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 backward receives 102 * and sends. This is a fixed value because the Work Queues are 103 * 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 struct rpcrdma_mr_seg { /* chunk descriptors */ 287 u32 mr_len; /* length of chunk or segment */ 288 struct page *mr_page; /* owning page, if any */ 289 char *mr_offset; /* kva if no page, else offset */ 290 }; 291 292 /* The Send SGE array is provisioned to send a maximum size 293 * inline request: 294 * - RPC-over-RDMA header 295 * - xdr_buf head iovec 296 * - RPCRDMA_MAX_INLINE bytes, in pages 297 * - xdr_buf tail iovec 298 * 299 * The actual number of array elements consumed by each RPC 300 * depends on the device's max_sge limit. 301 */ 302 enum { 303 RPCRDMA_MIN_SEND_SGES = 3, 304 RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT, 305 RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1, 306 }; 307 308 struct rpcrdma_buffer; 309 struct rpcrdma_req { 310 struct list_head rl_list; 311 struct rpc_rqst rl_slot; 312 struct rpcrdma_rep *rl_reply; 313 struct xdr_stream rl_stream; 314 struct xdr_buf rl_hdrbuf; 315 struct ib_send_wr rl_wr; 316 struct rpcrdma_sendctx *rl_sendctx; 317 struct rpcrdma_regbuf *rl_rdmabuf; /* xprt header */ 318 struct rpcrdma_regbuf *rl_sendbuf; /* rq_snd_buf */ 319 struct rpcrdma_regbuf *rl_recvbuf; /* rq_rcv_buf */ 320 321 struct list_head rl_all; 322 struct kref rl_kref; 323 324 struct list_head rl_free_mrs; 325 struct list_head rl_registered; 326 struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS]; 327 }; 328 329 static inline struct rpcrdma_req * 330 rpcr_to_rdmar(const struct rpc_rqst *rqst) 331 { 332 return container_of(rqst, struct rpcrdma_req, rl_slot); 333 } 334 335 static inline void 336 rpcrdma_mr_push(struct rpcrdma_mr *mr, struct list_head *list) 337 { 338 list_add(&mr->mr_list, list); 339 } 340 341 static inline struct rpcrdma_mr * 342 rpcrdma_mr_pop(struct list_head *list) 343 { 344 struct rpcrdma_mr *mr; 345 346 mr = list_first_entry_or_null(list, struct rpcrdma_mr, mr_list); 347 if (mr) 348 list_del_init(&mr->mr_list); 349 return mr; 350 } 351 352 /* 353 * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for 354 * inline requests/replies, and client/server credits. 355 * 356 * One of these is associated with a transport instance 357 */ 358 struct rpcrdma_buffer { 359 spinlock_t rb_lock; 360 struct list_head rb_send_bufs; 361 struct list_head rb_mrs; 362 363 unsigned long rb_sc_head; 364 unsigned long rb_sc_tail; 365 unsigned long rb_sc_last; 366 struct rpcrdma_sendctx **rb_sc_ctxs; 367 368 struct list_head rb_allreqs; 369 struct list_head rb_all_mrs; 370 struct list_head rb_all_reps; 371 372 struct llist_head rb_free_reps; 373 374 __be32 rb_max_requests; 375 u32 rb_credits; /* most recent credit grant */ 376 377 u32 rb_bc_srv_max_requests; 378 u32 rb_bc_max_requests; 379 380 struct work_struct rb_refresh_worker; 381 }; 382 383 /* 384 * Statistics for RPCRDMA 385 */ 386 struct rpcrdma_stats { 387 /* accessed when sending a call */ 388 unsigned long read_chunk_count; 389 unsigned long write_chunk_count; 390 unsigned long reply_chunk_count; 391 unsigned long long total_rdma_request; 392 393 /* rarely accessed error counters */ 394 unsigned long long pullup_copy_count; 395 unsigned long hardway_register_count; 396 unsigned long failed_marshal_count; 397 unsigned long bad_reply_count; 398 unsigned long mrs_recycled; 399 unsigned long mrs_orphaned; 400 unsigned long mrs_allocated; 401 unsigned long empty_sendctx_q; 402 403 /* accessed when receiving a reply */ 404 unsigned long long total_rdma_reply; 405 unsigned long long fixup_copy_count; 406 unsigned long reply_waits_for_send; 407 unsigned long local_inv_needed; 408 unsigned long nomsg_call_count; 409 unsigned long bcall_count; 410 }; 411 412 /* 413 * RPCRDMA transport -- encapsulates the structures above for 414 * integration with RPC. 415 * 416 * The contained structures are embedded, not pointers, 417 * for convenience. This structure need not be visible externally. 418 * 419 * It is allocated and initialized during mount, and released 420 * during unmount. 421 */ 422 struct rpcrdma_xprt { 423 struct rpc_xprt rx_xprt; 424 struct rpcrdma_ep *rx_ep; 425 struct rpcrdma_buffer rx_buf; 426 struct delayed_work rx_connect_worker; 427 struct rpc_timeout rx_timeout; 428 struct rpcrdma_stats rx_stats; 429 }; 430 431 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt) 432 433 static inline const char * 434 rpcrdma_addrstr(const struct rpcrdma_xprt *r_xprt) 435 { 436 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_ADDR]; 437 } 438 439 static inline const char * 440 rpcrdma_portstr(const struct rpcrdma_xprt *r_xprt) 441 { 442 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_PORT]; 443 } 444 445 /* Setting this to 0 ensures interoperability with early servers. 446 * Setting this to 1 enhances certain unaligned read/write performance. 447 * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */ 448 extern int xprt_rdma_pad_optimize; 449 450 /* This setting controls the hunt for a supported memory 451 * registration strategy. 452 */ 453 extern unsigned int xprt_rdma_memreg_strategy; 454 455 /* 456 * Endpoint calls - xprtrdma/verbs.c 457 */ 458 void rpcrdma_flush_disconnect(struct rpcrdma_xprt *r_xprt, struct ib_wc *wc); 459 int rpcrdma_xprt_connect(struct rpcrdma_xprt *r_xprt); 460 void rpcrdma_xprt_disconnect(struct rpcrdma_xprt *r_xprt); 461 462 int rpcrdma_post_sends(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 463 void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp); 464 465 /* 466 * Buffer calls - xprtrdma/verbs.c 467 */ 468 struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, size_t size, 469 gfp_t flags); 470 int rpcrdma_req_setup(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 471 void rpcrdma_req_destroy(struct rpcrdma_req *req); 472 int rpcrdma_buffer_create(struct rpcrdma_xprt *); 473 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *); 474 struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt); 475 476 struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt); 477 void rpcrdma_mrs_refresh(struct rpcrdma_xprt *r_xprt); 478 479 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *); 480 void rpcrdma_buffer_put(struct rpcrdma_buffer *buffers, 481 struct rpcrdma_req *req); 482 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *); 483 484 bool rpcrdma_regbuf_realloc(struct rpcrdma_regbuf *rb, size_t size, 485 gfp_t flags); 486 bool __rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt, 487 struct rpcrdma_regbuf *rb); 488 489 /** 490 * rpcrdma_regbuf_is_mapped - check if buffer is DMA mapped 491 * 492 * Returns true if the buffer is now mapped to rb->rg_device. 493 */ 494 static inline bool rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb) 495 { 496 return rb->rg_device != NULL; 497 } 498 499 /** 500 * rpcrdma_regbuf_dma_map - DMA-map a regbuf 501 * @r_xprt: controlling transport instance 502 * @rb: regbuf to be mapped 503 * 504 * Returns true if the buffer is currently DMA mapped. 505 */ 506 static inline bool rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt, 507 struct rpcrdma_regbuf *rb) 508 { 509 if (likely(rpcrdma_regbuf_is_mapped(rb))) 510 return true; 511 return __rpcrdma_regbuf_dma_map(r_xprt, rb); 512 } 513 514 /* 515 * Wrappers for chunk registration, shared by read/write chunk code. 516 */ 517 518 static inline enum dma_data_direction 519 rpcrdma_data_dir(bool writing) 520 { 521 return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE; 522 } 523 524 /* Memory registration calls xprtrdma/frwr_ops.c 525 */ 526 void frwr_reset(struct rpcrdma_req *req); 527 int frwr_query_device(struct rpcrdma_ep *ep, const struct ib_device *device); 528 int frwr_mr_init(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr); 529 void frwr_release_mr(struct rpcrdma_mr *mr); 530 struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt, 531 struct rpcrdma_mr_seg *seg, 532 int nsegs, bool writing, __be32 xid, 533 struct rpcrdma_mr *mr); 534 int frwr_send(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 535 void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs); 536 void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 537 void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 538 539 /* 540 * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c 541 */ 542 543 enum rpcrdma_chunktype { 544 rpcrdma_noch = 0, 545 rpcrdma_noch_pullup, 546 rpcrdma_noch_mapped, 547 rpcrdma_readch, 548 rpcrdma_areadch, 549 rpcrdma_writech, 550 rpcrdma_replych 551 }; 552 553 int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt, 554 struct rpcrdma_req *req, u32 hdrlen, 555 struct xdr_buf *xdr, 556 enum rpcrdma_chunktype rtype); 557 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc); 558 int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst); 559 void rpcrdma_set_max_header_sizes(struct rpcrdma_ep *ep); 560 void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt); 561 void rpcrdma_complete_rqst(struct rpcrdma_rep *rep); 562 void rpcrdma_reply_handler(struct rpcrdma_rep *rep); 563 564 static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len) 565 { 566 xdr->head[0].iov_len = len; 567 xdr->len = len; 568 } 569 570 /* RPC/RDMA module init - xprtrdma/transport.c 571 */ 572 extern unsigned int xprt_rdma_max_inline_read; 573 extern unsigned int xprt_rdma_max_inline_write; 574 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap); 575 void xprt_rdma_free_addresses(struct rpc_xprt *xprt); 576 void xprt_rdma_close(struct rpc_xprt *xprt); 577 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq); 578 int xprt_rdma_init(void); 579 void xprt_rdma_cleanup(void); 580 581 /* Backchannel calls - xprtrdma/backchannel.c 582 */ 583 #if defined(CONFIG_SUNRPC_BACKCHANNEL) 584 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int); 585 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *); 586 unsigned int xprt_rdma_bc_max_slots(struct rpc_xprt *); 587 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int); 588 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *); 589 int xprt_rdma_bc_send_reply(struct rpc_rqst *rqst); 590 void xprt_rdma_bc_free_rqst(struct rpc_rqst *); 591 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int); 592 #endif /* CONFIG_SUNRPC_BACKCHANNEL */ 593 594 extern struct xprt_class xprt_rdma_bc; 595 596 #endif /* _LINUX_SUNRPC_XPRT_RDMA_H */ 597