xref: /openbmc/linux/net/sunrpc/xprtrdma/xprt_rdma.h (revision d236d361)
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 	unsigned int		rr_len;
222 	int			rr_wc_flags;
223 	u32			rr_inv_rkey;
224 	struct rpcrdma_xprt	*rr_rxprt;
225 	struct work_struct	rr_work;
226 	struct list_head	rr_list;
227 	struct ib_recv_wr	rr_recv_wr;
228 	struct rpcrdma_regbuf	*rr_rdmabuf;
229 };
230 
231 #define RPCRDMA_BAD_LEN		(~0U)
232 
233 /*
234  * struct rpcrdma_mw - 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  * Each rpcrdma_buffer has a list of free MWs anchored in rb_mws. During
240  * call_allocate, rpcrdma_buffer_get() assigns one to each segment in
241  * an rpcrdma_req. Then rpcrdma_register_external() grabs these to keep
242  * track of registration metadata while each RPC is pending.
243  * rpcrdma_deregister_external() uses this metadata to unmap and
244  * release these resources when an RPC is complete.
245  */
246 enum rpcrdma_frmr_state {
247 	FRMR_IS_INVALID,	/* ready to be used */
248 	FRMR_IS_VALID,		/* in use */
249 	FRMR_FLUSHED_FR,	/* flushed FASTREG WR */
250 	FRMR_FLUSHED_LI,	/* flushed LOCALINV WR */
251 };
252 
253 struct rpcrdma_frmr {
254 	struct ib_mr			*fr_mr;
255 	struct ib_cqe			fr_cqe;
256 	enum rpcrdma_frmr_state		fr_state;
257 	struct completion		fr_linv_done;
258 	union {
259 		struct ib_reg_wr	fr_regwr;
260 		struct ib_send_wr	fr_invwr;
261 	};
262 };
263 
264 struct rpcrdma_fmr {
265 	struct ib_fmr		*fm_mr;
266 	u64			*fm_physaddrs;
267 };
268 
269 struct rpcrdma_mw {
270 	struct list_head	mw_list;
271 	struct scatterlist	*mw_sg;
272 	int			mw_nents;
273 	enum dma_data_direction	mw_dir;
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 /*
286  * struct rpcrdma_req -- structure central to the request/reply sequence.
287  *
288  * N of these are associated with a transport instance, and stored in
289  * struct rpcrdma_buffer. N is the max number of outstanding requests.
290  *
291  * It includes pre-registered buffer memory for send AND recv.
292  * The recv buffer, however, is not owned by this structure, and
293  * is "donated" to the hardware when a recv is posted. When a
294  * reply is handled, the recv buffer used is given back to the
295  * struct rpcrdma_req associated with the request.
296  *
297  * In addition to the basic memory, this structure includes an array
298  * of iovs for send operations. The reason is that the iovs passed to
299  * ib_post_{send,recv} must not be modified until the work request
300  * completes.
301  */
302 
303 /* Maximum number of page-sized "segments" per chunk list to be
304  * registered or invalidated. Must handle a Reply chunk:
305  */
306 enum {
307 	RPCRDMA_MAX_IOV_SEGS	= 3,
308 	RPCRDMA_MAX_DATA_SEGS	= ((1 * 1024 * 1024) / PAGE_SIZE) + 1,
309 	RPCRDMA_MAX_SEGS	= RPCRDMA_MAX_DATA_SEGS +
310 				  RPCRDMA_MAX_IOV_SEGS,
311 };
312 
313 struct rpcrdma_mr_seg {		/* chunk descriptors */
314 	u32		mr_len;		/* length of chunk or segment */
315 	struct page	*mr_page;	/* owning page, if any */
316 	char		*mr_offset;	/* kva if no page, else offset */
317 };
318 
319 /* The Send SGE array is provisioned to send a maximum size
320  * inline request:
321  * - RPC-over-RDMA header
322  * - xdr_buf head iovec
323  * - RPCRDMA_MAX_INLINE bytes, in pages
324  * - xdr_buf tail iovec
325  *
326  * The actual number of array elements consumed by each RPC
327  * depends on the device's max_sge limit.
328  */
329 enum {
330 	RPCRDMA_MIN_SEND_SGES = 3,
331 	RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT,
332 	RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1,
333 };
334 
335 struct rpcrdma_buffer;
336 struct rpcrdma_req {
337 	struct list_head	rl_free;
338 	unsigned int		rl_mapped_sges;
339 	unsigned int		rl_connect_cookie;
340 	struct rpcrdma_buffer	*rl_buffer;
341 	struct rpcrdma_rep	*rl_reply;
342 	struct ib_send_wr	rl_send_wr;
343 	struct ib_sge		rl_send_sge[RPCRDMA_MAX_SEND_SGES];
344 	struct rpcrdma_regbuf	*rl_rdmabuf;	/* xprt header */
345 	struct rpcrdma_regbuf	*rl_sendbuf;	/* rq_snd_buf */
346 	struct rpcrdma_regbuf	*rl_recvbuf;	/* rq_rcv_buf */
347 
348 	struct ib_cqe		rl_cqe;
349 	struct list_head	rl_all;
350 	bool			rl_backchannel;
351 
352 	struct list_head	rl_registered;	/* registered segments */
353 	struct rpcrdma_mr_seg	rl_segments[RPCRDMA_MAX_SEGS];
354 };
355 
356 static inline void
357 rpcrdma_set_xprtdata(struct rpc_rqst *rqst, struct rpcrdma_req *req)
358 {
359 	rqst->rq_xprtdata = req;
360 }
361 
362 static inline struct rpcrdma_req *
363 rpcr_to_rdmar(struct rpc_rqst *rqst)
364 {
365 	return rqst->rq_xprtdata;
366 }
367 
368 static inline void
369 rpcrdma_push_mw(struct rpcrdma_mw *mw, struct list_head *list)
370 {
371 	list_add_tail(&mw->mw_list, list);
372 }
373 
374 static inline struct rpcrdma_mw *
375 rpcrdma_pop_mw(struct list_head *list)
376 {
377 	struct rpcrdma_mw *mw;
378 
379 	mw = list_first_entry(list, struct rpcrdma_mw, mw_list);
380 	list_del(&mw->mw_list);
381 	return mw;
382 }
383 
384 /*
385  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
386  * inline requests/replies, and client/server credits.
387  *
388  * One of these is associated with a transport instance
389  */
390 struct rpcrdma_buffer {
391 	spinlock_t		rb_mwlock;	/* protect rb_mws list */
392 	struct list_head	rb_mws;
393 	struct list_head	rb_all;
394 
395 	spinlock_t		rb_lock;	/* protect buf lists */
396 	int			rb_send_count, rb_recv_count;
397 	struct list_head	rb_send_bufs;
398 	struct list_head	rb_recv_bufs;
399 	u32			rb_max_requests;
400 	atomic_t		rb_credits;	/* most recent credit grant */
401 
402 	u32			rb_bc_srv_max_requests;
403 	spinlock_t		rb_reqslock;	/* protect rb_allreqs */
404 	struct list_head	rb_allreqs;
405 
406 	u32			rb_bc_max_requests;
407 
408 	spinlock_t		rb_recovery_lock; /* protect rb_stale_mrs */
409 	struct list_head	rb_stale_mrs;
410 	struct delayed_work	rb_recovery_worker;
411 	struct delayed_work	rb_refresh_worker;
412 };
413 #define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)
414 
415 /*
416  * Internal structure for transport instance creation. This
417  * exists primarily for modularity.
418  *
419  * This data should be set with mount options
420  */
421 struct rpcrdma_create_data_internal {
422 	struct sockaddr_storage	addr;	/* RDMA server address */
423 	unsigned int	max_requests;	/* max requests (slots) in flight */
424 	unsigned int	rsize;		/* mount rsize - max read hdr+data */
425 	unsigned int	wsize;		/* mount wsize - max write hdr+data */
426 	unsigned int	inline_rsize;	/* max non-rdma read data payload */
427 	unsigned int	inline_wsize;	/* max non-rdma write data payload */
428 	unsigned int	padding;	/* non-rdma write header padding */
429 };
430 
431 /*
432  * Statistics for RPCRDMA
433  */
434 struct rpcrdma_stats {
435 	unsigned long		read_chunk_count;
436 	unsigned long		write_chunk_count;
437 	unsigned long		reply_chunk_count;
438 
439 	unsigned long long	total_rdma_request;
440 	unsigned long long	total_rdma_reply;
441 
442 	unsigned long long	pullup_copy_count;
443 	unsigned long long	fixup_copy_count;
444 	unsigned long		hardway_register_count;
445 	unsigned long		failed_marshal_count;
446 	unsigned long		bad_reply_count;
447 	unsigned long		nomsg_call_count;
448 	unsigned long		bcall_count;
449 	unsigned long		mrs_recovered;
450 	unsigned long		mrs_orphaned;
451 	unsigned long		mrs_allocated;
452 	unsigned long		local_inv_needed;
453 };
454 
455 /*
456  * Per-registration mode operations
457  */
458 struct rpcrdma_xprt;
459 struct rpcrdma_memreg_ops {
460 	int		(*ro_map)(struct rpcrdma_xprt *,
461 				  struct rpcrdma_mr_seg *, int, bool,
462 				  struct rpcrdma_mw **);
463 	void		(*ro_unmap_sync)(struct rpcrdma_xprt *,
464 					 struct rpcrdma_req *);
465 	void		(*ro_unmap_safe)(struct rpcrdma_xprt *,
466 					 struct rpcrdma_req *, bool);
467 	void		(*ro_recover_mr)(struct rpcrdma_mw *);
468 	int		(*ro_open)(struct rpcrdma_ia *,
469 				   struct rpcrdma_ep *,
470 				   struct rpcrdma_create_data_internal *);
471 	size_t		(*ro_maxpages)(struct rpcrdma_xprt *);
472 	int		(*ro_init_mr)(struct rpcrdma_ia *,
473 				      struct rpcrdma_mw *);
474 	void		(*ro_release_mr)(struct rpcrdma_mw *);
475 	const char	*ro_displayname;
476 	const int	ro_send_w_inv_ok;
477 };
478 
479 extern const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops;
480 extern const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops;
481 
482 /*
483  * RPCRDMA transport -- encapsulates the structures above for
484  * integration with RPC.
485  *
486  * The contained structures are embedded, not pointers,
487  * for convenience. This structure need not be visible externally.
488  *
489  * It is allocated and initialized during mount, and released
490  * during unmount.
491  */
492 struct rpcrdma_xprt {
493 	struct rpc_xprt		rx_xprt;
494 	struct rpcrdma_ia	rx_ia;
495 	struct rpcrdma_ep	rx_ep;
496 	struct rpcrdma_buffer	rx_buf;
497 	struct rpcrdma_create_data_internal rx_data;
498 	struct delayed_work	rx_connect_worker;
499 	struct rpcrdma_stats	rx_stats;
500 };
501 
502 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
503 #define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
504 
505 /* Setting this to 0 ensures interoperability with early servers.
506  * Setting this to 1 enhances certain unaligned read/write performance.
507  * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
508 extern int xprt_rdma_pad_optimize;
509 
510 /* This setting controls the hunt for a supported memory
511  * registration strategy.
512  */
513 extern unsigned int xprt_rdma_memreg_strategy;
514 
515 /*
516  * Interface Adapter calls - xprtrdma/verbs.c
517  */
518 int rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr);
519 void rpcrdma_ia_remove(struct rpcrdma_ia *ia);
520 void rpcrdma_ia_close(struct rpcrdma_ia *);
521 bool frwr_is_supported(struct rpcrdma_ia *);
522 bool fmr_is_supported(struct rpcrdma_ia *);
523 
524 /*
525  * Endpoint calls - xprtrdma/verbs.c
526  */
527 int rpcrdma_ep_create(struct rpcrdma_ep *, struct rpcrdma_ia *,
528 				struct rpcrdma_create_data_internal *);
529 void rpcrdma_ep_destroy(struct rpcrdma_ep *, struct rpcrdma_ia *);
530 int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
531 void rpcrdma_conn_func(struct rpcrdma_ep *ep);
532 void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
533 
534 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
535 				struct rpcrdma_req *);
536 int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_rep *);
537 
538 /*
539  * Buffer calls - xprtrdma/verbs.c
540  */
541 struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
542 struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);
543 void rpcrdma_destroy_req(struct rpcrdma_req *);
544 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
545 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
546 
547 struct rpcrdma_mw *rpcrdma_get_mw(struct rpcrdma_xprt *);
548 void rpcrdma_put_mw(struct rpcrdma_xprt *, struct rpcrdma_mw *);
549 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
550 void rpcrdma_buffer_put(struct rpcrdma_req *);
551 void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
552 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
553 
554 void rpcrdma_defer_mr_recovery(struct rpcrdma_mw *);
555 
556 struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(size_t, enum dma_data_direction,
557 					    gfp_t);
558 bool __rpcrdma_dma_map_regbuf(struct rpcrdma_ia *, struct rpcrdma_regbuf *);
559 void rpcrdma_free_regbuf(struct rpcrdma_regbuf *);
560 
561 static inline bool
562 rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb)
563 {
564 	return rb->rg_device != NULL;
565 }
566 
567 static inline bool
568 rpcrdma_dma_map_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
569 {
570 	if (likely(rpcrdma_regbuf_is_mapped(rb)))
571 		return true;
572 	return __rpcrdma_dma_map_regbuf(ia, rb);
573 }
574 
575 int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *, unsigned int);
576 
577 int rpcrdma_alloc_wq(void);
578 void rpcrdma_destroy_wq(void);
579 
580 /*
581  * Wrappers for chunk registration, shared by read/write chunk code.
582  */
583 
584 static inline enum dma_data_direction
585 rpcrdma_data_dir(bool writing)
586 {
587 	return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
588 }
589 
590 /*
591  * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
592  */
593 
594 enum rpcrdma_chunktype {
595 	rpcrdma_noch = 0,
596 	rpcrdma_readch,
597 	rpcrdma_areadch,
598 	rpcrdma_writech,
599 	rpcrdma_replych
600 };
601 
602 bool rpcrdma_prepare_send_sges(struct rpcrdma_ia *, struct rpcrdma_req *,
603 			       u32, struct xdr_buf *, enum rpcrdma_chunktype);
604 void rpcrdma_unmap_sges(struct rpcrdma_ia *, struct rpcrdma_req *);
605 int rpcrdma_marshal_req(struct rpc_rqst *);
606 void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *);
607 void rpcrdma_reply_handler(struct work_struct *work);
608 
609 /* RPC/RDMA module init - xprtrdma/transport.c
610  */
611 extern unsigned int xprt_rdma_max_inline_read;
612 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
613 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
614 void rpcrdma_connect_worker(struct work_struct *work);
615 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
616 int xprt_rdma_init(void);
617 void xprt_rdma_cleanup(void);
618 
619 /* Backchannel calls - xprtrdma/backchannel.c
620  */
621 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
622 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
623 int xprt_rdma_bc_up(struct svc_serv *, struct net *);
624 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *);
625 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
626 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
627 int rpcrdma_bc_marshal_reply(struct rpc_rqst *);
628 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
629 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
630 #endif	/* CONFIG_SUNRPC_BACKCHANNEL */
631 
632 extern struct xprt_class xprt_rdma_bc;
633 
634 #endif				/* _LINUX_SUNRPC_XPRT_RDMA_H */
635