xref: /openbmc/linux/net/sunrpc/xprtrdma/xprt_rdma.h (revision b78412b8)
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 	struct completion	ri_remove_done;
73 	int			ri_async_rc;
74 	unsigned int		ri_max_segs;
75 	unsigned int		ri_max_frmr_depth;
76 	unsigned int		ri_max_inline_write;
77 	unsigned int		ri_max_inline_read;
78 	unsigned int		ri_max_send_sges;
79 	bool			ri_reminv_expected;
80 	bool			ri_implicit_roundup;
81 	enum ib_mr_type		ri_mrtype;
82 	unsigned long		ri_flags;
83 	struct ib_qp_attr	ri_qp_attr;
84 	struct ib_qp_init_attr	ri_qp_init_attr;
85 };
86 
87 enum {
88 	RPCRDMA_IAF_REMOVING = 0,
89 };
90 
91 /*
92  * RDMA Endpoint -- one per transport instance
93  */
94 
95 struct rpcrdma_ep {
96 	atomic_t		rep_cqcount;
97 	int			rep_cqinit;
98 	int			rep_connected;
99 	struct ib_qp_init_attr	rep_attr;
100 	wait_queue_head_t 	rep_connect_wait;
101 	struct rpcrdma_connect_private	rep_cm_private;
102 	struct rdma_conn_param	rep_remote_cma;
103 	struct sockaddr_storage	rep_remote_addr;
104 	struct delayed_work	rep_connect_worker;
105 };
106 
107 static inline void
108 rpcrdma_init_cqcount(struct rpcrdma_ep *ep, int count)
109 {
110 	atomic_set(&ep->rep_cqcount, ep->rep_cqinit - count);
111 }
112 
113 /* To update send queue accounting, provider must take a
114  * send completion every now and then.
115  */
116 static inline void
117 rpcrdma_set_signaled(struct rpcrdma_ep *ep, struct ib_send_wr *send_wr)
118 {
119 	send_wr->send_flags = 0;
120 	if (unlikely(atomic_sub_return(1, &ep->rep_cqcount) <= 0)) {
121 		rpcrdma_init_cqcount(ep, 0);
122 		send_wr->send_flags = IB_SEND_SIGNALED;
123 	}
124 }
125 
126 /* Pre-allocate extra Work Requests for handling backward receives
127  * and sends. This is a fixed value because the Work Queues are
128  * allocated when the forward channel is set up.
129  */
130 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
131 #define RPCRDMA_BACKWARD_WRS		(8)
132 #else
133 #define RPCRDMA_BACKWARD_WRS		(0)
134 #endif
135 
136 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
137  *
138  * The below structure appears at the front of a large region of kmalloc'd
139  * memory, which always starts on a good alignment boundary.
140  */
141 
142 struct rpcrdma_regbuf {
143 	struct ib_sge		rg_iov;
144 	struct ib_device	*rg_device;
145 	enum dma_data_direction	rg_direction;
146 	__be32			rg_base[0] __attribute__ ((aligned(256)));
147 };
148 
149 static inline u64
150 rdmab_addr(struct rpcrdma_regbuf *rb)
151 {
152 	return rb->rg_iov.addr;
153 }
154 
155 static inline u32
156 rdmab_length(struct rpcrdma_regbuf *rb)
157 {
158 	return rb->rg_iov.length;
159 }
160 
161 static inline u32
162 rdmab_lkey(struct rpcrdma_regbuf *rb)
163 {
164 	return rb->rg_iov.lkey;
165 }
166 
167 static inline struct rpcrdma_msg *
168 rdmab_to_msg(struct rpcrdma_regbuf *rb)
169 {
170 	return (struct rpcrdma_msg *)rb->rg_base;
171 }
172 
173 static inline struct ib_device *
174 rdmab_device(struct rpcrdma_regbuf *rb)
175 {
176 	return rb->rg_device;
177 }
178 
179 #define RPCRDMA_DEF_GFP		(GFP_NOIO | __GFP_NOWARN)
180 
181 /* To ensure a transport can always make forward progress,
182  * the number of RDMA segments allowed in header chunk lists
183  * is capped at 8. This prevents less-capable devices and
184  * memory registrations from overrunning the Send buffer
185  * while building chunk lists.
186  *
187  * Elements of the Read list take up more room than the
188  * Write list or Reply chunk. 8 read segments means the Read
189  * list (or Write list or Reply chunk) cannot consume more
190  * than
191  *
192  * ((8 + 2) * read segment size) + 1 XDR words, or 244 bytes.
193  *
194  * And the fixed part of the header is another 24 bytes.
195  *
196  * The smallest inline threshold is 1024 bytes, ensuring that
197  * at least 750 bytes are available for RPC messages.
198  */
199 enum {
200 	RPCRDMA_MAX_HDR_SEGS = 8,
201 	RPCRDMA_HDRBUF_SIZE = 256,
202 };
203 
204 /*
205  * struct rpcrdma_rep -- this structure encapsulates state required to recv
206  * and complete a reply, asychronously. It needs several pieces of
207  * state:
208  *   o recv buffer (posted to provider)
209  *   o ib_sge (also donated to provider)
210  *   o status of reply (length, success or not)
211  *   o bookkeeping state to get run by reply handler (list, etc)
212  *
213  * These are allocated during initialization, per-transport instance.
214  *
215  * N of these are associated with a transport instance, and stored in
216  * struct rpcrdma_buffer. N is the max number of outstanding requests.
217  */
218 
219 struct rpcrdma_rep {
220 	struct ib_cqe		rr_cqe;
221 	int			rr_wc_flags;
222 	u32			rr_inv_rkey;
223 	struct rpcrdma_regbuf	*rr_rdmabuf;
224 	struct rpcrdma_xprt	*rr_rxprt;
225 	struct work_struct	rr_work;
226 	struct xdr_buf		rr_hdrbuf;
227 	struct xdr_stream	rr_stream;
228 	struct list_head	rr_list;
229 	struct ib_recv_wr	rr_recv_wr;
230 };
231 
232 /*
233  * struct rpcrdma_mw - external memory region metadata
234  *
235  * An external memory region is any buffer or page that is registered
236  * on the fly (ie, not pre-registered).
237  *
238  * Each rpcrdma_buffer has a list of free MWs anchored in rb_mws. During
239  * call_allocate, rpcrdma_buffer_get() assigns one to each segment in
240  * an rpcrdma_req. Then rpcrdma_register_external() grabs these to keep
241  * track of registration metadata while each RPC is pending.
242  * rpcrdma_deregister_external() uses this metadata to unmap and
243  * release these resources when an RPC is complete.
244  */
245 enum rpcrdma_frmr_state {
246 	FRMR_IS_INVALID,	/* ready to be used */
247 	FRMR_IS_VALID,		/* in use */
248 	FRMR_FLUSHED_FR,	/* flushed FASTREG WR */
249 	FRMR_FLUSHED_LI,	/* flushed LOCALINV WR */
250 };
251 
252 struct rpcrdma_frmr {
253 	struct ib_mr			*fr_mr;
254 	struct ib_cqe			fr_cqe;
255 	enum rpcrdma_frmr_state		fr_state;
256 	struct completion		fr_linv_done;
257 	union {
258 		struct ib_reg_wr	fr_regwr;
259 		struct ib_send_wr	fr_invwr;
260 	};
261 };
262 
263 struct rpcrdma_fmr {
264 	struct ib_fmr		*fm_mr;
265 	u64			*fm_physaddrs;
266 };
267 
268 struct rpcrdma_mw {
269 	struct list_head	mw_list;
270 	struct scatterlist	*mw_sg;
271 	int			mw_nents;
272 	enum dma_data_direction	mw_dir;
273 	unsigned long		mw_flags;
274 	union {
275 		struct rpcrdma_fmr	fmr;
276 		struct rpcrdma_frmr	frmr;
277 	};
278 	struct rpcrdma_xprt	*mw_xprt;
279 	u32			mw_handle;
280 	u32			mw_length;
281 	u64			mw_offset;
282 	struct list_head	mw_all;
283 };
284 
285 /* mw_flags */
286 enum {
287 	RPCRDMA_MW_F_RI		= 1,
288 };
289 
290 /*
291  * struct rpcrdma_req -- structure central to the request/reply sequence.
292  *
293  * N of these are associated with a transport instance, and stored in
294  * struct rpcrdma_buffer. N is the max number of outstanding requests.
295  *
296  * It includes pre-registered buffer memory for send AND recv.
297  * The recv buffer, however, is not owned by this structure, and
298  * is "donated" to the hardware when a recv is posted. When a
299  * reply is handled, the recv buffer used is given back to the
300  * struct rpcrdma_req associated with the request.
301  *
302  * In addition to the basic memory, this structure includes an array
303  * of iovs for send operations. The reason is that the iovs passed to
304  * ib_post_{send,recv} must not be modified until the work request
305  * completes.
306  */
307 
308 /* Maximum number of page-sized "segments" per chunk list to be
309  * registered or invalidated. Must handle a Reply chunk:
310  */
311 enum {
312 	RPCRDMA_MAX_IOV_SEGS	= 3,
313 	RPCRDMA_MAX_DATA_SEGS	= ((1 * 1024 * 1024) / PAGE_SIZE) + 1,
314 	RPCRDMA_MAX_SEGS	= RPCRDMA_MAX_DATA_SEGS +
315 				  RPCRDMA_MAX_IOV_SEGS,
316 };
317 
318 struct rpcrdma_mr_seg {		/* chunk descriptors */
319 	u32		mr_len;		/* length of chunk or segment */
320 	struct page	*mr_page;	/* owning page, if any */
321 	char		*mr_offset;	/* kva if no page, else offset */
322 };
323 
324 /* The Send SGE array is provisioned to send a maximum size
325  * inline request:
326  * - RPC-over-RDMA header
327  * - xdr_buf head iovec
328  * - RPCRDMA_MAX_INLINE bytes, in pages
329  * - xdr_buf tail iovec
330  *
331  * The actual number of array elements consumed by each RPC
332  * depends on the device's max_sge limit.
333  */
334 enum {
335 	RPCRDMA_MIN_SEND_SGES = 3,
336 	RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT,
337 	RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1,
338 };
339 
340 struct rpcrdma_buffer;
341 struct rpcrdma_req {
342 	struct list_head	rl_list;
343 	unsigned int		rl_mapped_sges;
344 	unsigned int		rl_connect_cookie;
345 	struct rpcrdma_buffer	*rl_buffer;
346 	struct rpcrdma_rep	*rl_reply;
347 	struct xdr_stream	rl_stream;
348 	struct xdr_buf		rl_hdrbuf;
349 	struct ib_send_wr	rl_send_wr;
350 	struct ib_sge		rl_send_sge[RPCRDMA_MAX_SEND_SGES];
351 	struct rpcrdma_regbuf	*rl_rdmabuf;	/* xprt header */
352 	struct rpcrdma_regbuf	*rl_sendbuf;	/* rq_snd_buf */
353 	struct rpcrdma_regbuf	*rl_recvbuf;	/* rq_rcv_buf */
354 
355 	struct ib_cqe		rl_cqe;
356 	struct list_head	rl_all;
357 	bool			rl_backchannel;
358 
359 	struct list_head	rl_registered;	/* registered segments */
360 	struct rpcrdma_mr_seg	rl_segments[RPCRDMA_MAX_SEGS];
361 };
362 
363 static inline void
364 rpcrdma_set_xprtdata(struct rpc_rqst *rqst, struct rpcrdma_req *req)
365 {
366 	rqst->rq_xprtdata = req;
367 }
368 
369 static inline struct rpcrdma_req *
370 rpcr_to_rdmar(struct rpc_rqst *rqst)
371 {
372 	return rqst->rq_xprtdata;
373 }
374 
375 static inline void
376 rpcrdma_push_mw(struct rpcrdma_mw *mw, struct list_head *list)
377 {
378 	list_add_tail(&mw->mw_list, list);
379 }
380 
381 static inline struct rpcrdma_mw *
382 rpcrdma_pop_mw(struct list_head *list)
383 {
384 	struct rpcrdma_mw *mw;
385 
386 	mw = list_first_entry(list, struct rpcrdma_mw, mw_list);
387 	list_del(&mw->mw_list);
388 	return mw;
389 }
390 
391 /*
392  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
393  * inline requests/replies, and client/server credits.
394  *
395  * One of these is associated with a transport instance
396  */
397 struct rpcrdma_buffer {
398 	spinlock_t		rb_mwlock;	/* protect rb_mws list */
399 	struct list_head	rb_mws;
400 	struct list_head	rb_all;
401 
402 	spinlock_t		rb_lock;	/* protect buf lists */
403 	int			rb_send_count, rb_recv_count;
404 	struct list_head	rb_send_bufs;
405 	struct list_head	rb_recv_bufs;
406 	u32			rb_max_requests;
407 	atomic_t		rb_credits;	/* most recent credit grant */
408 
409 	u32			rb_bc_srv_max_requests;
410 	spinlock_t		rb_reqslock;	/* protect rb_allreqs */
411 	struct list_head	rb_allreqs;
412 
413 	u32			rb_bc_max_requests;
414 
415 	spinlock_t		rb_recovery_lock; /* protect rb_stale_mrs */
416 	struct list_head	rb_stale_mrs;
417 	struct delayed_work	rb_recovery_worker;
418 	struct delayed_work	rb_refresh_worker;
419 };
420 #define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)
421 
422 /*
423  * Internal structure for transport instance creation. This
424  * exists primarily for modularity.
425  *
426  * This data should be set with mount options
427  */
428 struct rpcrdma_create_data_internal {
429 	struct sockaddr_storage	addr;	/* RDMA server address */
430 	unsigned int	max_requests;	/* max requests (slots) in flight */
431 	unsigned int	rsize;		/* mount rsize - max read hdr+data */
432 	unsigned int	wsize;		/* mount wsize - max write hdr+data */
433 	unsigned int	inline_rsize;	/* max non-rdma read data payload */
434 	unsigned int	inline_wsize;	/* max non-rdma write data payload */
435 	unsigned int	padding;	/* non-rdma write header padding */
436 };
437 
438 /*
439  * Statistics for RPCRDMA
440  */
441 struct rpcrdma_stats {
442 	/* accessed when sending a call */
443 	unsigned long		read_chunk_count;
444 	unsigned long		write_chunk_count;
445 	unsigned long		reply_chunk_count;
446 	unsigned long long	total_rdma_request;
447 
448 	/* rarely accessed error counters */
449 	unsigned long long	pullup_copy_count;
450 	unsigned long		hardway_register_count;
451 	unsigned long		failed_marshal_count;
452 	unsigned long		bad_reply_count;
453 	unsigned long		mrs_recovered;
454 	unsigned long		mrs_orphaned;
455 	unsigned long		mrs_allocated;
456 
457 	/* accessed when receiving a reply */
458 	unsigned long long	total_rdma_reply;
459 	unsigned long long	fixup_copy_count;
460 	unsigned long		local_inv_needed;
461 	unsigned long		nomsg_call_count;
462 	unsigned long		bcall_count;
463 };
464 
465 /*
466  * Per-registration mode operations
467  */
468 struct rpcrdma_xprt;
469 struct rpcrdma_memreg_ops {
470 	struct rpcrdma_mr_seg *
471 			(*ro_map)(struct rpcrdma_xprt *,
472 				  struct rpcrdma_mr_seg *, int, bool,
473 				  struct rpcrdma_mw **);
474 	void		(*ro_unmap_sync)(struct rpcrdma_xprt *,
475 					 struct list_head *);
476 	void		(*ro_unmap_safe)(struct rpcrdma_xprt *,
477 					 struct rpcrdma_req *, bool);
478 	void		(*ro_recover_mr)(struct rpcrdma_mw *);
479 	int		(*ro_open)(struct rpcrdma_ia *,
480 				   struct rpcrdma_ep *,
481 				   struct rpcrdma_create_data_internal *);
482 	size_t		(*ro_maxpages)(struct rpcrdma_xprt *);
483 	int		(*ro_init_mr)(struct rpcrdma_ia *,
484 				      struct rpcrdma_mw *);
485 	void		(*ro_release_mr)(struct rpcrdma_mw *);
486 	const char	*ro_displayname;
487 	const int	ro_send_w_inv_ok;
488 };
489 
490 extern const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops;
491 extern const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops;
492 
493 /*
494  * RPCRDMA transport -- encapsulates the structures above for
495  * integration with RPC.
496  *
497  * The contained structures are embedded, not pointers,
498  * for convenience. This structure need not be visible externally.
499  *
500  * It is allocated and initialized during mount, and released
501  * during unmount.
502  */
503 struct rpcrdma_xprt {
504 	struct rpc_xprt		rx_xprt;
505 	struct rpcrdma_ia	rx_ia;
506 	struct rpcrdma_ep	rx_ep;
507 	struct rpcrdma_buffer	rx_buf;
508 	struct rpcrdma_create_data_internal rx_data;
509 	struct delayed_work	rx_connect_worker;
510 	struct rpcrdma_stats	rx_stats;
511 };
512 
513 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
514 #define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
515 
516 /* Setting this to 0 ensures interoperability with early servers.
517  * Setting this to 1 enhances certain unaligned read/write performance.
518  * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
519 extern int xprt_rdma_pad_optimize;
520 
521 /* This setting controls the hunt for a supported memory
522  * registration strategy.
523  */
524 extern unsigned int xprt_rdma_memreg_strategy;
525 
526 /*
527  * Interface Adapter calls - xprtrdma/verbs.c
528  */
529 int rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr);
530 void rpcrdma_ia_remove(struct rpcrdma_ia *ia);
531 void rpcrdma_ia_close(struct rpcrdma_ia *);
532 bool frwr_is_supported(struct rpcrdma_ia *);
533 bool fmr_is_supported(struct rpcrdma_ia *);
534 
535 /*
536  * Endpoint calls - xprtrdma/verbs.c
537  */
538 int rpcrdma_ep_create(struct rpcrdma_ep *, struct rpcrdma_ia *,
539 				struct rpcrdma_create_data_internal *);
540 void rpcrdma_ep_destroy(struct rpcrdma_ep *, struct rpcrdma_ia *);
541 int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
542 void rpcrdma_conn_func(struct rpcrdma_ep *ep);
543 void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
544 
545 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
546 				struct rpcrdma_req *);
547 int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_rep *);
548 
549 /*
550  * Buffer calls - xprtrdma/verbs.c
551  */
552 struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
553 struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);
554 void rpcrdma_destroy_req(struct rpcrdma_req *);
555 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
556 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
557 
558 struct rpcrdma_mw *rpcrdma_get_mw(struct rpcrdma_xprt *);
559 void rpcrdma_put_mw(struct rpcrdma_xprt *, struct rpcrdma_mw *);
560 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
561 void rpcrdma_buffer_put(struct rpcrdma_req *);
562 void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
563 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
564 
565 void rpcrdma_defer_mr_recovery(struct rpcrdma_mw *);
566 
567 struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(size_t, enum dma_data_direction,
568 					    gfp_t);
569 bool __rpcrdma_dma_map_regbuf(struct rpcrdma_ia *, struct rpcrdma_regbuf *);
570 void rpcrdma_free_regbuf(struct rpcrdma_regbuf *);
571 
572 static inline bool
573 rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb)
574 {
575 	return rb->rg_device != NULL;
576 }
577 
578 static inline bool
579 rpcrdma_dma_map_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
580 {
581 	if (likely(rpcrdma_regbuf_is_mapped(rb)))
582 		return true;
583 	return __rpcrdma_dma_map_regbuf(ia, rb);
584 }
585 
586 int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *, unsigned int);
587 
588 int rpcrdma_alloc_wq(void);
589 void rpcrdma_destroy_wq(void);
590 
591 /*
592  * Wrappers for chunk registration, shared by read/write chunk code.
593  */
594 
595 static inline enum dma_data_direction
596 rpcrdma_data_dir(bool writing)
597 {
598 	return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
599 }
600 
601 /*
602  * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
603  */
604 
605 enum rpcrdma_chunktype {
606 	rpcrdma_noch = 0,
607 	rpcrdma_readch,
608 	rpcrdma_areadch,
609 	rpcrdma_writech,
610 	rpcrdma_replych
611 };
612 
613 bool rpcrdma_prepare_send_sges(struct rpcrdma_ia *, struct rpcrdma_req *,
614 			       u32, struct xdr_buf *, enum rpcrdma_chunktype);
615 void rpcrdma_unmap_sges(struct rpcrdma_ia *, struct rpcrdma_req *);
616 int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst);
617 void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *);
618 void rpcrdma_reply_handler(struct work_struct *work);
619 
620 static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len)
621 {
622 	xdr->head[0].iov_len = len;
623 	xdr->len = len;
624 }
625 
626 /* RPC/RDMA module init - xprtrdma/transport.c
627  */
628 extern unsigned int xprt_rdma_max_inline_read;
629 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
630 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
631 void rpcrdma_connect_worker(struct work_struct *work);
632 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
633 int xprt_rdma_init(void);
634 void xprt_rdma_cleanup(void);
635 
636 /* Backchannel calls - xprtrdma/backchannel.c
637  */
638 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
639 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
640 int xprt_rdma_bc_up(struct svc_serv *, struct net *);
641 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *);
642 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
643 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
644 int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
645 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
646 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
647 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
648 
649 extern struct xprt_class xprt_rdma_bc;
650 
651 #endif				/* _LINUX_SUNRPC_XPRT_RDMA_H */
652