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_receiving; 87 atomic_t re_force_disconnect; 88 struct ib_qp_init_attr re_attr; 89 wait_queue_head_t re_connect_wait; 90 struct rpc_xprt *re_xprt; 91 struct rpcrdma_connect_private 92 re_cm_private; 93 struct rdma_conn_param re_remote_cma; 94 int re_receive_count; 95 unsigned int re_max_requests; /* depends on device */ 96 unsigned int re_inline_send; /* negotiated */ 97 unsigned int re_inline_recv; /* negotiated */ 98 99 atomic_t re_completion_ids; 100 }; 101 102 /* Pre-allocate extra Work Requests for handling reverse-direction 103 * Receives and Sends. This is a fixed value because the Work Queues 104 * are allocated when the forward channel is set up, long before the 105 * backchannel is provisioned. This value is two times 106 * NFS4_DEF_CB_SLOT_TABLE_SIZE. 107 */ 108 #if defined(CONFIG_SUNRPC_BACKCHANNEL) 109 #define RPCRDMA_BACKWARD_WRS (32) 110 #else 111 #define RPCRDMA_BACKWARD_WRS (0) 112 #endif 113 114 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV 115 */ 116 117 struct rpcrdma_regbuf { 118 struct ib_sge rg_iov; 119 struct ib_device *rg_device; 120 enum dma_data_direction rg_direction; 121 void *rg_data; 122 }; 123 124 static inline u64 rdmab_addr(struct rpcrdma_regbuf *rb) 125 { 126 return rb->rg_iov.addr; 127 } 128 129 static inline u32 rdmab_length(struct rpcrdma_regbuf *rb) 130 { 131 return rb->rg_iov.length; 132 } 133 134 static inline u32 rdmab_lkey(struct rpcrdma_regbuf *rb) 135 { 136 return rb->rg_iov.lkey; 137 } 138 139 static inline struct ib_device *rdmab_device(struct rpcrdma_regbuf *rb) 140 { 141 return rb->rg_device; 142 } 143 144 static inline void *rdmab_data(const struct rpcrdma_regbuf *rb) 145 { 146 return rb->rg_data; 147 } 148 149 #define RPCRDMA_DEF_GFP (GFP_NOIO | __GFP_NOWARN) 150 151 /* To ensure a transport can always make forward progress, 152 * the number of RDMA segments allowed in header chunk lists 153 * is capped at 16. This prevents less-capable devices from 154 * overrunning the Send buffer while building chunk lists. 155 * 156 * Elements of the Read list take up more room than the 157 * Write list or Reply chunk. 16 read segments means the 158 * chunk lists cannot consume more than 159 * 160 * ((16 + 2) * read segment size) + 1 XDR words, 161 * 162 * or about 400 bytes. The fixed part of the header is 163 * another 24 bytes. Thus when the inline threshold is 164 * 1024 bytes, at least 600 bytes are available for RPC 165 * message bodies. 166 */ 167 enum { 168 RPCRDMA_MAX_HDR_SEGS = 16, 169 }; 170 171 /* 172 * struct rpcrdma_rep -- this structure encapsulates state required 173 * to receive and complete an RPC Reply, asychronously. It needs 174 * several pieces of state: 175 * 176 * o receive buffer and ib_sge (donated to provider) 177 * o status of receive (success or not, length, inv rkey) 178 * o bookkeeping state to get run by reply handler (XDR stream) 179 * 180 * These structures are allocated during transport initialization. 181 * N of these are associated with a transport instance, managed by 182 * struct rpcrdma_buffer. N is the max number of outstanding RPCs. 183 */ 184 185 struct rpcrdma_rep { 186 struct ib_cqe rr_cqe; 187 struct rpc_rdma_cid rr_cid; 188 189 __be32 rr_xid; 190 __be32 rr_vers; 191 __be32 rr_proc; 192 int rr_wc_flags; 193 u32 rr_inv_rkey; 194 bool rr_temp; 195 struct rpcrdma_regbuf *rr_rdmabuf; 196 struct rpcrdma_xprt *rr_rxprt; 197 struct rpc_rqst *rr_rqst; 198 struct xdr_buf rr_hdrbuf; 199 struct xdr_stream rr_stream; 200 struct llist_node rr_node; 201 struct ib_recv_wr rr_recv_wr; 202 struct list_head rr_all; 203 }; 204 205 /* To reduce the rate at which a transport invokes ib_post_recv 206 * (and thus the hardware doorbell rate), xprtrdma posts Receive 207 * WRs in batches. 208 * 209 * Setting this to zero disables Receive post batching. 210 */ 211 enum { 212 RPCRDMA_MAX_RECV_BATCH = 7, 213 }; 214 215 /* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes 216 */ 217 struct rpcrdma_req; 218 struct rpcrdma_sendctx { 219 struct ib_cqe sc_cqe; 220 struct rpc_rdma_cid sc_cid; 221 struct rpcrdma_req *sc_req; 222 unsigned int sc_unmap_count; 223 struct ib_sge sc_sges[]; 224 }; 225 226 /* 227 * struct rpcrdma_mr - external memory region metadata 228 * 229 * An external memory region is any buffer or page that is registered 230 * on the fly (ie, not pre-registered). 231 */ 232 struct rpcrdma_req; 233 struct rpcrdma_mr { 234 struct list_head mr_list; 235 struct rpcrdma_req *mr_req; 236 237 struct ib_mr *mr_ibmr; 238 struct ib_device *mr_device; 239 struct scatterlist *mr_sg; 240 int mr_nents; 241 enum dma_data_direction mr_dir; 242 struct ib_cqe mr_cqe; 243 struct completion mr_linv_done; 244 union { 245 struct ib_reg_wr mr_regwr; 246 struct ib_send_wr mr_invwr; 247 }; 248 struct rpcrdma_xprt *mr_xprt; 249 u32 mr_handle; 250 u32 mr_length; 251 u64 mr_offset; 252 struct list_head mr_all; 253 struct rpc_rdma_cid mr_cid; 254 }; 255 256 /* 257 * struct rpcrdma_req -- structure central to the request/reply sequence. 258 * 259 * N of these are associated with a transport instance, and stored in 260 * struct rpcrdma_buffer. N is the max number of outstanding requests. 261 * 262 * It includes pre-registered buffer memory for send AND recv. 263 * The recv buffer, however, is not owned by this structure, and 264 * is "donated" to the hardware when a recv is posted. When a 265 * reply is handled, the recv buffer used is given back to the 266 * struct rpcrdma_req associated with the request. 267 * 268 * In addition to the basic memory, this structure includes an array 269 * of iovs for send operations. The reason is that the iovs passed to 270 * ib_post_{send,recv} must not be modified until the work request 271 * completes. 272 */ 273 274 /* Maximum number of page-sized "segments" per chunk list to be 275 * registered or invalidated. Must handle a Reply chunk: 276 */ 277 enum { 278 RPCRDMA_MAX_IOV_SEGS = 3, 279 RPCRDMA_MAX_DATA_SEGS = ((1 * 1024 * 1024) / PAGE_SIZE) + 1, 280 RPCRDMA_MAX_SEGS = RPCRDMA_MAX_DATA_SEGS + 281 RPCRDMA_MAX_IOV_SEGS, 282 }; 283 284 /* Arguments for DMA mapping and registration */ 285 struct rpcrdma_mr_seg { 286 u32 mr_len; /* length of segment */ 287 struct page *mr_page; /* underlying struct page */ 288 u64 mr_offset; /* IN: page offset, OUT: iova */ 289 }; 290 291 /* The Send SGE array is provisioned to send a maximum size 292 * inline request: 293 * - RPC-over-RDMA header 294 * - xdr_buf head iovec 295 * - RPCRDMA_MAX_INLINE bytes, in pages 296 * - xdr_buf tail iovec 297 * 298 * The actual number of array elements consumed by each RPC 299 * depends on the device's max_sge limit. 300 */ 301 enum { 302 RPCRDMA_MIN_SEND_SGES = 3, 303 RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT, 304 RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1, 305 }; 306 307 struct rpcrdma_buffer; 308 struct rpcrdma_req { 309 struct list_head rl_list; 310 struct rpc_rqst rl_slot; 311 struct rpcrdma_rep *rl_reply; 312 struct xdr_stream rl_stream; 313 struct xdr_buf rl_hdrbuf; 314 struct ib_send_wr rl_wr; 315 struct rpcrdma_sendctx *rl_sendctx; 316 struct rpcrdma_regbuf *rl_rdmabuf; /* xprt header */ 317 struct rpcrdma_regbuf *rl_sendbuf; /* rq_snd_buf */ 318 struct rpcrdma_regbuf *rl_recvbuf; /* rq_rcv_buf */ 319 320 struct list_head rl_all; 321 struct kref rl_kref; 322 323 struct list_head rl_free_mrs; 324 struct list_head rl_registered; 325 struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS]; 326 }; 327 328 static inline struct rpcrdma_req * 329 rpcr_to_rdmar(const struct rpc_rqst *rqst) 330 { 331 return container_of(rqst, struct rpcrdma_req, rl_slot); 332 } 333 334 static inline void 335 rpcrdma_mr_push(struct rpcrdma_mr *mr, struct list_head *list) 336 { 337 list_add(&mr->mr_list, list); 338 } 339 340 static inline struct rpcrdma_mr * 341 rpcrdma_mr_pop(struct list_head *list) 342 { 343 struct rpcrdma_mr *mr; 344 345 mr = list_first_entry_or_null(list, struct rpcrdma_mr, mr_list); 346 if (mr) 347 list_del_init(&mr->mr_list); 348 return mr; 349 } 350 351 /* 352 * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for 353 * inline requests/replies, and client/server credits. 354 * 355 * One of these is associated with a transport instance 356 */ 357 struct rpcrdma_buffer { 358 spinlock_t rb_lock; 359 struct list_head rb_send_bufs; 360 struct list_head rb_mrs; 361 362 unsigned long rb_sc_head; 363 unsigned long rb_sc_tail; 364 unsigned long rb_sc_last; 365 struct rpcrdma_sendctx **rb_sc_ctxs; 366 367 struct list_head rb_allreqs; 368 struct list_head rb_all_mrs; 369 struct list_head rb_all_reps; 370 371 struct llist_head rb_free_reps; 372 373 __be32 rb_max_requests; 374 u32 rb_credits; /* most recent credit grant */ 375 376 u32 rb_bc_srv_max_requests; 377 u32 rb_bc_max_requests; 378 379 struct work_struct rb_refresh_worker; 380 }; 381 382 /* 383 * Statistics for RPCRDMA 384 */ 385 struct rpcrdma_stats { 386 /* accessed when sending a call */ 387 unsigned long read_chunk_count; 388 unsigned long write_chunk_count; 389 unsigned long reply_chunk_count; 390 unsigned long long total_rdma_request; 391 392 /* rarely accessed error counters */ 393 unsigned long long pullup_copy_count; 394 unsigned long hardway_register_count; 395 unsigned long failed_marshal_count; 396 unsigned long bad_reply_count; 397 unsigned long mrs_recycled; 398 unsigned long mrs_orphaned; 399 unsigned long mrs_allocated; 400 unsigned long empty_sendctx_q; 401 402 /* accessed when receiving a reply */ 403 unsigned long long total_rdma_reply; 404 unsigned long long fixup_copy_count; 405 unsigned long reply_waits_for_send; 406 unsigned long local_inv_needed; 407 unsigned long nomsg_call_count; 408 unsigned long bcall_count; 409 }; 410 411 /* 412 * RPCRDMA transport -- encapsulates the structures above for 413 * integration with RPC. 414 * 415 * The contained structures are embedded, not pointers, 416 * for convenience. This structure need not be visible externally. 417 * 418 * It is allocated and initialized during mount, and released 419 * during unmount. 420 */ 421 struct rpcrdma_xprt { 422 struct rpc_xprt rx_xprt; 423 struct rpcrdma_ep *rx_ep; 424 struct rpcrdma_buffer rx_buf; 425 struct delayed_work rx_connect_worker; 426 struct rpc_timeout rx_timeout; 427 struct rpcrdma_stats rx_stats; 428 }; 429 430 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt) 431 432 static inline const char * 433 rpcrdma_addrstr(const struct rpcrdma_xprt *r_xprt) 434 { 435 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_ADDR]; 436 } 437 438 static inline const char * 439 rpcrdma_portstr(const struct rpcrdma_xprt *r_xprt) 440 { 441 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_PORT]; 442 } 443 444 /* Setting this to 0 ensures interoperability with early servers. 445 * Setting this to 1 enhances certain unaligned read/write performance. 446 * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */ 447 extern int xprt_rdma_pad_optimize; 448 449 /* This setting controls the hunt for a supported memory 450 * registration strategy. 451 */ 452 extern unsigned int xprt_rdma_memreg_strategy; 453 454 /* 455 * Endpoint calls - xprtrdma/verbs.c 456 */ 457 void rpcrdma_flush_disconnect(struct rpcrdma_xprt *r_xprt, struct ib_wc *wc); 458 int rpcrdma_xprt_connect(struct rpcrdma_xprt *r_xprt); 459 void rpcrdma_xprt_disconnect(struct rpcrdma_xprt *r_xprt); 460 461 int rpcrdma_post_sends(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 462 void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, int needed, bool temp); 463 464 /* 465 * Buffer calls - xprtrdma/verbs.c 466 */ 467 struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, size_t size, 468 gfp_t flags); 469 int rpcrdma_req_setup(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req); 470 void rpcrdma_req_destroy(struct rpcrdma_req *req); 471 int rpcrdma_buffer_create(struct rpcrdma_xprt *); 472 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *); 473 struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt); 474 475 struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt); 476 void rpcrdma_mrs_refresh(struct rpcrdma_xprt *r_xprt); 477 478 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *); 479 void rpcrdma_buffer_put(struct rpcrdma_buffer *buffers, 480 struct rpcrdma_req *req); 481 void rpcrdma_rep_put(struct rpcrdma_buffer *buf, struct rpcrdma_rep *rep); 482 void rpcrdma_reply_put(struct rpcrdma_buffer *buffers, struct rpcrdma_req *req); 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_mr_release(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_unpin_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