1 /* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
3 * Copyright (c) 2014-2017 Oracle. All rights reserved.
4 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
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42 #ifndef _LINUX_SUNRPC_XPRT_RDMA_H
43 #define _LINUX_SUNRPC_XPRT_RDMA_H
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 */
51 #include <rdma/rdma_cm.h> /* RDMA connection api */
52 #include <rdma/ib_verbs.h> /* RDMA verbs api */
54 #include <linux/sunrpc/clnt.h> /* rpc_xprt */
55 #include <linux/sunrpc/rpc_rdma.h> /* RPC/RDMA protocol */
56 #include <linux/sunrpc/xprtrdma.h> /* xprt parameters */
58 #define RDMA_RESOLVE_TIMEOUT (5000) /* 5 seconds */
59 #define RDMA_CONNECT_RETRY_MAX (2) /* retries if no listener backlog */
61 #define RPCRDMA_BIND_TO (60U * HZ)
62 #define RPCRDMA_INIT_REEST_TO (5U * HZ)
63 #define RPCRDMA_MAX_REEST_TO (30U * HZ)
64 #define RPCRDMA_IDLE_DISC_TO (5U * 60 * HZ)
67 * Interface Adapter -- one per transport instance
70 struct rdma_cm_id *ri_id;
73 unsigned int ri_max_segs;
74 unsigned int ri_max_frwr_depth;
75 unsigned int ri_max_send_sges;
76 bool ri_implicit_roundup;
77 enum ib_mr_type ri_mrtype;
78 unsigned long ri_flags;
79 struct completion ri_done;
80 struct completion ri_remove_done;
84 RPCRDMA_IAF_REMOVING = 0,
88 * RDMA Endpoint -- one per transport instance
92 unsigned int rep_send_count;
93 unsigned int rep_send_batch;
94 unsigned int rep_max_inline_send;
95 unsigned int rep_max_inline_recv;
97 struct ib_qp_init_attr rep_attr;
98 wait_queue_head_t rep_connect_wait;
99 struct rpcrdma_connect_private rep_cm_private;
100 struct rdma_conn_param rep_remote_cma;
101 unsigned int rep_max_requests; /* set by /proc */
102 unsigned int rep_inline_send; /* negotiated */
103 unsigned int rep_inline_recv; /* negotiated */
104 int rep_receive_count;
107 /* Pre-allocate extra Work Requests for handling backward receives
108 * and sends. This is a fixed value because the Work Queues are
109 * allocated when the forward channel is set up, long before the
110 * backchannel is provisioned. This value is two times
111 * NFS4_DEF_CB_SLOT_TABLE_SIZE.
113 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
114 #define RPCRDMA_BACKWARD_WRS (32)
116 #define RPCRDMA_BACKWARD_WRS (0)
119 /* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
121 * The below structure appears at the front of a large region of kmalloc'd
122 * memory, which always starts on a good alignment boundary.
125 struct rpcrdma_regbuf {
126 struct ib_sge rg_iov;
127 struct ib_device *rg_device;
128 enum dma_data_direction rg_direction;
132 static inline u64 rdmab_addr(struct rpcrdma_regbuf *rb)
134 return rb->rg_iov.addr;
137 static inline u32 rdmab_length(struct rpcrdma_regbuf *rb)
139 return rb->rg_iov.length;
142 static inline u32 rdmab_lkey(struct rpcrdma_regbuf *rb)
144 return rb->rg_iov.lkey;
147 static inline struct ib_device *rdmab_device(struct rpcrdma_regbuf *rb)
149 return rb->rg_device;
152 static inline void *rdmab_data(const struct rpcrdma_regbuf *rb)
157 #define RPCRDMA_DEF_GFP (GFP_NOIO | __GFP_NOWARN)
159 /* To ensure a transport can always make forward progress,
160 * the number of RDMA segments allowed in header chunk lists
161 * is capped at 8. This prevents less-capable devices and
162 * memory registrations from overrunning the Send buffer
163 * while building chunk lists.
165 * Elements of the Read list take up more room than the
166 * Write list or Reply chunk. 8 read segments means the Read
167 * list (or Write list or Reply chunk) cannot consume more
170 * ((8 + 2) * read segment size) + 1 XDR words, or 244 bytes.
172 * And the fixed part of the header is another 24 bytes.
174 * The smallest inline threshold is 1024 bytes, ensuring that
175 * at least 750 bytes are available for RPC messages.
178 RPCRDMA_MAX_HDR_SEGS = 8,
179 RPCRDMA_HDRBUF_SIZE = 256,
183 * struct rpcrdma_rep -- this structure encapsulates state required
184 * to receive and complete an RPC Reply, asychronously. It needs
185 * several pieces of state:
187 * o receive buffer and ib_sge (donated to provider)
188 * o status of receive (success or not, length, inv rkey)
189 * o bookkeeping state to get run by reply handler (XDR stream)
191 * These structures are allocated during transport initialization.
192 * N of these are associated with a transport instance, managed by
193 * struct rpcrdma_buffer. N is the max number of outstanding RPCs.
197 struct ib_cqe rr_cqe;
204 struct rpcrdma_regbuf *rr_rdmabuf;
205 struct rpcrdma_xprt *rr_rxprt;
206 struct rpc_rqst *rr_rqst;
207 struct xdr_buf rr_hdrbuf;
208 struct xdr_stream rr_stream;
209 struct list_head rr_list;
210 struct ib_recv_wr rr_recv_wr;
213 /* To reduce the rate at which a transport invokes ib_post_recv
214 * (and thus the hardware doorbell rate), xprtrdma posts Receive
217 * Setting this to zero disables Receive post batching.
220 RPCRDMA_MAX_RECV_BATCH = 7,
223 /* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes
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[];
238 * struct rpcrdma_mr - external memory region metadata
240 * An external memory region is any buffer or page that is registered
241 * on the fly (ie, not pre-registered).
244 struct rpcrdma_frwr {
246 struct ib_cqe fr_cqe;
247 struct completion fr_linv_done;
248 struct rpcrdma_req *fr_req;
250 struct ib_reg_wr fr_regwr;
251 struct ib_send_wr fr_invwr;
256 struct list_head mr_list;
257 struct scatterlist *mr_sg;
259 enum dma_data_direction mr_dir;
260 struct rpcrdma_frwr frwr;
261 struct rpcrdma_xprt *mr_xprt;
265 struct work_struct mr_recycle;
266 struct list_head mr_all;
270 * struct rpcrdma_req -- structure central to the request/reply sequence.
272 * N of these are associated with a transport instance, and stored in
273 * struct rpcrdma_buffer. N is the max number of outstanding requests.
275 * It includes pre-registered buffer memory for send AND recv.
276 * The recv buffer, however, is not owned by this structure, and
277 * is "donated" to the hardware when a recv is posted. When a
278 * reply is handled, the recv buffer used is given back to the
279 * struct rpcrdma_req associated with the request.
281 * In addition to the basic memory, this structure includes an array
282 * of iovs for send operations. The reason is that the iovs passed to
283 * ib_post_{send,recv} must not be modified until the work request
287 /* Maximum number of page-sized "segments" per chunk list to be
288 * registered or invalidated. Must handle a Reply chunk:
291 RPCRDMA_MAX_IOV_SEGS = 3,
292 RPCRDMA_MAX_DATA_SEGS = ((1 * 1024 * 1024) / PAGE_SIZE) + 1,
293 RPCRDMA_MAX_SEGS = RPCRDMA_MAX_DATA_SEGS +
294 RPCRDMA_MAX_IOV_SEGS,
297 struct rpcrdma_mr_seg { /* chunk descriptors */
298 u32 mr_len; /* length of chunk or segment */
299 struct page *mr_page; /* owning page, if any */
300 char *mr_offset; /* kva if no page, else offset */
303 /* The Send SGE array is provisioned to send a maximum size
305 * - RPC-over-RDMA header
306 * - xdr_buf head iovec
307 * - RPCRDMA_MAX_INLINE bytes, in pages
308 * - xdr_buf tail iovec
310 * The actual number of array elements consumed by each RPC
311 * depends on the device's max_sge limit.
314 RPCRDMA_MIN_SEND_SGES = 3,
315 RPCRDMA_MAX_PAGE_SGES = RPCRDMA_MAX_INLINE >> PAGE_SHIFT,
316 RPCRDMA_MAX_SEND_SGES = 1 + 1 + RPCRDMA_MAX_PAGE_SGES + 1,
319 struct rpcrdma_buffer;
321 struct list_head rl_list;
322 struct rpc_rqst rl_slot;
323 struct rpcrdma_buffer *rl_buffer;
324 struct rpcrdma_rep *rl_reply;
325 struct xdr_stream rl_stream;
326 struct xdr_buf rl_hdrbuf;
327 struct rpcrdma_sendctx *rl_sendctx;
328 struct rpcrdma_regbuf *rl_rdmabuf; /* xprt header */
329 struct rpcrdma_regbuf *rl_sendbuf; /* rq_snd_buf */
330 struct rpcrdma_regbuf *rl_recvbuf; /* rq_rcv_buf */
332 struct list_head rl_all;
335 struct list_head rl_registered; /* registered segments */
336 struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS];
339 static inline struct rpcrdma_req *
340 rpcr_to_rdmar(const struct rpc_rqst *rqst)
342 return container_of(rqst, struct rpcrdma_req, rl_slot);
346 rpcrdma_mr_push(struct rpcrdma_mr *mr, struct list_head *list)
348 list_add_tail(&mr->mr_list, list);
351 static inline struct rpcrdma_mr *
352 rpcrdma_mr_pop(struct list_head *list)
354 struct rpcrdma_mr *mr;
356 mr = list_first_entry(list, struct rpcrdma_mr, mr_list);
357 list_del_init(&mr->mr_list);
362 * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
363 * inline requests/replies, and client/server credits.
365 * One of these is associated with a transport instance
367 struct rpcrdma_buffer {
368 spinlock_t rb_mrlock; /* protect rb_mrs list */
369 struct list_head rb_mrs;
370 struct list_head rb_all;
372 unsigned long rb_sc_head;
373 unsigned long rb_sc_tail;
374 unsigned long rb_sc_last;
375 struct rpcrdma_sendctx **rb_sc_ctxs;
377 spinlock_t rb_lock; /* protect buf lists */
378 struct list_head rb_send_bufs;
379 struct list_head rb_recv_bufs;
380 struct list_head rb_allreqs;
383 u32 rb_credits; /* most recent credit grant */
385 u32 rb_bc_srv_max_requests;
386 u32 rb_bc_max_requests;
388 struct delayed_work rb_refresh_worker;
392 * Statistics for RPCRDMA
394 struct rpcrdma_stats {
395 /* accessed when sending a call */
396 unsigned long read_chunk_count;
397 unsigned long write_chunk_count;
398 unsigned long reply_chunk_count;
399 unsigned long long total_rdma_request;
401 /* rarely accessed error counters */
402 unsigned long long pullup_copy_count;
403 unsigned long hardway_register_count;
404 unsigned long failed_marshal_count;
405 unsigned long bad_reply_count;
406 unsigned long mrs_recycled;
407 unsigned long mrs_orphaned;
408 unsigned long mrs_allocated;
409 unsigned long empty_sendctx_q;
411 /* accessed when receiving a reply */
412 unsigned long long total_rdma_reply;
413 unsigned long long fixup_copy_count;
414 unsigned long reply_waits_for_send;
415 unsigned long local_inv_needed;
416 unsigned long nomsg_call_count;
417 unsigned long bcall_count;
421 * RPCRDMA transport -- encapsulates the structures above for
422 * integration with RPC.
424 * The contained structures are embedded, not pointers,
425 * for convenience. This structure need not be visible externally.
427 * It is allocated and initialized during mount, and released
430 struct rpcrdma_xprt {
431 struct rpc_xprt rx_xprt;
432 struct rpcrdma_ia rx_ia;
433 struct rpcrdma_ep rx_ep;
434 struct rpcrdma_buffer rx_buf;
435 struct delayed_work rx_connect_worker;
436 struct rpcrdma_stats rx_stats;
439 #define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
441 static inline const char *
442 rpcrdma_addrstr(const struct rpcrdma_xprt *r_xprt)
444 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_ADDR];
447 static inline const char *
448 rpcrdma_portstr(const struct rpcrdma_xprt *r_xprt)
450 return r_xprt->rx_xprt.address_strings[RPC_DISPLAY_PORT];
453 /* Setting this to 0 ensures interoperability with early servers.
454 * Setting this to 1 enhances certain unaligned read/write performance.
455 * Default is 0, see sysctl entry and rpc_rdma.c rpcrdma_convert_iovs() */
456 extern int xprt_rdma_pad_optimize;
458 /* This setting controls the hunt for a supported memory
459 * registration strategy.
461 extern unsigned int xprt_rdma_memreg_strategy;
464 * Interface Adapter calls - xprtrdma/verbs.c
466 int rpcrdma_ia_open(struct rpcrdma_xprt *xprt);
467 void rpcrdma_ia_remove(struct rpcrdma_ia *ia);
468 void rpcrdma_ia_close(struct rpcrdma_ia *);
471 * Endpoint calls - xprtrdma/verbs.c
473 int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt);
474 void rpcrdma_ep_destroy(struct rpcrdma_xprt *r_xprt);
475 int rpcrdma_ep_connect(struct rpcrdma_ep *, struct rpcrdma_ia *);
476 void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
478 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
479 struct rpcrdma_req *);
482 * Buffer calls - xprtrdma/verbs.c
484 struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt, size_t size,
486 void rpcrdma_req_destroy(struct rpcrdma_req *req);
487 int rpcrdma_buffer_create(struct rpcrdma_xprt *);
488 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
489 struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt);
491 struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt);
492 void rpcrdma_mr_put(struct rpcrdma_mr *mr);
493 void rpcrdma_mr_unmap_and_put(struct rpcrdma_mr *mr);
496 rpcrdma_mr_recycle(struct rpcrdma_mr *mr)
498 schedule_work(&mr->mr_recycle);
501 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
502 void rpcrdma_buffer_put(struct rpcrdma_req *);
503 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
505 bool rpcrdma_regbuf_realloc(struct rpcrdma_regbuf *rb, size_t size,
507 bool __rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
508 struct rpcrdma_regbuf *rb);
511 * rpcrdma_regbuf_is_mapped - check if buffer is DMA mapped
513 * Returns true if the buffer is now mapped to rb->rg_device.
515 static inline bool rpcrdma_regbuf_is_mapped(struct rpcrdma_regbuf *rb)
517 return rb->rg_device != NULL;
521 * rpcrdma_regbuf_dma_map - DMA-map a regbuf
522 * @r_xprt: controlling transport instance
523 * @rb: regbuf to be mapped
525 * Returns true if the buffer is currently DMA mapped.
527 static inline bool rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
528 struct rpcrdma_regbuf *rb)
530 if (likely(rpcrdma_regbuf_is_mapped(rb)))
532 return __rpcrdma_regbuf_dma_map(r_xprt, rb);
536 * Wrappers for chunk registration, shared by read/write chunk code.
539 static inline enum dma_data_direction
540 rpcrdma_data_dir(bool writing)
542 return writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
545 /* Memory registration calls xprtrdma/frwr_ops.c
547 bool frwr_is_supported(struct ib_device *device);
548 void frwr_reset(struct rpcrdma_req *req);
549 int frwr_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep);
550 int frwr_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr);
551 void frwr_release_mr(struct rpcrdma_mr *mr);
552 size_t frwr_maxpages(struct rpcrdma_xprt *r_xprt);
553 struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
554 struct rpcrdma_mr_seg *seg,
555 int nsegs, bool writing, __be32 xid,
556 struct rpcrdma_mr **mr);
557 int frwr_send(struct rpcrdma_ia *ia, struct rpcrdma_req *req);
558 void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs);
559 void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req);
560 void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req);
563 * RPC/RDMA protocol calls - xprtrdma/rpc_rdma.c
566 enum rpcrdma_chunktype {
574 int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
575 struct rpcrdma_req *req, u32 hdrlen,
577 enum rpcrdma_chunktype rtype);
578 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc);
579 int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst);
580 void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *);
581 void rpcrdma_complete_rqst(struct rpcrdma_rep *rep);
582 void rpcrdma_reply_handler(struct rpcrdma_rep *rep);
584 static inline void rpcrdma_set_xdrlen(struct xdr_buf *xdr, size_t len)
586 xdr->head[0].iov_len = len;
590 /* RPC/RDMA module init - xprtrdma/transport.c
592 extern unsigned int xprt_rdma_slot_table_entries;
593 extern unsigned int xprt_rdma_max_inline_read;
594 extern unsigned int xprt_rdma_max_inline_write;
595 void xprt_rdma_format_addresses(struct rpc_xprt *xprt, struct sockaddr *sap);
596 void xprt_rdma_free_addresses(struct rpc_xprt *xprt);
597 void xprt_rdma_close(struct rpc_xprt *xprt);
598 void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq);
599 int xprt_rdma_init(void);
600 void xprt_rdma_cleanup(void);
602 /* Backchannel calls - xprtrdma/backchannel.c
604 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
605 int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
606 size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *);
607 int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
608 void rpcrdma_bc_receive_call(struct rpcrdma_xprt *, struct rpcrdma_rep *);
609 int xprt_rdma_bc_send_reply(struct rpc_rqst *rqst);
610 void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
611 void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
612 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
614 extern struct xprt_class xprt_rdma_bc;
616 #endif /* _LINUX_SUNRPC_XPRT_RDMA_H */