net/sunrpc/xprtrdma/xprt_rdma.h

   1 /*
   2  * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the BSD-type
   8  * license below:
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  *
  14  *      Redistributions of source code must retain the above copyright
  15  *      notice, this list of conditions and the following disclaimer.
  16  *
  17  *      Redistributions in binary form must reproduce the above
  18  *      copyright notice, this list of conditions and the following
  19  *      disclaimer in the documentation and/or other materials provided
  20  *      with the distribution.
  21  *
  22  *      Neither the name of the Network Appliance, Inc. nor the names of
  23  *      its contributors may be used to endorse or promote products
  24  *      derived from this software without specific prior written
  25  *      permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  30  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  31  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  32  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  33  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  37  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  38  */
  39
  40 #ifndef _LINUX_SUNRPC_XPRT_RDMA_H
  41 #define _LINUX_SUNRPC_XPRT_RDMA_H
  42
  43 #include <linux/wait.h>                 /* wait_queue_head_t, etc */
  44 #include <linux/spinlock.h>             /* spinlock_t, etc */
  45 #include <linux/atomic.h>                       /* atomic_t, etc */
  46 #include <linux/workqueue.h>            /* struct work_struct */
  47
  48 #include <rdma/rdma_cm.h>               /* RDMA connection api */
  49 #include <rdma/ib_verbs.h>              /* RDMA verbs api */
  50
  51 #include <linux/sunrpc/clnt.h>          /* rpc_xprt */
  52 #include <linux/sunrpc/rpc_rdma.h>      /* RPC/RDMA protocol */
  53 #include <linux/sunrpc/xprtrdma.h>      /* xprt parameters */
  54
  55 #define RDMA_RESOLVE_TIMEOUT    (5000)  /* 5 seconds */
  56 #define RDMA_CONNECT_RETRY_MAX  (2)     /* retries if no listener backlog */
  57
  58 #define RPCRDMA_BIND_TO         (60U * HZ)
  59 #define RPCRDMA_INIT_REEST_TO   (5U * HZ)
  60 #define RPCRDMA_MAX_REEST_TO    (30U * HZ)
  61 #define RPCRDMA_IDLE_DISC_TO    (5U * 60 * HZ)
  62
  63 /*
  64  * Interface Adapter -- one per transport instance
  65  */
  66 struct rpcrdma_ia {
  67         const struct rpcrdma_memreg_ops *ri_ops;
  68         struct ib_device        *ri_device;
  69         struct rdma_cm_id       *ri_id;
  70         struct ib_pd            *ri_pd;
  71         struct completion       ri_done;
  72         int                     ri_async_rc;
  73         unsigned int            ri_max_frmr_depth;
  74         unsigned int            ri_max_inline_write;
  75         unsigned int            ri_max_inline_read;
  76         struct ib_qp_attr       ri_qp_attr;
  77         struct ib_qp_init_attr  ri_qp_init_attr;
  78 };
  79
  80 /*
  81  * RDMA Endpoint -- one per transport instance
  82  */
  83
  84 struct rpcrdma_ep {
  85         atomic_t                rep_cqcount;
  86         int                     rep_cqinit;
  87         int                     rep_connected;
  88         struct ib_qp_init_attr  rep_attr;
  89         wait_queue_head_t       rep_connect_wait;
  90         struct rdma_conn_param  rep_remote_cma;
  91         struct sockaddr_storage rep_remote_addr;
  92         struct delayed_work     rep_connect_worker;
  93 };
  94
  95 #define INIT_CQCOUNT(ep) atomic_set(&(ep)->rep_cqcount, (ep)->rep_cqinit)
  96 #define DECR_CQCOUNT(ep) atomic_sub_return(1, &(ep)->rep_cqcount)
  97
  98 /* Pre-allocate extra Work Requests for handling backward receives
  99  * and sends. This is a fixed value because the Work Queues are
 100  * allocated when the forward channel is set up.
 101  */
 102 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 103 #define RPCRDMA_BACKWARD_WRS            (8)
 104 #else
 105 #define RPCRDMA_BACKWARD_WRS            (0)
 106 #endif
 107
 108 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
 109  *
 110  * The below structure appears at the front of a large region of kmalloc'd
 111  * memory, which always starts on a good alignment boundary.
 112  */
 113
 114 struct rpcrdma_regbuf {
 115         size_t                  rg_size;
 116         struct rpcrdma_req      *rg_owner;
 117         struct ib_sge           rg_iov;
 118         __be32                  rg_base[0] __attribute__ ((aligned(256)));
 119 };
 120
 121 static inline u64
 122 rdmab_addr(struct rpcrdma_regbuf *rb)
 123 {
 124         return rb->rg_iov.addr;
 125 }
 126
 127 static inline u32
 128 rdmab_length(struct rpcrdma_regbuf *rb)
 129 {
 130         return rb->rg_iov.length;
 131 }
 132
 133 static inline u32
 134 rdmab_lkey(struct rpcrdma_regbuf *rb)
 135 {
 136         return rb->rg_iov.lkey;
 137 }
 138
 139 static inline struct rpcrdma_msg *
 140 rdmab_to_msg(struct rpcrdma_regbuf *rb)
 141 {
 142         return (struct rpcrdma_msg *)rb->rg_base;
 143 }
 144
 145 #define RPCRDMA_DEF_GFP         (GFP_NOIO | __GFP_NOWARN)
 146
 147 /* To ensure a transport can always make forward progress,
 148  * the number of RDMA segments allowed in header chunk lists
 149  * is capped at 8. This prevents less-capable devices and
 150  * memory registrations from overrunning the Send buffer
 151  * while building chunk lists.
 152  *
 153  * Elements of the Read list take up more room than the
 154  * Write list or Reply chunk. 8 read segments means the Read
 155  * list (or Write list or Reply chunk) cannot consume more
 156  * than
 157  *
 158  * ((8 + 2) * read segment size) + 1 XDR words, or 244 bytes.
 159  *
 160  * And the fixed part of the header is another 24 bytes.
 161  *
 162  * The smallest inline threshold is 1024 bytes, ensuring that
 163  * at least 750 bytes are available for RPC messages.
 164  */
 165 #define RPCRDMA_MAX_HDR_SEGS    (8)
 166
 167 /*
 168  * struct rpcrdma_rep -- this structure encapsulates state required to recv
 169  * and complete a reply, asychronously. It needs several pieces of
 170  * state:
 171  *   o recv buffer (posted to provider)
 172  *   o ib_sge (also donated to provider)
 173  *   o status of reply (length, success or not)
 174  *   o bookkeeping state to get run by reply handler (list, etc)
 175  *
 176  * These are allocated during initialization, per-transport instance.
 177  *
 178  * N of these are associated with a transport instance, and stored in
 179  * struct rpcrdma_buffer. N is the max number of outstanding requests.
 180  */
 181
 182 struct rpcrdma_rep {
 183         struct ib_cqe           rr_cqe;
 184         unsigned int            rr_len;
 185         struct ib_device        *rr_device;
 186         struct rpcrdma_xprt     *rr_rxprt;
 187         struct work_struct      rr_work;
 188         struct list_head        rr_list;
 189         struct rpcrdma_regbuf   *rr_rdmabuf;
 190 };
 191
 192 #define RPCRDMA_BAD_LEN         (~0U)
 193
 194 /*
 195  * struct rpcrdma_mw - external memory region metadata
 196  *
 197  * An external memory region is any buffer or page that is registered
 198  * on the fly (ie, not pre-registered).
 199  *
 200  * Each rpcrdma_buffer has a list of free MWs anchored in rb_mws. During
 201  * call_allocate, rpcrdma_buffer_get() assigns one to each segment in
 202  * an rpcrdma_req. Then rpcrdma_register_external() grabs these to keep
 203  * track of registration metadata while each RPC is pending.
 204  * rpcrdma_deregister_external() uses this metadata to unmap and
 205  * release these resources when an RPC is complete.
 206  */
 207 enum rpcrdma_frmr_state {
 208         FRMR_IS_INVALID,        /* ready to be used */
 209         FRMR_IS_VALID,          /* in use */
 210         FRMR_IS_STALE,          /* failed completion */
 211 };
 212
 213 struct rpcrdma_frmr {
 214         struct ib_mr                    *fr_mr;
 215         struct ib_cqe                   fr_cqe;
 216         enum rpcrdma_frmr_state         fr_state;
 217         struct completion               fr_linv_done;
 218         union {
 219                 struct ib_reg_wr        fr_regwr;
 220                 struct ib_send_wr       fr_invwr;
 221         };
 222 };
 223
 224 struct rpcrdma_fmr {
 225         struct ib_fmr           *fm_mr;
 226         u64                     *fm_physaddrs;
 227 };
 228
 229 struct rpcrdma_mw {
 230         struct list_head        mw_list;
 231         struct scatterlist      *mw_sg;
 232         int                     mw_nents;
 233         enum dma_data_direction mw_dir;
 234         union {
 235                 struct rpcrdma_fmr      fmr;
 236                 struct rpcrdma_frmr     frmr;
 237         };
 238         struct rpcrdma_xprt     *mw_xprt;
 239         u32                     mw_handle;
 240         u32                     mw_length;
 241         u64                     mw_offset;
 242         struct list_head        mw_all;
 243 };
 244
 245 /*
 246  * struct rpcrdma_req -- structure central to the request/reply sequence.
 247  *
 248  * N of these are associated with a transport instance, and stored in
 249  * struct rpcrdma_buffer. N is the max number of outstanding requests.
 250  *
 251  * It includes pre-registered buffer memory for send AND recv.
 252  * The recv buffer, however, is not owned by this structure, and
 253  * is "donated" to the hardware when a recv is posted. When a
 254  * reply is handled, the recv buffer used is given back to the
 255  * struct rpcrdma_req associated with the request.
 256  *
 257  * In addition to the basic memory, this structure includes an array
 258  * of iovs for send operations. The reason is that the iovs passed to
 259  * ib_post_{send,recv} must not be modified until the work request
 260  * completes.
 261  */
 262
 263 /* Maximum number of page-sized "segments" per chunk list to be
 264  * registered or invalidated. Must handle a Reply chunk:
 265  */
 266 enum {
 267         RPCRDMA_MAX_IOV_SEGS    = 3,
 268         RPCRDMA_MAX_DATA_SEGS   = ((1 * 1024 * 1024) / PAGE_SIZE) + 1,
 269         RPCRDMA_MAX_SEGS        = RPCRDMA_MAX_DATA_SEGS +
 270                                   RPCRDMA_MAX_IOV_SEGS,
 271 };
 272
 273 struct rpcrdma_mr_seg {         /* chunk descriptors */
 274         u32             mr_len;         /* length of chunk or segment */
 275         struct page     *mr_page;       /* owning page, if any */
 276         char            *mr_offset;     /* kva if no page, else offset */
 277 };
 278
 279 #define RPCRDMA_MAX_IOVS        (2)
 280
 281 struct rpcrdma_buffer;
 282 struct rpcrdma_req {
 283         struct list_head        rl_free;
 284         unsigned int            rl_niovs;
 285         unsigned int            rl_connect_cookie;
 286         struct rpc_task         *rl_task;
 287         struct rpcrdma_buffer   *rl_buffer;
 288         struct rpcrdma_rep      *rl_reply;/* holder for reply buffer */
 289         struct ib_sge           rl_send_iov[RPCRDMA_MAX_IOVS];
 290         struct rpcrdma_regbuf   *rl_rdmabuf;
 291         struct rpcrdma_regbuf   *rl_sendbuf;
 292
 293         struct ib_cqe           rl_cqe;
 294         struct list_head        rl_all;
 295         bool                    rl_backchannel;
 296
 297         struct list_head        rl_registered;  /* registered segments */
 298         struct rpcrdma_mr_seg   rl_segments[RPCRDMA_MAX_SEGS];
 299 };
 300
 301 static inline struct rpcrdma_req *
 302 rpcr_to_rdmar(struct rpc_rqst *rqst)
 303 {
 304         void *buffer = rqst->rq_buffer;
 305         struct rpcrdma_regbuf *rb;
 306
 307         rb = container_of(buffer, struct rpcrdma_regbuf, rg_base);
 308         return rb->rg_owner;
 309 }
 310
 311 /*
 312  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
 313  * inline requests/replies, and client/server credits.
 314  *
 315  * One of these is associated with a transport instance
 316  */
 317 struct rpcrdma_buffer {
 318         spinlock_t              rb_mwlock;      /* protect rb_mws list */
 319         struct list_head        rb_mws;
 320         struct list_head        rb_all;
 321         char                    *rb_pool;
 322
 323         spinlock_t              rb_lock;        /* protect buf lists */
 324         int                     rb_send_count, rb_recv_count;
 325         struct list_head        rb_send_bufs;
 326         struct list_head        rb_recv_bufs;
 327         u32                     rb_max_requests;
 328         atomic_t                rb_credits;     /* most recent credit grant */
 329
 330         u32                     rb_bc_srv_max_requests;
 331         spinlock_t              rb_reqslock;    /* protect rb_allreqs */
 332         struct list_head        rb_allreqs;
 333
 334         u32                     rb_bc_max_requests;
 335
 336         spinlock_t              rb_recovery_lock; /* protect rb_stale_mrs */
 337         struct list_head        rb_stale_mrs;
 338         struct delayed_work     rb_recovery_worker;
 339         struct delayed_work     rb_refresh_worker;
 340 };
 341 #define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)
 342
 343 /*
 344  * Internal structure for transport instance creation. This
 345  * exists primarily for modularity.
 346  *
 347  * This data should be set with mount options
 348  */
 349 struct rpcrdma_create_data_internal {
 350         struct sockaddr_storage addr;   /* RDMA server address */
 351         unsigned int    max_requests;   /* max requests (slots) in flight */
 352         unsigned int    rsize;          /* mount rsize - max read hdr+data */
 353         unsigned int    wsize;          /* mount wsize - max write hdr+data */
 354         unsigned int    inline_rsize;   /* max non-rdma read data payload */
 355         unsigned int    inline_wsize;   /* max non-rdma write data payload */
 356         unsigned int    padding;        /* non-rdma write header padding */
 357 };
 358
 359 #define RPCRDMA_INLINE_READ_THRESHOLD(rq) \
 360         (rpcx_to_rdmad(rq->rq_xprt).inline_rsize)
 361
 362 #define RPCRDMA_INLINE_WRITE_THRESHOLD(rq)\
 363         (rpcx_to_rdmad(rq->rq_xprt).inline_wsize)
 364
 365 #define RPCRDMA_INLINE_PAD_VALUE(rq)\
 366         rpcx_to_rdmad(rq->rq_xprt).padding
 367
 368 /*
 369  * Statistics for RPCRDMA
 370  */
 371 struct rpcrdma_stats {
 372         unsigned long           read_chunk_count;
 373         unsigned long           write_chunk_count;
 374         unsigned long           reply_chunk_count;
 375
 376         unsigned long long      total_rdma_request;
 377         unsigned long long      total_rdma_reply;
 378
 379         unsigned long long      pullup_copy_count;
 380         unsigned long long      fixup_copy_count;
 381         unsigned long           hardway_register_count;
 382         unsigned long           failed_marshal_count;
 383         unsigned long           bad_reply_count;
 384         unsigned long           nomsg_call_count;
 385         unsigned long           bcall_count;
 386         unsigned long           mrs_recovered;
 387         unsigned long           mrs_orphaned;
 388         unsigned long           mrs_allocated;
 389 };
 390
 391 /*
 392  * Per-registration mode operations
 393  */
 394 struct rpcrdma_xprt;
 395 struct rpcrdma_memreg_ops {
 396         int             (*ro_map)(struct rpcrdma_xprt *,
 397                                   struct rpcrdma_mr_seg *, int, bool,
 398                                   struct rpcrdma_mw **);
 399         void            (*ro_unmap_sync)(struct rpcrdma_xprt *,
 400                                          struct rpcrdma_req *);
 401         void            (*ro_unmap_safe)(struct rpcrdma_xprt *,
 402                                          struct rpcrdma_req *, bool);
 403         void            (*ro_recover_mr)(struct rpcrdma_mw *);
 404         int             (*ro_open)(struct rpcrdma_ia *,
 405                                    struct rpcrdma_ep *,
 406                                    struct rpcrdma_create_data_internal *);
 407         size_t          (*ro_maxpages)(struct rpcrdma_xprt *);
 408         int             (*ro_init_mr)(struct rpcrdma_ia *,
 409                                       struct rpcrdma_mw *);
 410         void            (*ro_release_mr)(struct rpcrdma_mw *);
 411         const char      *ro_displayname;
 412 };
 413
 414 extern const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops;
 415 extern const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops;
 416
 417 /*
 418  * RPCRDMA transport -- encapsulates the structures above for
 419  * integration with RPC.
 420  *
 421  * The contained structures are embedded, not pointers,
 422  * for convenience. This structure need not be visible externally.
 423  *
 424  * It is allocated and initialized during mount, and released
 425  * during unmount.
 426  */
 427 struct rpcrdma_xprt {
 428         struct rpc_xprt         rx_xprt;
 429         struct rpcrdma_ia       rx_ia;
 430         struct rpcrdma_ep       rx_ep;
 431         struct rpcrdma_buffer   rx_buf;
 432         struct rpcrdma_create_data_internal rx_data;
 433         struct delayed_work     rx_connect_worker;
 434         struct rpcrdma_stats    rx_stats;
 435 };
 436
 437 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
 438 #define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
 439
 440 /* Setting this to 0 ensures interoperability with early servers.
 441  * Setting this to 1 enhances certain unaligned read/write performance.
 442  * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
 443 extern int xprt_rdma_pad_optimize;
 444
 445 /*
 446  * Interface Adapter calls - xprtrdma/verbs.c
 447  */
 448 int rpcrdma_ia_open(struct rpcrdma_xprt *, struct sockaddr *, int);
 449 void rpcrdma_ia_close(struct rpcrdma_ia *);
 450 bool frwr_is_supported(struct rpcrdma_ia *);
 451 bool fmr_is_supported(struct rpcrdma_ia *);
 452
 453 /*
 454  * Endpoint calls - xprtrdma/verbs.c
 455  */
 456 int rpcrdma_ep_create(struct rpcrdma_ep *, struct rpcrdma_ia *,
 457                                 struct rpcrdma_create_data_internal *);
 458 void rpcrdma_ep_destroy(struct rpcrdma_ep *, struct rpcrdma_ia *);
 459 int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
 460 void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
 461
 462 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
 463                                 struct rpcrdma_req *);
 464 int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_ep *,
 465                                 struct rpcrdma_rep *);
 466
 467 /*
 468  * Buffer calls - xprtrdma/verbs.c
 469  */
 470 struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
 471 struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);
 472 void rpcrdma_destroy_req(struct rpcrdma_ia *, struct rpcrdma_req *);
 473 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
 474 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
 475
 476 struct rpcrdma_mw *rpcrdma_get_mw(struct rpcrdma_xprt *);
 477 void rpcrdma_put_mw(struct rpcrdma_xprt *, struct rpcrdma_mw *);
 478 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
 479 void rpcrdma_buffer_put(struct rpcrdma_req *);
 480 void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
 481 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
 482
 483 void rpcrdma_defer_mr_recovery(struct rpcrdma_mw *);
 484
 485 struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(struct rpcrdma_ia *,
 486                                             size_t, gfp_t);
 487 void rpcrdma_free_regbuf(struct rpcrdma_ia *,
 488                          struct rpcrdma_regbuf *);
 489
 490 int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *, unsigned int);
 491
 492 int rpcrdma_alloc_wq(void);
 493 void rpcrdma_destroy_wq(void);
 494
 495 /*
 496  * Wrappers for chunk registration, shared by read/write chunk code.
 497  */
 498
 499 static inline enum dma_data_direction
 500 rpcrdma_data_dir(bool writing)
 501 {
 502         return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 503 }
 504
 505 /*
 506  * RPC/RDMA connection management calls - xprtrdma/rpc_rdma.c
 507  */
 508 void rpcrdma_connect_worker(struct work_struct *);
 509 void rpcrdma_conn_func(struct rpcrdma_ep *);
 510 void rpcrdma_reply_handler(struct rpcrdma_rep *);
 511
 512 /*
 513  * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
 514  */
 515 int rpcrdma_marshal_req(struct rpc_rqst *);
 516 void rpcrdma_set_max_header_sizes(struct rpcrdma_ia *,
 517                                   struct rpcrdma_create_data_internal *,
 518                                   unsigned int);
 519
 520 /* RPC/RDMA module init - xprtrdma/transport.c
 521  */
 522 extern unsigned int xprt_rdma_max_inline_read;
 523 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
 524 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
 525 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
 526 int xprt_rdma_init(void);
 527 void xprt_rdma_cleanup(void);
 528
 529 /* Backchannel calls - xprtrdma/backchannel.c
 530  */
 531 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 532 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
 533 int xprt_rdma_bc_up(struct svc_serv *, struct net *);
 534 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *);
 535 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
 536 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
 537 int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
 538 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
 539 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
 540 #endif  /* CONFIG_SUNRPC_BACKCHANNEL */
 541
 542 extern struct xprt_class xprt_rdma_bc;
 543
 544 #endif                          /* _LINUX_SUNRPC_XPRT_RDMA_H */