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 /* Force completion handler to ignore the signal
  99  */
 100 #define RPCRDMA_IGNORE_COMPLETION       (0ULL)
 101
 102 /* Pre-allocate extra Work Requests for handling backward receives
 103  * and sends. This is a fixed value because the Work Queues are
 104  * allocated when the forward channel is set up.
 105  */
 106 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 107 #define RPCRDMA_BACKWARD_WRS            (8)
 108 #else
 109 #define RPCRDMA_BACKWARD_WRS            (0)
 110 #endif
 111
 112 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
 113  *
 114  * The below structure appears at the front of a large region of kmalloc'd
 115  * memory, which always starts on a good alignment boundary.
 116  */
 117
 118 struct rpcrdma_regbuf {
 119         size_t                  rg_size;
 120         struct rpcrdma_req      *rg_owner;
 121         struct ib_sge           rg_iov;
 122         __be32                  rg_base[0] __attribute__ ((aligned(256)));
 123 };
 124
 125 static inline u64
 126 rdmab_addr(struct rpcrdma_regbuf *rb)
 127 {
 128         return rb->rg_iov.addr;
 129 }
 130
 131 static inline u32
 132 rdmab_length(struct rpcrdma_regbuf *rb)
 133 {
 134         return rb->rg_iov.length;
 135 }
 136
 137 static inline u32
 138 rdmab_lkey(struct rpcrdma_regbuf *rb)
 139 {
 140         return rb->rg_iov.lkey;
 141 }
 142
 143 static inline struct rpcrdma_msg *
 144 rdmab_to_msg(struct rpcrdma_regbuf *rb)
 145 {
 146         return (struct rpcrdma_msg *)rb->rg_base;
 147 }
 148
 149 #define RPCRDMA_DEF_GFP         (GFP_NOIO | __GFP_NOWARN)
 150
 151 /*
 152  * struct rpcrdma_rep -- this structure encapsulates state required to recv
 153  * and complete a reply, asychronously. It needs several pieces of
 154  * state:
 155  *   o recv buffer (posted to provider)
 156  *   o ib_sge (also donated to provider)
 157  *   o status of reply (length, success or not)
 158  *   o bookkeeping state to get run by tasklet (list, etc)
 159  *
 160  * These are allocated during initialization, per-transport instance;
 161  * however, the tasklet execution list itself is global, as it should
 162  * always be pretty short.
 163  *
 164  * N of these are associated with a transport instance, and stored in
 165  * struct rpcrdma_buffer. N is the max number of outstanding requests.
 166  */
 167
 168 #define RPCRDMA_MAX_DATA_SEGS   ((1 * 1024 * 1024) / PAGE_SIZE)
 169 #define RPCRDMA_MAX_SEGS        (RPCRDMA_MAX_DATA_SEGS + 2) /* head+tail = 2 */
 170
 171 struct rpcrdma_buffer;
 172
 173 struct rpcrdma_rep {
 174         unsigned int            rr_len;
 175         struct ib_device        *rr_device;
 176         struct rpcrdma_xprt     *rr_rxprt;
 177         struct work_struct      rr_work;
 178         struct list_head        rr_list;
 179         struct rpcrdma_regbuf   *rr_rdmabuf;
 180 };
 181
 182 #define RPCRDMA_BAD_LEN         (~0U)
 183
 184 /*
 185  * struct rpcrdma_mw - external memory region metadata
 186  *
 187  * An external memory region is any buffer or page that is registered
 188  * on the fly (ie, not pre-registered).
 189  *
 190  * Each rpcrdma_buffer has a list of free MWs anchored in rb_mws. During
 191  * call_allocate, rpcrdma_buffer_get() assigns one to each segment in
 192  * an rpcrdma_req. Then rpcrdma_register_external() grabs these to keep
 193  * track of registration metadata while each RPC is pending.
 194  * rpcrdma_deregister_external() uses this metadata to unmap and
 195  * release these resources when an RPC is complete.
 196  */
 197 enum rpcrdma_frmr_state {
 198         FRMR_IS_INVALID,        /* ready to be used */
 199         FRMR_IS_VALID,          /* in use */
 200         FRMR_IS_STALE,          /* failed completion */
 201 };
 202
 203 struct rpcrdma_frmr {
 204         struct scatterlist              *sg;
 205         int                             sg_nents;
 206         struct ib_mr                    *fr_mr;
 207         enum rpcrdma_frmr_state         fr_state;
 208         struct work_struct              fr_work;
 209         struct rpcrdma_xprt             *fr_xprt;
 210         bool                            fr_waiter;
 211         struct completion               fr_linv_done;;
 212         union {
 213                 struct ib_reg_wr        fr_regwr;
 214                 struct ib_send_wr       fr_invwr;
 215         };
 216 };
 217
 218 struct rpcrdma_fmr {
 219         struct ib_fmr           *fmr;
 220         u64                     *physaddrs;
 221 };
 222
 223 struct rpcrdma_mw {
 224         union {
 225                 struct rpcrdma_fmr      fmr;
 226                 struct rpcrdma_frmr     frmr;
 227         } r;
 228         void                    (*mw_sendcompletion)(struct ib_wc *);
 229         struct list_head        mw_list;
 230         struct list_head        mw_all;
 231 };
 232
 233 /*
 234  * struct rpcrdma_req -- structure central to the request/reply sequence.
 235  *
 236  * N of these are associated with a transport instance, and stored in
 237  * struct rpcrdma_buffer. N is the max number of outstanding requests.
 238  *
 239  * It includes pre-registered buffer memory for send AND recv.
 240  * The recv buffer, however, is not owned by this structure, and
 241  * is "donated" to the hardware when a recv is posted. When a
 242  * reply is handled, the recv buffer used is given back to the
 243  * struct rpcrdma_req associated with the request.
 244  *
 245  * In addition to the basic memory, this structure includes an array
 246  * of iovs for send operations. The reason is that the iovs passed to
 247  * ib_post_{send,recv} must not be modified until the work request
 248  * completes.
 249  *
 250  * NOTES:
 251  *   o RPCRDMA_MAX_SEGS is the max number of addressible chunk elements we
 252  *     marshal. The number needed varies depending on the iov lists that
 253  *     are passed to us, the memory registration mode we are in, and if
 254  *     physical addressing is used, the layout.
 255  */
 256
 257 struct rpcrdma_mr_seg {         /* chunk descriptors */
 258         struct rpcrdma_mw *rl_mw;       /* registered MR */
 259         u64             mr_base;        /* registration result */
 260         u32             mr_rkey;        /* registration result */
 261         u32             mr_len;         /* length of chunk or segment */
 262         int             mr_nsegs;       /* number of segments in chunk or 0 */
 263         enum dma_data_direction mr_dir; /* segment mapping direction */
 264         dma_addr_t      mr_dma;         /* segment mapping address */
 265         size_t          mr_dmalen;      /* segment mapping length */
 266         struct page     *mr_page;       /* owning page, if any */
 267         char            *mr_offset;     /* kva if no page, else offset */
 268 };
 269
 270 #define RPCRDMA_MAX_IOVS        (2)
 271
 272 struct rpcrdma_req {
 273         struct list_head        rl_free;
 274         unsigned int            rl_niovs;
 275         unsigned int            rl_nchunks;
 276         unsigned int            rl_connect_cookie;
 277         struct rpcrdma_buffer   *rl_buffer;
 278         struct rpcrdma_rep      *rl_reply;/* holder for reply buffer */
 279         struct ib_sge           rl_send_iov[RPCRDMA_MAX_IOVS];
 280         struct rpcrdma_regbuf   *rl_rdmabuf;
 281         struct rpcrdma_regbuf   *rl_sendbuf;
 282         struct rpcrdma_mr_seg   rl_segments[RPCRDMA_MAX_SEGS];
 283
 284         struct list_head        rl_all;
 285         bool                    rl_backchannel;
 286 };
 287
 288 static inline struct rpcrdma_req *
 289 rpcr_to_rdmar(struct rpc_rqst *rqst)
 290 {
 291         void *buffer = rqst->rq_buffer;
 292         struct rpcrdma_regbuf *rb;
 293
 294         rb = container_of(buffer, struct rpcrdma_regbuf, rg_base);
 295         return rb->rg_owner;
 296 }
 297
 298 /*
 299  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
 300  * inline requests/replies, and client/server credits.
 301  *
 302  * One of these is associated with a transport instance
 303  */
 304 struct rpcrdma_buffer {
 305         spinlock_t              rb_mwlock;      /* protect rb_mws list */
 306         struct list_head        rb_mws;
 307         struct list_head        rb_all;
 308         char                    *rb_pool;
 309
 310         spinlock_t              rb_lock;        /* protect buf lists */
 311         struct list_head        rb_send_bufs;
 312         struct list_head        rb_recv_bufs;
 313         u32                     rb_max_requests;
 314
 315         u32                     rb_bc_srv_max_requests;
 316         spinlock_t              rb_reqslock;    /* protect rb_allreqs */
 317         struct list_head        rb_allreqs;
 318
 319         u32                     rb_bc_max_requests;
 320 };
 321 #define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)
 322
 323 /*
 324  * Internal structure for transport instance creation. This
 325  * exists primarily for modularity.
 326  *
 327  * This data should be set with mount options
 328  */
 329 struct rpcrdma_create_data_internal {
 330         struct sockaddr_storage addr;   /* RDMA server address */
 331         unsigned int    max_requests;   /* max requests (slots) in flight */
 332         unsigned int    rsize;          /* mount rsize - max read hdr+data */
 333         unsigned int    wsize;          /* mount wsize - max write hdr+data */
 334         unsigned int    inline_rsize;   /* max non-rdma read data payload */
 335         unsigned int    inline_wsize;   /* max non-rdma write data payload */
 336         unsigned int    padding;        /* non-rdma write header padding */
 337 };
 338
 339 #define RPCRDMA_INLINE_READ_THRESHOLD(rq) \
 340         (rpcx_to_rdmad(rq->rq_xprt).inline_rsize)
 341
 342 #define RPCRDMA_INLINE_WRITE_THRESHOLD(rq)\
 343         (rpcx_to_rdmad(rq->rq_xprt).inline_wsize)
 344
 345 #define RPCRDMA_INLINE_PAD_VALUE(rq)\
 346         rpcx_to_rdmad(rq->rq_xprt).padding
 347
 348 /*
 349  * Statistics for RPCRDMA
 350  */
 351 struct rpcrdma_stats {
 352         unsigned long           read_chunk_count;
 353         unsigned long           write_chunk_count;
 354         unsigned long           reply_chunk_count;
 355
 356         unsigned long long      total_rdma_request;
 357         unsigned long long      total_rdma_reply;
 358
 359         unsigned long long      pullup_copy_count;
 360         unsigned long long      fixup_copy_count;
 361         unsigned long           hardway_register_count;
 362         unsigned long           failed_marshal_count;
 363         unsigned long           bad_reply_count;
 364         unsigned long           nomsg_call_count;
 365         unsigned long           bcall_count;
 366 };
 367
 368 /*
 369  * Per-registration mode operations
 370  */
 371 struct rpcrdma_xprt;
 372 struct rpcrdma_memreg_ops {
 373         int             (*ro_map)(struct rpcrdma_xprt *,
 374                                   struct rpcrdma_mr_seg *, int, bool);
 375         void            (*ro_unmap_sync)(struct rpcrdma_xprt *,
 376                                          struct rpcrdma_req *);
 377         int             (*ro_unmap)(struct rpcrdma_xprt *,
 378                                     struct rpcrdma_mr_seg *);
 379         int             (*ro_open)(struct rpcrdma_ia *,
 380                                    struct rpcrdma_ep *,
 381                                    struct rpcrdma_create_data_internal *);
 382         size_t          (*ro_maxpages)(struct rpcrdma_xprt *);
 383         int             (*ro_init)(struct rpcrdma_xprt *);
 384         void            (*ro_destroy)(struct rpcrdma_buffer *);
 385         const char      *ro_displayname;
 386 };
 387
 388 extern const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops;
 389 extern const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops;
 390 extern const struct rpcrdma_memreg_ops rpcrdma_physical_memreg_ops;
 391
 392 /*
 393  * RPCRDMA transport -- encapsulates the structures above for
 394  * integration with RPC.
 395  *
 396  * The contained structures are embedded, not pointers,
 397  * for convenience. This structure need not be visible externally.
 398  *
 399  * It is allocated and initialized during mount, and released
 400  * during unmount.
 401  */
 402 struct rpcrdma_xprt {
 403         struct rpc_xprt         rx_xprt;
 404         struct rpcrdma_ia       rx_ia;
 405         struct rpcrdma_ep       rx_ep;
 406         struct rpcrdma_buffer   rx_buf;
 407         struct rpcrdma_create_data_internal rx_data;
 408         struct delayed_work     rx_connect_worker;
 409         struct rpcrdma_stats    rx_stats;
 410 };
 411
 412 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
 413 #define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
 414
 415 /* Setting this to 0 ensures interoperability with early servers.
 416  * Setting this to 1 enhances certain unaligned read/write performance.
 417  * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
 418 extern int xprt_rdma_pad_optimize;
 419
 420 /*
 421  * Interface Adapter calls - xprtrdma/verbs.c
 422  */
 423 int rpcrdma_ia_open(struct rpcrdma_xprt *, struct sockaddr *, int);
 424 void rpcrdma_ia_close(struct rpcrdma_ia *);
 425
 426 /*
 427  * Endpoint calls - xprtrdma/verbs.c
 428  */
 429 int rpcrdma_ep_create(struct rpcrdma_ep *, struct rpcrdma_ia *,
 430                                 struct rpcrdma_create_data_internal *);
 431 void rpcrdma_ep_destroy(struct rpcrdma_ep *, struct rpcrdma_ia *);
 432 int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
 433 void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
 434
 435 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
 436                                 struct rpcrdma_req *);
 437 int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_ep *,
 438                                 struct rpcrdma_rep *);
 439
 440 /*
 441  * Buffer calls - xprtrdma/verbs.c
 442  */
 443 struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
 444 struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);
 445 void rpcrdma_destroy_req(struct rpcrdma_ia *, struct rpcrdma_req *);
 446 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
 447 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
 448
 449 struct rpcrdma_mw *rpcrdma_get_mw(struct rpcrdma_xprt *);
 450 void rpcrdma_put_mw(struct rpcrdma_xprt *, struct rpcrdma_mw *);
 451 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
 452 void rpcrdma_buffer_put(struct rpcrdma_req *);
 453 void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
 454 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
 455
 456 struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(struct rpcrdma_ia *,
 457                                             size_t, gfp_t);
 458 void rpcrdma_free_regbuf(struct rpcrdma_ia *,
 459                          struct rpcrdma_regbuf *);
 460
 461 unsigned int rpcrdma_max_segments(struct rpcrdma_xprt *);
 462 int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *, unsigned int);
 463
 464 int frwr_alloc_recovery_wq(void);
 465 void frwr_destroy_recovery_wq(void);
 466
 467 int rpcrdma_alloc_wq(void);
 468 void rpcrdma_destroy_wq(void);
 469
 470 /*
 471  * Wrappers for chunk registration, shared by read/write chunk code.
 472  */
 473
 474 void rpcrdma_mapping_error(struct rpcrdma_mr_seg *);
 475
 476 static inline enum dma_data_direction
 477 rpcrdma_data_dir(bool writing)
 478 {
 479         return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 480 }
 481
 482 static inline void
 483 rpcrdma_map_one(struct ib_device *device, struct rpcrdma_mr_seg *seg,
 484                 enum dma_data_direction direction)
 485 {
 486         seg->mr_dir = direction;
 487         seg->mr_dmalen = seg->mr_len;
 488
 489         if (seg->mr_page)
 490                 seg->mr_dma = ib_dma_map_page(device,
 491                                 seg->mr_page, offset_in_page(seg->mr_offset),
 492                                 seg->mr_dmalen, seg->mr_dir);
 493         else
 494                 seg->mr_dma = ib_dma_map_single(device,
 495                                 seg->mr_offset,
 496                                 seg->mr_dmalen, seg->mr_dir);
 497
 498         if (ib_dma_mapping_error(device, seg->mr_dma))
 499                 rpcrdma_mapping_error(seg);
 500 }
 501
 502 static inline void
 503 rpcrdma_unmap_one(struct ib_device *device, struct rpcrdma_mr_seg *seg)
 504 {
 505         if (seg->mr_page)
 506                 ib_dma_unmap_page(device,
 507                                   seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
 508         else
 509                 ib_dma_unmap_single(device,
 510                                     seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
 511 }
 512
 513 /*
 514  * RPC/RDMA connection management calls - xprtrdma/rpc_rdma.c
 515  */
 516 void rpcrdma_connect_worker(struct work_struct *);
 517 void rpcrdma_conn_func(struct rpcrdma_ep *);
 518 void rpcrdma_reply_handler(struct rpcrdma_rep *);
 519
 520 /*
 521  * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
 522  */
 523 int rpcrdma_marshal_req(struct rpc_rqst *);
 524
 525 /* RPC/RDMA module init - xprtrdma/transport.c
 526  */
 527 extern unsigned int xprt_rdma_max_inline_read;
 528 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
 529 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
 530 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
 531 int xprt_rdma_init(void);
 532 void xprt_rdma_cleanup(void);
 533
 534 /* Backchannel calls - xprtrdma/backchannel.c
 535  */
 536 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 537 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
 538 int xprt_rdma_bc_up(struct svc_serv *, struct net *);
 539 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
 540 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
 541 int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
 542 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
 543 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
 544 #endif  /* CONFIG_SUNRPC_BACKCHANNEL */
 545
 546 extern struct xprt_class xprt_rdma_bc;
 547
 548 #endif                          /* _LINUX_SUNRPC_XPRT_RDMA_H */