xref: /openbmc/linux/net/sunrpc/xprtrdma/xprt_rdma.h (revision 113094f7)
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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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/workqueue.h>		/* struct work_struct */
49 
50 #include <rdma/rdma_cm.h>		/* RDMA connection api */
51 #include <rdma/ib_verbs.h>		/* RDMA verbs api */
52 
53 #include <linux/sunrpc/clnt.h> 		/* rpc_xprt */
54 #include <linux/sunrpc/rpc_rdma.h> 	/* RPC/RDMA protocol */
55 #include <linux/sunrpc/xprtrdma.h> 	/* xprt parameters */
56 
57 #define RDMA_RESOLVE_TIMEOUT	(5000)	/* 5 seconds */
58 #define RDMA_CONNECT_RETRY_MAX	(2)	/* retries if no listener backlog */
59 
60 #define RPCRDMA_BIND_TO		(60U * HZ)
61 #define RPCRDMA_INIT_REEST_TO	(5U * HZ)
62 #define RPCRDMA_MAX_REEST_TO	(30U * HZ)
63 #define RPCRDMA_IDLE_DISC_TO	(5U * 60 * HZ)
64 
65 /*
66  * Interface Adapter -- one per transport instance
67  */
68 struct rpcrdma_ia {
69 	struct rdma_cm_id 	*ri_id;
70 	struct ib_pd		*ri_pd;
71 	int			ri_async_rc;
72 	unsigned int		ri_max_segs;
73 	unsigned int		ri_max_frwr_depth;
74 	unsigned int		ri_max_send_sges;
75 	bool			ri_implicit_roundup;
76 	enum ib_mr_type		ri_mrtype;
77 	unsigned long		ri_flags;
78 	struct completion	ri_done;
79 	struct completion	ri_remove_done;
80 };
81 
82 enum {
83 	RPCRDMA_IAF_REMOVING = 0,
84 };
85 
86 /*
87  * RDMA Endpoint -- one per transport instance
88  */
89 
90 struct rpcrdma_ep {
91 	unsigned int		rep_send_count;
92 	unsigned int		rep_send_batch;
93 	unsigned int		rep_max_inline_send;
94 	unsigned int		rep_max_inline_recv;
95 	int			rep_connected;
96 	struct ib_qp_init_attr	rep_attr;
97 	wait_queue_head_t 	rep_connect_wait;
98 	struct rpcrdma_connect_private	rep_cm_private;
99 	struct rdma_conn_param	rep_remote_cma;
100 	unsigned int		rep_max_requests;	/* set by /proc */
101 	unsigned int		rep_inline_send;	/* negotiated */
102 	unsigned int		rep_inline_recv;	/* negotiated */
103 	int			rep_receive_count;
104 };
105 
106 /* Pre-allocate extra Work Requests for handling backward receives
107  * and sends. This is a fixed value because the Work Queues are
108  * allocated when the forward channel is set up, long before the
109  * backchannel is provisioned. This value is two times
110  * NFS4_DEF_CB_SLOT_TABLE_SIZE.
111  */
112 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
113 #define RPCRDMA_BACKWARD_WRS (32)
114 #else
115 #define RPCRDMA_BACKWARD_WRS (0)
116 #endif
117 
118 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
119  *
120  * The below structure appears at the front of a large region of kmalloc'd
121  * memory, which always starts on a good alignment boundary.
122  */
123 
124 struct rpcrdma_regbuf {
125 	struct ib_sge		rg_iov;
126 	struct ib_device	*rg_device;
127 	enum dma_data_direction	rg_direction;
128 	void			*rg_data;
129 };
130 
131 static inline u64 rdmab_addr(struct rpcrdma_regbuf *rb)
132 {
133 	return rb->rg_iov.addr;
134 }
135 
136 static inline u32 rdmab_length(struct rpcrdma_regbuf *rb)
137 {
138 	return rb->rg_iov.length;
139 }
140 
141 static inline u32 rdmab_lkey(struct rpcrdma_regbuf *rb)
142 {
143 	return rb->rg_iov.lkey;
144 }
145 
146 static inline struct ib_device *rdmab_device(struct rpcrdma_regbuf *rb)
147 {
148 	return rb->rg_device;
149 }
150 
151 static inline void *rdmab_data(const struct rpcrdma_regbuf *rb)
152 {
153 	return rb->rg_data;
154 }
155 
156 #define RPCRDMA_DEF_GFP		(GFP_NOIO | __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 8. This prevents less-capable devices and
161  * memory registrations from overrunning the Send buffer
162  * while building chunk lists.
163  *
164  * Elements of the Read list take up more room than the
165  * Write list or Reply chunk. 8 read segments means the Read
166  * list (or Write list or Reply chunk) cannot consume more
167  * than
168  *
169  * ((8 + 2) * read segment size) + 1 XDR words, or 244 bytes.
170  *
171  * And the fixed part of the header is another 24 bytes.
172  *
173  * The smallest inline threshold is 1024 bytes, ensuring that
174  * at least 750 bytes are available for RPC messages.
175  */
176 enum {
177 	RPCRDMA_MAX_HDR_SEGS = 8,
178 	RPCRDMA_HDRBUF_SIZE = 256,
179 };
180 
181 /*
182  * struct rpcrdma_rep -- this structure encapsulates state required
183  * to receive and complete an RPC Reply, asychronously. It needs
184  * several pieces of state:
185  *
186  *   o receive buffer and ib_sge (donated to provider)
187  *   o status of receive (success or not, length, inv rkey)
188  *   o bookkeeping state to get run by reply handler (XDR stream)
189  *
190  * These structures are allocated during transport initialization.
191  * N of these are associated with a transport instance, managed by
192  * struct rpcrdma_buffer. N is the max number of outstanding RPCs.
193  */
194 
195 struct rpcrdma_rep {
196 	struct ib_cqe		rr_cqe;
197 	__be32			rr_xid;
198 	__be32			rr_vers;
199 	__be32			rr_proc;
200 	int			rr_wc_flags;
201 	u32			rr_inv_rkey;
202 	bool			rr_temp;
203 	struct rpcrdma_regbuf	*rr_rdmabuf;
204 	struct rpcrdma_xprt	*rr_rxprt;
205 	struct work_struct	rr_work;
206 	struct xdr_buf		rr_hdrbuf;
207 	struct xdr_stream	rr_stream;
208 	struct rpc_rqst		*rr_rqst;
209 	struct list_head	rr_list;
210 	struct ib_recv_wr	rr_recv_wr;
211 };
212 
213 /* To reduce the rate at which a transport invokes ib_post_recv
214  * (and thus the hardware doorbell rate), xprtrdma posts Receive
215  * WRs in batches.
216  *
217  * Setting this to zero disables Receive post batching.
218  */
219 enum {
220 	RPCRDMA_MAX_RECV_BATCH = 7,
221 };
222 
223 /* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes
224  */
225 struct rpcrdma_req;
226 struct rpcrdma_xprt;
227 struct rpcrdma_sendctx {
228 	struct ib_send_wr	sc_wr;
229 	struct ib_cqe		sc_cqe;
230 	struct ib_device	*sc_device;
231 	struct rpcrdma_xprt	*sc_xprt;
232 	struct rpcrdma_req	*sc_req;
233 	unsigned int		sc_unmap_count;
234 	struct ib_sge		sc_sges[];
235 };
236 
237 /*
238  * struct rpcrdma_mr - external memory region metadata
239  *
240  * An external memory region is any buffer or page that is registered
241  * on the fly (ie, not pre-registered).
242  */
243 enum rpcrdma_frwr_state {
244 	FRWR_IS_INVALID,	/* ready to be used */
245 	FRWR_IS_VALID,		/* in use */
246 	FRWR_FLUSHED_FR,	/* flushed FASTREG WR */
247 	FRWR_FLUSHED_LI,	/* flushed LOCALINV WR */
248 };
249 
250 struct rpcrdma_frwr {
251 	struct ib_mr			*fr_mr;
252 	struct ib_cqe			fr_cqe;
253 	enum rpcrdma_frwr_state		fr_state;
254 	struct completion		fr_linv_done;
255 	union {
256 		struct ib_reg_wr	fr_regwr;
257 		struct ib_send_wr	fr_invwr;
258 	};
259 };
260 
261 struct rpcrdma_mr {
262 	struct list_head	mr_list;
263 	struct scatterlist	*mr_sg;
264 	int			mr_nents;
265 	enum dma_data_direction	mr_dir;
266 	struct rpcrdma_frwr	frwr;
267 	struct rpcrdma_xprt	*mr_xprt;
268 	u32			mr_handle;
269 	u32			mr_length;
270 	u64			mr_offset;
271 	struct work_struct	mr_recycle;
272 	struct list_head	mr_all;
273 };
274 
275 /*
276  * struct rpcrdma_req -- structure central to the request/reply sequence.
277  *
278  * N of these are associated with a transport instance, and stored in
279  * struct rpcrdma_buffer. N is the max number of outstanding requests.
280  *
281  * It includes pre-registered buffer memory for send AND recv.
282  * The recv buffer, however, is not owned by this structure, and
283  * is "donated" to the hardware when a recv is posted. When a
284  * reply is handled, the recv buffer used is given back to the
285  * struct rpcrdma_req associated with the request.
286  *
287  * In addition to the basic memory, this structure includes an array
288  * of iovs for send operations. The reason is that the iovs passed to
289  * ib_post_{send,recv} must not be modified until the work request
290  * completes.
291  */
292 
293 /* Maximum number of page-sized "segments" per chunk list to be
294  * registered or invalidated. Must handle a Reply chunk:
295  */
296 enum {
297 	RPCRDMA_MAX_IOV_SEGS	= 3,
298 	RPCRDMA_MAX_DATA_SEGS	= ((1 * 1024 * 1024) / PAGE_SIZE) + 1,
299 	RPCRDMA_MAX_SEGS	= RPCRDMA_MAX_DATA_SEGS +
300 				  RPCRDMA_MAX_IOV_SEGS,
301 };
302 
303 struct rpcrdma_mr_seg {		/* chunk descriptors */
304 	u32		mr_len;		/* length of chunk or segment */
305 	struct page	*mr_page;	/* owning page, if any */
306 	char		*mr_offset;	/* kva if no page, else offset */
307 };
308 
309 /* The Send SGE array is provisioned to send a maximum size
310  * inline request:
311  * - RPC-over-RDMA header
312  * - xdr_buf head iovec
313  * - RPCRDMA_MAX_INLINE bytes, in pages
314  * - xdr_buf tail iovec
315  *
316  * The actual number of array elements consumed by each RPC
317  * depends on the device's max_sge limit.
318  */
319 enum {
320 	RPCRDMA_MIN_SEND_SGES = 3,
321 	RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT,
322 	RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1,
323 };
324 
325 struct rpcrdma_buffer;
326 struct rpcrdma_req {
327 	struct list_head	rl_list;
328 	struct rpc_rqst		rl_slot;
329 	struct rpcrdma_buffer	*rl_buffer;
330 	struct rpcrdma_rep	*rl_reply;
331 	struct xdr_stream	rl_stream;
332 	struct xdr_buf		rl_hdrbuf;
333 	struct rpcrdma_sendctx	*rl_sendctx;
334 	struct rpcrdma_regbuf	*rl_rdmabuf;	/* xprt header */
335 	struct rpcrdma_regbuf	*rl_sendbuf;	/* rq_snd_buf */
336 	struct rpcrdma_regbuf	*rl_recvbuf;	/* rq_rcv_buf */
337 
338 	struct list_head	rl_all;
339 	unsigned long		rl_flags;
340 
341 	struct list_head	rl_registered;	/* registered segments */
342 	struct rpcrdma_mr_seg	rl_segments[RPCRDMA_MAX_SEGS];
343 };
344 
345 /* rl_flags */
346 enum {
347 	RPCRDMA_REQ_F_PENDING = 0,
348 	RPCRDMA_REQ_F_TX_RESOURCES,
349 };
350 
351 static inline struct rpcrdma_req *
352 rpcr_to_rdmar(const struct rpc_rqst *rqst)
353 {
354 	return container_of(rqst, struct rpcrdma_req, rl_slot);
355 }
356 
357 static inline void
358 rpcrdma_mr_push(struct rpcrdma_mr *mr, struct list_head *list)
359 {
360 	list_add_tail(&mr->mr_list, list);
361 }
362 
363 static inline struct rpcrdma_mr *
364 rpcrdma_mr_pop(struct list_head *list)
365 {
366 	struct rpcrdma_mr *mr;
367 
368 	mr = list_first_entry(list, struct rpcrdma_mr, mr_list);
369 	list_del_init(&mr->mr_list);
370 	return mr;
371 }
372 
373 /*
374  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
375  * inline requests/replies, and client/server credits.
376  *
377  * One of these is associated with a transport instance
378  */
379 struct rpcrdma_buffer {
380 	spinlock_t		rb_mrlock;	/* protect rb_mrs list */
381 	struct list_head	rb_mrs;
382 	struct list_head	rb_all;
383 
384 	unsigned long		rb_sc_head;
385 	unsigned long		rb_sc_tail;
386 	unsigned long		rb_sc_last;
387 	struct rpcrdma_sendctx	**rb_sc_ctxs;
388 
389 	spinlock_t		rb_lock;	/* protect buf lists */
390 	struct list_head	rb_send_bufs;
391 	struct list_head	rb_recv_bufs;
392 	struct list_head	rb_allreqs;
393 
394 	unsigned long		rb_flags;
395 	u32			rb_max_requests;
396 	u32			rb_credits;	/* most recent credit grant */
397 
398 	u32			rb_bc_srv_max_requests;
399 	u32			rb_bc_max_requests;
400 
401 	struct workqueue_struct *rb_completion_wq;
402 	struct delayed_work	rb_refresh_worker;
403 };
404 
405 /* rb_flags */
406 enum {
407 	RPCRDMA_BUF_F_EMPTY_SCQ = 0,
408 };
409 
410 /*
411  * Statistics for RPCRDMA
412  */
413 struct rpcrdma_stats {
414 	/* accessed when sending a call */
415 	unsigned long		read_chunk_count;
416 	unsigned long		write_chunk_count;
417 	unsigned long		reply_chunk_count;
418 	unsigned long long	total_rdma_request;
419 
420 	/* rarely accessed error counters */
421 	unsigned long long	pullup_copy_count;
422 	unsigned long		hardway_register_count;
423 	unsigned long		failed_marshal_count;
424 	unsigned long		bad_reply_count;
425 	unsigned long		mrs_recycled;
426 	unsigned long		mrs_orphaned;
427 	unsigned long		mrs_allocated;
428 	unsigned long		empty_sendctx_q;
429 
430 	/* accessed when receiving a reply */
431 	unsigned long long	total_rdma_reply;
432 	unsigned long long	fixup_copy_count;
433 	unsigned long		reply_waits_for_send;
434 	unsigned long		local_inv_needed;
435 	unsigned long		nomsg_call_count;
436 	unsigned long		bcall_count;
437 };
438 
439 /*
440  * RPCRDMA transport -- encapsulates the structures above for
441  * integration with RPC.
442  *
443  * The contained structures are embedded, not pointers,
444  * for convenience. This structure need not be visible externally.
445  *
446  * It is allocated and initialized during mount, and released
447  * during unmount.
448  */
449 struct rpcrdma_xprt {
450 	struct rpc_xprt		rx_xprt;
451 	struct rpcrdma_ia	rx_ia;
452 	struct rpcrdma_ep	rx_ep;
453 	struct rpcrdma_buffer	rx_buf;
454 	struct delayed_work	rx_connect_worker;
455 	struct rpcrdma_stats	rx_stats;
456 };
457 
458 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
459 
460 static inline const char *
461 rpcrdma_addrstr(const struct rpcrdma_xprt *r_xprt)
462 {
463 	return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_ADDR];
464 }
465 
466 static inline const char *
467 rpcrdma_portstr(const struct rpcrdma_xprt *r_xprt)
468 {
469 	return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_PORT];
470 }
471 
472 /* Setting this to 0 ensures interoperability with early servers.
473  * Setting this to 1 enhances certain unaligned read/write performance.
474  * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
475 extern int xprt_rdma_pad_optimize;
476 
477 /* This setting controls the hunt for a supported memory
478  * registration strategy.
479  */
480 extern unsigned int xprt_rdma_memreg_strategy;
481 
482 /*
483  * Interface Adapter calls - xprtrdma/verbs.c
484  */
485 int rpcrdma_ia_open(struct rpcrdma_xprt *xprt);
486 void rpcrdma_ia_remove(struct rpcrdma_ia *ia);
487 void rpcrdma_ia_close(struct rpcrdma_ia *);
488 
489 /*
490  * Endpoint calls - xprtrdma/verbs.c
491  */
492 int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt);
493 void rpcrdma_ep_destroy(struct rpcrdma_xprt *r_xprt);
494 int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
495 void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
496 
497 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
498 				struct rpcrdma_req *);
499 
500 /*
501  * Buffer calls - xprtrdma/verbs.c
502  */
503 struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, size_t size,
504 				       gfp_t flags);
505 void rpcrdma_req_destroy(struct rpcrdma_req *req);
506 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
507 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
508 struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt);
509 
510 struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt);
511 void rpcrdma_mr_put(struct rpcrdma_mr *mr);
512 void rpcrdma_mr_unmap_and_put(struct rpcrdma_mr *mr);
513 
514 static inline void
515 rpcrdma_mr_recycle(struct rpcrdma_mr *mr)
516 {
517 	schedule_work(&mr->mr_recycle);
518 }
519 
520 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
521 void rpcrdma_buffer_put(struct rpcrdma_req *);
522 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
523 
524 bool rpcrdma_regbuf_realloc(struct rpcrdma_regbuf *rb, size_t size,
525 			    gfp_t flags);
526 bool __rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
527 			      struct rpcrdma_regbuf *rb);
528 
529 /**
530  * rpcrdma_regbuf_is_mapped - check if buffer is DMA mapped
531  *
532  * Returns true if the buffer is now mapped to rb->rg_device.
533  */
534 static inline bool rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb)
535 {
536 	return rb->rg_device != NULL;
537 }
538 
539 /**
540  * rpcrdma_regbuf_dma_map - DMA-map a regbuf
541  * @r_xprt: controlling transport instance
542  * @rb: regbuf to be mapped
543  *
544  * Returns true if the buffer is currently DMA mapped.
545  */
546 static inline bool rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
547 					  struct rpcrdma_regbuf *rb)
548 {
549 	if (likely(rpcrdma_regbuf_is_mapped(rb)))
550 		return true;
551 	return __rpcrdma_regbuf_dma_map(r_xprt, rb);
552 }
553 
554 /*
555  * Wrappers for chunk registration, shared by read/write chunk code.
556  */
557 
558 static inline enum dma_data_direction
559 rpcrdma_data_dir(bool writing)
560 {
561 	return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
562 }
563 
564 /* Memory registration calls xprtrdma/frwr_ops.c
565  */
566 bool frwr_is_supported(struct ib_device *device);
567 int frwr_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep);
568 int frwr_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr);
569 void frwr_release_mr(struct rpcrdma_mr *mr);
570 size_t frwr_maxpages(struct rpcrdma_xprt *r_xprt);
571 struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
572 				struct rpcrdma_mr_seg *seg,
573 				int nsegs, bool writing, __be32 xid,
574 				struct rpcrdma_mr **mr);
575 int frwr_send(struct rpcrdma_ia *ia, struct rpcrdma_req *req);
576 void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs);
577 void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt,
578 		     struct list_head *mrs);
579 
580 /*
581  * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
582  */
583 
584 enum rpcrdma_chunktype {
585 	rpcrdma_noch = 0,
586 	rpcrdma_readch,
587 	rpcrdma_areadch,
588 	rpcrdma_writech,
589 	rpcrdma_replych
590 };
591 
592 int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
593 			      struct rpcrdma_req *req, u32 hdrlen,
594 			      struct xdr_buf *xdr,
595 			      enum rpcrdma_chunktype rtype);
596 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc);
597 int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst);
598 void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *);
599 void rpcrdma_complete_rqst(struct rpcrdma_rep *rep);
600 void rpcrdma_reply_handler(struct rpcrdma_rep *rep);
601 void rpcrdma_release_rqst(struct rpcrdma_xprt *r_xprt,
602 			  struct rpcrdma_req *req);
603 void rpcrdma_deferred_completion(struct work_struct *work);
604 
605 static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len)
606 {
607 	xdr->head[0].iov_len = len;
608 	xdr->len = len;
609 }
610 
611 /* RPC/RDMA module init - xprtrdma/transport.c
612  */
613 extern unsigned int xprt_rdma_slot_table_entries;
614 extern unsigned int xprt_rdma_max_inline_read;
615 extern unsigned int xprt_rdma_max_inline_write;
616 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
617 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
618 void xprt_rdma_close(struct rpc_xprt *xprt);
619 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
620 int xprt_rdma_init(void);
621 void xprt_rdma_cleanup(void);
622 
623 /* Backchannel calls - xprtrdma/backchannel.c
624  */
625 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
626 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
627 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *);
628 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
629 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
630 int xprt_rdma_bc_send_reply(struct rpc_rqst *rqst);
631 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
632 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
633 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
634 
635 extern struct xprt_class xprt_rdma_bc;
636 
637 #endif				/* _LINUX_SUNRPC_XPRT_RDMA_H */
638