and Sends. This is a fixed value because the Work Queues 103 * are allocated when the forward channel is set up, long before the 104 * backchannel is provisioned. This value is two times 105 * NFS4_DEF_CB_SLOT_TABLE_SIZE. 106 */ 107 #if defined(CONFIG_SUNRPC_BACKCHANNEL) 108 #define RPCRDMA_BACKWARD_WRS (32) 109 #else 110 #define RPCRDMA_BACKWARD_WRS (0) 111 #endif 112 113 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV 114 */ 115 116 struct rpcrdma_regbuf { 117 struct ib_sge rg_iov; 118 struct ib_device *rg_device; 119 enum dma_data_direction rg_direction; 120 void *rg_data; 121 }; 122 123 static inline u64 rdmab_addr(struct rpcrdma_regbuf *rb) 124 { 125 return rb->rg_iov.addr; 126 } 127 128 static inline u32 rdmab_length(struct rpcrdma_regbuf *rb) 129 { 130 return rb->rg_iov.length; 131 } 132 133 static inline u32 rdmab_lkey(struct rpcrdma_regbuf *rb) 134 { 135 return rb->rg_iov.lkey; 136 } 137 138 static inline struct ib_device *rdmab_device(struct rpcrdma_regbuf *rb) 139 { 140 return rb->rg_device; 141 } 142 143 static inline void *rdmab_data(const struct rpcrdma_regbuf *rb) 144 { 145 return rb->rg_data; 146 } 147 148 #define RPCRDMA_DEF_GFP (GFP_NOIO | __GFP_NOWARN) 149 150 /* To ensure a transport can always make forward progress, 151 * the number of RDMA segments allowed in header chunk lists 152 * is capped at 16. This prevents less-capable devices from 153 * overrunning the Send buffer while building chunk lists. 154 * 155 * Elements of the Read list take up more room than the 156 * Write list or Reply chunk. 16 read segments means the 157 * chunk lists cannot consume more than 158 * 159 * ((16 + 2) * read segment size) + 1 XDR words, 160 * 161 * or about 400 bytes. The fixed part of the header is 162 * another 24 bytes. Thus when the inline threshold is 163 * 1024 bytes, at least 600 bytes are available for RPC 164 * message bodies. 165 */ 166 enum { 167 RPCRDMA_MAX_HDR_SEGS = 16, 168 }; 169 170 /* 171 * struct rpcrdma_rep -- this structure encapsulates state required 172 * to receive and complete an RPC Reply, asychronously. It needs 173 * several pieces of state: 174 * 175 * o receive buffer and ib_sge (donated to provider) 176 * o status of receive (success or not, length, inv rkey) 177 * o bookkeeping state to get run by reply handler (XDR stream) 178 * 179 * These structures are allocated during transport initialization. 180 * N of these are associated with a transport instance, managed by 181 * struct rpcrdma_buffer. N is the max number of outstanding RPCs. 182 */ 183 184 struct rpcrdma_rep { 185 struct ib_cqe rr_cqe; 186 struct rpc_rdma_cid rr_cid; 187 188 __be32 rr_xid; 189 __be32 rr_vers; 190 __be32 rr_proc; 191 int rr_wc_flags; 192 u32 rr_inv_rkey; 193 bool rr_temp; 194 struct rpcrdma_regbuf *rr_rdmabuf; 195 struct rpcrdma_xprt *rr_rxprt; 196 struct rpc_rqst *rr_rqst; 197 struct xdr_buf rr_hdrbuf; 198 struct xdr_stream rr_stream; 199 struct llist_node rr_node; 200 struct ib_recv_wr rr_recv_wr; 201 struct list_head rr_all; 202 }; 203 204 /* To reduce the rate at which a transport invokes ib_post_recv 205 * (and thus the hardware doorbell rate), xprtrdma posts Receive 206 * WRs in batches. 207 * 208 * Setting this to zero disables Receive post batching. 209 */ 210 enum { 211 RPCRDMA_MAX_RECV_BATCH = 7, 212 }; 213 214 /* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes 215 */ 216 struct rpcrdma_req; 217 struct rpcrdma_sendctx { 218 struct ib_cqe sc_cqe; 219 struct rpc_rdma_cid sc_cid; 220 struct rpcrdma_req *sc_req; 221 unsigned int sc_unmap_count; 222 struct ib_sge sc_sges[]; 223 }; 224 225 /* 226 * struct rpcrdma_mr - external memory region metadata 227 * 228 * An external memory region is any buffer or page that is registered 229 * on the fly (ie, not pre-registered). 230 */ 231 struct rpcrdma_frwr { 232 struct ib_mr *fr_mr; 233 struct ib_cqe fr_cqe; 234 struct rpc_rdma_cid fr_cid; 235 struct completion fr_linv_done; 236 union { 237 struct ib_reg_wr fr_regwr; 238 struct ib_send_wr fr_invwr; 239 }; 240 }; 241 242 struct rpcrdma_req; 243 struct rpcrdma_mr { 244 struct list_head mr_list; 245 struct rpcrdma_req *mr_req; 246 struct ib_device *mr_device; 247 struct scatterlist *mr_sg; 248 int mr_nents; 249 enum dma_data_direction mr_dir; 250 struct rpcrdma_frwr frwr; 251 struct rpcrdma_xprt *mr_xprt; 252 u32 mr_handle; 253 u32 mr_length; 254 u64 mr_offset; 255 struct list_head mr_all; 256 }; 257 258 /* 259 * struct rpcrdma_req -- structure central to the request/reply sequence. 260 * 261 * N of these are associated with a transport instance, and stored in 262 * struct rpcrdma_buffer. N is the max number of outstanding requests. 263 * 264 * It includes pre-registered buffer memory for send AND recv. 265 * The recv buffer, however, is not owned by this structure, and 266 * is "donated" to the hardware when a recv is posted. When a 267 * reply is handled, the recv buffer used is given back to the 268 * struct rpcrdma_req associated with the request. 269 * 270 * In addition to the basic memory, this structure includes an array 271 * of iovs for send operations. The reason is that the iovs passed to 272 * ib_post_{send,recv} must not be modified until the work request 273 * completes. 274 */ 275 276 /* Maximum number of page-sized "segments" per chunk list to be 277 * registered or invalidated. Must handle a Reply chunk: 278 */ 279 enum { 280 RPCRDMA_MAX_IOV_SEGS = 3, 281 RPCRDMA_MAX_DATA_SEGS = ((1 * 1024 * 1024) / PAGE_SIZE) + 1, 282 RPCRDMA_MAX_SEGS = RPCRDMA_MAX_DATA_SEGS + 283 RPCRDMA_MAX_IOV_SEGS, 284 }; 285 286 /* Arguments for DMA mapping and registration */ 287 struct rpcrdma_mr_seg { 288 u32 mr_len; /* length of segment */ 289 struct page *mr_page; /* underlying struct page */ 290 u64 mr_offset; /* IN: page offset, OUT: iova */ 291 }; 292 293 /* The Send SGE array is provisioned to send a maximum size 294 * inline request: 295 * - RPC-over-RDMA header 296 * - xdr_buf head iovec 297 * - RPCRDMA_MAX_INLINE bytes, in pages 298 * - xdr_buf tail iovec 299 * 300 * The actual number of array elements consumed by each RPC 301 * depends on the device's max_sge limit. 302 */ 303 enum { 304 RPCRDMA_MIN_SEND_SGES = 3, 305 RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT, 306 RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1, 307 }; 308 309 struct rpcrdma_buffer; 310 struct rpcrdma_req { 311 struct list_head rl_list; 312 struct rpc_rqst rl_slot; 313 struct rpcrdma_rep *rl_reply; 314 struct xdr_stream rl_stream; 315 struct xdr_buf rl_hdrbuf; 316 struct ib_send_wr rl_wr; 317 struct rpcrdma_sendctx *rl_sendctx; 318 struct rpcrdma_regbuf *rl_rdmabuf; /* xprt header */ 319 struct rpcrdma_regbuf *rl_sendbuf; /* rq_snd_buf */ 320 struct rpcrdma_regbuf *rl_recvbuf; /* rq_rcv_buf */ 321 322 struct list_head rl_all; 323 struct kref rl_kref; 324 325 struct list_head rl_free_mrs; 326 struct list_head rl_registered; 327 struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS]; 328 }; 329 330 static inline struct rpcrdma_req * 331 rpcr_to_rdmar(const struct rpc_rqst *rqst) 332 { 333 return container_of(rqst, struct rpcrdma_req, rl_slot); 334 } 335 336 static inline void 337 rpcrdma_mr_push(struct rpcrdma_mr *mr, struct list_head *list) 338 { 339 list_add(&mr->mr_list, list); 340 } 341 342 static inline struct rpcrdma_mr * 343 rpcrdma_mr_pop(struct list_head *list) 344 { 345 struct rpcrdma_mr *mr; 346 347 mr = list_first_entry_or_null(list, struct rpcrdma_mr, mr_list); 348 if (mr) 349 list_del_init(&mr->mr_list); 350 return mr; 351 } 352 353 /* 354 * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for 355 * inline requests/replies, and client/server credits. 356 * 357 * One of these is associated with a transport instance 358 */ 359 struct rpcrdma_buffer { 360 spinlock_t rb_lock; 361 struct list_head rb_send_bufs; 362 struct list_head rb_mrs; 363 364 unsigned long rb_sc_head; 365 unsigned long rb_sc_tail; 366 unsigned long rb_sc_last; 367 struct rpcrdma_sendctx **rb_sc_ctxs; 368 369 struct list_head rb_allreqs; 370 struct list_head rb_all_mrs; 371 struct list_head rb_all_reps; 372 373 struct llist_head rb_free_reps; 374 375 __be32 rb_max_requests; 376 u32 rb_credits; /* most recent credit grant */ 377 378 u32 rb_bc_srv_max_requests; 379 u32 rb_bc_max_requests; 380 381 struct work_struct rb_refresh_worker; 382 }; 383 384 /* 385 * Statistics for RPCRDMA 386 */ 387 struct rpcrdma_stats { 388 /* accessed when sending a call */ 389 unsigned long read_chunk_count; 390 unsigned long write_chunk_count; 391 unsigned long reply_chunk_count; 392 unsigned long long total_rdma_request; 393 394 /* rarely accessed error counters */ 395 unsigned long long pullup_copy_count; 396 unsigned long hardway_register_count; 397 unsigned long failed_marshal_count; 398 unsigned long bad_reply_count; 399 unsigned long mrs_recycled; 400 unsigned long mrs_orphaned; 401 unsigned long mrs_allocated; 402 unsigned long empty_sendctx_q; 403 404 /* accessed when receiving a reply */ 405 unsigned long long total_rdma_reply; 406 unsigned long long fixup_copy_count; 407 unsigned long reply_waits_for_send; 408 unsigned long local_inv_needed; 409 unsigned long nomsg_call_count; 410 unsigned long bcall_count; 411 }; 412 413 /* 414 * RPCRDMA transport -- encapsulates the structures above for 415 * integration with RPC. 416 * 417 * The contained structures are embedded, not pointers, 418 * for convenience. This structure need not be visible externally. 419 * 420 * It is allocated and initialized during mount, and released 421 * during unmount. 422 */ 423 struct rpcrdma_xprt { 424 struct rpc_xprt rx_xprt; 425 struct rpcrdma_ep *rx_ep; 426 struct rpcrdma_buffer rx_buf; 427 struct delayed_work rx_connect_worker; 428 struct rpc_timeout rx_timeout; 429 struct rpcrdma_stats rx_stats; 430 }; 431 432 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt) 433 434 static inline const char * 435 rpcrdma_addrstr(const struct rpcrdma_xprt *r_xprt) 436 { 437 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_ADDR]; 438 } 439 440 static inline const char * 441 rpcrdma_portstr(const struct rpcrdma_xprt *r_xprt) 442 { 443 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_PORT]; 444 } 445 446 /* Setting this to 0 ensures interoperability with early servers. 447 * Setting this to 1 enhances certain unaligned read/write performance. 448 * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */ 449 extern int xprt_rdma_pad_optimize; 450 451 /* This setting controls the hunt for a supported memory 452 * registration strategy. 453 */ 454 extern unsigned int xprt_rdma_memreg_strategy; 455 456 /* 457 * Endpoint calls - xprtrdma/verbs.c 458 */ 459 void rpcrdma_flush_disconnect(struct rpcrdma_xprt *r_xprt, struct ib_wc *wc); 460 int rpcrdma_xprt_connect(struct rpcrdma_xprt *r_xprt); 461 void rpcrdma_xprt_disconnect(struct rpcrdma_xprt *r_xprt); 462 463 int rpcrdma_post_sends(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 464 void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp); 465 466 /* 467 * Buffer calls - xprtrdma/verbs.c 468 */ 469 struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, size_t size, 470 gfp_t flags); 471 int rpcrdma_req_setup(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 472 void rpcrdma_req_destroy(struct rpcrdma_req *req); 473 int rpcrdma_buffer_create(struct rpcrdma_xprt *); 474 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *); 475 struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt); 476 477 struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt); 478 void rpcrdma_mrs_refresh(struct rpcrdma_xprt *r_xprt); 479 480 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *); 481 void rpcrdma_buffer_put(struct rpcrdma_buffer *buffers, 482 struct rpcrdma_req *req); 483 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *); 484 485 bool rpcrdma_regbuf_realloc(struct rpcrdma_regbuf *rb, size_t size, 486 gfp_t flags); 487 bool __rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt, 488 struct rpcrdma_regbuf *rb); 489 490 /** 491 * rpcrdma_regbuf_is_mapped - check if buffer is DMA mapped 492 * 493 * Returns true if the buffer is now mapped to rb->rg_device. 494 */ 495 static inline bool rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb) 496 { 497 return rb->rg_device != NULL; 498 } 499 500 /** 501 * rpcrdma_regbuf_dma_map - DMA-map a regbuf 502 * @r_xprt: controlling transport instance 503 * @rb: regbuf to be mapped 504 * 505 * Returns true if the buffer is currently DMA mapped. 506 */ 507 static inline bool rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt, 508 struct rpcrdma_regbuf *rb) 509 { 510 if (likely(rpcrdma_regbuf_is_mapped(rb))) 511 return true; 512 return __rpcrdma_regbuf_dma_map(r_xprt, rb); 513 } 514 515 /* 516 * Wrappers for chunk registration, shared by read/write chunk code. 517 */ 518 519 static inline enum dma_data_direction 520 rpcrdma_data_dir(bool writing) 521 { 522 return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE; 523 } 524 525 /* Memory registration calls xprtrdma/frwr_ops.c 526 */ 527 void frwr_reset(struct rpcrdma_req *req); 528 int frwr_query_device(struct rpcrdma_ep *ep, const struct ib_device *device); 529 int frwr_mr_init(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr); 530 void frwr_release_mr(struct rpcrdma_mr *mr); 531 struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt, 532 struct rpcrdma_mr_seg *seg, 533 int nsegs, bool writing, __be32 xid, 534 struct rpcrdma_mr *mr); 535 int frwr_send(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 536 void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs); 537 void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 538 void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 539 540 /* 541 * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c 542 */ 543 544 enum rpcrdma_chunktype { 545 rpcrdma_noch = 0, 546 rpcrdma_noch_pullup, 547 rpcrdma_noch_mapped, 548 rpcrdma_readch, 549 rpcrdma_areadch, 550 rpcrdma_writech, 551 rpcrdma_replych 552 }; 553 554 int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt, 555 struct rpcrdma_req *req, u32 hdrlen, 556 struct xdr_buf *xdr, 557 enum rpcrdma_chunktype rtype); 558 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc); 559 int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst); 560 void rpcrdma_set_max_header_sizes(struct rpcrdma_ep *ep); 561 void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt); 562 void rpcrdma_complete_rqst(struct rpcrdma_rep *rep); 563 void rpcrdma_reply_handler(struct rpcrdma_rep *rep); 564 565 static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len) 566 { 567 xdr->head[0].iov_len = len; 568 xdr->len = len; 569 } 570 571 /* RPC/RDMA module init - xprtrdma/transport.c 572 */ 573 extern unsigned int xprt_rdma_max_inline_read; 574 extern unsigned int xprt_rdma_max_inline_write; 575 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap); 576 void xprt_rdma_free_addresses(struct rpc_xprt *xprt); 577 void xprt_rdma_close(struct rpc_xprt *xprt); 578 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq); 579 int xprt_rdma_init(void); 580 void xprt_rdma_cleanup(void); 581 582 /* Backchannel calls - xprtrdma/backchannel.c 583 */ 584 #if defined(CONFIG_SUNRPC_BACKCHANNEL) 585 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int); 586 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *); 587 unsigned int xprt_rdma_bc_max_slots(struct rpc_xprt *); 588 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int); 589 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *); 590 int xprt_rdma_bc_send_reply(struct rpc_rqst *rqst); 591 void xprt_rdma_bc_free_rqst(struct rpc_rqst *); 592 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int); 593 #endif /* CONFIG_SUNRPC_BACKCHANNEL */ 594 595 extern struct xprt_class xprt_rdma_bc; 596 597 #endif /* _LINUX_SUNRPC_XPRT_RDMA_H */ 598