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 /*
  59  * Interface Adapter -- one per transport instance
  60  */
  61 struct rpcrdma_ia {
  62         const struct rpcrdma_memreg_ops *ri_ops;
  63         rwlock_t                ri_qplock;
  64         struct ib_device        *ri_device;
  65         struct rdma_cm_id       *ri_id;
  66         struct ib_pd            *ri_pd;
  67         struct ib_mr            *ri_dma_mr;
  68         struct completion       ri_done;
  69         int                     ri_async_rc;
  70         unsigned int            ri_max_frmr_depth;
  71         struct ib_qp_attr       ri_qp_attr;
  72         struct ib_qp_init_attr  ri_qp_init_attr;
  73 };
  74
  75 /*
  76  * RDMA Endpoint -- one per transport instance
  77  */
  78
  79 struct rpcrdma_ep {
  80         atomic_t                rep_cqcount;
  81         int                     rep_cqinit;
  82         int                     rep_connected;
  83         struct ib_qp_init_attr  rep_attr;
  84         wait_queue_head_t       rep_connect_wait;
  85         struct rdma_conn_param  rep_remote_cma;
  86         struct sockaddr_storage rep_remote_addr;
  87         struct delayed_work     rep_connect_worker;
  88 };
  89
  90 /*
  91  * Force a signaled SEND Work Request every so often,
  92  * in case the provider needs to do some housekeeping.
  93  */
  94 #define RPCRDMA_MAX_UNSIGNALED_SENDS    (32)
  95
  96 #define INIT_CQCOUNT(ep) atomic_set(&(ep)->rep_cqcount, (ep)->rep_cqinit)
  97 #define DECR_CQCOUNT(ep) atomic_sub_return(1, &(ep)->rep_cqcount)
  98
  99 /* Force completion handler to ignore the signal
 100  */
 101 #define RPCRDMA_IGNORE_COMPLETION       (0ULL)
 102
 103 /* Pre-allocate extra Work Requests for handling backward receives
 104  * and sends. This is a fixed value because the Work Queues are
 105  * allocated when the forward channel is set up.
 106  */
 107 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 108 #define RPCRDMA_BACKWARD_WRS            (8)
 109 #else
 110 #define RPCRDMA_BACKWARD_WRS            (0)
 111 #endif
 112
 113 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
 114  *
 115  * The below structure appears at the front of a large region of kmalloc'd
 116  * memory, which always starts on a good alignment boundary.
 117  */
 118
 119 struct rpcrdma_regbuf {
 120         size_t                  rg_size;
 121         struct rpcrdma_req      *rg_owner;
 122         struct ib_sge           rg_iov;
 123         __be32                  rg_base[0] __attribute__ ((aligned(256)));
 124 };
 125
 126 static inline u64
 127 rdmab_addr(struct rpcrdma_regbuf *rb)
 128 {
 129         return rb->rg_iov.addr;
 130 }
 131
 132 static inline u32
 133 rdmab_length(struct rpcrdma_regbuf *rb)
 134 {
 135         return rb->rg_iov.length;
 136 }
 137
 138 static inline u32
 139 rdmab_lkey(struct rpcrdma_regbuf *rb)
 140 {
 141         return rb->rg_iov.lkey;
 142 }
 143
 144 static inline struct rpcrdma_msg *
 145 rdmab_to_msg(struct rpcrdma_regbuf *rb)
 146 {
 147         return (struct rpcrdma_msg *)rb->rg_base;
 148 }
 149
 150 /*
 151  * struct rpcrdma_rep -- this structure encapsulates state required to recv
 152  * and complete a reply, asychronously. It needs several pieces of
 153  * state:
 154  *   o recv buffer (posted to provider)
 155  *   o ib_sge (also donated to provider)
 156  *   o status of reply (length, success or not)
 157  *   o bookkeeping state to get run by tasklet (list, etc)
 158  *
 159  * These are allocated during initialization, per-transport instance;
 160  * however, the tasklet execution list itself is global, as it should
 161  * always be pretty short.
 162  *
 163  * N of these are associated with a transport instance, and stored in
 164  * struct rpcrdma_buffer. N is the max number of outstanding requests.
 165  */
 166
 167 #define RPCRDMA_MAX_DATA_SEGS   ((1 * 1024 * 1024) / PAGE_SIZE)
 168 #define RPCRDMA_MAX_SEGS        (RPCRDMA_MAX_DATA_SEGS + 2) /* head+tail = 2 */
 169
 170 struct rpcrdma_buffer;
 171
 172 struct rpcrdma_rep {
 173         unsigned int            rr_len;
 174         struct ib_device        *rr_device;
 175         struct rpcrdma_xprt     *rr_rxprt;
 176         struct work_struct      rr_work;
 177         struct list_head        rr_list;
 178         struct rpcrdma_regbuf   *rr_rdmabuf;
 179 };
 180
 181 #define RPCRDMA_BAD_LEN         (~0U)
 182
 183 /*
 184  * struct rpcrdma_mw - external memory region metadata
 185  *
 186  * An external memory region is any buffer or page that is registered
 187  * on the fly (ie, not pre-registered).
 188  *
 189  * Each rpcrdma_buffer has a list of free MWs anchored in rb_mws. During
 190  * call_allocate, rpcrdma_buffer_get() assigns one to each segment in
 191  * an rpcrdma_req. Then rpcrdma_register_external() grabs these to keep
 192  * track of registration metadata while each RPC is pending.
 193  * rpcrdma_deregister_external() uses this metadata to unmap and
 194  * release these resources when an RPC is complete.
 195  */
 196 enum rpcrdma_frmr_state {
 197         FRMR_IS_INVALID,        /* ready to be used */
 198         FRMR_IS_VALID,          /* in use */
 199         FRMR_IS_STALE,          /* failed completion */
 200 };
 201
 202 struct rpcrdma_frmr {
 203         struct scatterlist              *sg;
 204         int                             sg_nents;
 205         struct ib_mr                    *fr_mr;
 206         enum rpcrdma_frmr_state         fr_state;
 207         struct work_struct              fr_work;
 208         struct rpcrdma_xprt             *fr_xprt;
 209 };
 210
 211 struct rpcrdma_fmr {
 212         struct ib_fmr           *fmr;
 213         u64                     *physaddrs;
 214 };
 215
 216 struct rpcrdma_mw {
 217         union {
 218                 struct rpcrdma_fmr      fmr;
 219                 struct rpcrdma_frmr     frmr;
 220         } r;
 221         void                    (*mw_sendcompletion)(struct ib_wc *);
 222         struct list_head        mw_list;
 223         struct list_head        mw_all;
 224 };
 225
 226 /*
 227  * struct rpcrdma_req -- structure central to the request/reply sequence.
 228  *
 229  * N of these are associated with a transport instance, and stored in
 230  * struct rpcrdma_buffer. N is the max number of outstanding requests.
 231  *
 232  * It includes pre-registered buffer memory for send AND recv.
 233  * The recv buffer, however, is not owned by this structure, and
 234  * is "donated" to the hardware when a recv is posted. When a
 235  * reply is handled, the recv buffer used is given back to the
 236  * struct rpcrdma_req associated with the request.
 237  *
 238  * In addition to the basic memory, this structure includes an array
 239  * of iovs for send operations. The reason is that the iovs passed to
 240  * ib_post_{send,recv} must not be modified until the work request
 241  * completes.
 242  *
 243  * NOTES:
 244  *   o RPCRDMA_MAX_SEGS is the max number of addressible chunk elements we
 245  *     marshal. The number needed varies depending on the iov lists that
 246  *     are passed to us, the memory registration mode we are in, and if
 247  *     physical addressing is used, the layout.
 248  */
 249
 250 struct rpcrdma_mr_seg {         /* chunk descriptors */
 251         struct rpcrdma_mw *rl_mw;       /* registered MR */
 252         u64             mr_base;        /* registration result */
 253         u32             mr_rkey;        /* registration result */
 254         u32             mr_len;         /* length of chunk or segment */
 255         int             mr_nsegs;       /* number of segments in chunk or 0 */
 256         enum dma_data_direction mr_dir; /* segment mapping direction */
 257         dma_addr_t      mr_dma;         /* segment mapping address */
 258         size_t          mr_dmalen;      /* segment mapping length */
 259         struct page     *mr_page;       /* owning page, if any */
 260         char            *mr_offset;     /* kva if no page, else offset */
 261 };
 262
 263 #define RPCRDMA_MAX_IOVS        (2)
 264
 265 struct rpcrdma_req {
 266         struct list_head        rl_free;
 267         unsigned int            rl_niovs;
 268         unsigned int            rl_nchunks;
 269         unsigned int            rl_connect_cookie;
 270         struct rpcrdma_buffer   *rl_buffer;
 271         struct rpcrdma_rep      *rl_reply;/* holder for reply buffer */
 272         struct ib_sge           rl_send_iov[RPCRDMA_MAX_IOVS];
 273         struct rpcrdma_regbuf   *rl_rdmabuf;
 274         struct rpcrdma_regbuf   *rl_sendbuf;
 275         struct rpcrdma_mr_seg   rl_segments[RPCRDMA_MAX_SEGS];
 276
 277         struct list_head        rl_all;
 278         bool                    rl_backchannel;
 279 };
 280
 281 static inline struct rpcrdma_req *
 282 rpcr_to_rdmar(struct rpc_rqst *rqst)
 283 {
 284         void *buffer = rqst->rq_buffer;
 285         struct rpcrdma_regbuf *rb;
 286
 287         rb = container_of(buffer, struct rpcrdma_regbuf, rg_base);
 288         return rb->rg_owner;
 289 }
 290
 291 /*
 292  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
 293  * inline requests/replies, and client/server credits.
 294  *
 295  * One of these is associated with a transport instance
 296  */
 297 struct rpcrdma_buffer {
 298         spinlock_t              rb_mwlock;      /* protect rb_mws list */
 299         struct list_head        rb_mws;
 300         struct list_head        rb_all;
 301         char                    *rb_pool;
 302
 303         spinlock_t              rb_lock;        /* protect buf lists */
 304         struct list_head        rb_send_bufs;
 305         struct list_head        rb_recv_bufs;
 306         u32                     rb_max_requests;
 307
 308         u32                     rb_bc_srv_max_requests;
 309         spinlock_t              rb_reqslock;    /* protect rb_allreqs */
 310         struct list_head        rb_allreqs;
 311 };
 312 #define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)
 313
 314 /*
 315  * Internal structure for transport instance creation. This
 316  * exists primarily for modularity.
 317  *
 318  * This data should be set with mount options
 319  */
 320 struct rpcrdma_create_data_internal {
 321         struct sockaddr_storage addr;   /* RDMA server address */
 322         unsigned int    max_requests;   /* max requests (slots) in flight */
 323         unsigned int    rsize;          /* mount rsize - max read hdr+data */
 324         unsigned int    wsize;          /* mount wsize - max write hdr+data */
 325         unsigned int    inline_rsize;   /* max non-rdma read data payload */
 326         unsigned int    inline_wsize;   /* max non-rdma write data payload */
 327         unsigned int    padding;        /* non-rdma write header padding */
 328 };
 329
 330 #define RPCRDMA_INLINE_READ_THRESHOLD(rq) \
 331         (rpcx_to_rdmad(rq->rq_xprt).inline_rsize)
 332
 333 #define RPCRDMA_INLINE_WRITE_THRESHOLD(rq)\
 334         (rpcx_to_rdmad(rq->rq_xprt).inline_wsize)
 335
 336 #define RPCRDMA_INLINE_PAD_VALUE(rq)\
 337         rpcx_to_rdmad(rq->rq_xprt).padding
 338
 339 /*
 340  * Statistics for RPCRDMA
 341  */
 342 struct rpcrdma_stats {
 343         unsigned long           read_chunk_count;
 344         unsigned long           write_chunk_count;
 345         unsigned long           reply_chunk_count;
 346
 347         unsigned long long      total_rdma_request;
 348         unsigned long long      total_rdma_reply;
 349
 350         unsigned long long      pullup_copy_count;
 351         unsigned long long      fixup_copy_count;
 352         unsigned long           hardway_register_count;
 353         unsigned long           failed_marshal_count;
 354         unsigned long           bad_reply_count;
 355         unsigned long           nomsg_call_count;
 356         unsigned long           bcall_count;
 357 };
 358
 359 /*
 360  * Per-registration mode operations
 361  */
 362 struct rpcrdma_xprt;
 363 struct rpcrdma_memreg_ops {
 364         int             (*ro_map)(struct rpcrdma_xprt *,
 365                                   struct rpcrdma_mr_seg *, int, bool);
 366         int             (*ro_unmap)(struct rpcrdma_xprt *,
 367                                     struct rpcrdma_mr_seg *);
 368         int             (*ro_open)(struct rpcrdma_ia *,
 369                                    struct rpcrdma_ep *,
 370                                    struct rpcrdma_create_data_internal *);
 371         size_t          (*ro_maxpages)(struct rpcrdma_xprt *);
 372         int             (*ro_init)(struct rpcrdma_xprt *);
 373         void            (*ro_destroy)(struct rpcrdma_buffer *);
 374         const char      *ro_displayname;
 375 };
 376
 377 extern const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops;
 378 extern const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops;
 379 extern const struct rpcrdma_memreg_ops rpcrdma_physical_memreg_ops;
 380
 381 /*
 382  * RPCRDMA transport -- encapsulates the structures above for
 383  * integration with RPC.
 384  *
 385  * The contained structures are embedded, not pointers,
 386  * for convenience. This structure need not be visible externally.
 387  *
 388  * It is allocated and initialized during mount, and released
 389  * during unmount.
 390  */
 391 struct rpcrdma_xprt {
 392         struct rpc_xprt         rx_xprt;
 393         struct rpcrdma_ia       rx_ia;
 394         struct rpcrdma_ep       rx_ep;
 395         struct rpcrdma_buffer   rx_buf;
 396         struct rpcrdma_create_data_internal rx_data;
 397         struct delayed_work     rx_connect_worker;
 398         struct rpcrdma_stats    rx_stats;
 399 };
 400
 401 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
 402 #define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
 403
 404 /* Setting this to 0 ensures interoperability with early servers.
 405  * Setting this to 1 enhances certain unaligned read/write performance.
 406  * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
 407 extern int xprt_rdma_pad_optimize;
 408
 409 /*
 410  * Interface Adapter calls - xprtrdma/verbs.c
 411  */
 412 int rpcrdma_ia_open(struct rpcrdma_xprt *, struct sockaddr *, int);
 413 void rpcrdma_ia_close(struct rpcrdma_ia *);
 414
 415 /*
 416  * Endpoint calls - xprtrdma/verbs.c
 417  */
 418 int rpcrdma_ep_create(struct rpcrdma_ep *, struct rpcrdma_ia *,
 419                                 struct rpcrdma_create_data_internal *);
 420 void rpcrdma_ep_destroy(struct rpcrdma_ep *, struct rpcrdma_ia *);
 421 int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
 422 void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
 423
 424 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
 425                                 struct rpcrdma_req *);
 426 int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_ep *,
 427                                 struct rpcrdma_rep *);
 428
 429 /*
 430  * Buffer calls - xprtrdma/verbs.c
 431  */
 432 struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
 433 struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);
 434 void rpcrdma_destroy_req(struct rpcrdma_ia *, struct rpcrdma_req *);
 435 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
 436 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
 437
 438 struct rpcrdma_mw *rpcrdma_get_mw(struct rpcrdma_xprt *);
 439 void rpcrdma_put_mw(struct rpcrdma_xprt *, struct rpcrdma_mw *);
 440 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
 441 void rpcrdma_buffer_put(struct rpcrdma_req *);
 442 void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
 443 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
 444
 445 struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(struct rpcrdma_ia *,
 446                                             size_t, gfp_t);
 447 void rpcrdma_free_regbuf(struct rpcrdma_ia *,
 448                          struct rpcrdma_regbuf *);
 449
 450 unsigned int rpcrdma_max_segments(struct rpcrdma_xprt *);
 451 int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *, unsigned int);
 452
 453 int frwr_alloc_recovery_wq(void);
 454 void frwr_destroy_recovery_wq(void);
 455
 456 int rpcrdma_alloc_wq(void);
 457 void rpcrdma_destroy_wq(void);
 458
 459 /*
 460  * Wrappers for chunk registration, shared by read/write chunk code.
 461  */
 462
 463 void rpcrdma_mapping_error(struct rpcrdma_mr_seg *);
 464
 465 static inline enum dma_data_direction
 466 rpcrdma_data_dir(bool writing)
 467 {
 468         return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 469 }
 470
 471 static inline void
 472 rpcrdma_map_one(struct ib_device *device, struct rpcrdma_mr_seg *seg,
 473                 enum dma_data_direction direction)
 474 {
 475         seg->mr_dir = direction;
 476         seg->mr_dmalen = seg->mr_len;
 477
 478         if (seg->mr_page)
 479                 seg->mr_dma = ib_dma_map_page(device,
 480                                 seg->mr_page, offset_in_page(seg->mr_offset),
 481                                 seg->mr_dmalen, seg->mr_dir);
 482         else
 483                 seg->mr_dma = ib_dma_map_single(device,
 484                                 seg->mr_offset,
 485                                 seg->mr_dmalen, seg->mr_dir);
 486
 487         if (ib_dma_mapping_error(device, seg->mr_dma))
 488                 rpcrdma_mapping_error(seg);
 489 }
 490
 491 static inline void
 492 rpcrdma_unmap_one(struct ib_device *device, struct rpcrdma_mr_seg *seg)
 493 {
 494         if (seg->mr_page)
 495                 ib_dma_unmap_page(device,
 496                                   seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
 497         else
 498                 ib_dma_unmap_single(device,
 499                                     seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
 500 }
 501
 502 /*
 503  * RPC/RDMA connection management calls - xprtrdma/rpc_rdma.c
 504  */
 505 void rpcrdma_connect_worker(struct work_struct *);
 506 void rpcrdma_conn_func(struct rpcrdma_ep *);
 507 void rpcrdma_reply_handler(struct rpcrdma_rep *);
 508
 509 /*
 510  * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
 511  */
 512 int rpcrdma_marshal_req(struct rpc_rqst *);
 513
 514 /* RPC/RDMA module init - xprtrdma/transport.c
 515  */
 516 int xprt_rdma_init(void);
 517 void xprt_rdma_cleanup(void);
 518
 519 /* Backchannel calls - xprtrdma/backchannel.c
 520  */
 521 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 522 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
 523 int xprt_rdma_bc_up(struct svc_serv *, struct net *);
 524 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
 525 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
 526 int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
 527 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
 528 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
 529 #endif  /* CONFIG_SUNRPC_BACKCHANNEL */
 530
 531 /* Temporary NFS request map cache. Created in svc_rdma.c  */
 532 extern struct kmem_cache *svc_rdma_map_cachep;
 533 /* WR context cache. Created in svc_rdma.c  */
 534 extern struct kmem_cache *svc_rdma_ctxt_cachep;
 535 /* Workqueue created in svc_rdma.c */
 536 extern struct workqueue_struct *svc_rdma_wq;
 537
 538 #endif                          /* _LINUX_SUNRPC_XPRT_RDMA_H */