xref: /openbmc/linux/net/sunrpc/xprtrdma/xprt_rdma.h (revision 79a93295)
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 	struct ib_device	*ri_device;
69 	struct rdma_cm_id 	*ri_id;
70 	struct ib_pd		*ri_pd;
71 	struct completion	ri_done;
72 	int			ri_async_rc;
73 	unsigned int		ri_max_segs;
74 	unsigned int		ri_max_frmr_depth;
75 	unsigned int		ri_max_inline_write;
76 	unsigned int		ri_max_inline_read;
77 	bool			ri_reminv_expected;
78 	enum ib_mr_type		ri_mrtype;
79 	struct ib_qp_attr	ri_qp_attr;
80 	struct ib_qp_init_attr	ri_qp_init_attr;
81 };
82 
83 /*
84  * RDMA Endpoint -- one per transport instance
85  */
86 
87 struct rpcrdma_ep {
88 	atomic_t		rep_cqcount;
89 	int			rep_cqinit;
90 	int			rep_connected;
91 	struct ib_qp_init_attr	rep_attr;
92 	wait_queue_head_t 	rep_connect_wait;
93 	struct rpcrdma_connect_private	rep_cm_private;
94 	struct rdma_conn_param	rep_remote_cma;
95 	struct sockaddr_storage	rep_remote_addr;
96 	struct delayed_work	rep_connect_worker;
97 };
98 
99 static inline void
100 rpcrdma_init_cqcount(struct rpcrdma_ep *ep, int count)
101 {
102 	atomic_set(&ep->rep_cqcount, ep->rep_cqinit - count);
103 }
104 
105 /* To update send queue accounting, provider must take a
106  * send completion every now and then.
107  */
108 static inline void
109 rpcrdma_set_signaled(struct rpcrdma_ep *ep, struct ib_send_wr *send_wr)
110 {
111 	send_wr->send_flags = 0;
112 	if (unlikely(atomic_sub_return(1, &ep->rep_cqcount) <= 0)) {
113 		rpcrdma_init_cqcount(ep, 0);
114 		send_wr->send_flags = IB_SEND_SIGNALED;
115 	}
116 }
117 
118 /* Pre-allocate extra Work Requests for handling backward receives
119  * and sends. This is a fixed value because the Work Queues are
120  * allocated when the forward channel is set up.
121  */
122 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
123 #define RPCRDMA_BACKWARD_WRS		(8)
124 #else
125 #define RPCRDMA_BACKWARD_WRS		(0)
126 #endif
127 
128 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
129  *
130  * The below structure appears at the front of a large region of kmalloc'd
131  * memory, which always starts on a good alignment boundary.
132  */
133 
134 struct rpcrdma_regbuf {
135 	struct ib_sge		rg_iov;
136 	struct ib_device	*rg_device;
137 	enum dma_data_direction	rg_direction;
138 	__be32			rg_base[0] __attribute__ ((aligned(256)));
139 };
140 
141 static inline u64
142 rdmab_addr(struct rpcrdma_regbuf *rb)
143 {
144 	return rb->rg_iov.addr;
145 }
146 
147 static inline u32
148 rdmab_length(struct rpcrdma_regbuf *rb)
149 {
150 	return rb->rg_iov.length;
151 }
152 
153 static inline u32
154 rdmab_lkey(struct rpcrdma_regbuf *rb)
155 {
156 	return rb->rg_iov.lkey;
157 }
158 
159 static inline struct rpcrdma_msg *
160 rdmab_to_msg(struct rpcrdma_regbuf *rb)
161 {
162 	return (struct rpcrdma_msg *)rb->rg_base;
163 }
164 
165 #define RPCRDMA_DEF_GFP		(GFP_NOIO | __GFP_NOWARN)
166 
167 /* To ensure a transport can always make forward progress,
168  * the number of RDMA segments allowed in header chunk lists
169  * is capped at 8. This prevents less-capable devices and
170  * memory registrations from overrunning the Send buffer
171  * while building chunk lists.
172  *
173  * Elements of the Read list take up more room than the
174  * Write list or Reply chunk. 8 read segments means the Read
175  * list (or Write list or Reply chunk) cannot consume more
176  * than
177  *
178  * ((8 + 2) * read segment size) + 1 XDR words, or 244 bytes.
179  *
180  * And the fixed part of the header is another 24 bytes.
181  *
182  * The smallest inline threshold is 1024 bytes, ensuring that
183  * at least 750 bytes are available for RPC messages.
184  */
185 enum {
186 	RPCRDMA_MAX_HDR_SEGS = 8,
187 	RPCRDMA_HDRBUF_SIZE = 256,
188 };
189 
190 /*
191  * struct rpcrdma_rep -- this structure encapsulates state required to recv
192  * and complete a reply, asychronously. It needs several pieces of
193  * state:
194  *   o recv buffer (posted to provider)
195  *   o ib_sge (also donated to provider)
196  *   o status of reply (length, success or not)
197  *   o bookkeeping state to get run by reply handler (list, etc)
198  *
199  * These are allocated during initialization, per-transport instance.
200  *
201  * N of these are associated with a transport instance, and stored in
202  * struct rpcrdma_buffer. N is the max number of outstanding requests.
203  */
204 
205 struct rpcrdma_rep {
206 	struct ib_cqe		rr_cqe;
207 	unsigned int		rr_len;
208 	int			rr_wc_flags;
209 	u32			rr_inv_rkey;
210 	struct ib_device	*rr_device;
211 	struct rpcrdma_xprt	*rr_rxprt;
212 	struct work_struct	rr_work;
213 	struct list_head	rr_list;
214 	struct ib_recv_wr	rr_recv_wr;
215 	struct rpcrdma_regbuf	*rr_rdmabuf;
216 };
217 
218 #define RPCRDMA_BAD_LEN		(~0U)
219 
220 /*
221  * struct rpcrdma_mw - external memory region metadata
222  *
223  * An external memory region is any buffer or page that is registered
224  * on the fly (ie, not pre-registered).
225  *
226  * Each rpcrdma_buffer has a list of free MWs anchored in rb_mws. During
227  * call_allocate, rpcrdma_buffer_get() assigns one to each segment in
228  * an rpcrdma_req. Then rpcrdma_register_external() grabs these to keep
229  * track of registration metadata while each RPC is pending.
230  * rpcrdma_deregister_external() uses this metadata to unmap and
231  * release these resources when an RPC is complete.
232  */
233 enum rpcrdma_frmr_state {
234 	FRMR_IS_INVALID,	/* ready to be used */
235 	FRMR_IS_VALID,		/* in use */
236 	FRMR_FLUSHED_FR,	/* flushed FASTREG WR */
237 	FRMR_FLUSHED_LI,	/* flushed LOCALINV WR */
238 };
239 
240 struct rpcrdma_frmr {
241 	struct ib_mr			*fr_mr;
242 	struct ib_cqe			fr_cqe;
243 	enum rpcrdma_frmr_state		fr_state;
244 	struct completion		fr_linv_done;
245 	union {
246 		struct ib_reg_wr	fr_regwr;
247 		struct ib_send_wr	fr_invwr;
248 	};
249 };
250 
251 struct rpcrdma_fmr {
252 	struct ib_fmr		*fm_mr;
253 	u64			*fm_physaddrs;
254 };
255 
256 struct rpcrdma_mw {
257 	struct list_head	mw_list;
258 	struct scatterlist	*mw_sg;
259 	int			mw_nents;
260 	enum dma_data_direction	mw_dir;
261 	union {
262 		struct rpcrdma_fmr	fmr;
263 		struct rpcrdma_frmr	frmr;
264 	};
265 	struct rpcrdma_xprt	*mw_xprt;
266 	u32			mw_handle;
267 	u32			mw_length;
268 	u64			mw_offset;
269 	struct list_head	mw_all;
270 };
271 
272 /*
273  * struct rpcrdma_req -- structure central to the request/reply sequence.
274  *
275  * N of these are associated with a transport instance, and stored in
276  * struct rpcrdma_buffer. N is the max number of outstanding requests.
277  *
278  * It includes pre-registered buffer memory for send AND recv.
279  * The recv buffer, however, is not owned by this structure, and
280  * is "donated" to the hardware when a recv is posted. When a
281  * reply is handled, the recv buffer used is given back to the
282  * struct rpcrdma_req associated with the request.
283  *
284  * In addition to the basic memory, this structure includes an array
285  * of iovs for send operations. The reason is that the iovs passed to
286  * ib_post_{send,recv} must not be modified until the work request
287  * completes.
288  */
289 
290 /* Maximum number of page-sized "segments" per chunk list to be
291  * registered or invalidated. Must handle a Reply chunk:
292  */
293 enum {
294 	RPCRDMA_MAX_IOV_SEGS	= 3,
295 	RPCRDMA_MAX_DATA_SEGS	= ((1 * 1024 * 1024) / PAGE_SIZE) + 1,
296 	RPCRDMA_MAX_SEGS	= RPCRDMA_MAX_DATA_SEGS +
297 				  RPCRDMA_MAX_IOV_SEGS,
298 };
299 
300 struct rpcrdma_mr_seg {		/* chunk descriptors */
301 	u32		mr_len;		/* length of chunk or segment */
302 	struct page	*mr_page;	/* owning page, if any */
303 	char		*mr_offset;	/* kva if no page, else offset */
304 };
305 
306 /* Reserve enough Send SGEs to send a maximum size inline request:
307  * - RPC-over-RDMA header
308  * - xdr_buf head iovec
309  * - RPCRDMA_MAX_INLINE bytes, possibly unaligned, in pages
310  * - xdr_buf tail iovec
311  */
312 enum {
313 	RPCRDMA_MAX_SEND_PAGES = PAGE_SIZE + RPCRDMA_MAX_INLINE - 1,
314 	RPCRDMA_MAX_PAGE_SGES = (RPCRDMA_MAX_SEND_PAGES >> PAGE_SHIFT) + 1,
315 	RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1,
316 };
317 
318 struct rpcrdma_buffer;
319 struct rpcrdma_req {
320 	struct list_head	rl_free;
321 	unsigned int		rl_mapped_sges;
322 	unsigned int		rl_connect_cookie;
323 	struct rpcrdma_buffer	*rl_buffer;
324 	struct rpcrdma_rep	*rl_reply;
325 	struct ib_send_wr	rl_send_wr;
326 	struct ib_sge		rl_send_sge[RPCRDMA_MAX_SEND_SGES];
327 	struct rpcrdma_regbuf	*rl_rdmabuf;	/* xprt header */
328 	struct rpcrdma_regbuf	*rl_sendbuf;	/* rq_snd_buf */
329 	struct rpcrdma_regbuf	*rl_recvbuf;	/* rq_rcv_buf */
330 
331 	struct ib_cqe		rl_cqe;
332 	struct list_head	rl_all;
333 	bool			rl_backchannel;
334 
335 	struct list_head	rl_registered;	/* registered segments */
336 	struct rpcrdma_mr_seg	rl_segments[RPCRDMA_MAX_SEGS];
337 };
338 
339 static inline void
340 rpcrdma_set_xprtdata(struct rpc_rqst *rqst, struct rpcrdma_req *req)
341 {
342 	rqst->rq_xprtdata = req;
343 }
344 
345 static inline struct rpcrdma_req *
346 rpcr_to_rdmar(struct rpc_rqst *rqst)
347 {
348 	return rqst->rq_xprtdata;
349 }
350 
351 /*
352  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
353  * inline requests/replies, and client/server credits.
354  *
355  * One of these is associated with a transport instance
356  */
357 struct rpcrdma_buffer {
358 	spinlock_t		rb_mwlock;	/* protect rb_mws list */
359 	struct list_head	rb_mws;
360 	struct list_head	rb_all;
361 	char			*rb_pool;
362 
363 	spinlock_t		rb_lock;	/* protect buf lists */
364 	int			rb_send_count, rb_recv_count;
365 	struct list_head	rb_send_bufs;
366 	struct list_head	rb_recv_bufs;
367 	u32			rb_max_requests;
368 	atomic_t		rb_credits;	/* most recent credit grant */
369 
370 	u32			rb_bc_srv_max_requests;
371 	spinlock_t		rb_reqslock;	/* protect rb_allreqs */
372 	struct list_head	rb_allreqs;
373 
374 	u32			rb_bc_max_requests;
375 
376 	spinlock_t		rb_recovery_lock; /* protect rb_stale_mrs */
377 	struct list_head	rb_stale_mrs;
378 	struct delayed_work	rb_recovery_worker;
379 	struct delayed_work	rb_refresh_worker;
380 };
381 #define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)
382 
383 /*
384  * Internal structure for transport instance creation. This
385  * exists primarily for modularity.
386  *
387  * This data should be set with mount options
388  */
389 struct rpcrdma_create_data_internal {
390 	struct sockaddr_storage	addr;	/* RDMA server address */
391 	unsigned int	max_requests;	/* max requests (slots) in flight */
392 	unsigned int	rsize;		/* mount rsize - max read hdr+data */
393 	unsigned int	wsize;		/* mount wsize - max write hdr+data */
394 	unsigned int	inline_rsize;	/* max non-rdma read data payload */
395 	unsigned int	inline_wsize;	/* max non-rdma write data payload */
396 	unsigned int	padding;	/* non-rdma write header padding */
397 };
398 
399 /*
400  * Statistics for RPCRDMA
401  */
402 struct rpcrdma_stats {
403 	unsigned long		read_chunk_count;
404 	unsigned long		write_chunk_count;
405 	unsigned long		reply_chunk_count;
406 
407 	unsigned long long	total_rdma_request;
408 	unsigned long long	total_rdma_reply;
409 
410 	unsigned long long	pullup_copy_count;
411 	unsigned long long	fixup_copy_count;
412 	unsigned long		hardway_register_count;
413 	unsigned long		failed_marshal_count;
414 	unsigned long		bad_reply_count;
415 	unsigned long		nomsg_call_count;
416 	unsigned long		bcall_count;
417 	unsigned long		mrs_recovered;
418 	unsigned long		mrs_orphaned;
419 	unsigned long		mrs_allocated;
420 	unsigned long		local_inv_needed;
421 };
422 
423 /*
424  * Per-registration mode operations
425  */
426 struct rpcrdma_xprt;
427 struct rpcrdma_memreg_ops {
428 	int		(*ro_map)(struct rpcrdma_xprt *,
429 				  struct rpcrdma_mr_seg *, int, bool,
430 				  struct rpcrdma_mw **);
431 	void		(*ro_unmap_sync)(struct rpcrdma_xprt *,
432 					 struct rpcrdma_req *);
433 	void		(*ro_unmap_safe)(struct rpcrdma_xprt *,
434 					 struct rpcrdma_req *, bool);
435 	void		(*ro_recover_mr)(struct rpcrdma_mw *);
436 	int		(*ro_open)(struct rpcrdma_ia *,
437 				   struct rpcrdma_ep *,
438 				   struct rpcrdma_create_data_internal *);
439 	size_t		(*ro_maxpages)(struct rpcrdma_xprt *);
440 	int		(*ro_init_mr)(struct rpcrdma_ia *,
441 				      struct rpcrdma_mw *);
442 	void		(*ro_release_mr)(struct rpcrdma_mw *);
443 	const char	*ro_displayname;
444 	const int	ro_send_w_inv_ok;
445 };
446 
447 extern const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops;
448 extern const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops;
449 
450 /*
451  * RPCRDMA transport -- encapsulates the structures above for
452  * integration with RPC.
453  *
454  * The contained structures are embedded, not pointers,
455  * for convenience. This structure need not be visible externally.
456  *
457  * It is allocated and initialized during mount, and released
458  * during unmount.
459  */
460 struct rpcrdma_xprt {
461 	struct rpc_xprt		rx_xprt;
462 	struct rpcrdma_ia	rx_ia;
463 	struct rpcrdma_ep	rx_ep;
464 	struct rpcrdma_buffer	rx_buf;
465 	struct rpcrdma_create_data_internal rx_data;
466 	struct delayed_work	rx_connect_worker;
467 	struct rpcrdma_stats	rx_stats;
468 };
469 
470 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
471 #define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
472 
473 /* Setting this to 0 ensures interoperability with early servers.
474  * Setting this to 1 enhances certain unaligned read/write performance.
475  * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
476 extern int xprt_rdma_pad_optimize;
477 
478 /*
479  * Interface Adapter calls - xprtrdma/verbs.c
480  */
481 int rpcrdma_ia_open(struct rpcrdma_xprt *, struct sockaddr *, int);
482 void rpcrdma_ia_close(struct rpcrdma_ia *);
483 bool frwr_is_supported(struct rpcrdma_ia *);
484 bool fmr_is_supported(struct rpcrdma_ia *);
485 
486 /*
487  * Endpoint calls - xprtrdma/verbs.c
488  */
489 int rpcrdma_ep_create(struct rpcrdma_ep *, struct rpcrdma_ia *,
490 				struct rpcrdma_create_data_internal *);
491 void rpcrdma_ep_destroy(struct rpcrdma_ep *, struct rpcrdma_ia *);
492 int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
493 void rpcrdma_conn_func(struct rpcrdma_ep *ep);
494 void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
495 
496 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
497 				struct rpcrdma_req *);
498 int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_rep *);
499 
500 /*
501  * Buffer calls - xprtrdma/verbs.c
502  */
503 struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
504 struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);
505 void rpcrdma_destroy_req(struct rpcrdma_req *);
506 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
507 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
508 
509 struct rpcrdma_mw *rpcrdma_get_mw(struct rpcrdma_xprt *);
510 void rpcrdma_put_mw(struct rpcrdma_xprt *, struct rpcrdma_mw *);
511 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
512 void rpcrdma_buffer_put(struct rpcrdma_req *);
513 void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
514 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
515 
516 void rpcrdma_defer_mr_recovery(struct rpcrdma_mw *);
517 
518 struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(size_t, enum dma_data_direction,
519 					    gfp_t);
520 bool __rpcrdma_dma_map_regbuf(struct rpcrdma_ia *, struct rpcrdma_regbuf *);
521 void rpcrdma_free_regbuf(struct rpcrdma_regbuf *);
522 
523 static inline bool
524 rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb)
525 {
526 	return rb->rg_device != NULL;
527 }
528 
529 static inline bool
530 rpcrdma_dma_map_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
531 {
532 	if (likely(rpcrdma_regbuf_is_mapped(rb)))
533 		return true;
534 	return __rpcrdma_dma_map_regbuf(ia, rb);
535 }
536 
537 int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *, unsigned int);
538 
539 int rpcrdma_alloc_wq(void);
540 void rpcrdma_destroy_wq(void);
541 
542 /*
543  * Wrappers for chunk registration, shared by read/write chunk code.
544  */
545 
546 static inline enum dma_data_direction
547 rpcrdma_data_dir(bool writing)
548 {
549 	return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
550 }
551 
552 /*
553  * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
554  */
555 
556 enum rpcrdma_chunktype {
557 	rpcrdma_noch = 0,
558 	rpcrdma_readch,
559 	rpcrdma_areadch,
560 	rpcrdma_writech,
561 	rpcrdma_replych
562 };
563 
564 bool rpcrdma_prepare_send_sges(struct rpcrdma_ia *, struct rpcrdma_req *,
565 			       u32, struct xdr_buf *, enum rpcrdma_chunktype);
566 void rpcrdma_unmap_sges(struct rpcrdma_ia *, struct rpcrdma_req *);
567 int rpcrdma_marshal_req(struct rpc_rqst *);
568 void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *);
569 void rpcrdma_reply_handler(struct work_struct *work);
570 
571 /* RPC/RDMA module init - xprtrdma/transport.c
572  */
573 extern unsigned int xprt_rdma_max_inline_read;
574 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
575 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
576 void rpcrdma_connect_worker(struct work_struct *work);
577 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
578 int xprt_rdma_init(void);
579 void xprt_rdma_cleanup(void);
580 
581 /* Backchannel calls - xprtrdma/backchannel.c
582  */
583 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
584 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
585 int xprt_rdma_bc_up(struct svc_serv *, struct net *);
586 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *);
587 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
588 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
589 int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
590 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
591 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
592 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
593 
594 extern struct xprt_class xprt_rdma_bc;
595 
596 #endif				/* _LINUX_SUNRPC_XPRT_RDMA_H */
597