xref: /openbmc/linux/net/sunrpc/xprtrdma/xprt_rdma.h (revision f9597ba8)
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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28  *
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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38  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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_cid.h> 	/* completion IDs */
57 #include <linux/sunrpc/rpc_rdma.h> 	/* RPC/RDMA protocol */
58 #include <linux/sunrpc/xprtrdma.h> 	/* xprt parameters */
59 
60 #define RDMA_RESOLVE_TIMEOUT	(5000)	/* 5 seconds */
61 #define RDMA_CONNECT_RETRY_MAX	(2)	/* retries if no listener backlog */
62 
63 #define RPCRDMA_BIND_TO		(60U * HZ)
64 #define RPCRDMA_INIT_REEST_TO	(5U * HZ)
65 #define RPCRDMA_MAX_REEST_TO	(30U * HZ)
66 #define RPCRDMA_IDLE_DISC_TO	(5U * 60 * HZ)
67 
68 /*
69  * RDMA Endpoint -- connection endpoint details
70  */
71 struct rpcrdma_mr;
72 struct rpcrdma_ep {
73 	struct kref		re_kref;
74 	struct rdma_cm_id 	*re_id;
75 	struct ib_pd		*re_pd;
76 	unsigned int		re_max_rdma_segs;
77 	unsigned int		re_max_fr_depth;
78 	struct rpcrdma_mr	*re_write_pad_mr;
79 	enum ib_mr_type		re_mrtype;
80 	struct completion	re_done;
81 	unsigned int		re_send_count;
82 	unsigned int		re_send_batch;
83 	unsigned int		re_max_inline_send;
84 	unsigned int		re_max_inline_recv;
85 	int			re_async_rc;
86 	int			re_connect_status;
87 	atomic_t		re_receiving;
88 	atomic_t		re_force_disconnect;
89 	struct ib_qp_init_attr	re_attr;
90 	wait_queue_head_t       re_connect_wait;
91 	struct rpc_xprt		*re_xprt;
92 	struct rpcrdma_connect_private
93 				re_cm_private;
94 	struct rdma_conn_param	re_remote_cma;
95 	int			re_receive_count;
96 	unsigned int		re_max_requests; /* depends on device */
97 	unsigned int		re_inline_send;	/* negotiated */
98 	unsigned int		re_inline_recv;	/* negotiated */
99 
100 	atomic_t		re_completion_ids;
101 
102 	char			re_write_pad[XDR_UNIT];
103 };
104 
105 /* Pre-allocate extra Work Requests for handling reverse-direction
106  * Receives and Sends. This is a fixed value because the Work Queues
107  * are allocated when the forward channel is set up, long before the
108  * backchannel is provisioned. This value is two times
109  * NFS4_DEF_CB_SLOT_TABLE_SIZE.
110  */
111 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
112 #define RPCRDMA_BACKWARD_WRS (32)
113 #else
114 #define RPCRDMA_BACKWARD_WRS (0)
115 #endif
116 
117 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
118  */
119 
120 struct rpcrdma_regbuf {
121 	struct ib_sge		rg_iov;
122 	struct ib_device	*rg_device;
123 	enum dma_data_direction	rg_direction;
124 	void			*rg_data;
125 };
126 
rdmab_addr(struct rpcrdma_regbuf * rb)127 static inline u64 rdmab_addr(struct rpcrdma_regbuf *rb)
128 {
129 	return rb->rg_iov.addr;
130 }
131 
rdmab_length(struct rpcrdma_regbuf * rb)132 static inline u32 rdmab_length(struct rpcrdma_regbuf *rb)
133 {
134 	return rb->rg_iov.length;
135 }
136 
rdmab_lkey(struct rpcrdma_regbuf * rb)137 static inline u32 rdmab_lkey(struct rpcrdma_regbuf *rb)
138 {
139 	return rb->rg_iov.lkey;
140 }
141 
rdmab_device(struct rpcrdma_regbuf * rb)142 static inline struct ib_device *rdmab_device(struct rpcrdma_regbuf *rb)
143 {
144 	return rb->rg_device;
145 }
146 
rdmab_data(const struct rpcrdma_regbuf * rb)147 static inline void *rdmab_data(const struct rpcrdma_regbuf *rb)
148 {
149 	return rb->rg_data;
150 }
151 
152 /* Do not use emergency memory reserves, and fail quickly if memory
153  * cannot be allocated easily. These flags may be used wherever there
154  * is robust logic to handle a failure to allocate.
155  */
156 #define XPRTRDMA_GFP_FLAGS  (__GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN)
157 
158 /* To ensure a transport can always make forward progress,
159  * the number of RDMA segments allowed in header chunk lists
160  * is capped at 16. This prevents less-capable devices from
161  * overrunning the Send buffer while building chunk lists.
162  *
163  * Elements of the Read list take up more room than the
164  * Write list or Reply chunk. 16 read segments means the
165  * chunk lists cannot consume more than
166  *
167  * ((16 + 2) * read segment size) + 1 XDR words,
168  *
169  * or about 400 bytes. The fixed part of the header is
170  * another 24 bytes. Thus when the inline threshold is
171  * 1024 bytes, at least 600 bytes are available for RPC
172  * message bodies.
173  */
174 enum {
175 	RPCRDMA_MAX_HDR_SEGS = 16,
176 };
177 
178 /*
179  * struct rpcrdma_rep -- this structure encapsulates state required
180  * to receive and complete an RPC Reply, asychronously. It needs
181  * several pieces of state:
182  *
183  *   o receive buffer and ib_sge (donated to provider)
184  *   o status of receive (success or not, length, inv rkey)
185  *   o bookkeeping state to get run by reply handler (XDR stream)
186  *
187  * These structures are allocated during transport initialization.
188  * N of these are associated with a transport instance, managed by
189  * struct rpcrdma_buffer. N is the max number of outstanding RPCs.
190  */
191 
192 struct rpcrdma_rep {
193 	struct ib_cqe		rr_cqe;
194 	struct rpc_rdma_cid	rr_cid;
195 
196 	__be32			rr_xid;
197 	__be32			rr_vers;
198 	__be32			rr_proc;
199 	int			rr_wc_flags;
200 	u32			rr_inv_rkey;
201 	bool			rr_temp;
202 	struct rpcrdma_regbuf	*rr_rdmabuf;
203 	struct rpcrdma_xprt	*rr_rxprt;
204 	struct rpc_rqst		*rr_rqst;
205 	struct xdr_buf		rr_hdrbuf;
206 	struct xdr_stream	rr_stream;
207 	struct llist_node	rr_node;
208 	struct ib_recv_wr	rr_recv_wr;
209 	struct list_head	rr_all;
210 };
211 
212 /* To reduce the rate at which a transport invokes ib_post_recv
213  * (and thus the hardware doorbell rate), xprtrdma posts Receive
214  * WRs in batches.
215  *
216  * Setting this to zero disables Receive post batching.
217  */
218 enum {
219 	RPCRDMA_MAX_RECV_BATCH = 7,
220 };
221 
222 /* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes
223  */
224 struct rpcrdma_req;
225 struct rpcrdma_sendctx {
226 	struct ib_cqe		sc_cqe;
227 	struct rpc_rdma_cid	sc_cid;
228 	struct rpcrdma_req	*sc_req;
229 	unsigned int		sc_unmap_count;
230 	struct ib_sge		sc_sges[];
231 };
232 
233 /*
234  * struct rpcrdma_mr - external memory region metadata
235  *
236  * An external memory region is any buffer or page that is registered
237  * on the fly (ie, not pre-registered).
238  */
239 struct rpcrdma_req;
240 struct rpcrdma_mr {
241 	struct list_head	mr_list;
242 	struct rpcrdma_req	*mr_req;
243 
244 	struct ib_mr		*mr_ibmr;
245 	struct ib_device	*mr_device;
246 	struct scatterlist	*mr_sg;
247 	int			mr_nents;
248 	enum dma_data_direction	mr_dir;
249 	struct ib_cqe		mr_cqe;
250 	struct completion	mr_linv_done;
251 	union {
252 		struct ib_reg_wr	mr_regwr;
253 		struct ib_send_wr	mr_invwr;
254 	};
255 	struct rpcrdma_xprt	*mr_xprt;
256 	u32			mr_handle;
257 	u32			mr_length;
258 	u64			mr_offset;
259 	struct list_head	mr_all;
260 	struct rpc_rdma_cid	mr_cid;
261 };
262 
263 /*
264  * struct rpcrdma_req -- structure central to the request/reply sequence.
265  *
266  * N of these are associated with a transport instance, and stored in
267  * struct rpcrdma_buffer. N is the max number of outstanding requests.
268  *
269  * It includes pre-registered buffer memory for send AND recv.
270  * The recv buffer, however, is not owned by this structure, and
271  * is "donated" to the hardware when a recv is posted. When a
272  * reply is handled, the recv buffer used is given back to the
273  * struct rpcrdma_req associated with the request.
274  *
275  * In addition to the basic memory, this structure includes an array
276  * of iovs for send operations. The reason is that the iovs passed to
277  * ib_post_{send,recv} must not be modified until the work request
278  * completes.
279  */
280 
281 /* Maximum number of page-sized "segments" per chunk list to be
282  * registered or invalidated. Must handle a Reply chunk:
283  */
284 enum {
285 	RPCRDMA_MAX_IOV_SEGS	= 3,
286 	RPCRDMA_MAX_DATA_SEGS	= ((1 * 1024 * 1024) / PAGE_SIZE) + 1,
287 	RPCRDMA_MAX_SEGS	= RPCRDMA_MAX_DATA_SEGS +
288 				  RPCRDMA_MAX_IOV_SEGS,
289 };
290 
291 /* Arguments for DMA mapping and registration */
292 struct rpcrdma_mr_seg {
293 	u32		mr_len;		/* length of segment */
294 	struct page	*mr_page;	/* underlying struct page */
295 	u64		mr_offset;	/* IN: page offset, OUT: iova */
296 };
297 
298 /* The Send SGE array is provisioned to send a maximum size
299  * inline request:
300  * - RPC-over-RDMA header
301  * - xdr_buf head iovec
302  * - RPCRDMA_MAX_INLINE bytes, in pages
303  * - xdr_buf tail iovec
304  *
305  * The actual number of array elements consumed by each RPC
306  * depends on the device's max_sge limit.
307  */
308 enum {
309 	RPCRDMA_MIN_SEND_SGES = 3,
310 	RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT,
311 	RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1,
312 };
313 
314 struct rpcrdma_buffer;
315 struct rpcrdma_req {
316 	struct list_head	rl_list;
317 	struct rpc_rqst		rl_slot;
318 	struct rpcrdma_rep	*rl_reply;
319 	struct xdr_stream	rl_stream;
320 	struct xdr_buf		rl_hdrbuf;
321 	struct ib_send_wr	rl_wr;
322 	struct rpcrdma_sendctx	*rl_sendctx;
323 	struct rpcrdma_regbuf	*rl_rdmabuf;	/* xprt header */
324 	struct rpcrdma_regbuf	*rl_sendbuf;	/* rq_snd_buf */
325 	struct rpcrdma_regbuf	*rl_recvbuf;	/* rq_rcv_buf */
326 
327 	struct list_head	rl_all;
328 	struct kref		rl_kref;
329 
330 	struct list_head	rl_free_mrs;
331 	struct list_head	rl_registered;
332 	struct rpcrdma_mr_seg	rl_segments[RPCRDMA_MAX_SEGS];
333 };
334 
335 static inline struct rpcrdma_req *
rpcr_to_rdmar(const struct rpc_rqst * rqst)336 rpcr_to_rdmar(const struct rpc_rqst *rqst)
337 {
338 	return container_of(rqst, struct rpcrdma_req, rl_slot);
339 }
340 
341 static inline void
rpcrdma_mr_push(struct rpcrdma_mr * mr,struct list_head * list)342 rpcrdma_mr_push(struct rpcrdma_mr *mr, struct list_head *list)
343 {
344 	list_add(&mr->mr_list, list);
345 }
346 
347 static inline struct rpcrdma_mr *
rpcrdma_mr_pop(struct list_head * list)348 rpcrdma_mr_pop(struct list_head *list)
349 {
350 	struct rpcrdma_mr *mr;
351 
352 	mr = list_first_entry_or_null(list, struct rpcrdma_mr, mr_list);
353 	if (mr)
354 		list_del_init(&mr->mr_list);
355 	return mr;
356 }
357 
358 /*
359  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
360  * inline requests/replies, and client/server credits.
361  *
362  * One of these is associated with a transport instance
363  */
364 struct rpcrdma_buffer {
365 	spinlock_t		rb_lock;
366 	struct list_head	rb_send_bufs;
367 	struct list_head	rb_mrs;
368 
369 	unsigned long		rb_sc_head;
370 	unsigned long		rb_sc_tail;
371 	unsigned long		rb_sc_last;
372 	struct rpcrdma_sendctx	**rb_sc_ctxs;
373 
374 	struct list_head	rb_allreqs;
375 	struct list_head	rb_all_mrs;
376 	struct list_head	rb_all_reps;
377 
378 	struct llist_head	rb_free_reps;
379 
380 	__be32			rb_max_requests;
381 	u32			rb_credits;	/* most recent credit grant */
382 
383 	u32			rb_bc_srv_max_requests;
384 	u32			rb_bc_max_requests;
385 
386 	struct work_struct	rb_refresh_worker;
387 };
388 
389 /*
390  * Statistics for RPCRDMA
391  */
392 struct rpcrdma_stats {
393 	/* accessed when sending a call */
394 	unsigned long		read_chunk_count;
395 	unsigned long		write_chunk_count;
396 	unsigned long		reply_chunk_count;
397 	unsigned long long	total_rdma_request;
398 
399 	/* rarely accessed error counters */
400 	unsigned long long	pullup_copy_count;
401 	unsigned long		hardway_register_count;
402 	unsigned long		failed_marshal_count;
403 	unsigned long		bad_reply_count;
404 	unsigned long		mrs_recycled;
405 	unsigned long		mrs_orphaned;
406 	unsigned long		mrs_allocated;
407 	unsigned long		empty_sendctx_q;
408 
409 	/* accessed when receiving a reply */
410 	unsigned long long	total_rdma_reply;
411 	unsigned long long	fixup_copy_count;
412 	unsigned long		reply_waits_for_send;
413 	unsigned long		local_inv_needed;
414 	unsigned long		nomsg_call_count;
415 	unsigned long		bcall_count;
416 };
417 
418 /*
419  * RPCRDMA transport -- encapsulates the structures above for
420  * integration with RPC.
421  *
422  * The contained structures are embedded, not pointers,
423  * for convenience. This structure need not be visible externally.
424  *
425  * It is allocated and initialized during mount, and released
426  * during unmount.
427  */
428 struct rpcrdma_xprt {
429 	struct rpc_xprt		rx_xprt;
430 	struct rpcrdma_ep	*rx_ep;
431 	struct rpcrdma_buffer	rx_buf;
432 	struct delayed_work	rx_connect_worker;
433 	struct rpc_timeout	rx_timeout;
434 	struct rpcrdma_stats	rx_stats;
435 };
436 
437 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
438 
439 static inline const char *
rpcrdma_addrstr(const struct rpcrdma_xprt * r_xprt)440 rpcrdma_addrstr(const struct rpcrdma_xprt *r_xprt)
441 {
442 	return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_ADDR];
443 }
444 
445 static inline const char *
rpcrdma_portstr(const struct rpcrdma_xprt * r_xprt)446 rpcrdma_portstr(const struct rpcrdma_xprt *r_xprt)
447 {
448 	return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_PORT];
449 }
450 
451 /* Setting this to 0 ensures interoperability with early servers.
452  * Setting this to 1 enhances certain unaligned read/write performance.
453  * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
454 extern int xprt_rdma_pad_optimize;
455 
456 /* This setting controls the hunt for a supported memory
457  * registration strategy.
458  */
459 extern unsigned int xprt_rdma_memreg_strategy;
460 
461 /*
462  * Endpoint calls - xprtrdma/verbs.c
463  */
464 void rpcrdma_force_disconnect(struct rpcrdma_ep *ep);
465 void rpcrdma_flush_disconnect(struct rpcrdma_xprt *r_xprt, struct ib_wc *wc);
466 int rpcrdma_xprt_connect(struct rpcrdma_xprt *r_xprt);
467 void rpcrdma_xprt_disconnect(struct rpcrdma_xprt *r_xprt);
468 
469 void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, int needed, bool temp);
470 
471 /*
472  * Buffer calls - xprtrdma/verbs.c
473  */
474 struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt,
475 				       size_t size);
476 int rpcrdma_req_setup(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req);
477 void rpcrdma_req_destroy(struct rpcrdma_req *req);
478 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
479 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
480 struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt);
481 
482 struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt);
483 void rpcrdma_mrs_refresh(struct rpcrdma_xprt *r_xprt);
484 
485 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
486 void rpcrdma_buffer_put(struct rpcrdma_buffer *buffers,
487 			struct rpcrdma_req *req);
488 void rpcrdma_rep_put(struct rpcrdma_buffer *buf, struct rpcrdma_rep *rep);
489 void rpcrdma_reply_put(struct rpcrdma_buffer *buffers, struct rpcrdma_req *req);
490 
491 bool rpcrdma_regbuf_realloc(struct rpcrdma_regbuf *rb, size_t size,
492 			    gfp_t flags);
493 bool __rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
494 			      struct rpcrdma_regbuf *rb);
495 
496 /**
497  * rpcrdma_regbuf_is_mapped - check if buffer is DMA mapped
498  *
499  * Returns true if the buffer is now mapped to rb->rg_device.
500  */
rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf * rb)501 static inline bool rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb)
502 {
503 	return rb->rg_device != NULL;
504 }
505 
506 /**
507  * rpcrdma_regbuf_dma_map - DMA-map a regbuf
508  * @r_xprt: controlling transport instance
509  * @rb: regbuf to be mapped
510  *
511  * Returns true if the buffer is currently DMA mapped.
512  */
rpcrdma_regbuf_dma_map(struct rpcrdma_xprt * r_xprt,struct rpcrdma_regbuf * rb)513 static inline bool rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
514 					  struct rpcrdma_regbuf *rb)
515 {
516 	if (likely(rpcrdma_regbuf_is_mapped(rb)))
517 		return true;
518 	return __rpcrdma_regbuf_dma_map(r_xprt, rb);
519 }
520 
521 /*
522  * Wrappers for chunk registration, shared by read/write chunk code.
523  */
524 
525 static inline enum dma_data_direction
rpcrdma_data_dir(bool writing)526 rpcrdma_data_dir(bool writing)
527 {
528 	return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
529 }
530 
531 /* Memory registration calls xprtrdma/frwr_ops.c
532  */
533 void frwr_reset(struct rpcrdma_req *req);
534 int frwr_query_device(struct rpcrdma_ep *ep, const struct ib_device *device);
535 int frwr_mr_init(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr);
536 void frwr_mr_release(struct rpcrdma_mr *mr);
537 struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
538 				struct rpcrdma_mr_seg *seg,
539 				int nsegs, bool writing, __be32 xid,
540 				struct rpcrdma_mr *mr);
541 int frwr_send(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req);
542 void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs);
543 void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req);
544 void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req);
545 int frwr_wp_create(struct rpcrdma_xprt *r_xprt);
546 
547 /*
548  * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
549  */
550 
551 enum rpcrdma_chunktype {
552 	rpcrdma_noch = 0,
553 	rpcrdma_noch_pullup,
554 	rpcrdma_noch_mapped,
555 	rpcrdma_readch,
556 	rpcrdma_areadch,
557 	rpcrdma_writech,
558 	rpcrdma_replych
559 };
560 
561 int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
562 			      struct rpcrdma_req *req, u32 hdrlen,
563 			      struct xdr_buf *xdr,
564 			      enum rpcrdma_chunktype rtype);
565 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc);
566 int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst);
567 void rpcrdma_set_max_header_sizes(struct rpcrdma_ep *ep);
568 void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt);
569 void rpcrdma_complete_rqst(struct rpcrdma_rep *rep);
570 void rpcrdma_unpin_rqst(struct rpcrdma_rep *rep);
571 void rpcrdma_reply_handler(struct rpcrdma_rep *rep);
572 
rpcrdma_set_xdrlen(struct xdr_buf * xdr,size_t len)573 static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len)
574 {
575 	xdr->head[0].iov_len = len;
576 	xdr->len = len;
577 }
578 
579 /* RPC/RDMA module init - xprtrdma/transport.c
580  */
581 extern unsigned int xprt_rdma_max_inline_read;
582 extern unsigned int xprt_rdma_max_inline_write;
583 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
584 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
585 void xprt_rdma_close(struct rpc_xprt *xprt);
586 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
587 int xprt_rdma_init(void);
588 void xprt_rdma_cleanup(void);
589 
590 /* Backchannel calls - xprtrdma/backchannel.c
591  */
592 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
593 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
594 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *);
595 unsigned int xprt_rdma_bc_max_slots(struct rpc_xprt *);
596 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
597 int xprt_rdma_bc_send_reply(struct rpc_rqst *rqst);
598 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
599 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
600 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
601 
602 extern struct xprt_class xprt_rdma_bc;
603 
604 #endif				/* _LINUX_SUNRPC_XPRT_RDMA_H */
605