xref: /openbmc/linux/net/sunrpc/xprtrdma/xprt_rdma.h (revision 4d1356ac)
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.
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24  *      Neither the name of the Network Appliance, Inc. nor the names of
25  *      its contributors may be used to endorse or promote products
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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
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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,
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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.h> 	/* RPC/RDMA protocol */
57 #include <linux/sunrpc/xprtrdma.h> 	/* xprt parameters */
58 
59 #define RDMA_RESOLVE_TIMEOUT	(5000)	/* 5 seconds */
60 #define RDMA_CONNECT_RETRY_MAX	(2)	/* retries if no listener backlog */
61 
62 #define RPCRDMA_BIND_TO		(60U * HZ)
63 #define RPCRDMA_INIT_REEST_TO	(5U * HZ)
64 #define RPCRDMA_MAX_REEST_TO	(30U * HZ)
65 #define RPCRDMA_IDLE_DISC_TO	(5U * 60 * HZ)
66 
67 /*
68  * Interface Adapter -- one per transport instance
69  */
70 struct rpcrdma_ia {
71 	struct rdma_cm_id 	*ri_id;
72 	struct ib_pd		*ri_pd;
73 	int			ri_async_rc;
74 	unsigned int		ri_max_segs;
75 	unsigned int		ri_max_frwr_depth;
76 	unsigned int		ri_max_send_sges;
77 	bool			ri_implicit_roundup;
78 	enum ib_mr_type		ri_mrtype;
79 	unsigned long		ri_flags;
80 	struct completion	ri_done;
81 	struct completion	ri_remove_done;
82 };
83 
84 enum {
85 	RPCRDMA_IAF_REMOVING = 0,
86 };
87 
88 /*
89  * RDMA Endpoint -- one per transport instance
90  */
91 
92 struct rpcrdma_ep {
93 	unsigned int		rep_send_count;
94 	unsigned int		rep_send_batch;
95 	unsigned int		rep_max_inline_send;
96 	unsigned int		rep_max_inline_recv;
97 	int			rep_connected;
98 	struct ib_qp_init_attr	rep_attr;
99 	wait_queue_head_t 	rep_connect_wait;
100 	struct rpcrdma_connect_private	rep_cm_private;
101 	struct rdma_conn_param	rep_remote_cma;
102 	unsigned int		rep_max_requests;	/* set by /proc */
103 	unsigned int		rep_inline_send;	/* negotiated */
104 	unsigned int		rep_inline_recv;	/* negotiated */
105 	int			rep_receive_count;
106 };
107 
108 /* Pre-allocate extra Work Requests for handling backward receives
109  * and sends. This is a fixed value because the Work Queues are
110  * allocated when the forward channel is set up, long before the
111  * backchannel is provisioned. This value is two times
112  * NFS4_DEF_CB_SLOT_TABLE_SIZE.
113  */
114 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
115 #define RPCRDMA_BACKWARD_WRS (32)
116 #else
117 #define RPCRDMA_BACKWARD_WRS (0)
118 #endif
119 
120 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
121  */
122 
123 struct rpcrdma_regbuf {
124 	struct ib_sge		rg_iov;
125 	struct ib_device	*rg_device;
126 	enum dma_data_direction	rg_direction;
127 	void			*rg_data;
128 };
129 
130 static inline u64 rdmab_addr(struct rpcrdma_regbuf *rb)
131 {
132 	return rb->rg_iov.addr;
133 }
134 
135 static inline u32 rdmab_length(struct rpcrdma_regbuf *rb)
136 {
137 	return rb->rg_iov.length;
138 }
139 
140 static inline u32 rdmab_lkey(struct rpcrdma_regbuf *rb)
141 {
142 	return rb->rg_iov.lkey;
143 }
144 
145 static inline struct ib_device *rdmab_device(struct rpcrdma_regbuf *rb)
146 {
147 	return rb->rg_device;
148 }
149 
150 static inline void *rdmab_data(const struct rpcrdma_regbuf *rb)
151 {
152 	return rb->rg_data;
153 }
154 
155 #define RPCRDMA_DEF_GFP		(GFP_NOIO | __GFP_NOWARN)
156 
157 /* To ensure a transport can always make forward progress,
158  * the number of RDMA segments allowed in header chunk lists
159  * is capped at 16. This prevents less-capable devices from
160  * overrunning the Send buffer while building chunk lists.
161  *
162  * Elements of the Read list take up more room than the
163  * Write list or Reply chunk. 16 read segments means the
164  * chunk lists cannot consume more than
165  *
166  * ((16 + 2) * read segment size) + 1 XDR words,
167  *
168  * or about 400 bytes. The fixed part of the header is
169  * another 24 bytes. Thus when the inline threshold is
170  * 1024 bytes, at least 600 bytes are available for RPC
171  * message bodies.
172  */
173 enum {
174 	RPCRDMA_MAX_HDR_SEGS = 16,
175 };
176 
177 /*
178  * struct rpcrdma_rep -- this structure encapsulates state required
179  * to receive and complete an RPC Reply, asychronously. It needs
180  * several pieces of state:
181  *
182  *   o receive buffer and ib_sge (donated to provider)
183  *   o status of receive (success or not, length, inv rkey)
184  *   o bookkeeping state to get run by reply handler (XDR stream)
185  *
186  * These structures are allocated during transport initialization.
187  * N of these are associated with a transport instance, managed by
188  * struct rpcrdma_buffer. N is the max number of outstanding RPCs.
189  */
190 
191 struct rpcrdma_rep {
192 	struct ib_cqe		rr_cqe;
193 	__be32			rr_xid;
194 	__be32			rr_vers;
195 	__be32			rr_proc;
196 	int			rr_wc_flags;
197 	u32			rr_inv_rkey;
198 	bool			rr_temp;
199 	struct rpcrdma_regbuf	*rr_rdmabuf;
200 	struct rpcrdma_xprt	*rr_rxprt;
201 	struct rpc_rqst		*rr_rqst;
202 	struct xdr_buf		rr_hdrbuf;
203 	struct xdr_stream	rr_stream;
204 	struct llist_node	rr_node;
205 	struct ib_recv_wr	rr_recv_wr;
206 	struct list_head	rr_all;
207 };
208 
209 /* To reduce the rate at which a transport invokes ib_post_recv
210  * (and thus the hardware doorbell rate), xprtrdma posts Receive
211  * WRs in batches.
212  *
213  * Setting this to zero disables Receive post batching.
214  */
215 enum {
216 	RPCRDMA_MAX_RECV_BATCH = 7,
217 };
218 
219 /* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes
220  */
221 struct rpcrdma_req;
222 struct rpcrdma_sendctx {
223 	struct ib_cqe		sc_cqe;
224 	struct rpcrdma_req	*sc_req;
225 	unsigned int		sc_unmap_count;
226 	struct ib_sge		sc_sges[];
227 };
228 
229 /*
230  * struct rpcrdma_mr - external memory region metadata
231  *
232  * An external memory region is any buffer or page that is registered
233  * on the fly (ie, not pre-registered).
234  */
235 struct rpcrdma_frwr {
236 	struct ib_mr			*fr_mr;
237 	struct ib_cqe			fr_cqe;
238 	struct completion		fr_linv_done;
239 	union {
240 		struct ib_reg_wr	fr_regwr;
241 		struct ib_send_wr	fr_invwr;
242 	};
243 };
244 
245 struct rpcrdma_req;
246 struct rpcrdma_mr {
247 	struct list_head	mr_list;
248 	struct rpcrdma_req	*mr_req;
249 	struct scatterlist	*mr_sg;
250 	int			mr_nents;
251 	enum dma_data_direction	mr_dir;
252 	struct rpcrdma_frwr	frwr;
253 	struct rpcrdma_xprt	*mr_xprt;
254 	u32			mr_handle;
255 	u32			mr_length;
256 	u64			mr_offset;
257 	struct list_head	mr_all;
258 };
259 
260 /*
261  * struct rpcrdma_req -- structure central to the request/reply sequence.
262  *
263  * N of these are associated with a transport instance, and stored in
264  * struct rpcrdma_buffer. N is the max number of outstanding requests.
265  *
266  * It includes pre-registered buffer memory for send AND recv.
267  * The recv buffer, however, is not owned by this structure, and
268  * is "donated" to the hardware when a recv is posted. When a
269  * reply is handled, the recv buffer used is given back to the
270  * struct rpcrdma_req associated with the request.
271  *
272  * In addition to the basic memory, this structure includes an array
273  * of iovs for send operations. The reason is that the iovs passed to
274  * ib_post_{send,recv} must not be modified until the work request
275  * completes.
276  */
277 
278 /* Maximum number of page-sized "segments" per chunk list to be
279  * registered or invalidated. Must handle a Reply chunk:
280  */
281 enum {
282 	RPCRDMA_MAX_IOV_SEGS	= 3,
283 	RPCRDMA_MAX_DATA_SEGS	= ((1 * 1024 * 1024) / PAGE_SIZE) + 1,
284 	RPCRDMA_MAX_SEGS	= RPCRDMA_MAX_DATA_SEGS +
285 				  RPCRDMA_MAX_IOV_SEGS,
286 };
287 
288 struct rpcrdma_mr_seg {		/* chunk descriptors */
289 	u32		mr_len;		/* length of chunk or segment */
290 	struct page	*mr_page;	/* owning page, if any */
291 	char		*mr_offset;	/* kva if no page, else offset */
292 };
293 
294 /* The Send SGE array is provisioned to send a maximum size
295  * inline request:
296  * - RPC-over-RDMA header
297  * - xdr_buf head iovec
298  * - RPCRDMA_MAX_INLINE bytes, in pages
299  * - xdr_buf tail iovec
300  *
301  * The actual number of array elements consumed by each RPC
302  * depends on the device's max_sge limit.
303  */
304 enum {
305 	RPCRDMA_MIN_SEND_SGES = 3,
306 	RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT,
307 	RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1,
308 };
309 
310 struct rpcrdma_buffer;
311 struct rpcrdma_req {
312 	struct list_head	rl_list;
313 	struct rpc_rqst		rl_slot;
314 	struct rpcrdma_rep	*rl_reply;
315 	struct xdr_stream	rl_stream;
316 	struct xdr_buf		rl_hdrbuf;
317 	struct ib_send_wr	rl_wr;
318 	struct rpcrdma_sendctx	*rl_sendctx;
319 	struct rpcrdma_regbuf	*rl_rdmabuf;	/* xprt header */
320 	struct rpcrdma_regbuf	*rl_sendbuf;	/* rq_snd_buf */
321 	struct rpcrdma_regbuf	*rl_recvbuf;	/* rq_rcv_buf */
322 
323 	struct list_head	rl_all;
324 	struct kref		rl_kref;
325 
326 	struct list_head	rl_free_mrs;
327 	struct list_head	rl_registered;
328 	struct rpcrdma_mr_seg	rl_segments[RPCRDMA_MAX_SEGS];
329 };
330 
331 static inline struct rpcrdma_req *
332 rpcr_to_rdmar(const struct rpc_rqst *rqst)
333 {
334 	return container_of(rqst, struct rpcrdma_req, rl_slot);
335 }
336 
337 static inline void
338 rpcrdma_mr_push(struct rpcrdma_mr *mr, struct list_head *list)
339 {
340 	list_add(&mr->mr_list, list);
341 }
342 
343 static inline struct rpcrdma_mr *
344 rpcrdma_mr_pop(struct list_head *list)
345 {
346 	struct rpcrdma_mr *mr;
347 
348 	mr = list_first_entry_or_null(list, struct rpcrdma_mr, mr_list);
349 	if (mr)
350 		list_del_init(&mr->mr_list);
351 	return mr;
352 }
353 
354 /*
355  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
356  * inline requests/replies, and client/server credits.
357  *
358  * One of these is associated with a transport instance
359  */
360 struct rpcrdma_buffer {
361 	spinlock_t		rb_lock;
362 	struct list_head	rb_send_bufs;
363 	struct list_head	rb_mrs;
364 
365 	unsigned long		rb_sc_head;
366 	unsigned long		rb_sc_tail;
367 	unsigned long		rb_sc_last;
368 	struct rpcrdma_sendctx	**rb_sc_ctxs;
369 
370 	struct list_head	rb_allreqs;
371 	struct list_head	rb_all_mrs;
372 	struct list_head	rb_all_reps;
373 
374 	struct llist_head	rb_free_reps;
375 
376 	u32			rb_max_requests;
377 	u32			rb_credits;	/* most recent credit grant */
378 
379 	u32			rb_bc_srv_max_requests;
380 	u32			rb_bc_max_requests;
381 
382 	struct work_struct	rb_refresh_worker;
383 };
384 
385 /*
386  * Statistics for RPCRDMA
387  */
388 struct rpcrdma_stats {
389 	/* accessed when sending a call */
390 	unsigned long		read_chunk_count;
391 	unsigned long		write_chunk_count;
392 	unsigned long		reply_chunk_count;
393 	unsigned long long	total_rdma_request;
394 
395 	/* rarely accessed error counters */
396 	unsigned long long	pullup_copy_count;
397 	unsigned long		hardway_register_count;
398 	unsigned long		failed_marshal_count;
399 	unsigned long		bad_reply_count;
400 	unsigned long		mrs_recycled;
401 	unsigned long		mrs_orphaned;
402 	unsigned long		mrs_allocated;
403 	unsigned long		empty_sendctx_q;
404 
405 	/* accessed when receiving a reply */
406 	unsigned long long	total_rdma_reply;
407 	unsigned long long	fixup_copy_count;
408 	unsigned long		reply_waits_for_send;
409 	unsigned long		local_inv_needed;
410 	unsigned long		nomsg_call_count;
411 	unsigned long		bcall_count;
412 };
413 
414 /*
415  * RPCRDMA transport -- encapsulates the structures above for
416  * integration with RPC.
417  *
418  * The contained structures are embedded, not pointers,
419  * for convenience. This structure need not be visible externally.
420  *
421  * It is allocated and initialized during mount, and released
422  * during unmount.
423  */
424 struct rpcrdma_xprt {
425 	struct rpc_xprt		rx_xprt;
426 	struct rpcrdma_ia	rx_ia;
427 	struct rpcrdma_ep	rx_ep;
428 	struct rpcrdma_buffer	rx_buf;
429 	struct delayed_work	rx_connect_worker;
430 	struct rpc_timeout	rx_timeout;
431 	struct rpcrdma_stats	rx_stats;
432 };
433 
434 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
435 
436 static inline const char *
437 rpcrdma_addrstr(const struct rpcrdma_xprt *r_xprt)
438 {
439 	return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_ADDR];
440 }
441 
442 static inline const char *
443 rpcrdma_portstr(const struct rpcrdma_xprt *r_xprt)
444 {
445 	return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_PORT];
446 }
447 
448 /* Setting this to 0 ensures interoperability with early servers.
449  * Setting this to 1 enhances certain unaligned read/write performance.
450  * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
451 extern int xprt_rdma_pad_optimize;
452 
453 /* This setting controls the hunt for a supported memory
454  * registration strategy.
455  */
456 extern unsigned int xprt_rdma_memreg_strategy;
457 
458 /*
459  * Interface Adapter calls - xprtrdma/verbs.c
460  */
461 int rpcrdma_ia_open(struct rpcrdma_xprt *xprt);
462 void rpcrdma_ia_remove(struct rpcrdma_ia *ia);
463 void rpcrdma_ia_close(struct rpcrdma_ia *);
464 
465 /*
466  * Endpoint calls - xprtrdma/verbs.c
467  */
468 int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt);
469 void rpcrdma_ep_destroy(struct rpcrdma_xprt *r_xprt);
470 int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
471 void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
472 
473 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
474 				struct rpcrdma_req *);
475 void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp);
476 
477 /*
478  * Buffer calls - xprtrdma/verbs.c
479  */
480 struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, size_t size,
481 				       gfp_t flags);
482 void rpcrdma_req_destroy(struct rpcrdma_req *req);
483 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
484 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
485 struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt);
486 
487 struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt);
488 void rpcrdma_mr_put(struct rpcrdma_mr *mr);
489 void rpcrdma_mrs_refresh(struct rpcrdma_xprt *r_xprt);
490 
491 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
492 void rpcrdma_buffer_put(struct rpcrdma_buffer *buffers,
493 			struct rpcrdma_req *req);
494 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
495 
496 bool rpcrdma_regbuf_realloc(struct rpcrdma_regbuf *rb, size_t size,
497 			    gfp_t flags);
498 bool __rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
499 			      struct rpcrdma_regbuf *rb);
500 
501 /**
502  * rpcrdma_regbuf_is_mapped - check if buffer is DMA mapped
503  *
504  * Returns true if the buffer is now mapped to rb->rg_device.
505  */
506 static inline bool rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb)
507 {
508 	return rb->rg_device != NULL;
509 }
510 
511 /**
512  * rpcrdma_regbuf_dma_map - DMA-map a regbuf
513  * @r_xprt: controlling transport instance
514  * @rb: regbuf to be mapped
515  *
516  * Returns true if the buffer is currently DMA mapped.
517  */
518 static inline bool rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
519 					  struct rpcrdma_regbuf *rb)
520 {
521 	if (likely(rpcrdma_regbuf_is_mapped(rb)))
522 		return true;
523 	return __rpcrdma_regbuf_dma_map(r_xprt, rb);
524 }
525 
526 /*
527  * Wrappers for chunk registration, shared by read/write chunk code.
528  */
529 
530 static inline enum dma_data_direction
531 rpcrdma_data_dir(bool writing)
532 {
533 	return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
534 }
535 
536 /* Memory registration calls xprtrdma/frwr_ops.c
537  */
538 bool frwr_is_supported(struct ib_device *device);
539 void frwr_reset(struct rpcrdma_req *req);
540 int frwr_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep);
541 int frwr_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr);
542 void frwr_release_mr(struct rpcrdma_mr *mr);
543 size_t frwr_maxpages(struct rpcrdma_xprt *r_xprt);
544 struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
545 				struct rpcrdma_mr_seg *seg,
546 				int nsegs, bool writing, __be32 xid,
547 				struct rpcrdma_mr *mr);
548 int frwr_send(struct rpcrdma_ia *ia, struct rpcrdma_req *req);
549 void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs);
550 void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req);
551 void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req);
552 
553 /*
554  * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
555  */
556 
557 enum rpcrdma_chunktype {
558 	rpcrdma_noch = 0,
559 	rpcrdma_noch_pullup,
560 	rpcrdma_noch_mapped,
561 	rpcrdma_readch,
562 	rpcrdma_areadch,
563 	rpcrdma_writech,
564 	rpcrdma_replych
565 };
566 
567 int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
568 			      struct rpcrdma_req *req, u32 hdrlen,
569 			      struct xdr_buf *xdr,
570 			      enum rpcrdma_chunktype rtype);
571 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc);
572 int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst);
573 void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *);
574 void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt);
575 void rpcrdma_complete_rqst(struct rpcrdma_rep *rep);
576 void rpcrdma_reply_handler(struct rpcrdma_rep *rep);
577 
578 static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len)
579 {
580 	xdr->head[0].iov_len = len;
581 	xdr->len = len;
582 }
583 
584 /* RPC/RDMA module init - xprtrdma/transport.c
585  */
586 extern unsigned int xprt_rdma_slot_table_entries;
587 extern unsigned int xprt_rdma_max_inline_read;
588 extern unsigned int xprt_rdma_max_inline_write;
589 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
590 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
591 void xprt_rdma_close(struct rpc_xprt *xprt);
592 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
593 int xprt_rdma_init(void);
594 void xprt_rdma_cleanup(void);
595 
596 /* Backchannel calls - xprtrdma/backchannel.c
597  */
598 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
599 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
600 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *);
601 unsigned int xprt_rdma_bc_max_slots(struct rpc_xprt *);
602 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
603 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
604 int xprt_rdma_bc_send_reply(struct rpc_rqst *rqst);
605 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
606 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
607 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
608 
609 extern struct xprt_class xprt_rdma_bc;
610 
611 #endif				/* _LINUX_SUNRPC_XPRT_RDMA_H */
612