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         rwlock_t                ri_qplock;
  69         struct ib_device        *ri_device;
  70         struct rdma_cm_id       *ri_id;
  71         struct ib_pd            *ri_pd;
  72         struct ib_mr            *ri_dma_mr;
  73         struct completion       ri_done;
  74         int                     ri_async_rc;
  75         unsigned int            ri_max_frmr_depth;
  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 /*
 148  * struct rpcrdma_rep -- this structure encapsulates state required to recv
 149  * and complete a reply, asychronously. It needs several pieces of
 150  * state:
 151  *   o recv buffer (posted to provider)
 152  *   o ib_sge (also donated to provider)
 153  *   o status of reply (length, success or not)
 154  *   o bookkeeping state to get run by tasklet (list, etc)
 155  *
 156  * These are allocated during initialization, per-transport instance;
 157  * however, the tasklet execution list itself is global, as it should
 158  * always be pretty short.
 159  *
 160  * N of these are associated with a transport instance, and stored in
 161  * struct rpcrdma_buffer. N is the max number of outstanding requests.
 162  */
 163
 164 #define RPCRDMA_MAX_DATA_SEGS   ((1 * 1024 * 1024) / PAGE_SIZE)
 165 #define RPCRDMA_MAX_SEGS        (RPCRDMA_MAX_DATA_SEGS + 2) /* head+tail = 2 */
 166
 167 struct rpcrdma_buffer;
 168
 169 struct rpcrdma_rep {
 170         struct ib_cqe           rr_cqe;
 171         unsigned int            rr_len;
 172         struct ib_device        *rr_device;
 173         struct rpcrdma_xprt     *rr_rxprt;
 174         struct work_struct      rr_work;
 175         struct list_head        rr_list;
 176         struct rpcrdma_regbuf   *rr_rdmabuf;
 177 };
 178
 179 #define RPCRDMA_BAD_LEN         (~0U)
 180
 181 /*
 182  * struct rpcrdma_mw - external memory region metadata
 183  *
 184  * An external memory region is any buffer or page that is registered
 185  * on the fly (ie, not pre-registered).
 186  *
 187  * Each rpcrdma_buffer has a list of free MWs anchored in rb_mws. During
 188  * call_allocate, rpcrdma_buffer_get() assigns one to each segment in
 189  * an rpcrdma_req. Then rpcrdma_register_external() grabs these to keep
 190  * track of registration metadata while each RPC is pending.
 191  * rpcrdma_deregister_external() uses this metadata to unmap and
 192  * release these resources when an RPC is complete.
 193  */
 194 enum rpcrdma_frmr_state {
 195         FRMR_IS_INVALID,        /* ready to be used */
 196         FRMR_IS_VALID,          /* in use */
 197         FRMR_IS_STALE,          /* failed completion */
 198 };
 199
 200 struct rpcrdma_frmr {
 201         struct scatterlist              *sg;
 202         int                             sg_nents;
 203         struct ib_mr                    *fr_mr;
 204         struct ib_cqe                   fr_cqe;
 205         enum rpcrdma_frmr_state         fr_state;
 206         struct completion               fr_linv_done;
 207         struct work_struct              fr_work;
 208         struct rpcrdma_xprt             *fr_xprt;
 209         union {
 210                 struct ib_reg_wr        fr_regwr;
 211                 struct ib_send_wr       fr_invwr;
 212         };
 213 };
 214
 215 struct rpcrdma_fmr {
 216         struct ib_fmr           *fmr;
 217         u64                     *physaddrs;
 218 };
 219
 220 struct rpcrdma_mw {
 221         union {
 222                 struct rpcrdma_fmr      fmr;
 223                 struct rpcrdma_frmr     frmr;
 224         };
 225         struct list_head        mw_list;
 226         struct list_head        mw_all;
 227 };
 228
 229 /*
 230  * struct rpcrdma_req -- structure central to the request/reply sequence.
 231  *
 232  * N of these are associated with a transport instance, and stored in
 233  * struct rpcrdma_buffer. N is the max number of outstanding requests.
 234  *
 235  * It includes pre-registered buffer memory for send AND recv.
 236  * The recv buffer, however, is not owned by this structure, and
 237  * is "donated" to the hardware when a recv is posted. When a
 238  * reply is handled, the recv buffer used is given back to the
 239  * struct rpcrdma_req associated with the request.
 240  *
 241  * In addition to the basic memory, this structure includes an array
 242  * of iovs for send operations. The reason is that the iovs passed to
 243  * ib_post_{send,recv} must not be modified until the work request
 244  * completes.
 245  *
 246  * NOTES:
 247  *   o RPCRDMA_MAX_SEGS is the max number of addressible chunk elements we
 248  *     marshal. The number needed varies depending on the iov lists that
 249  *     are passed to us, the memory registration mode we are in, and if
 250  *     physical addressing is used, the layout.
 251  */
 252
 253 struct rpcrdma_mr_seg {         /* chunk descriptors */
 254         struct rpcrdma_mw *rl_mw;       /* registered MR */
 255         u64             mr_base;        /* registration result */
 256         u32             mr_rkey;        /* registration result */
 257         u32             mr_len;         /* length of chunk or segment */
 258         int             mr_nsegs;       /* number of segments in chunk or 0 */
 259         enum dma_data_direction mr_dir; /* segment mapping direction */
 260         dma_addr_t      mr_dma;         /* segment mapping address */
 261         size_t          mr_dmalen;      /* segment mapping length */
 262         struct page     *mr_page;       /* owning page, if any */
 263         char            *mr_offset;     /* kva if no page, else offset */
 264 };
 265
 266 #define RPCRDMA_MAX_IOVS        (2)
 267
 268 struct rpcrdma_req {
 269         struct list_head        rl_free;
 270         unsigned int            rl_niovs;
 271         unsigned int            rl_nchunks;
 272         unsigned int            rl_connect_cookie;
 273         struct rpcrdma_buffer   *rl_buffer;
 274         struct rpcrdma_rep      *rl_reply;/* holder for reply buffer */
 275         struct ib_sge           rl_send_iov[RPCRDMA_MAX_IOVS];
 276         struct rpcrdma_regbuf   *rl_rdmabuf;
 277         struct rpcrdma_regbuf   *rl_sendbuf;
 278         struct rpcrdma_mr_seg   rl_segments[RPCRDMA_MAX_SEGS];
 279
 280         struct ib_cqe           rl_cqe;
 281         struct list_head        rl_all;
 282         bool                    rl_backchannel;
 283 };
 284
 285 static inline struct rpcrdma_req *
 286 rpcr_to_rdmar(struct rpc_rqst *rqst)
 287 {
 288         void *buffer = rqst->rq_buffer;
 289         struct rpcrdma_regbuf *rb;
 290
 291         rb = container_of(buffer, struct rpcrdma_regbuf, rg_base);
 292         return rb->rg_owner;
 293 }
 294
 295 /*
 296  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
 297  * inline requests/replies, and client/server credits.
 298  *
 299  * One of these is associated with a transport instance
 300  */
 301 struct rpcrdma_buffer {
 302         spinlock_t              rb_mwlock;      /* protect rb_mws list */
 303         struct list_head        rb_mws;
 304         struct list_head        rb_all;
 305         char                    *rb_pool;
 306
 307         spinlock_t              rb_lock;        /* protect buf lists */
 308         struct list_head        rb_send_bufs;
 309         struct list_head        rb_recv_bufs;
 310         u32                     rb_max_requests;
 311         atomic_t                rb_credits;     /* most recent credit grant */
 312
 313         u32                     rb_bc_srv_max_requests;
 314         spinlock_t              rb_reqslock;    /* protect rb_allreqs */
 315         struct list_head        rb_allreqs;
 316
 317         u32                     rb_bc_max_requests;
 318 };
 319 #define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)
 320
 321 /*
 322  * Internal structure for transport instance creation. This
 323  * exists primarily for modularity.
 324  *
 325  * This data should be set with mount options
 326  */
 327 struct rpcrdma_create_data_internal {
 328         struct sockaddr_storage addr;   /* RDMA server address */
 329         unsigned int    max_requests;   /* max requests (slots) in flight */
 330         unsigned int    rsize;          /* mount rsize - max read hdr+data */
 331         unsigned int    wsize;          /* mount wsize - max write hdr+data */
 332         unsigned int    inline_rsize;   /* max non-rdma read data payload */
 333         unsigned int    inline_wsize;   /* max non-rdma write data payload */
 334         unsigned int    padding;        /* non-rdma write header padding */
 335 };
 336
 337 #define RPCRDMA_INLINE_READ_THRESHOLD(rq) \
 338         (rpcx_to_rdmad(rq->rq_xprt).inline_rsize)
 339
 340 #define RPCRDMA_INLINE_WRITE_THRESHOLD(rq)\
 341         (rpcx_to_rdmad(rq->rq_xprt).inline_wsize)
 342
 343 #define RPCRDMA_INLINE_PAD_VALUE(rq)\
 344         rpcx_to_rdmad(rq->rq_xprt).padding
 345
 346 /*
 347  * Statistics for RPCRDMA
 348  */
 349 struct rpcrdma_stats {
 350         unsigned long           read_chunk_count;
 351         unsigned long           write_chunk_count;
 352         unsigned long           reply_chunk_count;
 353
 354         unsigned long long      total_rdma_request;
 355         unsigned long long      total_rdma_reply;
 356
 357         unsigned long long      pullup_copy_count;
 358         unsigned long long      fixup_copy_count;
 359         unsigned long           hardway_register_count;
 360         unsigned long           failed_marshal_count;
 361         unsigned long           bad_reply_count;
 362         unsigned long           nomsg_call_count;
 363         unsigned long           bcall_count;
 364 };
 365
 366 /*
 367  * Per-registration mode operations
 368  */
 369 struct rpcrdma_xprt;
 370 struct rpcrdma_memreg_ops {
 371         int             (*ro_map)(struct rpcrdma_xprt *,
 372                                   struct rpcrdma_mr_seg *, int, bool);
 373         void            (*ro_unmap_sync)(struct rpcrdma_xprt *,
 374                                          struct rpcrdma_req *);
 375         int             (*ro_unmap)(struct rpcrdma_xprt *,
 376                                     struct rpcrdma_mr_seg *);
 377         int             (*ro_open)(struct rpcrdma_ia *,
 378                                    struct rpcrdma_ep *,
 379                                    struct rpcrdma_create_data_internal *);
 380         size_t          (*ro_maxpages)(struct rpcrdma_xprt *);
 381         int             (*ro_init)(struct rpcrdma_xprt *);
 382         void            (*ro_destroy)(struct rpcrdma_buffer *);
 383         const char      *ro_displayname;
 384 };
 385
 386 extern const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops;
 387 extern const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops;
 388 extern const struct rpcrdma_memreg_ops rpcrdma_physical_memreg_ops;
 389
 390 /*
 391  * RPCRDMA transport -- encapsulates the structures above for
 392  * integration with RPC.
 393  *
 394  * The contained structures are embedded, not pointers,
 395  * for convenience. This structure need not be visible externally.
 396  *
 397  * It is allocated and initialized during mount, and released
 398  * during unmount.
 399  */
 400 struct rpcrdma_xprt {
 401         struct rpc_xprt         rx_xprt;
 402         struct rpcrdma_ia       rx_ia;
 403         struct rpcrdma_ep       rx_ep;
 404         struct rpcrdma_buffer   rx_buf;
 405         struct rpcrdma_create_data_internal rx_data;
 406         struct delayed_work     rx_connect_worker;
 407         struct rpcrdma_stats    rx_stats;
 408 };
 409
 410 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
 411 #define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
 412
 413 /* Setting this to 0 ensures interoperability with early servers.
 414  * Setting this to 1 enhances certain unaligned read/write performance.
 415  * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
 416 extern int xprt_rdma_pad_optimize;
 417
 418 /*
 419  * Interface Adapter calls - xprtrdma/verbs.c
 420  */
 421 int rpcrdma_ia_open(struct rpcrdma_xprt *, struct sockaddr *, int);
 422 void rpcrdma_ia_close(struct rpcrdma_ia *);
 423
 424 /*
 425  * Endpoint calls - xprtrdma/verbs.c
 426  */
 427 int rpcrdma_ep_create(struct rpcrdma_ep *, struct rpcrdma_ia *,
 428                                 struct rpcrdma_create_data_internal *);
 429 void rpcrdma_ep_destroy(struct rpcrdma_ep *, struct rpcrdma_ia *);
 430 int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
 431 void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
 432
 433 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
 434                                 struct rpcrdma_req *);
 435 int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_ep *,
 436                                 struct rpcrdma_rep *);
 437
 438 /*
 439  * Buffer calls - xprtrdma/verbs.c
 440  */
 441 struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
 442 struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);
 443 void rpcrdma_destroy_req(struct rpcrdma_ia *, struct rpcrdma_req *);
 444 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
 445 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
 446
 447 struct rpcrdma_mw *rpcrdma_get_mw(struct rpcrdma_xprt *);
 448 void rpcrdma_put_mw(struct rpcrdma_xprt *, struct rpcrdma_mw *);
 449 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
 450 void rpcrdma_buffer_put(struct rpcrdma_req *);
 451 void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
 452 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
 453
 454 struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(struct rpcrdma_ia *,
 455                                             size_t, gfp_t);
 456 void rpcrdma_free_regbuf(struct rpcrdma_ia *,
 457                          struct rpcrdma_regbuf *);
 458
 459 unsigned int rpcrdma_max_segments(struct rpcrdma_xprt *);
 460 int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *, unsigned int);
 461
 462 int frwr_alloc_recovery_wq(void);
 463 void frwr_destroy_recovery_wq(void);
 464
 465 int rpcrdma_alloc_wq(void);
 466 void rpcrdma_destroy_wq(void);
 467
 468 /*
 469  * Wrappers for chunk registration, shared by read/write chunk code.
 470  */
 471
 472 void rpcrdma_mapping_error(struct rpcrdma_mr_seg *);
 473
 474 static inline enum dma_data_direction
 475 rpcrdma_data_dir(bool writing)
 476 {
 477         return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 478 }
 479
 480 static inline void
 481 rpcrdma_map_one(struct ib_device *device, struct rpcrdma_mr_seg *seg,
 482                 enum dma_data_direction direction)
 483 {
 484         seg->mr_dir = direction;
 485         seg->mr_dmalen = seg->mr_len;
 486
 487         if (seg->mr_page)
 488                 seg->mr_dma = ib_dma_map_page(device,
 489                                 seg->mr_page, offset_in_page(seg->mr_offset),
 490                                 seg->mr_dmalen, seg->mr_dir);
 491         else
 492                 seg->mr_dma = ib_dma_map_single(device,
 493                                 seg->mr_offset,
 494                                 seg->mr_dmalen, seg->mr_dir);
 495
 496         if (ib_dma_mapping_error(device, seg->mr_dma))
 497                 rpcrdma_mapping_error(seg);
 498 }
 499
 500 static inline void
 501 rpcrdma_unmap_one(struct ib_device *device, struct rpcrdma_mr_seg *seg)
 502 {
 503         if (seg->mr_page)
 504                 ib_dma_unmap_page(device,
 505                                   seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
 506         else
 507                 ib_dma_unmap_single(device,
 508                                     seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
 509 }
 510
 511 /*
 512  * RPC/RDMA connection management calls - xprtrdma/rpc_rdma.c
 513  */
 514 void rpcrdma_connect_worker(struct work_struct *);
 515 void rpcrdma_conn_func(struct rpcrdma_ep *);
 516 void rpcrdma_reply_handler(struct rpcrdma_rep *);
 517
 518 /*
 519  * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
 520  */
 521 int rpcrdma_marshal_req(struct rpc_rqst *);
 522
 523 /* RPC/RDMA module init - xprtrdma/transport.c
 524  */
 525 extern unsigned int xprt_rdma_max_inline_read;
 526 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
 527 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
 528 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
 529 int xprt_rdma_init(void);
 530 void xprt_rdma_cleanup(void);
 531
 532 /* Backchannel calls - xprtrdma/backchannel.c
 533  */
 534 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 535 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
 536 int xprt_rdma_bc_up(struct svc_serv *, struct net *);
 537 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
 538 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
 539 int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
 540 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
 541 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
 542 #endif  /* CONFIG_SUNRPC_BACKCHANNEL */
 543
 544 extern struct xprt_class xprt_rdma_bc;
 545
 546 #endif                          /* _LINUX_SUNRPC_XPRT_RDMA_H */