xref: /openbmc/linux/net/smc/smc_llc.c (revision 8bd1369b)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Shared Memory Communications over RDMA (SMC-R) and RoCE
4  *
5  *  Link Layer Control (LLC)
6  *
7  *  Copyright IBM Corp. 2016
8  *
9  *  Author(s):  Klaus Wacker <Klaus.Wacker@de.ibm.com>
10  *              Ursula Braun <ubraun@linux.vnet.ibm.com>
11  */
12 
13 #include <net/tcp.h>
14 #include <rdma/ib_verbs.h>
15 
16 #include "smc.h"
17 #include "smc_core.h"
18 #include "smc_clc.h"
19 #include "smc_llc.h"
20 
21 #define SMC_LLC_DATA_LEN		40
22 
23 struct smc_llc_hdr {
24 	struct smc_wr_rx_hdr common;
25 	u8 length;	/* 44 */
26 #if defined(__BIG_ENDIAN_BITFIELD)
27 	u8 reserved:4,
28 	   add_link_rej_rsn:4;
29 #elif defined(__LITTLE_ENDIAN_BITFIELD)
30 	u8 add_link_rej_rsn:4,
31 	   reserved:4;
32 #endif
33 	u8 flags;
34 };
35 
36 #define SMC_LLC_FLAG_NO_RMBE_EYEC	0x03
37 
38 struct smc_llc_msg_confirm_link {	/* type 0x01 */
39 	struct smc_llc_hdr hd;
40 	u8 sender_mac[ETH_ALEN];
41 	u8 sender_gid[SMC_GID_SIZE];
42 	u8 sender_qp_num[3];
43 	u8 link_num;
44 	u8 link_uid[SMC_LGR_ID_SIZE];
45 	u8 max_links;
46 	u8 reserved[9];
47 };
48 
49 #define SMC_LLC_FLAG_ADD_LNK_REJ	0x40
50 #define SMC_LLC_REJ_RSN_NO_ALT_PATH	1
51 
52 #define SMC_LLC_ADD_LNK_MAX_LINKS	2
53 
54 struct smc_llc_msg_add_link {		/* type 0x02 */
55 	struct smc_llc_hdr hd;
56 	u8 sender_mac[ETH_ALEN];
57 	u8 reserved2[2];
58 	u8 sender_gid[SMC_GID_SIZE];
59 	u8 sender_qp_num[3];
60 	u8 link_num;
61 	u8 flags2;	/* QP mtu */
62 	u8 initial_psn[3];
63 	u8 reserved[8];
64 };
65 
66 #define SMC_LLC_FLAG_DEL_LINK_ALL	0x40
67 #define SMC_LLC_FLAG_DEL_LINK_ORDERLY	0x20
68 
69 struct smc_llc_msg_del_link {		/* type 0x04 */
70 	struct smc_llc_hdr hd;
71 	u8 link_num;
72 	__be32 reason;
73 	u8 reserved[35];
74 } __packed;			/* format defined in RFC7609 */
75 
76 struct smc_llc_msg_test_link {		/* type 0x07 */
77 	struct smc_llc_hdr hd;
78 	u8 user_data[16];
79 	u8 reserved[24];
80 };
81 
82 struct smc_rmb_rtoken {
83 	union {
84 		u8 num_rkeys;	/* first rtoken byte of CONFIRM LINK msg */
85 				/* is actually the num of rtokens, first */
86 				/* rtoken is always for the current link */
87 		u8 link_id;	/* link id of the rtoken */
88 	};
89 	__be32 rmb_key;
90 	__be64 rmb_vaddr;
91 } __packed;			/* format defined in RFC7609 */
92 
93 #define SMC_LLC_RKEYS_PER_MSG	3
94 
95 struct smc_llc_msg_confirm_rkey {	/* type 0x06 */
96 	struct smc_llc_hdr hd;
97 	struct smc_rmb_rtoken rtoken[SMC_LLC_RKEYS_PER_MSG];
98 	u8 reserved;
99 };
100 
101 struct smc_llc_msg_confirm_rkey_cont {	/* type 0x08 */
102 	struct smc_llc_hdr hd;
103 	u8 num_rkeys;
104 	struct smc_rmb_rtoken rtoken[SMC_LLC_RKEYS_PER_MSG];
105 };
106 
107 #define SMC_LLC_DEL_RKEY_MAX	8
108 #define SMC_LLC_FLAG_RKEY_NEG	0x20
109 
110 struct smc_llc_msg_delete_rkey {	/* type 0x09 */
111 	struct smc_llc_hdr hd;
112 	u8 num_rkeys;
113 	u8 err_mask;
114 	u8 reserved[2];
115 	__be32 rkey[8];
116 	u8 reserved2[4];
117 };
118 
119 union smc_llc_msg {
120 	struct smc_llc_msg_confirm_link confirm_link;
121 	struct smc_llc_msg_add_link add_link;
122 	struct smc_llc_msg_del_link delete_link;
123 
124 	struct smc_llc_msg_confirm_rkey confirm_rkey;
125 	struct smc_llc_msg_confirm_rkey_cont confirm_rkey_cont;
126 	struct smc_llc_msg_delete_rkey delete_rkey;
127 
128 	struct smc_llc_msg_test_link test_link;
129 	struct {
130 		struct smc_llc_hdr hdr;
131 		u8 data[SMC_LLC_DATA_LEN];
132 	} raw;
133 };
134 
135 #define SMC_LLC_FLAG_RESP		0x80
136 
137 /********************************** send *************************************/
138 
139 struct smc_llc_tx_pend {
140 };
141 
142 /* handler for send/transmission completion of an LLC msg */
143 static void smc_llc_tx_handler(struct smc_wr_tx_pend_priv *pend,
144 			       struct smc_link *link,
145 			       enum ib_wc_status wc_status)
146 {
147 	/* future work: handle wc_status error for recovery and failover */
148 }
149 
150 /**
151  * smc_llc_add_pending_send() - add LLC control message to pending WQE transmits
152  * @link: Pointer to SMC link used for sending LLC control message.
153  * @wr_buf: Out variable returning pointer to work request payload buffer.
154  * @pend: Out variable returning pointer to private pending WR tracking.
155  *	  It's the context the transmit complete handler will get.
156  *
157  * Reserves and pre-fills an entry for a pending work request send/tx.
158  * Used by mid-level smc_llc_send_msg() to prepare for later actual send/tx.
159  * Can sleep due to smc_get_ctrl_buf (if not in softirq context).
160  *
161  * Return: 0 on success, otherwise an error value.
162  */
163 static int smc_llc_add_pending_send(struct smc_link *link,
164 				    struct smc_wr_buf **wr_buf,
165 				    struct smc_wr_tx_pend_priv **pend)
166 {
167 	int rc;
168 
169 	rc = smc_wr_tx_get_free_slot(link, smc_llc_tx_handler, wr_buf, pend);
170 	if (rc < 0)
171 		return rc;
172 	BUILD_BUG_ON_MSG(
173 		sizeof(union smc_llc_msg) > SMC_WR_BUF_SIZE,
174 		"must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_llc_msg)");
175 	BUILD_BUG_ON_MSG(
176 		sizeof(union smc_llc_msg) != SMC_WR_TX_SIZE,
177 		"must adapt SMC_WR_TX_SIZE to sizeof(struct smc_llc_msg); if not all smc_wr upper layer protocols use the same message size any more, must start to set link->wr_tx_sges[i].length on each individual smc_wr_tx_send()");
178 	BUILD_BUG_ON_MSG(
179 		sizeof(struct smc_llc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
180 		"must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_llc_tx_pend)");
181 	return 0;
182 }
183 
184 /* high-level API to send LLC confirm link */
185 int smc_llc_send_confirm_link(struct smc_link *link, u8 mac[],
186 			      union ib_gid *gid,
187 			      enum smc_llc_reqresp reqresp)
188 {
189 	struct smc_link_group *lgr = container_of(link, struct smc_link_group,
190 						  lnk[SMC_SINGLE_LINK]);
191 	struct smc_llc_msg_confirm_link *confllc;
192 	struct smc_wr_tx_pend_priv *pend;
193 	struct smc_wr_buf *wr_buf;
194 	int rc;
195 
196 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
197 	if (rc)
198 		return rc;
199 	confllc = (struct smc_llc_msg_confirm_link *)wr_buf;
200 	memset(confllc, 0, sizeof(*confllc));
201 	confllc->hd.common.type = SMC_LLC_CONFIRM_LINK;
202 	confllc->hd.length = sizeof(struct smc_llc_msg_confirm_link);
203 	confllc->hd.flags |= SMC_LLC_FLAG_NO_RMBE_EYEC;
204 	if (reqresp == SMC_LLC_RESP)
205 		confllc->hd.flags |= SMC_LLC_FLAG_RESP;
206 	memcpy(confllc->sender_mac, mac, ETH_ALEN);
207 	memcpy(confllc->sender_gid, gid, SMC_GID_SIZE);
208 	hton24(confllc->sender_qp_num, link->roce_qp->qp_num);
209 	confllc->link_num = link->link_id;
210 	memcpy(confllc->link_uid, lgr->id, SMC_LGR_ID_SIZE);
211 	confllc->max_links = SMC_LLC_ADD_LNK_MAX_LINKS; /* enforce peer resp. */
212 	/* send llc message */
213 	rc = smc_wr_tx_send(link, pend);
214 	return rc;
215 }
216 
217 /* send LLC confirm rkey request */
218 static int smc_llc_send_confirm_rkey(struct smc_link *link,
219 				     struct smc_buf_desc *rmb_desc)
220 {
221 	struct smc_llc_msg_confirm_rkey *rkeyllc;
222 	struct smc_wr_tx_pend_priv *pend;
223 	struct smc_wr_buf *wr_buf;
224 	int rc;
225 
226 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
227 	if (rc)
228 		return rc;
229 	rkeyllc = (struct smc_llc_msg_confirm_rkey *)wr_buf;
230 	memset(rkeyllc, 0, sizeof(*rkeyllc));
231 	rkeyllc->hd.common.type = SMC_LLC_CONFIRM_RKEY;
232 	rkeyllc->hd.length = sizeof(struct smc_llc_msg_confirm_rkey);
233 	rkeyllc->rtoken[0].rmb_key =
234 		htonl(rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
235 	rkeyllc->rtoken[0].rmb_vaddr = cpu_to_be64(
236 		(u64)sg_dma_address(rmb_desc->sgt[SMC_SINGLE_LINK].sgl));
237 	/* send llc message */
238 	rc = smc_wr_tx_send(link, pend);
239 	return rc;
240 }
241 
242 /* prepare an add link message */
243 static void smc_llc_prep_add_link(struct smc_llc_msg_add_link *addllc,
244 				  struct smc_link *link, u8 mac[],
245 				  union ib_gid *gid,
246 				  enum smc_llc_reqresp reqresp)
247 {
248 	memset(addllc, 0, sizeof(*addllc));
249 	addllc->hd.common.type = SMC_LLC_ADD_LINK;
250 	addllc->hd.length = sizeof(struct smc_llc_msg_add_link);
251 	if (reqresp == SMC_LLC_RESP) {
252 		addllc->hd.flags |= SMC_LLC_FLAG_RESP;
253 		/* always reject more links for now */
254 		addllc->hd.flags |= SMC_LLC_FLAG_ADD_LNK_REJ;
255 		addllc->hd.add_link_rej_rsn = SMC_LLC_REJ_RSN_NO_ALT_PATH;
256 	}
257 	memcpy(addllc->sender_mac, mac, ETH_ALEN);
258 	memcpy(addllc->sender_gid, gid, SMC_GID_SIZE);
259 }
260 
261 /* send ADD LINK request or response */
262 int smc_llc_send_add_link(struct smc_link *link, u8 mac[],
263 			  union ib_gid *gid,
264 			  enum smc_llc_reqresp reqresp)
265 {
266 	struct smc_llc_msg_add_link *addllc;
267 	struct smc_wr_tx_pend_priv *pend;
268 	struct smc_wr_buf *wr_buf;
269 	int rc;
270 
271 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
272 	if (rc)
273 		return rc;
274 	addllc = (struct smc_llc_msg_add_link *)wr_buf;
275 	smc_llc_prep_add_link(addllc, link, mac, gid, reqresp);
276 	/* send llc message */
277 	rc = smc_wr_tx_send(link, pend);
278 	return rc;
279 }
280 
281 /* prepare a delete link message */
282 static void smc_llc_prep_delete_link(struct smc_llc_msg_del_link *delllc,
283 				     struct smc_link *link,
284 				     enum smc_llc_reqresp reqresp)
285 {
286 	memset(delllc, 0, sizeof(*delllc));
287 	delllc->hd.common.type = SMC_LLC_DELETE_LINK;
288 	delllc->hd.length = sizeof(struct smc_llc_msg_add_link);
289 	if (reqresp == SMC_LLC_RESP)
290 		delllc->hd.flags |= SMC_LLC_FLAG_RESP;
291 	/* DEL_LINK_ALL because only 1 link supported */
292 	delllc->hd.flags |= SMC_LLC_FLAG_DEL_LINK_ALL;
293 	delllc->hd.flags |= SMC_LLC_FLAG_DEL_LINK_ORDERLY;
294 	delllc->link_num = link->link_id;
295 }
296 
297 /* send DELETE LINK request or response */
298 int smc_llc_send_delete_link(struct smc_link *link,
299 			     enum smc_llc_reqresp reqresp)
300 {
301 	struct smc_llc_msg_del_link *delllc;
302 	struct smc_wr_tx_pend_priv *pend;
303 	struct smc_wr_buf *wr_buf;
304 	int rc;
305 
306 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
307 	if (rc)
308 		return rc;
309 	delllc = (struct smc_llc_msg_del_link *)wr_buf;
310 	smc_llc_prep_delete_link(delllc, link, reqresp);
311 	/* send llc message */
312 	rc = smc_wr_tx_send(link, pend);
313 	return rc;
314 }
315 
316 /* send LLC test link request */
317 static int smc_llc_send_test_link(struct smc_link *link, u8 user_data[16])
318 {
319 	struct smc_llc_msg_test_link *testllc;
320 	struct smc_wr_tx_pend_priv *pend;
321 	struct smc_wr_buf *wr_buf;
322 	int rc;
323 
324 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
325 	if (rc)
326 		return rc;
327 	testllc = (struct smc_llc_msg_test_link *)wr_buf;
328 	memset(testllc, 0, sizeof(*testllc));
329 	testllc->hd.common.type = SMC_LLC_TEST_LINK;
330 	testllc->hd.length = sizeof(struct smc_llc_msg_test_link);
331 	memcpy(testllc->user_data, user_data, sizeof(testllc->user_data));
332 	/* send llc message */
333 	rc = smc_wr_tx_send(link, pend);
334 	return rc;
335 }
336 
337 struct smc_llc_send_work {
338 	struct work_struct work;
339 	struct smc_link *link;
340 	int llclen;
341 	union smc_llc_msg llcbuf;
342 };
343 
344 /* worker that sends a prepared message */
345 static void smc_llc_send_message_work(struct work_struct *work)
346 {
347 	struct smc_llc_send_work *llcwrk = container_of(work,
348 						struct smc_llc_send_work, work);
349 	struct smc_wr_tx_pend_priv *pend;
350 	struct smc_wr_buf *wr_buf;
351 	int rc;
352 
353 	if (llcwrk->link->state == SMC_LNK_INACTIVE)
354 		goto out;
355 	rc = smc_llc_add_pending_send(llcwrk->link, &wr_buf, &pend);
356 	if (rc)
357 		goto out;
358 	memcpy(wr_buf, &llcwrk->llcbuf, llcwrk->llclen);
359 	smc_wr_tx_send(llcwrk->link, pend);
360 out:
361 	kfree(llcwrk);
362 }
363 
364 /* copy llcbuf and schedule an llc send on link */
365 static int smc_llc_send_message(struct smc_link *link, void *llcbuf, int llclen)
366 {
367 	struct smc_llc_send_work *wrk = kmalloc(sizeof(*wrk), GFP_ATOMIC);
368 
369 	if (!wrk)
370 		return -ENOMEM;
371 	INIT_WORK(&wrk->work, smc_llc_send_message_work);
372 	wrk->link = link;
373 	wrk->llclen = llclen;
374 	memcpy(&wrk->llcbuf, llcbuf, llclen);
375 	queue_work(link->llc_wq, &wrk->work);
376 	return 0;
377 }
378 
379 /********************************* receive ***********************************/
380 
381 static void smc_llc_rx_confirm_link(struct smc_link *link,
382 				    struct smc_llc_msg_confirm_link *llc)
383 {
384 	struct smc_link_group *lgr;
385 	int conf_rc;
386 
387 	lgr = container_of(link, struct smc_link_group, lnk[SMC_SINGLE_LINK]);
388 
389 	/* RMBE eyecatchers are not supported */
390 	if (llc->hd.flags & SMC_LLC_FLAG_NO_RMBE_EYEC)
391 		conf_rc = 0;
392 	else
393 		conf_rc = ENOTSUPP;
394 
395 	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
396 		if (lgr->role == SMC_SERV &&
397 		    link->state == SMC_LNK_ACTIVATING) {
398 			link->llc_confirm_resp_rc = conf_rc;
399 			complete(&link->llc_confirm_resp);
400 		}
401 	} else {
402 		if (lgr->role == SMC_CLNT &&
403 		    link->state == SMC_LNK_ACTIVATING) {
404 			link->llc_confirm_rc = conf_rc;
405 			link->link_id = llc->link_num;
406 			complete(&link->llc_confirm);
407 		}
408 	}
409 }
410 
411 static void smc_llc_rx_add_link(struct smc_link *link,
412 				struct smc_llc_msg_add_link *llc)
413 {
414 	struct smc_link_group *lgr = container_of(link, struct smc_link_group,
415 						  lnk[SMC_SINGLE_LINK]);
416 
417 	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
418 		if (link->state == SMC_LNK_ACTIVATING)
419 			complete(&link->llc_add_resp);
420 	} else {
421 		if (link->state == SMC_LNK_ACTIVATING) {
422 			complete(&link->llc_add);
423 			return;
424 		}
425 
426 		if (lgr->role == SMC_SERV) {
427 			smc_llc_prep_add_link(llc, link,
428 					link->smcibdev->mac[link->ibport - 1],
429 					&link->smcibdev->gid[link->ibport - 1],
430 					SMC_LLC_REQ);
431 
432 		} else {
433 			smc_llc_prep_add_link(llc, link,
434 					link->smcibdev->mac[link->ibport - 1],
435 					&link->smcibdev->gid[link->ibport - 1],
436 					SMC_LLC_RESP);
437 		}
438 		smc_llc_send_message(link, llc, sizeof(*llc));
439 	}
440 }
441 
442 static void smc_llc_rx_delete_link(struct smc_link *link,
443 				   struct smc_llc_msg_del_link *llc)
444 {
445 	struct smc_link_group *lgr = container_of(link, struct smc_link_group,
446 						  lnk[SMC_SINGLE_LINK]);
447 
448 	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
449 		if (lgr->role == SMC_SERV)
450 			smc_lgr_terminate(lgr);
451 	} else {
452 		if (lgr->role == SMC_SERV) {
453 			smc_lgr_forget(lgr);
454 			smc_llc_prep_delete_link(llc, link, SMC_LLC_REQ);
455 			smc_llc_send_message(link, llc, sizeof(*llc));
456 		} else {
457 			smc_llc_prep_delete_link(llc, link, SMC_LLC_RESP);
458 			smc_llc_send_message(link, llc, sizeof(*llc));
459 			smc_lgr_terminate(lgr);
460 		}
461 	}
462 }
463 
464 static void smc_llc_rx_test_link(struct smc_link *link,
465 				 struct smc_llc_msg_test_link *llc)
466 {
467 	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
468 		if (link->state == SMC_LNK_ACTIVE)
469 			complete(&link->llc_testlink_resp);
470 	} else {
471 		llc->hd.flags |= SMC_LLC_FLAG_RESP;
472 		smc_llc_send_message(link, llc, sizeof(*llc));
473 	}
474 }
475 
476 static void smc_llc_rx_confirm_rkey(struct smc_link *link,
477 				    struct smc_llc_msg_confirm_rkey *llc)
478 {
479 	struct smc_link_group *lgr;
480 	int rc;
481 
482 	lgr = container_of(link, struct smc_link_group, lnk[SMC_SINGLE_LINK]);
483 
484 	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
485 		link->llc_confirm_rkey_rc = llc->hd.flags &
486 					    SMC_LLC_FLAG_RKEY_NEG;
487 		complete(&link->llc_confirm_rkey);
488 	} else {
489 		rc = smc_rtoken_add(lgr,
490 				    llc->rtoken[0].rmb_vaddr,
491 				    llc->rtoken[0].rmb_key);
492 
493 		/* ignore rtokens for other links, we have only one link */
494 
495 		llc->hd.flags |= SMC_LLC_FLAG_RESP;
496 		if (rc < 0)
497 			llc->hd.flags |= SMC_LLC_FLAG_RKEY_NEG;
498 		smc_llc_send_message(link, llc, sizeof(*llc));
499 	}
500 }
501 
502 static void smc_llc_rx_confirm_rkey_cont(struct smc_link *link,
503 				      struct smc_llc_msg_confirm_rkey_cont *llc)
504 {
505 	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
506 		/* unused as long as we don't send this type of msg */
507 	} else {
508 		/* ignore rtokens for other links, we have only one link */
509 		llc->hd.flags |= SMC_LLC_FLAG_RESP;
510 		smc_llc_send_message(link, llc, sizeof(*llc));
511 	}
512 }
513 
514 static void smc_llc_rx_delete_rkey(struct smc_link *link,
515 				   struct smc_llc_msg_delete_rkey *llc)
516 {
517 	struct smc_link_group *lgr;
518 	u8 err_mask = 0;
519 	int i, max;
520 
521 	lgr = container_of(link, struct smc_link_group, lnk[SMC_SINGLE_LINK]);
522 
523 	if (llc->hd.flags & SMC_LLC_FLAG_RESP) {
524 		/* unused as long as we don't send this type of msg */
525 	} else {
526 		max = min_t(u8, llc->num_rkeys, SMC_LLC_DEL_RKEY_MAX);
527 		for (i = 0; i < max; i++) {
528 			if (smc_rtoken_delete(lgr, llc->rkey[i]))
529 				err_mask |= 1 << (SMC_LLC_DEL_RKEY_MAX - 1 - i);
530 		}
531 
532 		if (err_mask) {
533 			llc->hd.flags |= SMC_LLC_FLAG_RKEY_NEG;
534 			llc->err_mask = err_mask;
535 		}
536 
537 		llc->hd.flags |= SMC_LLC_FLAG_RESP;
538 		smc_llc_send_message(link, llc, sizeof(*llc));
539 	}
540 }
541 
542 static void smc_llc_rx_handler(struct ib_wc *wc, void *buf)
543 {
544 	struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
545 	union smc_llc_msg *llc = buf;
546 
547 	if (wc->byte_len < sizeof(*llc))
548 		return; /* short message */
549 	if (llc->raw.hdr.length != sizeof(*llc))
550 		return; /* invalid message */
551 	if (link->state == SMC_LNK_INACTIVE)
552 		return; /* link not active, drop msg */
553 
554 	switch (llc->raw.hdr.common.type) {
555 	case SMC_LLC_TEST_LINK:
556 		smc_llc_rx_test_link(link, &llc->test_link);
557 		break;
558 	case SMC_LLC_CONFIRM_LINK:
559 		smc_llc_rx_confirm_link(link, &llc->confirm_link);
560 		break;
561 	case SMC_LLC_ADD_LINK:
562 		smc_llc_rx_add_link(link, &llc->add_link);
563 		break;
564 	case SMC_LLC_DELETE_LINK:
565 		smc_llc_rx_delete_link(link, &llc->delete_link);
566 		break;
567 	case SMC_LLC_CONFIRM_RKEY:
568 		smc_llc_rx_confirm_rkey(link, &llc->confirm_rkey);
569 		break;
570 	case SMC_LLC_CONFIRM_RKEY_CONT:
571 		smc_llc_rx_confirm_rkey_cont(link, &llc->confirm_rkey_cont);
572 		break;
573 	case SMC_LLC_DELETE_RKEY:
574 		smc_llc_rx_delete_rkey(link, &llc->delete_rkey);
575 		break;
576 	}
577 }
578 
579 /***************************** worker, utils *********************************/
580 
581 static void smc_llc_testlink_work(struct work_struct *work)
582 {
583 	struct smc_link *link = container_of(to_delayed_work(work),
584 					     struct smc_link, llc_testlink_wrk);
585 	unsigned long next_interval;
586 	struct smc_link_group *lgr;
587 	unsigned long expire_time;
588 	u8 user_data[16] = { 0 };
589 	int rc;
590 
591 	lgr = container_of(link, struct smc_link_group, lnk[SMC_SINGLE_LINK]);
592 	if (link->state != SMC_LNK_ACTIVE)
593 		return;		/* don't reschedule worker */
594 	expire_time = link->wr_rx_tstamp + link->llc_testlink_time;
595 	if (time_is_after_jiffies(expire_time)) {
596 		next_interval = expire_time - jiffies;
597 		goto out;
598 	}
599 	reinit_completion(&link->llc_testlink_resp);
600 	smc_llc_send_test_link(link, user_data);
601 	/* receive TEST LINK response over RoCE fabric */
602 	rc = wait_for_completion_interruptible_timeout(&link->llc_testlink_resp,
603 						       SMC_LLC_WAIT_TIME);
604 	if (rc <= 0) {
605 		smc_lgr_terminate(lgr);
606 		return;
607 	}
608 	next_interval = link->llc_testlink_time;
609 out:
610 	queue_delayed_work(link->llc_wq, &link->llc_testlink_wrk,
611 			   next_interval);
612 }
613 
614 int smc_llc_link_init(struct smc_link *link)
615 {
616 	struct smc_link_group *lgr = container_of(link, struct smc_link_group,
617 						  lnk[SMC_SINGLE_LINK]);
618 	link->llc_wq = alloc_ordered_workqueue("llc_wq-%x:%x)", WQ_MEM_RECLAIM,
619 					       *((u32 *)lgr->id),
620 					       link->link_id);
621 	if (!link->llc_wq)
622 		return -ENOMEM;
623 	init_completion(&link->llc_confirm);
624 	init_completion(&link->llc_confirm_resp);
625 	init_completion(&link->llc_add);
626 	init_completion(&link->llc_add_resp);
627 	init_completion(&link->llc_confirm_rkey);
628 	init_completion(&link->llc_testlink_resp);
629 	INIT_DELAYED_WORK(&link->llc_testlink_wrk, smc_llc_testlink_work);
630 	return 0;
631 }
632 
633 void smc_llc_link_active(struct smc_link *link, int testlink_time)
634 {
635 	link->state = SMC_LNK_ACTIVE;
636 	if (testlink_time) {
637 		link->llc_testlink_time = testlink_time * HZ;
638 		queue_delayed_work(link->llc_wq, &link->llc_testlink_wrk,
639 				   link->llc_testlink_time);
640 	}
641 }
642 
643 /* called in tasklet context */
644 void smc_llc_link_inactive(struct smc_link *link)
645 {
646 	link->state = SMC_LNK_INACTIVE;
647 	cancel_delayed_work(&link->llc_testlink_wrk);
648 }
649 
650 /* called in worker context */
651 void smc_llc_link_clear(struct smc_link *link)
652 {
653 	flush_workqueue(link->llc_wq);
654 	destroy_workqueue(link->llc_wq);
655 }
656 
657 /* register a new rtoken at the remote peer */
658 int smc_llc_do_confirm_rkey(struct smc_link *link,
659 			    struct smc_buf_desc *rmb_desc)
660 {
661 	int rc;
662 
663 	reinit_completion(&link->llc_confirm_rkey);
664 	smc_llc_send_confirm_rkey(link, rmb_desc);
665 	/* receive CONFIRM RKEY response from server over RoCE fabric */
666 	rc = wait_for_completion_interruptible_timeout(&link->llc_confirm_rkey,
667 						       SMC_LLC_WAIT_TIME);
668 	if (rc <= 0 || link->llc_confirm_rkey_rc)
669 		return -EFAULT;
670 	return 0;
671 }
672 
673 /***************************** init, exit, misc ******************************/
674 
675 static struct smc_wr_rx_handler smc_llc_rx_handlers[] = {
676 	{
677 		.handler	= smc_llc_rx_handler,
678 		.type		= SMC_LLC_CONFIRM_LINK
679 	},
680 	{
681 		.handler	= smc_llc_rx_handler,
682 		.type		= SMC_LLC_TEST_LINK
683 	},
684 	{
685 		.handler	= smc_llc_rx_handler,
686 		.type		= SMC_LLC_ADD_LINK
687 	},
688 	{
689 		.handler	= smc_llc_rx_handler,
690 		.type		= SMC_LLC_DELETE_LINK
691 	},
692 	{
693 		.handler	= smc_llc_rx_handler,
694 		.type		= SMC_LLC_CONFIRM_RKEY
695 	},
696 	{
697 		.handler	= smc_llc_rx_handler,
698 		.type		= SMC_LLC_CONFIRM_RKEY_CONT
699 	},
700 	{
701 		.handler	= smc_llc_rx_handler,
702 		.type		= SMC_LLC_DELETE_RKEY
703 	},
704 	{
705 		.handler	= NULL,
706 	}
707 };
708 
709 int __init smc_llc_init(void)
710 {
711 	struct smc_wr_rx_handler *handler;
712 	int rc = 0;
713 
714 	for (handler = smc_llc_rx_handlers; handler->handler; handler++) {
715 		INIT_HLIST_NODE(&handler->list);
716 		rc = smc_wr_rx_register_handler(handler);
717 		if (rc)
718 			break;
719 	}
720 	return rc;
721 }
722