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 */ 71struct rpcrdma_mr; 72struct rpcrdma_ep { 73 struct kref re_kref; 74 struct rdma_cm_id *re_id; 75 struct ib_pd *re_pd; 76 unsigned int re_max_rdma_segs; 77 unsigned int re_max_fr_depth; 78 struct rpcrdma_mr *re_write_pad_mr; 79 enum ib_mr_type re_mrtype; 80 struct completion re_done; 81 unsigned int re_send_count; 82 unsigned int re_send_batch; 83 unsigned int re_max_inline_send; 84 unsigned int re_max_inline_recv; 85 int re_async_rc; 86 int re_connect_status; 87 atomic_t re_receiving; 88 atomic_t re_force_disconnect; 89 struct ib_qp_init_attr re_attr; 90 wait_queue_head_t re_connect_wait; 91 struct rpc_xprt *re_xprt; 92 struct rpcrdma_connect_private 93 re_cm_private; 94 struct rdma_conn_param re_remote_cma; 95 int re_receive_count; 96 unsigned int re_max_requests; /* depends on device */ 97 unsigned int re_inline_send; /* negotiated */ 98 unsigned int re_inline_recv; /* negotiated */ 99 100 atomic_t re_completion_ids; 101 102 char re_write_pad[XDR_UNIT]; 103}; 104 105/* Pre-allocate extra Work Requests for handling reverse-direction 106 * Receives and Sends. This is a fixed value because the Work Queues 107 * are allocated when the forward channel is set up, long before the 108 * backchannel is provisioned. This value is two times 109 * NFS4_DEF_CB_SLOT_TABLE_SIZE. 110 */ 111#if defined(CONFIG_SUNRPC_BACKCHANNEL) 112#define RPCRDMA_BACKWARD_WRS (32) 113#else 114#define RPCRDMA_BACKWARD_WRS (0) 115#endif 116 117/* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV 118 */ 119 120struct rpcrdma_regbuf { 121 struct ib_sge rg_iov; 122 struct ib_device *rg_device; 123 enum dma_data_direction rg_direction; 124 void *rg_data; 125}; 126 127static inline u64 rdmab_addr(struct rpcrdma_regbuf *rb) 128{ 129 return rb->rg_iov.addr; 130} 131 132static inline u32 rdmab_length(struct rpcrdma_regbuf *rb) 133{ 134 return rb->rg_iov.length; 135} 136 137static inline u32 rdmab_lkey(struct rpcrdma_regbuf *rb) 138{ 139 return rb->rg_iov.lkey; 140} 141 142static inline struct ib_device *rdmab_device(struct rpcrdma_regbuf *rb) 143{ 144 return rb->rg_device; 145} 146 147static inline void *rdmab_data(const struct rpcrdma_regbuf *rb) 148{ 149 return rb->rg_data; 150} 151 152/* Do not use emergency memory reserves, and fail quickly if memory 153 * cannot be allocated easily. These flags may be used wherever there 154 * is robust logic to handle a failure to allocate. 155 */ 156#define XPRTRDMA_GFP_FLAGS (__GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN) 157 158/* To ensure a transport can always make forward progress, 159 * the number of RDMA segments allowed in header chunk lists 160 * is capped at 16. This prevents less-capable devices from 161 * overrunning the Send buffer while building chunk lists. 162 * 163 * Elements of the Read list take up more room than the 164 * Write list or Reply chunk. 16 read segments means the 165 * chunk lists cannot consume more than 166 * 167 * ((16 + 2) * read segment size) + 1 XDR words, 168 * 169 * or about 400 bytes. The fixed part of the header is 170 * another 24 bytes. Thus when the inline threshold is 171 * 1024 bytes, at least 600 bytes are available for RPC 172 * message bodies. 173 */ 174enum { 175 RPCRDMA_MAX_HDR_SEGS = 16, 176}; 177 178/* 179 * struct rpcrdma_rep -- this structure encapsulates state required 180 * to receive and complete an RPC Reply, asychronously. It needs 181 * several pieces of state: 182 * 183 * o receive buffer and ib_sge (donated to provider) 184 * o status of receive (success or not, length, inv rkey) 185 * o bookkeeping state to get run by reply handler (XDR stream) 186 * 187 * These structures are allocated during transport initialization. 188 * N of these are associated with a transport instance, managed by 189 * struct rpcrdma_buffer. N is the max number of outstanding RPCs. 190 */ 191 192struct rpcrdma_rep { 193 struct ib_cqe rr_cqe; 194 struct rpc_rdma_cid rr_cid; 195 196 __be32 rr_xid; 197 __be32 rr_vers; 198 __be32 rr_proc; 199 int rr_wc_flags; 200 u32 rr_inv_rkey; 201 bool rr_temp; 202 struct rpcrdma_regbuf *rr_rdmabuf; 203 struct rpcrdma_xprt *rr_rxprt; 204 struct rpc_rqst *rr_rqst; 205 struct xdr_buf rr_hdrbuf; 206 struct xdr_stream rr_stream; 207 struct llist_node rr_node; 208 struct ib_recv_wr rr_recv_wr; 209 struct list_head rr_all; 210}; 211 212/* To reduce the rate at which a transport invokes ib_post_recv 213 * (and thus the hardware doorbell rate), xprtrdma posts Receive 214 * WRs in batches. 215 * 216 * Setting this to zero disables Receive post batching. 217 */ 218enum { 219 RPCRDMA_MAX_RECV_BATCH = 7, 220}; 221 222/* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes 223 */ 224struct rpcrdma_req; 225struct rpcrdma_sendctx { 226 struct ib_cqe sc_cqe; 227 struct rpc_rdma_cid sc_cid; 228 struct rpcrdma_req *sc_req; 229 unsigned int sc_unmap_count; 230 struct ib_sge sc_sges[]; 231}; 232 233/* 234 * struct rpcrdma_mr - external memory region metadata 235 * 236 * An external memory region is any buffer or page that is registered 237 * on the fly (ie, not pre-registered). 238 */ 239struct rpcrdma_req; 240struct rpcrdma_mr { 241 struct list_head mr_list; 242 struct rpcrdma_req *mr_req; 243 244 struct ib_mr *mr_ibmr; 245 struct ib_device *mr_device; 246 struct scatterlist *mr_sg; 247 int mr_nents; 248 enum dma_data_direction mr_dir; 249 struct ib_cqe mr_cqe; 250 struct completion mr_linv_done; 251 union { 252 struct ib_reg_wr mr_regwr; 253 struct ib_send_wr mr_invwr; 254 }; 255 struct rpcrdma_xprt *mr_xprt; 256 u32 mr_handle; 257 u32 mr_length; 258 u64 mr_offset; 259 struct list_head mr_all; 260 struct rpc_rdma_cid mr_cid; 261}; 262 263/* 264 * struct rpcrdma_req -- structure central to the request/reply sequence. 265 * 266 * N of these are associated with a transport instance, and stored in 267 * struct rpcrdma_buffer. N is the max number of outstanding requests. 268 * 269 * It includes pre-registered buffer memory for send AND recv. 270 * The recv buffer, however, is not owned by this structure, and 271 * is "donated" to the hardware when a recv is posted. When a 272 * reply is handled, the recv buffer used is given back to the 273 * struct rpcrdma_req associated with the request. 274 * 275 * In addition to the basic memory, this structure includes an array 276 * of iovs for send operations. The reason is that the iovs passed to 277 * ib_post_{send,recv} must not be modified until the work request 278 * completes. 279 */ 280 281/* Maximum number of page-sized "segments" per chunk list to be 282 * registered or invalidated. Must handle a Reply chunk: 283 */ 284enum { 285 RPCRDMA_MAX_IOV_SEGS = 3, 286 RPCRDMA_MAX_DATA_SEGS = ((1 * 1024 * 1024) / PAGE_SIZE) + 1, 287 RPCRDMA_MAX_SEGS = RPCRDMA_MAX_DATA_SEGS + 288 RPCRDMA_MAX_IOV_SEGS, 289}; 290 291/* Arguments for DMA mapping and registration */ 292struct rpcrdma_mr_seg { 293 u32 mr_len; /* length of segment */ 294 struct page *mr_page; /* underlying struct page */ 295 u64 mr_offset; /* IN: page offset, OUT: iova */ 296}; 297 298/* The Send SGE array is provisioned to send a maximum size 299 * inline request: 300 * - RPC-over-RDMA header 301 * - xdr_buf head iovec 302 * - RPCRDMA_MAX_INLINE bytes, in pages 303 * - xdr_buf tail iovec 304 * 305 * The actual number of array elements consumed by each RPC 306 * depends on the device's max_sge limit. 307 */ 308enum { 309 RPCRDMA_MIN_SEND_SGES = 3, 310 RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT, 311 RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1, 312}; 313 314struct rpcrdma_buffer; 315struct rpcrdma_req { 316 struct list_head rl_list; 317 struct rpc_rqst rl_slot; 318 struct rpcrdma_rep *rl_reply; 319 struct xdr_stream rl_stream; 320 struct xdr_buf rl_hdrbuf; 321 struct ib_send_wr rl_wr; 322 struct rpcrdma_sendctx *rl_sendctx; 323 struct rpcrdma_regbuf *rl_rdmabuf; /* xprt header */ 324 struct rpcrdma_regbuf *rl_sendbuf; /* rq_snd_buf */ 325 struct rpcrdma_regbuf *rl_recvbuf; /* rq_rcv_buf */ 326 327 struct list_head rl_all; 328 struct kref rl_kref; 329 330 struct list_head rl_free_mrs; 331 struct list_head rl_registered; 332 struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS]; 333}; 334 335static inline struct rpcrdma_req * 336rpcr_to_rdmar(const struct rpc_rqst *rqst) 337{ 338 return container_of(rqst, struct rpcrdma_req, rl_slot); 339} 340 341static inline void 342rpcrdma_mr_push(struct rpcrdma_mr *mr, struct list_head *list) 343{ 344 list_add(&mr->mr_list, list); 345} 346 347static inline struct rpcrdma_mr * 348rpcrdma_mr_pop(struct list_head *list) 349{ 350 struct rpcrdma_mr *mr; 351 352 mr = list_first_entry_or_null(list, struct rpcrdma_mr, mr_list); 353 if (mr) 354 list_del_init(&mr->mr_list); 355 return mr; 356} 357 358/* 359 * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for 360 * inline requests/replies, and client/server credits. 361 * 362 * One of these is associated with a transport instance 363 */ 364struct rpcrdma_buffer { 365 spinlock_t rb_lock; 366 struct list_head rb_send_bufs; 367 struct list_head rb_mrs; 368 369 unsigned long rb_sc_head; 370 unsigned long rb_sc_tail; 371 unsigned long rb_sc_last; 372 struct rpcrdma_sendctx **rb_sc_ctxs; 373 374 struct list_head rb_allreqs; 375 struct list_head rb_all_mrs; 376 struct list_head rb_all_reps; 377 378 struct llist_head rb_free_reps; 379 380 __be32 rb_max_requests; 381 u32 rb_credits; /* most recent credit grant */ 382 383 u32 rb_bc_srv_max_requests; 384 u32 rb_bc_max_requests; 385 386 struct work_struct rb_refresh_worker; 387}; 388 389/* 390 * Statistics for RPCRDMA 391 */ 392struct rpcrdma_stats { 393 /* accessed when sending a call */ 394 unsigned long read_chunk_count; 395 unsigned long write_chunk_count; 396 unsigned long reply_chunk_count; 397 unsigned long long total_rdma_request; 398 399 /* rarely accessed error counters */ 400 unsigned long long pullup_copy_count; 401 unsigned long hardway_register_count; 402 unsigned long failed_marshal_count; 403 unsigned long bad_reply_count; 404 unsigned long mrs_recycled; 405 unsigned long mrs_orphaned; 406 unsigned long mrs_allocated; 407 unsigned long empty_sendctx_q; 408 409 /* accessed when receiving a reply */ 410 unsigned long long total_rdma_reply; 411 unsigned long long fixup_copy_count; 412 unsigned long reply_waits_for_send; 413 unsigned long local_inv_needed; 414 unsigned long nomsg_call_count; 415 unsigned long bcall_count; 416}; 417 418/* 419 * RPCRDMA transport -- encapsulates the structures above for 420 * integration with RPC. 421 * 422 * The contained structures are embedded, not pointers, 423 * for convenience. This structure need not be visible externally. 424 * 425 * It is allocated and initialized during mount, and released 426 * during unmount. 427 */ 428struct rpcrdma_xprt { 429 struct rpc_xprt rx_xprt; 430 struct rpcrdma_ep *rx_ep; 431 struct rpcrdma_buffer rx_buf; 432 struct delayed_work rx_connect_worker; 433 struct rpc_timeout rx_timeout; 434 struct rpcrdma_stats rx_stats; 435}; 436 437#define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt) 438 439static inline const char * 440rpcrdma_addrstr(const struct rpcrdma_xprt *r_xprt) 441{ 442 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_ADDR]; 443} 444 445static inline const char * 446rpcrdma_portstr(const struct rpcrdma_xprt *r_xprt) 447{ 448 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_PORT]; 449} 450 451/* Setting this to 0 ensures interoperability with early servers. 452 * Setting this to 1 enhances certain unaligned read/write performance. 453 * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */ 454extern int xprt_rdma_pad_optimize; 455 456/* This setting controls the hunt for a supported memory 457 * registration strategy. 458 */ 459extern unsigned int xprt_rdma_memreg_strategy; 460 461/* 462 * Endpoint calls - xprtrdma/verbs.c 463 */ 464void rpcrdma_force_disconnect(struct rpcrdma_ep *ep); 465void rpcrdma_flush_disconnect(struct rpcrdma_xprt *r_xprt, struct ib_wc *wc); 466int rpcrdma_xprt_connect(struct rpcrdma_xprt *r_xprt); 467void rpcrdma_xprt_disconnect(struct rpcrdma_xprt *r_xprt); 468 469void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, int needed, bool temp); 470 471/* 472 * Buffer calls - xprtrdma/verbs.c 473 */ 474struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, 475 size_t size); 476int rpcrdma_req_setup(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 477void rpcrdma_req_destroy(struct rpcrdma_req *req); 478int rpcrdma_buffer_create(struct rpcrdma_xprt *); 479void rpcrdma_buffer_destroy(struct rpcrdma_buffer *); 480struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt); 481 482struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt); 483void rpcrdma_mrs_refresh(struct rpcrdma_xprt *r_xprt); 484 485struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *); 486void rpcrdma_buffer_put(struct rpcrdma_buffer *buffers, 487 struct rpcrdma_req *req); 488void rpcrdma_rep_put(struct rpcrdma_buffer *buf, struct rpcrdma_rep *rep); 489void rpcrdma_reply_put(struct rpcrdma_buffer *buffers, struct rpcrdma_req *req); 490 491bool rpcrdma_regbuf_realloc(struct rpcrdma_regbuf *rb, size_t size, 492 gfp_t flags); 493bool __rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt, 494 struct rpcrdma_regbuf *rb); 495 496/** 497 * rpcrdma_regbuf_is_mapped - check if buffer is DMA mapped 498 * 499 * Returns true if the buffer is now mapped to rb->rg_device. 500 */ 501static inline bool rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb) 502{ 503 return rb->rg_device != NULL; 504} 505 506/** 507 * rpcrdma_regbuf_dma_map - DMA-map a regbuf 508 * @r_xprt: controlling transport instance 509 * @rb: regbuf to be mapped 510 * 511 * Returns true if the buffer is currently DMA mapped. 512 */ 513static inline bool rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt, 514 struct rpcrdma_regbuf *rb) 515{ 516 if (likely(rpcrdma_regbuf_is_mapped(rb))) 517 return true; 518 return __rpcrdma_regbuf_dma_map(r_xprt, rb); 519} 520 521/* 522 * Wrappers for chunk registration, shared by read/write chunk code. 523 */ 524 525static inline enum dma_data_direction 526rpcrdma_data_dir(bool writing) 527{ 528 return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE; 529} 530 531/* Memory registration calls xprtrdma/frwr_ops.c 532 */ 533void frwr_reset(struct rpcrdma_req *req); 534int frwr_query_device(struct rpcrdma_ep *ep, const struct ib_device *device); 535int frwr_mr_init(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr); 536void frwr_mr_release(struct rpcrdma_mr *mr); 537struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt, 538 struct rpcrdma_mr_seg *seg, 539 int nsegs, bool writing, __be32 xid, 540 struct rpcrdma_mr *mr); 541int frwr_send(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 542void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs); 543void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 544void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 545int frwr_wp_create(struct rpcrdma_xprt *r_xprt); 546 547/* 548 * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c 549 */ 550 551enum rpcrdma_chunktype { 552 rpcrdma_noch = 0, 553 rpcrdma_noch_pullup, 554 rpcrdma_noch_mapped, 555 rpcrdma_readch, 556 rpcrdma_areadch, 557 rpcrdma_writech, 558 rpcrdma_replych 559}; 560 561int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt, 562 struct rpcrdma_req *req, u32 hdrlen, 563 struct xdr_buf *xdr, 564 enum rpcrdma_chunktype rtype); 565void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc); 566int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst); 567void rpcrdma_set_max_header_sizes(struct rpcrdma_ep *ep); 568void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt); 569void rpcrdma_complete_rqst(struct rpcrdma_rep *rep); 570void rpcrdma_unpin_rqst(struct rpcrdma_rep *rep); 571void rpcrdma_reply_handler(struct rpcrdma_rep *rep); 572 573static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len) 574{ 575 xdr->head[0].iov_len = len; 576 xdr->len = len; 577} 578 579/* RPC/RDMA module init - xprtrdma/transport.c 580 */ 581extern unsigned int xprt_rdma_max_inline_read; 582extern unsigned int xprt_rdma_max_inline_write; 583void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap); 584void xprt_rdma_free_addresses(struct rpc_xprt *xprt); 585void xprt_rdma_close(struct rpc_xprt *xprt); 586void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq); 587int xprt_rdma_init(void); 588void xprt_rdma_cleanup(void); 589 590/* Backchannel calls - xprtrdma/backchannel.c 591 */ 592#if defined(CONFIG_SUNRPC_BACKCHANNEL) 593int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int); 594size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *); 595unsigned int xprt_rdma_bc_max_slots(struct rpc_xprt *); 596void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *); 597int xprt_rdma_bc_send_reply(struct rpc_rqst *rqst); 598void xprt_rdma_bc_free_rqst(struct rpc_rqst *); 599void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int); 600#endif /* CONFIG_SUNRPC_BACKCHANNEL */ 601 602extern struct xprt_class xprt_rdma_bc; 603 604#endif /* _LINUX_SUNRPC_XPRT_RDMA_H */ 605