xref: /openbmc/linux/net/smc/smc_llc.c (revision 002dff36)
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 #include "smc_pnet.h"
21 
22 #define SMC_LLC_DATA_LEN		40
23 
24 struct smc_llc_hdr {
25 	struct smc_wr_rx_hdr common;
26 	u8 length;	/* 44 */
27 #if defined(__BIG_ENDIAN_BITFIELD)
28 	u8 reserved:4,
29 	   add_link_rej_rsn:4;
30 #elif defined(__LITTLE_ENDIAN_BITFIELD)
31 	u8 add_link_rej_rsn:4,
32 	   reserved:4;
33 #endif
34 	u8 flags;
35 };
36 
37 #define SMC_LLC_FLAG_NO_RMBE_EYEC	0x03
38 
39 struct smc_llc_msg_confirm_link {	/* type 0x01 */
40 	struct smc_llc_hdr hd;
41 	u8 sender_mac[ETH_ALEN];
42 	u8 sender_gid[SMC_GID_SIZE];
43 	u8 sender_qp_num[3];
44 	u8 link_num;
45 	u8 link_uid[SMC_LGR_ID_SIZE];
46 	u8 max_links;
47 	u8 reserved[9];
48 };
49 
50 #define SMC_LLC_FLAG_ADD_LNK_REJ	0x40
51 #define SMC_LLC_REJ_RSN_NO_ALT_PATH	1
52 
53 #define SMC_LLC_ADD_LNK_MAX_LINKS	2
54 
55 struct smc_llc_msg_add_link {		/* type 0x02 */
56 	struct smc_llc_hdr hd;
57 	u8 sender_mac[ETH_ALEN];
58 	u8 reserved2[2];
59 	u8 sender_gid[SMC_GID_SIZE];
60 	u8 sender_qp_num[3];
61 	u8 link_num;
62 #if defined(__BIG_ENDIAN_BITFIELD)
63 	u8 reserved3 : 4,
64 	   qp_mtu   : 4;
65 #elif defined(__LITTLE_ENDIAN_BITFIELD)
66 	u8 qp_mtu   : 4,
67 	   reserved3 : 4;
68 #endif
69 	u8 initial_psn[3];
70 	u8 reserved[8];
71 };
72 
73 struct smc_llc_msg_add_link_cont_rt {
74 	__be32 rmb_key;
75 	__be32 rmb_key_new;
76 	__be64 rmb_vaddr_new;
77 };
78 
79 #define SMC_LLC_RKEYS_PER_CONT_MSG	2
80 
81 struct smc_llc_msg_add_link_cont {	/* type 0x03 */
82 	struct smc_llc_hdr hd;
83 	u8 link_num;
84 	u8 num_rkeys;
85 	u8 reserved2[2];
86 	struct smc_llc_msg_add_link_cont_rt rt[SMC_LLC_RKEYS_PER_CONT_MSG];
87 	u8 reserved[4];
88 } __packed;			/* format defined in RFC7609 */
89 
90 #define SMC_LLC_FLAG_DEL_LINK_ALL	0x40
91 #define SMC_LLC_FLAG_DEL_LINK_ORDERLY	0x20
92 
93 struct smc_llc_msg_del_link {		/* type 0x04 */
94 	struct smc_llc_hdr hd;
95 	u8 link_num;
96 	__be32 reason;
97 	u8 reserved[35];
98 } __packed;			/* format defined in RFC7609 */
99 
100 struct smc_llc_msg_test_link {		/* type 0x07 */
101 	struct smc_llc_hdr hd;
102 	u8 user_data[16];
103 	u8 reserved[24];
104 };
105 
106 struct smc_rmb_rtoken {
107 	union {
108 		u8 num_rkeys;	/* first rtoken byte of CONFIRM LINK msg */
109 				/* is actually the num of rtokens, first */
110 				/* rtoken is always for the current link */
111 		u8 link_id;	/* link id of the rtoken */
112 	};
113 	__be32 rmb_key;
114 	__be64 rmb_vaddr;
115 } __packed;			/* format defined in RFC7609 */
116 
117 #define SMC_LLC_RKEYS_PER_MSG	3
118 
119 struct smc_llc_msg_confirm_rkey {	/* type 0x06 */
120 	struct smc_llc_hdr hd;
121 	struct smc_rmb_rtoken rtoken[SMC_LLC_RKEYS_PER_MSG];
122 	u8 reserved;
123 };
124 
125 #define SMC_LLC_DEL_RKEY_MAX	8
126 #define SMC_LLC_FLAG_RKEY_RETRY	0x10
127 #define SMC_LLC_FLAG_RKEY_NEG	0x20
128 
129 struct smc_llc_msg_delete_rkey {	/* type 0x09 */
130 	struct smc_llc_hdr hd;
131 	u8 num_rkeys;
132 	u8 err_mask;
133 	u8 reserved[2];
134 	__be32 rkey[8];
135 	u8 reserved2[4];
136 };
137 
138 union smc_llc_msg {
139 	struct smc_llc_msg_confirm_link confirm_link;
140 	struct smc_llc_msg_add_link add_link;
141 	struct smc_llc_msg_add_link_cont add_link_cont;
142 	struct smc_llc_msg_del_link delete_link;
143 
144 	struct smc_llc_msg_confirm_rkey confirm_rkey;
145 	struct smc_llc_msg_delete_rkey delete_rkey;
146 
147 	struct smc_llc_msg_test_link test_link;
148 	struct {
149 		struct smc_llc_hdr hdr;
150 		u8 data[SMC_LLC_DATA_LEN];
151 	} raw;
152 };
153 
154 #define SMC_LLC_FLAG_RESP		0x80
155 
156 struct smc_llc_qentry {
157 	struct list_head list;
158 	struct smc_link *link;
159 	union smc_llc_msg msg;
160 };
161 
162 static void smc_llc_enqueue(struct smc_link *link, union smc_llc_msg *llc);
163 
164 struct smc_llc_qentry *smc_llc_flow_qentry_clr(struct smc_llc_flow *flow)
165 {
166 	struct smc_llc_qentry *qentry = flow->qentry;
167 
168 	flow->qentry = NULL;
169 	return qentry;
170 }
171 
172 void smc_llc_flow_qentry_del(struct smc_llc_flow *flow)
173 {
174 	struct smc_llc_qentry *qentry;
175 
176 	if (flow->qentry) {
177 		qentry = flow->qentry;
178 		flow->qentry = NULL;
179 		kfree(qentry);
180 	}
181 }
182 
183 static inline void smc_llc_flow_qentry_set(struct smc_llc_flow *flow,
184 					   struct smc_llc_qentry *qentry)
185 {
186 	flow->qentry = qentry;
187 }
188 
189 /* try to start a new llc flow, initiated by an incoming llc msg */
190 static bool smc_llc_flow_start(struct smc_llc_flow *flow,
191 			       struct smc_llc_qentry *qentry)
192 {
193 	struct smc_link_group *lgr = qentry->link->lgr;
194 
195 	spin_lock_bh(&lgr->llc_flow_lock);
196 	if (flow->type) {
197 		/* a flow is already active */
198 		if ((qentry->msg.raw.hdr.common.type == SMC_LLC_ADD_LINK ||
199 		     qentry->msg.raw.hdr.common.type == SMC_LLC_DELETE_LINK) &&
200 		    !lgr->delayed_event) {
201 			lgr->delayed_event = qentry;
202 		} else {
203 			/* forget this llc request */
204 			kfree(qentry);
205 		}
206 		spin_unlock_bh(&lgr->llc_flow_lock);
207 		return false;
208 	}
209 	switch (qentry->msg.raw.hdr.common.type) {
210 	case SMC_LLC_ADD_LINK:
211 		flow->type = SMC_LLC_FLOW_ADD_LINK;
212 		break;
213 	case SMC_LLC_DELETE_LINK:
214 		flow->type = SMC_LLC_FLOW_DEL_LINK;
215 		break;
216 	case SMC_LLC_CONFIRM_RKEY:
217 	case SMC_LLC_DELETE_RKEY:
218 		flow->type = SMC_LLC_FLOW_RKEY;
219 		break;
220 	default:
221 		flow->type = SMC_LLC_FLOW_NONE;
222 	}
223 	if (qentry == lgr->delayed_event)
224 		lgr->delayed_event = NULL;
225 	spin_unlock_bh(&lgr->llc_flow_lock);
226 	smc_llc_flow_qentry_set(flow, qentry);
227 	return true;
228 }
229 
230 /* start a new local llc flow, wait till current flow finished */
231 int smc_llc_flow_initiate(struct smc_link_group *lgr,
232 			  enum smc_llc_flowtype type)
233 {
234 	enum smc_llc_flowtype allowed_remote = SMC_LLC_FLOW_NONE;
235 	int rc;
236 
237 	/* all flows except confirm_rkey and delete_rkey are exclusive,
238 	 * confirm/delete rkey flows can run concurrently (local and remote)
239 	 */
240 	if (type == SMC_LLC_FLOW_RKEY)
241 		allowed_remote = SMC_LLC_FLOW_RKEY;
242 again:
243 	if (list_empty(&lgr->list))
244 		return -ENODEV;
245 	spin_lock_bh(&lgr->llc_flow_lock);
246 	if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_NONE &&
247 	    (lgr->llc_flow_rmt.type == SMC_LLC_FLOW_NONE ||
248 	     lgr->llc_flow_rmt.type == allowed_remote)) {
249 		lgr->llc_flow_lcl.type = type;
250 		spin_unlock_bh(&lgr->llc_flow_lock);
251 		return 0;
252 	}
253 	spin_unlock_bh(&lgr->llc_flow_lock);
254 	rc = wait_event_interruptible_timeout(lgr->llc_waiter,
255 			(lgr->llc_flow_lcl.type == SMC_LLC_FLOW_NONE &&
256 			 (lgr->llc_flow_rmt.type == SMC_LLC_FLOW_NONE ||
257 			  lgr->llc_flow_rmt.type == allowed_remote)),
258 			SMC_LLC_WAIT_TIME);
259 	if (!rc)
260 		return -ETIMEDOUT;
261 	goto again;
262 }
263 
264 /* finish the current llc flow */
265 void smc_llc_flow_stop(struct smc_link_group *lgr, struct smc_llc_flow *flow)
266 {
267 	spin_lock_bh(&lgr->llc_flow_lock);
268 	memset(flow, 0, sizeof(*flow));
269 	flow->type = SMC_LLC_FLOW_NONE;
270 	spin_unlock_bh(&lgr->llc_flow_lock);
271 	if (!list_empty(&lgr->list) && lgr->delayed_event &&
272 	    flow == &lgr->llc_flow_lcl)
273 		schedule_work(&lgr->llc_event_work);
274 	else
275 		wake_up_interruptible(&lgr->llc_waiter);
276 }
277 
278 /* lnk is optional and used for early wakeup when link goes down, useful in
279  * cases where we wait for a response on the link after we sent a request
280  */
281 struct smc_llc_qentry *smc_llc_wait(struct smc_link_group *lgr,
282 				    struct smc_link *lnk,
283 				    int time_out, u8 exp_msg)
284 {
285 	struct smc_llc_flow *flow = &lgr->llc_flow_lcl;
286 
287 	wait_event_interruptible_timeout(lgr->llc_waiter,
288 					 (flow->qentry ||
289 					  (lnk && !smc_link_usable(lnk)) ||
290 					  list_empty(&lgr->list)),
291 					 time_out);
292 	if (!flow->qentry ||
293 	    (lnk && !smc_link_usable(lnk)) || list_empty(&lgr->list)) {
294 		smc_llc_flow_qentry_del(flow);
295 		goto out;
296 	}
297 	if (exp_msg && flow->qentry->msg.raw.hdr.common.type != exp_msg) {
298 		if (exp_msg == SMC_LLC_ADD_LINK &&
299 		    flow->qentry->msg.raw.hdr.common.type ==
300 		    SMC_LLC_DELETE_LINK) {
301 			/* flow_start will delay the unexpected msg */
302 			smc_llc_flow_start(&lgr->llc_flow_lcl,
303 					   smc_llc_flow_qentry_clr(flow));
304 			return NULL;
305 		}
306 		smc_llc_flow_qentry_del(flow);
307 	}
308 out:
309 	return flow->qentry;
310 }
311 
312 /********************************** send *************************************/
313 
314 struct smc_llc_tx_pend {
315 };
316 
317 /* handler for send/transmission completion of an LLC msg */
318 static void smc_llc_tx_handler(struct smc_wr_tx_pend_priv *pend,
319 			       struct smc_link *link,
320 			       enum ib_wc_status wc_status)
321 {
322 	/* future work: handle wc_status error for recovery and failover */
323 }
324 
325 /**
326  * smc_llc_add_pending_send() - add LLC control message to pending WQE transmits
327  * @link: Pointer to SMC link used for sending LLC control message.
328  * @wr_buf: Out variable returning pointer to work request payload buffer.
329  * @pend: Out variable returning pointer to private pending WR tracking.
330  *	  It's the context the transmit complete handler will get.
331  *
332  * Reserves and pre-fills an entry for a pending work request send/tx.
333  * Used by mid-level smc_llc_send_msg() to prepare for later actual send/tx.
334  * Can sleep due to smc_get_ctrl_buf (if not in softirq context).
335  *
336  * Return: 0 on success, otherwise an error value.
337  */
338 static int smc_llc_add_pending_send(struct smc_link *link,
339 				    struct smc_wr_buf **wr_buf,
340 				    struct smc_wr_tx_pend_priv **pend)
341 {
342 	int rc;
343 
344 	rc = smc_wr_tx_get_free_slot(link, smc_llc_tx_handler, wr_buf, NULL,
345 				     pend);
346 	if (rc < 0)
347 		return rc;
348 	BUILD_BUG_ON_MSG(
349 		sizeof(union smc_llc_msg) > SMC_WR_BUF_SIZE,
350 		"must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_llc_msg)");
351 	BUILD_BUG_ON_MSG(
352 		sizeof(union smc_llc_msg) != SMC_WR_TX_SIZE,
353 		"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()");
354 	BUILD_BUG_ON_MSG(
355 		sizeof(struct smc_llc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
356 		"must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_llc_tx_pend)");
357 	return 0;
358 }
359 
360 /* high-level API to send LLC confirm link */
361 int smc_llc_send_confirm_link(struct smc_link *link,
362 			      enum smc_llc_reqresp reqresp)
363 {
364 	struct smc_llc_msg_confirm_link *confllc;
365 	struct smc_wr_tx_pend_priv *pend;
366 	struct smc_wr_buf *wr_buf;
367 	int rc;
368 
369 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
370 	if (rc)
371 		return rc;
372 	confllc = (struct smc_llc_msg_confirm_link *)wr_buf;
373 	memset(confllc, 0, sizeof(*confllc));
374 	confllc->hd.common.type = SMC_LLC_CONFIRM_LINK;
375 	confllc->hd.length = sizeof(struct smc_llc_msg_confirm_link);
376 	confllc->hd.flags |= SMC_LLC_FLAG_NO_RMBE_EYEC;
377 	if (reqresp == SMC_LLC_RESP)
378 		confllc->hd.flags |= SMC_LLC_FLAG_RESP;
379 	memcpy(confllc->sender_mac, link->smcibdev->mac[link->ibport - 1],
380 	       ETH_ALEN);
381 	memcpy(confllc->sender_gid, link->gid, SMC_GID_SIZE);
382 	hton24(confllc->sender_qp_num, link->roce_qp->qp_num);
383 	confllc->link_num = link->link_id;
384 	memcpy(confllc->link_uid, link->link_uid, SMC_LGR_ID_SIZE);
385 	confllc->max_links = SMC_LLC_ADD_LNK_MAX_LINKS;
386 	/* send llc message */
387 	rc = smc_wr_tx_send(link, pend);
388 	return rc;
389 }
390 
391 /* send LLC confirm rkey request */
392 static int smc_llc_send_confirm_rkey(struct smc_link *send_link,
393 				     struct smc_buf_desc *rmb_desc)
394 {
395 	struct smc_llc_msg_confirm_rkey *rkeyllc;
396 	struct smc_wr_tx_pend_priv *pend;
397 	struct smc_wr_buf *wr_buf;
398 	struct smc_link *link;
399 	int i, rc, rtok_ix;
400 
401 	rc = smc_llc_add_pending_send(send_link, &wr_buf, &pend);
402 	if (rc)
403 		return rc;
404 	rkeyllc = (struct smc_llc_msg_confirm_rkey *)wr_buf;
405 	memset(rkeyllc, 0, sizeof(*rkeyllc));
406 	rkeyllc->hd.common.type = SMC_LLC_CONFIRM_RKEY;
407 	rkeyllc->hd.length = sizeof(struct smc_llc_msg_confirm_rkey);
408 
409 	rtok_ix = 1;
410 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
411 		link = &send_link->lgr->lnk[i];
412 		if (link->state == SMC_LNK_ACTIVE && link != send_link) {
413 			rkeyllc->rtoken[rtok_ix].link_id = link->link_id;
414 			rkeyllc->rtoken[rtok_ix].rmb_key =
415 				htonl(rmb_desc->mr_rx[link->link_idx]->rkey);
416 			rkeyllc->rtoken[rtok_ix].rmb_vaddr = cpu_to_be64(
417 				(u64)sg_dma_address(
418 					rmb_desc->sgt[link->link_idx].sgl));
419 			rtok_ix++;
420 		}
421 	}
422 	/* rkey of send_link is in rtoken[0] */
423 	rkeyllc->rtoken[0].num_rkeys = rtok_ix - 1;
424 	rkeyllc->rtoken[0].rmb_key =
425 		htonl(rmb_desc->mr_rx[send_link->link_idx]->rkey);
426 	rkeyllc->rtoken[0].rmb_vaddr = cpu_to_be64(
427 		(u64)sg_dma_address(rmb_desc->sgt[send_link->link_idx].sgl));
428 	/* send llc message */
429 	rc = smc_wr_tx_send(send_link, pend);
430 	return rc;
431 }
432 
433 /* send LLC delete rkey request */
434 static int smc_llc_send_delete_rkey(struct smc_link *link,
435 				    struct smc_buf_desc *rmb_desc)
436 {
437 	struct smc_llc_msg_delete_rkey *rkeyllc;
438 	struct smc_wr_tx_pend_priv *pend;
439 	struct smc_wr_buf *wr_buf;
440 	int rc;
441 
442 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
443 	if (rc)
444 		return rc;
445 	rkeyllc = (struct smc_llc_msg_delete_rkey *)wr_buf;
446 	memset(rkeyllc, 0, sizeof(*rkeyllc));
447 	rkeyllc->hd.common.type = SMC_LLC_DELETE_RKEY;
448 	rkeyllc->hd.length = sizeof(struct smc_llc_msg_delete_rkey);
449 	rkeyllc->num_rkeys = 1;
450 	rkeyllc->rkey[0] = htonl(rmb_desc->mr_rx[link->link_idx]->rkey);
451 	/* send llc message */
452 	rc = smc_wr_tx_send(link, pend);
453 	return rc;
454 }
455 
456 /* send ADD LINK request or response */
457 int smc_llc_send_add_link(struct smc_link *link, u8 mac[], u8 gid[],
458 			  struct smc_link *link_new,
459 			  enum smc_llc_reqresp reqresp)
460 {
461 	struct smc_llc_msg_add_link *addllc;
462 	struct smc_wr_tx_pend_priv *pend;
463 	struct smc_wr_buf *wr_buf;
464 	int rc;
465 
466 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
467 	if (rc)
468 		return rc;
469 	addllc = (struct smc_llc_msg_add_link *)wr_buf;
470 
471 	memset(addllc, 0, sizeof(*addllc));
472 	addllc->hd.common.type = SMC_LLC_ADD_LINK;
473 	addllc->hd.length = sizeof(struct smc_llc_msg_add_link);
474 	if (reqresp == SMC_LLC_RESP)
475 		addllc->hd.flags |= SMC_LLC_FLAG_RESP;
476 	memcpy(addllc->sender_mac, mac, ETH_ALEN);
477 	memcpy(addllc->sender_gid, gid, SMC_GID_SIZE);
478 	if (link_new) {
479 		addllc->link_num = link_new->link_id;
480 		hton24(addllc->sender_qp_num, link_new->roce_qp->qp_num);
481 		hton24(addllc->initial_psn, link_new->psn_initial);
482 		if (reqresp == SMC_LLC_REQ)
483 			addllc->qp_mtu = link_new->path_mtu;
484 		else
485 			addllc->qp_mtu = min(link_new->path_mtu,
486 					     link_new->peer_mtu);
487 	}
488 	/* send llc message */
489 	rc = smc_wr_tx_send(link, pend);
490 	return rc;
491 }
492 
493 /* send DELETE LINK request or response */
494 int smc_llc_send_delete_link(struct smc_link *link, u8 link_del_id,
495 			     enum smc_llc_reqresp reqresp, bool orderly,
496 			     u32 reason)
497 {
498 	struct smc_llc_msg_del_link *delllc;
499 	struct smc_wr_tx_pend_priv *pend;
500 	struct smc_wr_buf *wr_buf;
501 	int rc;
502 
503 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
504 	if (rc)
505 		return rc;
506 	delllc = (struct smc_llc_msg_del_link *)wr_buf;
507 
508 	memset(delllc, 0, sizeof(*delllc));
509 	delllc->hd.common.type = SMC_LLC_DELETE_LINK;
510 	delllc->hd.length = sizeof(struct smc_llc_msg_del_link);
511 	if (reqresp == SMC_LLC_RESP)
512 		delllc->hd.flags |= SMC_LLC_FLAG_RESP;
513 	if (orderly)
514 		delllc->hd.flags |= SMC_LLC_FLAG_DEL_LINK_ORDERLY;
515 	if (link_del_id)
516 		delllc->link_num = link_del_id;
517 	else
518 		delllc->hd.flags |= SMC_LLC_FLAG_DEL_LINK_ALL;
519 	delllc->reason = htonl(reason);
520 	/* send llc message */
521 	rc = smc_wr_tx_send(link, pend);
522 	return rc;
523 }
524 
525 /* send LLC test link request */
526 static int smc_llc_send_test_link(struct smc_link *link, u8 user_data[16])
527 {
528 	struct smc_llc_msg_test_link *testllc;
529 	struct smc_wr_tx_pend_priv *pend;
530 	struct smc_wr_buf *wr_buf;
531 	int rc;
532 
533 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
534 	if (rc)
535 		return rc;
536 	testllc = (struct smc_llc_msg_test_link *)wr_buf;
537 	memset(testllc, 0, sizeof(*testllc));
538 	testllc->hd.common.type = SMC_LLC_TEST_LINK;
539 	testllc->hd.length = sizeof(struct smc_llc_msg_test_link);
540 	memcpy(testllc->user_data, user_data, sizeof(testllc->user_data));
541 	/* send llc message */
542 	rc = smc_wr_tx_send(link, pend);
543 	return rc;
544 }
545 
546 /* schedule an llc send on link, may wait for buffers */
547 static int smc_llc_send_message(struct smc_link *link, void *llcbuf)
548 {
549 	struct smc_wr_tx_pend_priv *pend;
550 	struct smc_wr_buf *wr_buf;
551 	int rc;
552 
553 	if (!smc_link_usable(link))
554 		return -ENOLINK;
555 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
556 	if (rc)
557 		return rc;
558 	memcpy(wr_buf, llcbuf, sizeof(union smc_llc_msg));
559 	return smc_wr_tx_send(link, pend);
560 }
561 
562 /* schedule an llc send on link, may wait for buffers,
563  * and wait for send completion notification.
564  * @return 0 on success
565  */
566 static int smc_llc_send_message_wait(struct smc_link *link, void *llcbuf)
567 {
568 	struct smc_wr_tx_pend_priv *pend;
569 	struct smc_wr_buf *wr_buf;
570 	int rc;
571 
572 	if (!smc_link_usable(link))
573 		return -ENOLINK;
574 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
575 	if (rc)
576 		return rc;
577 	memcpy(wr_buf, llcbuf, sizeof(union smc_llc_msg));
578 	return smc_wr_tx_send_wait(link, pend, SMC_LLC_WAIT_TIME);
579 }
580 
581 /********************************* receive ***********************************/
582 
583 static int smc_llc_alloc_alt_link(struct smc_link_group *lgr,
584 				  enum smc_lgr_type lgr_new_t)
585 {
586 	int i;
587 
588 	if (lgr->type == SMC_LGR_SYMMETRIC ||
589 	    (lgr->type != SMC_LGR_SINGLE &&
590 	     (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
591 	      lgr_new_t == SMC_LGR_ASYMMETRIC_PEER)))
592 		return -EMLINK;
593 
594 	if (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
595 	    lgr_new_t == SMC_LGR_ASYMMETRIC_PEER) {
596 		for (i = SMC_LINKS_PER_LGR_MAX - 1; i >= 0; i--)
597 			if (lgr->lnk[i].state == SMC_LNK_UNUSED)
598 				return i;
599 	} else {
600 		for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++)
601 			if (lgr->lnk[i].state == SMC_LNK_UNUSED)
602 				return i;
603 	}
604 	return -EMLINK;
605 }
606 
607 /* return first buffer from any of the next buf lists */
608 static struct smc_buf_desc *_smc_llc_get_next_rmb(struct smc_link_group *lgr,
609 						  int *buf_lst)
610 {
611 	struct smc_buf_desc *buf_pos;
612 
613 	while (*buf_lst < SMC_RMBE_SIZES) {
614 		buf_pos = list_first_entry_or_null(&lgr->rmbs[*buf_lst],
615 						   struct smc_buf_desc, list);
616 		if (buf_pos)
617 			return buf_pos;
618 		(*buf_lst)++;
619 	}
620 	return NULL;
621 }
622 
623 /* return next rmb from buffer lists */
624 static struct smc_buf_desc *smc_llc_get_next_rmb(struct smc_link_group *lgr,
625 						 int *buf_lst,
626 						 struct smc_buf_desc *buf_pos)
627 {
628 	struct smc_buf_desc *buf_next;
629 
630 	if (!buf_pos || list_is_last(&buf_pos->list, &lgr->rmbs[*buf_lst])) {
631 		(*buf_lst)++;
632 		return _smc_llc_get_next_rmb(lgr, buf_lst);
633 	}
634 	buf_next = list_next_entry(buf_pos, list);
635 	return buf_next;
636 }
637 
638 static struct smc_buf_desc *smc_llc_get_first_rmb(struct smc_link_group *lgr,
639 						  int *buf_lst)
640 {
641 	*buf_lst = 0;
642 	return smc_llc_get_next_rmb(lgr, buf_lst, NULL);
643 }
644 
645 /* send one add_link_continue msg */
646 static int smc_llc_add_link_cont(struct smc_link *link,
647 				 struct smc_link *link_new, u8 *num_rkeys_todo,
648 				 int *buf_lst, struct smc_buf_desc **buf_pos)
649 {
650 	struct smc_llc_msg_add_link_cont *addc_llc;
651 	struct smc_link_group *lgr = link->lgr;
652 	int prim_lnk_idx, lnk_idx, i, rc;
653 	struct smc_wr_tx_pend_priv *pend;
654 	struct smc_wr_buf *wr_buf;
655 	struct smc_buf_desc *rmb;
656 	u8 n;
657 
658 	rc = smc_llc_add_pending_send(link, &wr_buf, &pend);
659 	if (rc)
660 		return rc;
661 	addc_llc = (struct smc_llc_msg_add_link_cont *)wr_buf;
662 	memset(addc_llc, 0, sizeof(*addc_llc));
663 
664 	prim_lnk_idx = link->link_idx;
665 	lnk_idx = link_new->link_idx;
666 	addc_llc->link_num = link_new->link_id;
667 	addc_llc->num_rkeys = *num_rkeys_todo;
668 	n = *num_rkeys_todo;
669 	for (i = 0; i < min_t(u8, n, SMC_LLC_RKEYS_PER_CONT_MSG); i++) {
670 		if (!*buf_pos) {
671 			addc_llc->num_rkeys = addc_llc->num_rkeys -
672 					      *num_rkeys_todo;
673 			*num_rkeys_todo = 0;
674 			break;
675 		}
676 		rmb = *buf_pos;
677 
678 		addc_llc->rt[i].rmb_key = htonl(rmb->mr_rx[prim_lnk_idx]->rkey);
679 		addc_llc->rt[i].rmb_key_new = htonl(rmb->mr_rx[lnk_idx]->rkey);
680 		addc_llc->rt[i].rmb_vaddr_new =
681 			cpu_to_be64((u64)sg_dma_address(rmb->sgt[lnk_idx].sgl));
682 
683 		(*num_rkeys_todo)--;
684 		*buf_pos = smc_llc_get_next_rmb(lgr, buf_lst, *buf_pos);
685 		while (*buf_pos && !(*buf_pos)->used)
686 			*buf_pos = smc_llc_get_next_rmb(lgr, buf_lst, *buf_pos);
687 	}
688 	addc_llc->hd.common.type = SMC_LLC_ADD_LINK_CONT;
689 	addc_llc->hd.length = sizeof(struct smc_llc_msg_add_link_cont);
690 	if (lgr->role == SMC_CLNT)
691 		addc_llc->hd.flags |= SMC_LLC_FLAG_RESP;
692 	return smc_wr_tx_send(link, pend);
693 }
694 
695 static int smc_llc_cli_rkey_exchange(struct smc_link *link,
696 				     struct smc_link *link_new)
697 {
698 	struct smc_llc_msg_add_link_cont *addc_llc;
699 	struct smc_link_group *lgr = link->lgr;
700 	u8 max, num_rkeys_send, num_rkeys_recv;
701 	struct smc_llc_qentry *qentry;
702 	struct smc_buf_desc *buf_pos;
703 	int buf_lst;
704 	int rc = 0;
705 	int i;
706 
707 	mutex_lock(&lgr->rmbs_lock);
708 	num_rkeys_send = lgr->conns_num;
709 	buf_pos = smc_llc_get_first_rmb(lgr, &buf_lst);
710 	do {
711 		qentry = smc_llc_wait(lgr, NULL, SMC_LLC_WAIT_TIME,
712 				      SMC_LLC_ADD_LINK_CONT);
713 		if (!qentry) {
714 			rc = -ETIMEDOUT;
715 			break;
716 		}
717 		addc_llc = &qentry->msg.add_link_cont;
718 		num_rkeys_recv = addc_llc->num_rkeys;
719 		max = min_t(u8, num_rkeys_recv, SMC_LLC_RKEYS_PER_CONT_MSG);
720 		for (i = 0; i < max; i++) {
721 			smc_rtoken_set(lgr, link->link_idx, link_new->link_idx,
722 				       addc_llc->rt[i].rmb_key,
723 				       addc_llc->rt[i].rmb_vaddr_new,
724 				       addc_llc->rt[i].rmb_key_new);
725 			num_rkeys_recv--;
726 		}
727 		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
728 		rc = smc_llc_add_link_cont(link, link_new, &num_rkeys_send,
729 					   &buf_lst, &buf_pos);
730 		if (rc)
731 			break;
732 	} while (num_rkeys_send || num_rkeys_recv);
733 
734 	mutex_unlock(&lgr->rmbs_lock);
735 	return rc;
736 }
737 
738 /* prepare and send an add link reject response */
739 static int smc_llc_cli_add_link_reject(struct smc_llc_qentry *qentry)
740 {
741 	qentry->msg.raw.hdr.flags |= SMC_LLC_FLAG_RESP;
742 	qentry->msg.raw.hdr.flags |= SMC_LLC_FLAG_ADD_LNK_REJ;
743 	qentry->msg.raw.hdr.add_link_rej_rsn = SMC_LLC_REJ_RSN_NO_ALT_PATH;
744 	return smc_llc_send_message(qentry->link, &qentry->msg);
745 }
746 
747 static int smc_llc_cli_conf_link(struct smc_link *link,
748 				 struct smc_init_info *ini,
749 				 struct smc_link *link_new,
750 				 enum smc_lgr_type lgr_new_t)
751 {
752 	struct smc_link_group *lgr = link->lgr;
753 	struct smc_llc_qentry *qentry = NULL;
754 	int rc = 0;
755 
756 	/* receive CONFIRM LINK request over RoCE fabric */
757 	qentry = smc_llc_wait(lgr, NULL, SMC_LLC_WAIT_FIRST_TIME, 0);
758 	if (!qentry) {
759 		rc = smc_llc_send_delete_link(link, link_new->link_id,
760 					      SMC_LLC_REQ, false,
761 					      SMC_LLC_DEL_LOST_PATH);
762 		return -ENOLINK;
763 	}
764 	if (qentry->msg.raw.hdr.common.type != SMC_LLC_CONFIRM_LINK) {
765 		/* received DELETE_LINK instead */
766 		qentry->msg.raw.hdr.flags |= SMC_LLC_FLAG_RESP;
767 		smc_llc_send_message(link, &qentry->msg);
768 		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
769 		return -ENOLINK;
770 	}
771 	smc_llc_save_peer_uid(qentry);
772 	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
773 
774 	rc = smc_ib_modify_qp_rts(link_new);
775 	if (rc) {
776 		smc_llc_send_delete_link(link, link_new->link_id, SMC_LLC_REQ,
777 					 false, SMC_LLC_DEL_LOST_PATH);
778 		return -ENOLINK;
779 	}
780 	smc_wr_remember_qp_attr(link_new);
781 
782 	rc = smcr_buf_reg_lgr(link_new);
783 	if (rc) {
784 		smc_llc_send_delete_link(link, link_new->link_id, SMC_LLC_REQ,
785 					 false, SMC_LLC_DEL_LOST_PATH);
786 		return -ENOLINK;
787 	}
788 
789 	/* send CONFIRM LINK response over RoCE fabric */
790 	rc = smc_llc_send_confirm_link(link_new, SMC_LLC_RESP);
791 	if (rc) {
792 		smc_llc_send_delete_link(link, link_new->link_id, SMC_LLC_REQ,
793 					 false, SMC_LLC_DEL_LOST_PATH);
794 		return -ENOLINK;
795 	}
796 	smc_llc_link_active(link_new);
797 	if (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
798 	    lgr_new_t == SMC_LGR_ASYMMETRIC_PEER)
799 		smcr_lgr_set_type_asym(lgr, lgr_new_t, link_new->link_idx);
800 	else
801 		smcr_lgr_set_type(lgr, lgr_new_t);
802 	return 0;
803 }
804 
805 static void smc_llc_save_add_link_info(struct smc_link *link,
806 				       struct smc_llc_msg_add_link *add_llc)
807 {
808 	link->peer_qpn = ntoh24(add_llc->sender_qp_num);
809 	memcpy(link->peer_gid, add_llc->sender_gid, SMC_GID_SIZE);
810 	memcpy(link->peer_mac, add_llc->sender_mac, ETH_ALEN);
811 	link->peer_psn = ntoh24(add_llc->initial_psn);
812 	link->peer_mtu = add_llc->qp_mtu;
813 }
814 
815 /* as an SMC client, process an add link request */
816 int smc_llc_cli_add_link(struct smc_link *link, struct smc_llc_qentry *qentry)
817 {
818 	struct smc_llc_msg_add_link *llc = &qentry->msg.add_link;
819 	enum smc_lgr_type lgr_new_t = SMC_LGR_SYMMETRIC;
820 	struct smc_link_group *lgr = smc_get_lgr(link);
821 	struct smc_link *lnk_new = NULL;
822 	struct smc_init_info ini;
823 	int lnk_idx, rc = 0;
824 
825 	ini.vlan_id = lgr->vlan_id;
826 	smc_pnet_find_alt_roce(lgr, &ini, link->smcibdev);
827 	if (!memcmp(llc->sender_gid, link->peer_gid, SMC_GID_SIZE) &&
828 	    !memcmp(llc->sender_mac, link->peer_mac, ETH_ALEN)) {
829 		if (!ini.ib_dev)
830 			goto out_reject;
831 		lgr_new_t = SMC_LGR_ASYMMETRIC_PEER;
832 	}
833 	if (!ini.ib_dev) {
834 		lgr_new_t = SMC_LGR_ASYMMETRIC_LOCAL;
835 		ini.ib_dev = link->smcibdev;
836 		ini.ib_port = link->ibport;
837 	}
838 	lnk_idx = smc_llc_alloc_alt_link(lgr, lgr_new_t);
839 	if (lnk_idx < 0)
840 		goto out_reject;
841 	lnk_new = &lgr->lnk[lnk_idx];
842 	rc = smcr_link_init(lgr, lnk_new, lnk_idx, &ini);
843 	if (rc)
844 		goto out_reject;
845 	smc_llc_save_add_link_info(lnk_new, llc);
846 	lnk_new->link_id = llc->link_num;	/* SMC server assigns link id */
847 	smc_llc_link_set_uid(lnk_new);
848 
849 	rc = smc_ib_ready_link(lnk_new);
850 	if (rc)
851 		goto out_clear_lnk;
852 
853 	rc = smcr_buf_map_lgr(lnk_new);
854 	if (rc)
855 		goto out_clear_lnk;
856 
857 	rc = smc_llc_send_add_link(link,
858 				   lnk_new->smcibdev->mac[ini.ib_port - 1],
859 				   lnk_new->gid, lnk_new, SMC_LLC_RESP);
860 	if (rc)
861 		goto out_clear_lnk;
862 	rc = smc_llc_cli_rkey_exchange(link, lnk_new);
863 	if (rc) {
864 		rc = 0;
865 		goto out_clear_lnk;
866 	}
867 	rc = smc_llc_cli_conf_link(link, &ini, lnk_new, lgr_new_t);
868 	if (!rc)
869 		goto out;
870 out_clear_lnk:
871 	smcr_link_clear(lnk_new, false);
872 out_reject:
873 	smc_llc_cli_add_link_reject(qentry);
874 out:
875 	kfree(qentry);
876 	return rc;
877 }
878 
879 static void smc_llc_process_cli_add_link(struct smc_link_group *lgr)
880 {
881 	struct smc_llc_qentry *qentry;
882 
883 	qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl);
884 
885 	mutex_lock(&lgr->llc_conf_mutex);
886 	smc_llc_cli_add_link(qentry->link, qentry);
887 	mutex_unlock(&lgr->llc_conf_mutex);
888 }
889 
890 static int smc_llc_active_link_count(struct smc_link_group *lgr)
891 {
892 	int i, link_count = 0;
893 
894 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
895 		if (!smc_link_usable(&lgr->lnk[i]))
896 			continue;
897 		link_count++;
898 	}
899 	return link_count;
900 }
901 
902 /* find the asymmetric link when 3 links are established  */
903 static struct smc_link *smc_llc_find_asym_link(struct smc_link_group *lgr)
904 {
905 	int asym_idx = -ENOENT;
906 	int i, j, k;
907 	bool found;
908 
909 	/* determine asymmetric link */
910 	found = false;
911 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
912 		for (j = i + 1; j < SMC_LINKS_PER_LGR_MAX; j++) {
913 			if (!smc_link_usable(&lgr->lnk[i]) ||
914 			    !smc_link_usable(&lgr->lnk[j]))
915 				continue;
916 			if (!memcmp(lgr->lnk[i].gid, lgr->lnk[j].gid,
917 				    SMC_GID_SIZE)) {
918 				found = true;	/* asym_lnk is i or j */
919 				break;
920 			}
921 		}
922 		if (found)
923 			break;
924 	}
925 	if (!found)
926 		goto out; /* no asymmetric link */
927 	for (k = 0; k < SMC_LINKS_PER_LGR_MAX; k++) {
928 		if (!smc_link_usable(&lgr->lnk[k]))
929 			continue;
930 		if (k != i &&
931 		    !memcmp(lgr->lnk[i].peer_gid, lgr->lnk[k].peer_gid,
932 			    SMC_GID_SIZE)) {
933 			asym_idx = i;
934 			break;
935 		}
936 		if (k != j &&
937 		    !memcmp(lgr->lnk[j].peer_gid, lgr->lnk[k].peer_gid,
938 			    SMC_GID_SIZE)) {
939 			asym_idx = j;
940 			break;
941 		}
942 	}
943 out:
944 	return (asym_idx < 0) ? NULL : &lgr->lnk[asym_idx];
945 }
946 
947 static void smc_llc_delete_asym_link(struct smc_link_group *lgr)
948 {
949 	struct smc_link *lnk_new = NULL, *lnk_asym;
950 	struct smc_llc_qentry *qentry;
951 	int rc;
952 
953 	lnk_asym = smc_llc_find_asym_link(lgr);
954 	if (!lnk_asym)
955 		return; /* no asymmetric link */
956 	if (!smc_link_downing(&lnk_asym->state))
957 		return;
958 	lnk_new = smc_switch_conns(lgr, lnk_asym, false);
959 	smc_wr_tx_wait_no_pending_sends(lnk_asym);
960 	if (!lnk_new)
961 		goto out_free;
962 	/* change flow type from ADD_LINK into DEL_LINK */
963 	lgr->llc_flow_lcl.type = SMC_LLC_FLOW_DEL_LINK;
964 	rc = smc_llc_send_delete_link(lnk_new, lnk_asym->link_id, SMC_LLC_REQ,
965 				      true, SMC_LLC_DEL_NO_ASYM_NEEDED);
966 	if (rc) {
967 		smcr_link_down_cond(lnk_new);
968 		goto out_free;
969 	}
970 	qentry = smc_llc_wait(lgr, lnk_new, SMC_LLC_WAIT_TIME,
971 			      SMC_LLC_DELETE_LINK);
972 	if (!qentry) {
973 		smcr_link_down_cond(lnk_new);
974 		goto out_free;
975 	}
976 	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
977 out_free:
978 	smcr_link_clear(lnk_asym, true);
979 }
980 
981 static int smc_llc_srv_rkey_exchange(struct smc_link *link,
982 				     struct smc_link *link_new)
983 {
984 	struct smc_llc_msg_add_link_cont *addc_llc;
985 	struct smc_link_group *lgr = link->lgr;
986 	u8 max, num_rkeys_send, num_rkeys_recv;
987 	struct smc_llc_qentry *qentry = NULL;
988 	struct smc_buf_desc *buf_pos;
989 	int buf_lst;
990 	int rc = 0;
991 	int i;
992 
993 	mutex_lock(&lgr->rmbs_lock);
994 	num_rkeys_send = lgr->conns_num;
995 	buf_pos = smc_llc_get_first_rmb(lgr, &buf_lst);
996 	do {
997 		smc_llc_add_link_cont(link, link_new, &num_rkeys_send,
998 				      &buf_lst, &buf_pos);
999 		qentry = smc_llc_wait(lgr, link, SMC_LLC_WAIT_TIME,
1000 				      SMC_LLC_ADD_LINK_CONT);
1001 		if (!qentry) {
1002 			rc = -ETIMEDOUT;
1003 			goto out;
1004 		}
1005 		addc_llc = &qentry->msg.add_link_cont;
1006 		num_rkeys_recv = addc_llc->num_rkeys;
1007 		max = min_t(u8, num_rkeys_recv, SMC_LLC_RKEYS_PER_CONT_MSG);
1008 		for (i = 0; i < max; i++) {
1009 			smc_rtoken_set(lgr, link->link_idx, link_new->link_idx,
1010 				       addc_llc->rt[i].rmb_key,
1011 				       addc_llc->rt[i].rmb_vaddr_new,
1012 				       addc_llc->rt[i].rmb_key_new);
1013 			num_rkeys_recv--;
1014 		}
1015 		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
1016 	} while (num_rkeys_send || num_rkeys_recv);
1017 out:
1018 	mutex_unlock(&lgr->rmbs_lock);
1019 	return rc;
1020 }
1021 
1022 static int smc_llc_srv_conf_link(struct smc_link *link,
1023 				 struct smc_link *link_new,
1024 				 enum smc_lgr_type lgr_new_t)
1025 {
1026 	struct smc_link_group *lgr = link->lgr;
1027 	struct smc_llc_qentry *qentry = NULL;
1028 	int rc;
1029 
1030 	/* send CONFIRM LINK request over the RoCE fabric */
1031 	rc = smc_llc_send_confirm_link(link_new, SMC_LLC_REQ);
1032 	if (rc)
1033 		return -ENOLINK;
1034 	/* receive CONFIRM LINK response over the RoCE fabric */
1035 	qentry = smc_llc_wait(lgr, link, SMC_LLC_WAIT_FIRST_TIME,
1036 			      SMC_LLC_CONFIRM_LINK);
1037 	if (!qentry) {
1038 		/* send DELETE LINK */
1039 		smc_llc_send_delete_link(link, link_new->link_id, SMC_LLC_REQ,
1040 					 false, SMC_LLC_DEL_LOST_PATH);
1041 		return -ENOLINK;
1042 	}
1043 	smc_llc_save_peer_uid(qentry);
1044 	smc_llc_link_active(link_new);
1045 	if (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
1046 	    lgr_new_t == SMC_LGR_ASYMMETRIC_PEER)
1047 		smcr_lgr_set_type_asym(lgr, lgr_new_t, link_new->link_idx);
1048 	else
1049 		smcr_lgr_set_type(lgr, lgr_new_t);
1050 	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
1051 	return 0;
1052 }
1053 
1054 int smc_llc_srv_add_link(struct smc_link *link)
1055 {
1056 	enum smc_lgr_type lgr_new_t = SMC_LGR_SYMMETRIC;
1057 	struct smc_link_group *lgr = link->lgr;
1058 	struct smc_llc_msg_add_link *add_llc;
1059 	struct smc_llc_qentry *qentry = NULL;
1060 	struct smc_link *link_new;
1061 	struct smc_init_info ini;
1062 	int lnk_idx, rc = 0;
1063 
1064 	/* ignore client add link recommendation, start new flow */
1065 	ini.vlan_id = lgr->vlan_id;
1066 	smc_pnet_find_alt_roce(lgr, &ini, link->smcibdev);
1067 	if (!ini.ib_dev) {
1068 		lgr_new_t = SMC_LGR_ASYMMETRIC_LOCAL;
1069 		ini.ib_dev = link->smcibdev;
1070 		ini.ib_port = link->ibport;
1071 	}
1072 	lnk_idx = smc_llc_alloc_alt_link(lgr, lgr_new_t);
1073 	if (lnk_idx < 0)
1074 		return 0;
1075 
1076 	rc = smcr_link_init(lgr, &lgr->lnk[lnk_idx], lnk_idx, &ini);
1077 	if (rc)
1078 		return rc;
1079 	link_new = &lgr->lnk[lnk_idx];
1080 	rc = smc_llc_send_add_link(link,
1081 				   link_new->smcibdev->mac[ini.ib_port - 1],
1082 				   link_new->gid, link_new, SMC_LLC_REQ);
1083 	if (rc)
1084 		goto out_err;
1085 	/* receive ADD LINK response over the RoCE fabric */
1086 	qentry = smc_llc_wait(lgr, link, SMC_LLC_WAIT_TIME, SMC_LLC_ADD_LINK);
1087 	if (!qentry) {
1088 		rc = -ETIMEDOUT;
1089 		goto out_err;
1090 	}
1091 	add_llc = &qentry->msg.add_link;
1092 	if (add_llc->hd.flags & SMC_LLC_FLAG_ADD_LNK_REJ) {
1093 		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
1094 		rc = -ENOLINK;
1095 		goto out_err;
1096 	}
1097 	if (lgr->type == SMC_LGR_SINGLE &&
1098 	    (!memcmp(add_llc->sender_gid, link->peer_gid, SMC_GID_SIZE) &&
1099 	     !memcmp(add_llc->sender_mac, link->peer_mac, ETH_ALEN))) {
1100 		lgr_new_t = SMC_LGR_ASYMMETRIC_PEER;
1101 	}
1102 	smc_llc_save_add_link_info(link_new, add_llc);
1103 	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
1104 
1105 	rc = smc_ib_ready_link(link_new);
1106 	if (rc)
1107 		goto out_err;
1108 	rc = smcr_buf_map_lgr(link_new);
1109 	if (rc)
1110 		goto out_err;
1111 	rc = smcr_buf_reg_lgr(link_new);
1112 	if (rc)
1113 		goto out_err;
1114 	rc = smc_llc_srv_rkey_exchange(link, link_new);
1115 	if (rc)
1116 		goto out_err;
1117 	rc = smc_llc_srv_conf_link(link, link_new, lgr_new_t);
1118 	if (rc)
1119 		goto out_err;
1120 	return 0;
1121 out_err:
1122 	smcr_link_clear(link_new, false);
1123 	return rc;
1124 }
1125 
1126 static void smc_llc_process_srv_add_link(struct smc_link_group *lgr)
1127 {
1128 	struct smc_link *link = lgr->llc_flow_lcl.qentry->link;
1129 	int rc;
1130 
1131 	smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
1132 
1133 	mutex_lock(&lgr->llc_conf_mutex);
1134 	rc = smc_llc_srv_add_link(link);
1135 	if (!rc && lgr->type == SMC_LGR_SYMMETRIC) {
1136 		/* delete any asymmetric link */
1137 		smc_llc_delete_asym_link(lgr);
1138 	}
1139 	mutex_unlock(&lgr->llc_conf_mutex);
1140 }
1141 
1142 /* enqueue a local add_link req to trigger a new add_link flow, only as SERV */
1143 void smc_llc_srv_add_link_local(struct smc_link *link)
1144 {
1145 	struct smc_llc_msg_add_link add_llc = {0};
1146 
1147 	add_llc.hd.length = sizeof(add_llc);
1148 	add_llc.hd.common.type = SMC_LLC_ADD_LINK;
1149 	/* no dev and port needed, we as server ignore client data anyway */
1150 	smc_llc_enqueue(link, (union smc_llc_msg *)&add_llc);
1151 }
1152 
1153 /* worker to process an add link message */
1154 static void smc_llc_add_link_work(struct work_struct *work)
1155 {
1156 	struct smc_link_group *lgr = container_of(work, struct smc_link_group,
1157 						  llc_add_link_work);
1158 
1159 	if (list_empty(&lgr->list)) {
1160 		/* link group is terminating */
1161 		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
1162 		goto out;
1163 	}
1164 
1165 	if (lgr->role == SMC_CLNT)
1166 		smc_llc_process_cli_add_link(lgr);
1167 	else
1168 		smc_llc_process_srv_add_link(lgr);
1169 out:
1170 	smc_llc_flow_stop(lgr, &lgr->llc_flow_lcl);
1171 }
1172 
1173 /* enqueue a local del_link msg to trigger a new del_link flow,
1174  * called only for role SMC_SERV
1175  */
1176 void smc_llc_srv_delete_link_local(struct smc_link *link, u8 del_link_id)
1177 {
1178 	struct smc_llc_msg_del_link del_llc = {0};
1179 
1180 	del_llc.hd.length = sizeof(del_llc);
1181 	del_llc.hd.common.type = SMC_LLC_DELETE_LINK;
1182 	del_llc.link_num = del_link_id;
1183 	del_llc.reason = htonl(SMC_LLC_DEL_LOST_PATH);
1184 	del_llc.hd.flags |= SMC_LLC_FLAG_DEL_LINK_ORDERLY;
1185 	smc_llc_enqueue(link, (union smc_llc_msg *)&del_llc);
1186 }
1187 
1188 static void smc_llc_process_cli_delete_link(struct smc_link_group *lgr)
1189 {
1190 	struct smc_link *lnk_del = NULL, *lnk_asym, *lnk;
1191 	struct smc_llc_msg_del_link *del_llc;
1192 	struct smc_llc_qentry *qentry;
1193 	int active_links;
1194 	int lnk_idx;
1195 
1196 	qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl);
1197 	lnk = qentry->link;
1198 	del_llc = &qentry->msg.delete_link;
1199 
1200 	if (del_llc->hd.flags & SMC_LLC_FLAG_DEL_LINK_ALL) {
1201 		smc_lgr_terminate_sched(lgr);
1202 		goto out;
1203 	}
1204 	mutex_lock(&lgr->llc_conf_mutex);
1205 	/* delete single link */
1206 	for (lnk_idx = 0; lnk_idx < SMC_LINKS_PER_LGR_MAX; lnk_idx++) {
1207 		if (lgr->lnk[lnk_idx].link_id != del_llc->link_num)
1208 			continue;
1209 		lnk_del = &lgr->lnk[lnk_idx];
1210 		break;
1211 	}
1212 	del_llc->hd.flags |= SMC_LLC_FLAG_RESP;
1213 	if (!lnk_del) {
1214 		/* link was not found */
1215 		del_llc->reason = htonl(SMC_LLC_DEL_NOLNK);
1216 		smc_llc_send_message(lnk, &qentry->msg);
1217 		goto out_unlock;
1218 	}
1219 	lnk_asym = smc_llc_find_asym_link(lgr);
1220 
1221 	del_llc->reason = 0;
1222 	smc_llc_send_message(lnk, &qentry->msg); /* response */
1223 
1224 	if (smc_link_downing(&lnk_del->state)) {
1225 		smc_switch_conns(lgr, lnk_del, false);
1226 		smc_wr_tx_wait_no_pending_sends(lnk_del);
1227 	}
1228 	smcr_link_clear(lnk_del, true);
1229 
1230 	active_links = smc_llc_active_link_count(lgr);
1231 	if (lnk_del == lnk_asym) {
1232 		/* expected deletion of asym link, don't change lgr state */
1233 	} else if (active_links == 1) {
1234 		smcr_lgr_set_type(lgr, SMC_LGR_SINGLE);
1235 	} else if (!active_links) {
1236 		smcr_lgr_set_type(lgr, SMC_LGR_NONE);
1237 		smc_lgr_terminate_sched(lgr);
1238 	}
1239 out_unlock:
1240 	mutex_unlock(&lgr->llc_conf_mutex);
1241 out:
1242 	kfree(qentry);
1243 }
1244 
1245 /* try to send a DELETE LINK ALL request on any active link,
1246  * waiting for send completion
1247  */
1248 void smc_llc_send_link_delete_all(struct smc_link_group *lgr, bool ord, u32 rsn)
1249 {
1250 	struct smc_llc_msg_del_link delllc = {0};
1251 	int i;
1252 
1253 	delllc.hd.common.type = SMC_LLC_DELETE_LINK;
1254 	delllc.hd.length = sizeof(delllc);
1255 	if (ord)
1256 		delllc.hd.flags |= SMC_LLC_FLAG_DEL_LINK_ORDERLY;
1257 	delllc.hd.flags |= SMC_LLC_FLAG_DEL_LINK_ALL;
1258 	delllc.reason = htonl(rsn);
1259 
1260 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
1261 		if (!smc_link_usable(&lgr->lnk[i]))
1262 			continue;
1263 		if (!smc_llc_send_message_wait(&lgr->lnk[i], &delllc))
1264 			break;
1265 	}
1266 }
1267 
1268 static void smc_llc_process_srv_delete_link(struct smc_link_group *lgr)
1269 {
1270 	struct smc_llc_msg_del_link *del_llc;
1271 	struct smc_link *lnk, *lnk_del;
1272 	struct smc_llc_qentry *qentry;
1273 	int active_links;
1274 	int i;
1275 
1276 	mutex_lock(&lgr->llc_conf_mutex);
1277 	qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl);
1278 	lnk = qentry->link;
1279 	del_llc = &qentry->msg.delete_link;
1280 
1281 	if (qentry->msg.delete_link.hd.flags & SMC_LLC_FLAG_DEL_LINK_ALL) {
1282 		/* delete entire lgr */
1283 		smc_llc_send_link_delete_all(lgr, true, ntohl(
1284 					      qentry->msg.delete_link.reason));
1285 		smc_lgr_terminate_sched(lgr);
1286 		goto out;
1287 	}
1288 	/* delete single link */
1289 	lnk_del = NULL;
1290 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
1291 		if (lgr->lnk[i].link_id == del_llc->link_num) {
1292 			lnk_del = &lgr->lnk[i];
1293 			break;
1294 		}
1295 	}
1296 	if (!lnk_del)
1297 		goto out; /* asymmetric link already deleted */
1298 
1299 	if (smc_link_downing(&lnk_del->state)) {
1300 		smc_switch_conns(lgr, lnk_del, false);
1301 		smc_wr_tx_wait_no_pending_sends(lnk_del);
1302 	}
1303 	if (!list_empty(&lgr->list)) {
1304 		/* qentry is either a request from peer (send it back to
1305 		 * initiate the DELETE_LINK processing), or a locally
1306 		 * enqueued DELETE_LINK request (forward it)
1307 		 */
1308 		if (!smc_llc_send_message(lnk, &qentry->msg)) {
1309 			struct smc_llc_qentry *qentry2;
1310 
1311 			qentry2 = smc_llc_wait(lgr, lnk, SMC_LLC_WAIT_TIME,
1312 					       SMC_LLC_DELETE_LINK);
1313 			if (qentry2)
1314 				smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
1315 		}
1316 	}
1317 	smcr_link_clear(lnk_del, true);
1318 
1319 	active_links = smc_llc_active_link_count(lgr);
1320 	if (active_links == 1) {
1321 		smcr_lgr_set_type(lgr, SMC_LGR_SINGLE);
1322 	} else if (!active_links) {
1323 		smcr_lgr_set_type(lgr, SMC_LGR_NONE);
1324 		smc_lgr_terminate_sched(lgr);
1325 	}
1326 
1327 	if (lgr->type == SMC_LGR_SINGLE && !list_empty(&lgr->list)) {
1328 		/* trigger setup of asymm alt link */
1329 		smc_llc_srv_add_link_local(lnk);
1330 	}
1331 out:
1332 	mutex_unlock(&lgr->llc_conf_mutex);
1333 	kfree(qentry);
1334 }
1335 
1336 static void smc_llc_delete_link_work(struct work_struct *work)
1337 {
1338 	struct smc_link_group *lgr = container_of(work, struct smc_link_group,
1339 						  llc_del_link_work);
1340 
1341 	if (list_empty(&lgr->list)) {
1342 		/* link group is terminating */
1343 		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
1344 		goto out;
1345 	}
1346 
1347 	if (lgr->role == SMC_CLNT)
1348 		smc_llc_process_cli_delete_link(lgr);
1349 	else
1350 		smc_llc_process_srv_delete_link(lgr);
1351 out:
1352 	smc_llc_flow_stop(lgr, &lgr->llc_flow_lcl);
1353 }
1354 
1355 /* process a confirm_rkey request from peer, remote flow */
1356 static void smc_llc_rmt_conf_rkey(struct smc_link_group *lgr)
1357 {
1358 	struct smc_llc_msg_confirm_rkey *llc;
1359 	struct smc_llc_qentry *qentry;
1360 	struct smc_link *link;
1361 	int num_entries;
1362 	int rk_idx;
1363 	int i;
1364 
1365 	qentry = lgr->llc_flow_rmt.qentry;
1366 	llc = &qentry->msg.confirm_rkey;
1367 	link = qentry->link;
1368 
1369 	num_entries = llc->rtoken[0].num_rkeys;
1370 	/* first rkey entry is for receiving link */
1371 	rk_idx = smc_rtoken_add(link,
1372 				llc->rtoken[0].rmb_vaddr,
1373 				llc->rtoken[0].rmb_key);
1374 	if (rk_idx < 0)
1375 		goto out_err;
1376 
1377 	for (i = 1; i <= min_t(u8, num_entries, SMC_LLC_RKEYS_PER_MSG - 1); i++)
1378 		smc_rtoken_set2(lgr, rk_idx, llc->rtoken[i].link_id,
1379 				llc->rtoken[i].rmb_vaddr,
1380 				llc->rtoken[i].rmb_key);
1381 	/* max links is 3 so there is no need to support conf_rkey_cont msgs */
1382 	goto out;
1383 out_err:
1384 	llc->hd.flags |= SMC_LLC_FLAG_RKEY_NEG;
1385 	llc->hd.flags |= SMC_LLC_FLAG_RKEY_RETRY;
1386 out:
1387 	llc->hd.flags |= SMC_LLC_FLAG_RESP;
1388 	smc_llc_send_message(link, &qentry->msg);
1389 	smc_llc_flow_qentry_del(&lgr->llc_flow_rmt);
1390 }
1391 
1392 /* process a delete_rkey request from peer, remote flow */
1393 static void smc_llc_rmt_delete_rkey(struct smc_link_group *lgr)
1394 {
1395 	struct smc_llc_msg_delete_rkey *llc;
1396 	struct smc_llc_qentry *qentry;
1397 	struct smc_link *link;
1398 	u8 err_mask = 0;
1399 	int i, max;
1400 
1401 	qentry = lgr->llc_flow_rmt.qentry;
1402 	llc = &qentry->msg.delete_rkey;
1403 	link = qentry->link;
1404 
1405 	max = min_t(u8, llc->num_rkeys, SMC_LLC_DEL_RKEY_MAX);
1406 	for (i = 0; i < max; i++) {
1407 		if (smc_rtoken_delete(link, llc->rkey[i]))
1408 			err_mask |= 1 << (SMC_LLC_DEL_RKEY_MAX - 1 - i);
1409 	}
1410 	if (err_mask) {
1411 		llc->hd.flags |= SMC_LLC_FLAG_RKEY_NEG;
1412 		llc->err_mask = err_mask;
1413 	}
1414 	llc->hd.flags |= SMC_LLC_FLAG_RESP;
1415 	smc_llc_send_message(link, &qentry->msg);
1416 	smc_llc_flow_qentry_del(&lgr->llc_flow_rmt);
1417 }
1418 
1419 static void smc_llc_protocol_violation(struct smc_link_group *lgr, u8 type)
1420 {
1421 	pr_warn_ratelimited("smc: SMC-R lg %*phN LLC protocol violation: "
1422 			    "llc_type %d\n", SMC_LGR_ID_SIZE, &lgr->id, type);
1423 	smc_llc_set_termination_rsn(lgr, SMC_LLC_DEL_PROT_VIOL);
1424 	smc_lgr_terminate_sched(lgr);
1425 }
1426 
1427 /* flush the llc event queue */
1428 static void smc_llc_event_flush(struct smc_link_group *lgr)
1429 {
1430 	struct smc_llc_qentry *qentry, *q;
1431 
1432 	spin_lock_bh(&lgr->llc_event_q_lock);
1433 	list_for_each_entry_safe(qentry, q, &lgr->llc_event_q, list) {
1434 		list_del_init(&qentry->list);
1435 		kfree(qentry);
1436 	}
1437 	spin_unlock_bh(&lgr->llc_event_q_lock);
1438 }
1439 
1440 static void smc_llc_event_handler(struct smc_llc_qentry *qentry)
1441 {
1442 	union smc_llc_msg *llc = &qentry->msg;
1443 	struct smc_link *link = qentry->link;
1444 	struct smc_link_group *lgr = link->lgr;
1445 
1446 	if (!smc_link_usable(link))
1447 		goto out;
1448 
1449 	switch (llc->raw.hdr.common.type) {
1450 	case SMC_LLC_TEST_LINK:
1451 		llc->test_link.hd.flags |= SMC_LLC_FLAG_RESP;
1452 		smc_llc_send_message(link, llc);
1453 		break;
1454 	case SMC_LLC_ADD_LINK:
1455 		if (list_empty(&lgr->list))
1456 			goto out;	/* lgr is terminating */
1457 		if (lgr->role == SMC_CLNT) {
1458 			if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_ADD_LINK) {
1459 				/* a flow is waiting for this message */
1460 				smc_llc_flow_qentry_set(&lgr->llc_flow_lcl,
1461 							qentry);
1462 				wake_up_interruptible(&lgr->llc_waiter);
1463 			} else if (smc_llc_flow_start(&lgr->llc_flow_lcl,
1464 						      qentry)) {
1465 				schedule_work(&lgr->llc_add_link_work);
1466 			}
1467 		} else if (smc_llc_flow_start(&lgr->llc_flow_lcl, qentry)) {
1468 			/* as smc server, handle client suggestion */
1469 			schedule_work(&lgr->llc_add_link_work);
1470 		}
1471 		return;
1472 	case SMC_LLC_CONFIRM_LINK:
1473 	case SMC_LLC_ADD_LINK_CONT:
1474 		if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE) {
1475 			/* a flow is waiting for this message */
1476 			smc_llc_flow_qentry_set(&lgr->llc_flow_lcl, qentry);
1477 			wake_up_interruptible(&lgr->llc_waiter);
1478 			return;
1479 		}
1480 		break;
1481 	case SMC_LLC_DELETE_LINK:
1482 		if (lgr->role == SMC_CLNT) {
1483 			/* server requests to delete this link, send response */
1484 			if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE) {
1485 				/* DEL LINK REQ during ADD LINK SEQ */
1486 				smc_llc_flow_qentry_set(&lgr->llc_flow_lcl,
1487 							qentry);
1488 				wake_up_interruptible(&lgr->llc_waiter);
1489 			} else if (smc_llc_flow_start(&lgr->llc_flow_lcl,
1490 						      qentry)) {
1491 				schedule_work(&lgr->llc_del_link_work);
1492 			}
1493 		} else {
1494 			if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_ADD_LINK &&
1495 			    !lgr->llc_flow_lcl.qentry) {
1496 				/* DEL LINK REQ during ADD LINK SEQ */
1497 				smc_llc_flow_qentry_set(&lgr->llc_flow_lcl,
1498 							qentry);
1499 				wake_up_interruptible(&lgr->llc_waiter);
1500 			} else if (smc_llc_flow_start(&lgr->llc_flow_lcl,
1501 						      qentry)) {
1502 				schedule_work(&lgr->llc_del_link_work);
1503 			}
1504 		}
1505 		return;
1506 	case SMC_LLC_CONFIRM_RKEY:
1507 		/* new request from remote, assign to remote flow */
1508 		if (smc_llc_flow_start(&lgr->llc_flow_rmt, qentry)) {
1509 			/* process here, does not wait for more llc msgs */
1510 			smc_llc_rmt_conf_rkey(lgr);
1511 			smc_llc_flow_stop(lgr, &lgr->llc_flow_rmt);
1512 		}
1513 		return;
1514 	case SMC_LLC_CONFIRM_RKEY_CONT:
1515 		/* not used because max links is 3, and 3 rkeys fit into
1516 		 * one CONFIRM_RKEY message
1517 		 */
1518 		break;
1519 	case SMC_LLC_DELETE_RKEY:
1520 		/* new request from remote, assign to remote flow */
1521 		if (smc_llc_flow_start(&lgr->llc_flow_rmt, qentry)) {
1522 			/* process here, does not wait for more llc msgs */
1523 			smc_llc_rmt_delete_rkey(lgr);
1524 			smc_llc_flow_stop(lgr, &lgr->llc_flow_rmt);
1525 		}
1526 		return;
1527 	default:
1528 		smc_llc_protocol_violation(lgr, llc->raw.hdr.common.type);
1529 		break;
1530 	}
1531 out:
1532 	kfree(qentry);
1533 }
1534 
1535 /* worker to process llc messages on the event queue */
1536 static void smc_llc_event_work(struct work_struct *work)
1537 {
1538 	struct smc_link_group *lgr = container_of(work, struct smc_link_group,
1539 						  llc_event_work);
1540 	struct smc_llc_qentry *qentry;
1541 
1542 	if (!lgr->llc_flow_lcl.type && lgr->delayed_event) {
1543 		if (smc_link_usable(lgr->delayed_event->link)) {
1544 			smc_llc_event_handler(lgr->delayed_event);
1545 		} else {
1546 			qentry = lgr->delayed_event;
1547 			lgr->delayed_event = NULL;
1548 			kfree(qentry);
1549 		}
1550 	}
1551 
1552 again:
1553 	spin_lock_bh(&lgr->llc_event_q_lock);
1554 	if (!list_empty(&lgr->llc_event_q)) {
1555 		qentry = list_first_entry(&lgr->llc_event_q,
1556 					  struct smc_llc_qentry, list);
1557 		list_del_init(&qentry->list);
1558 		spin_unlock_bh(&lgr->llc_event_q_lock);
1559 		smc_llc_event_handler(qentry);
1560 		goto again;
1561 	}
1562 	spin_unlock_bh(&lgr->llc_event_q_lock);
1563 }
1564 
1565 /* process llc responses in tasklet context */
1566 static void smc_llc_rx_response(struct smc_link *link,
1567 				struct smc_llc_qentry *qentry)
1568 {
1569 	u8 llc_type = qentry->msg.raw.hdr.common.type;
1570 
1571 	switch (llc_type) {
1572 	case SMC_LLC_TEST_LINK:
1573 		if (link->state == SMC_LNK_ACTIVE)
1574 			complete(&link->llc_testlink_resp);
1575 		break;
1576 	case SMC_LLC_ADD_LINK:
1577 	case SMC_LLC_DELETE_LINK:
1578 	case SMC_LLC_CONFIRM_LINK:
1579 	case SMC_LLC_ADD_LINK_CONT:
1580 	case SMC_LLC_CONFIRM_RKEY:
1581 	case SMC_LLC_DELETE_RKEY:
1582 		/* assign responses to the local flow, we requested them */
1583 		smc_llc_flow_qentry_set(&link->lgr->llc_flow_lcl, qentry);
1584 		wake_up_interruptible(&link->lgr->llc_waiter);
1585 		return;
1586 	case SMC_LLC_CONFIRM_RKEY_CONT:
1587 		/* not used because max links is 3 */
1588 		break;
1589 	default:
1590 		smc_llc_protocol_violation(link->lgr, llc_type);
1591 		break;
1592 	}
1593 	kfree(qentry);
1594 }
1595 
1596 static void smc_llc_enqueue(struct smc_link *link, union smc_llc_msg *llc)
1597 {
1598 	struct smc_link_group *lgr = link->lgr;
1599 	struct smc_llc_qentry *qentry;
1600 	unsigned long flags;
1601 
1602 	qentry = kmalloc(sizeof(*qentry), GFP_ATOMIC);
1603 	if (!qentry)
1604 		return;
1605 	qentry->link = link;
1606 	INIT_LIST_HEAD(&qentry->list);
1607 	memcpy(&qentry->msg, llc, sizeof(union smc_llc_msg));
1608 
1609 	/* process responses immediately */
1610 	if (llc->raw.hdr.flags & SMC_LLC_FLAG_RESP) {
1611 		smc_llc_rx_response(link, qentry);
1612 		return;
1613 	}
1614 
1615 	/* add requests to event queue */
1616 	spin_lock_irqsave(&lgr->llc_event_q_lock, flags);
1617 	list_add_tail(&qentry->list, &lgr->llc_event_q);
1618 	spin_unlock_irqrestore(&lgr->llc_event_q_lock, flags);
1619 	schedule_work(&link->lgr->llc_event_work);
1620 }
1621 
1622 /* copy received msg and add it to the event queue */
1623 static void smc_llc_rx_handler(struct ib_wc *wc, void *buf)
1624 {
1625 	struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
1626 	union smc_llc_msg *llc = buf;
1627 
1628 	if (wc->byte_len < sizeof(*llc))
1629 		return; /* short message */
1630 	if (llc->raw.hdr.length != sizeof(*llc))
1631 		return; /* invalid message */
1632 
1633 	smc_llc_enqueue(link, llc);
1634 }
1635 
1636 /***************************** worker, utils *********************************/
1637 
1638 static void smc_llc_testlink_work(struct work_struct *work)
1639 {
1640 	struct smc_link *link = container_of(to_delayed_work(work),
1641 					     struct smc_link, llc_testlink_wrk);
1642 	unsigned long next_interval;
1643 	unsigned long expire_time;
1644 	u8 user_data[16] = { 0 };
1645 	int rc;
1646 
1647 	if (link->state != SMC_LNK_ACTIVE)
1648 		return;		/* don't reschedule worker */
1649 	expire_time = link->wr_rx_tstamp + link->llc_testlink_time;
1650 	if (time_is_after_jiffies(expire_time)) {
1651 		next_interval = expire_time - jiffies;
1652 		goto out;
1653 	}
1654 	reinit_completion(&link->llc_testlink_resp);
1655 	smc_llc_send_test_link(link, user_data);
1656 	/* receive TEST LINK response over RoCE fabric */
1657 	rc = wait_for_completion_interruptible_timeout(&link->llc_testlink_resp,
1658 						       SMC_LLC_WAIT_TIME);
1659 	if (link->state != SMC_LNK_ACTIVE)
1660 		return;		/* link state changed */
1661 	if (rc <= 0) {
1662 		smcr_link_down_cond_sched(link);
1663 		return;
1664 	}
1665 	next_interval = link->llc_testlink_time;
1666 out:
1667 	schedule_delayed_work(&link->llc_testlink_wrk, next_interval);
1668 }
1669 
1670 void smc_llc_lgr_init(struct smc_link_group *lgr, struct smc_sock *smc)
1671 {
1672 	struct net *net = sock_net(smc->clcsock->sk);
1673 
1674 	INIT_WORK(&lgr->llc_event_work, smc_llc_event_work);
1675 	INIT_WORK(&lgr->llc_add_link_work, smc_llc_add_link_work);
1676 	INIT_WORK(&lgr->llc_del_link_work, smc_llc_delete_link_work);
1677 	INIT_LIST_HEAD(&lgr->llc_event_q);
1678 	spin_lock_init(&lgr->llc_event_q_lock);
1679 	spin_lock_init(&lgr->llc_flow_lock);
1680 	init_waitqueue_head(&lgr->llc_waiter);
1681 	mutex_init(&lgr->llc_conf_mutex);
1682 	lgr->llc_testlink_time = net->ipv4.sysctl_tcp_keepalive_time;
1683 }
1684 
1685 /* called after lgr was removed from lgr_list */
1686 void smc_llc_lgr_clear(struct smc_link_group *lgr)
1687 {
1688 	smc_llc_event_flush(lgr);
1689 	wake_up_interruptible_all(&lgr->llc_waiter);
1690 	cancel_work_sync(&lgr->llc_event_work);
1691 	cancel_work_sync(&lgr->llc_add_link_work);
1692 	cancel_work_sync(&lgr->llc_del_link_work);
1693 	if (lgr->delayed_event) {
1694 		kfree(lgr->delayed_event);
1695 		lgr->delayed_event = NULL;
1696 	}
1697 }
1698 
1699 int smc_llc_link_init(struct smc_link *link)
1700 {
1701 	init_completion(&link->llc_testlink_resp);
1702 	INIT_DELAYED_WORK(&link->llc_testlink_wrk, smc_llc_testlink_work);
1703 	return 0;
1704 }
1705 
1706 void smc_llc_link_active(struct smc_link *link)
1707 {
1708 	pr_warn_ratelimited("smc: SMC-R lg %*phN link added: id %*phN, "
1709 			    "peerid %*phN, ibdev %s, ibport %d\n",
1710 			    SMC_LGR_ID_SIZE, &link->lgr->id,
1711 			    SMC_LGR_ID_SIZE, &link->link_uid,
1712 			    SMC_LGR_ID_SIZE, &link->peer_link_uid,
1713 			    link->smcibdev->ibdev->name, link->ibport);
1714 	link->state = SMC_LNK_ACTIVE;
1715 	if (link->lgr->llc_testlink_time) {
1716 		link->llc_testlink_time = link->lgr->llc_testlink_time * HZ;
1717 		schedule_delayed_work(&link->llc_testlink_wrk,
1718 				      link->llc_testlink_time);
1719 	}
1720 }
1721 
1722 /* called in worker context */
1723 void smc_llc_link_clear(struct smc_link *link, bool log)
1724 {
1725 	if (log)
1726 		pr_warn_ratelimited("smc: SMC-R lg %*phN link removed: id %*phN"
1727 				    ", peerid %*phN, ibdev %s, ibport %d\n",
1728 				    SMC_LGR_ID_SIZE, &link->lgr->id,
1729 				    SMC_LGR_ID_SIZE, &link->link_uid,
1730 				    SMC_LGR_ID_SIZE, &link->peer_link_uid,
1731 				    link->smcibdev->ibdev->name, link->ibport);
1732 	complete(&link->llc_testlink_resp);
1733 	cancel_delayed_work_sync(&link->llc_testlink_wrk);
1734 	smc_wr_wakeup_reg_wait(link);
1735 	smc_wr_wakeup_tx_wait(link);
1736 }
1737 
1738 /* register a new rtoken at the remote peer (for all links) */
1739 int smc_llc_do_confirm_rkey(struct smc_link *send_link,
1740 			    struct smc_buf_desc *rmb_desc)
1741 {
1742 	struct smc_link_group *lgr = send_link->lgr;
1743 	struct smc_llc_qentry *qentry = NULL;
1744 	int rc = 0;
1745 
1746 	rc = smc_llc_send_confirm_rkey(send_link, rmb_desc);
1747 	if (rc)
1748 		goto out;
1749 	/* receive CONFIRM RKEY response from server over RoCE fabric */
1750 	qentry = smc_llc_wait(lgr, send_link, SMC_LLC_WAIT_TIME,
1751 			      SMC_LLC_CONFIRM_RKEY);
1752 	if (!qentry || (qentry->msg.raw.hdr.flags & SMC_LLC_FLAG_RKEY_NEG))
1753 		rc = -EFAULT;
1754 out:
1755 	if (qentry)
1756 		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
1757 	return rc;
1758 }
1759 
1760 /* unregister an rtoken at the remote peer */
1761 int smc_llc_do_delete_rkey(struct smc_link_group *lgr,
1762 			   struct smc_buf_desc *rmb_desc)
1763 {
1764 	struct smc_llc_qentry *qentry = NULL;
1765 	struct smc_link *send_link;
1766 	int rc = 0;
1767 
1768 	send_link = smc_llc_usable_link(lgr);
1769 	if (!send_link)
1770 		return -ENOLINK;
1771 
1772 	/* protected by llc_flow control */
1773 	rc = smc_llc_send_delete_rkey(send_link, rmb_desc);
1774 	if (rc)
1775 		goto out;
1776 	/* receive DELETE RKEY response from server over RoCE fabric */
1777 	qentry = smc_llc_wait(lgr, send_link, SMC_LLC_WAIT_TIME,
1778 			      SMC_LLC_DELETE_RKEY);
1779 	if (!qentry || (qentry->msg.raw.hdr.flags & SMC_LLC_FLAG_RKEY_NEG))
1780 		rc = -EFAULT;
1781 out:
1782 	if (qentry)
1783 		smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
1784 	return rc;
1785 }
1786 
1787 void smc_llc_link_set_uid(struct smc_link *link)
1788 {
1789 	__be32 link_uid;
1790 
1791 	link_uid = htonl(*((u32 *)link->lgr->id) + link->link_id);
1792 	memcpy(link->link_uid, &link_uid, SMC_LGR_ID_SIZE);
1793 }
1794 
1795 /* save peers link user id, used for debug purposes */
1796 void smc_llc_save_peer_uid(struct smc_llc_qentry *qentry)
1797 {
1798 	memcpy(qentry->link->peer_link_uid, qentry->msg.confirm_link.link_uid,
1799 	       SMC_LGR_ID_SIZE);
1800 }
1801 
1802 /* evaluate confirm link request or response */
1803 int smc_llc_eval_conf_link(struct smc_llc_qentry *qentry,
1804 			   enum smc_llc_reqresp type)
1805 {
1806 	if (type == SMC_LLC_REQ) {	/* SMC server assigns link_id */
1807 		qentry->link->link_id = qentry->msg.confirm_link.link_num;
1808 		smc_llc_link_set_uid(qentry->link);
1809 	}
1810 	if (!(qentry->msg.raw.hdr.flags & SMC_LLC_FLAG_NO_RMBE_EYEC))
1811 		return -ENOTSUPP;
1812 	return 0;
1813 }
1814 
1815 /***************************** init, exit, misc ******************************/
1816 
1817 static struct smc_wr_rx_handler smc_llc_rx_handlers[] = {
1818 	{
1819 		.handler	= smc_llc_rx_handler,
1820 		.type		= SMC_LLC_CONFIRM_LINK
1821 	},
1822 	{
1823 		.handler	= smc_llc_rx_handler,
1824 		.type		= SMC_LLC_TEST_LINK
1825 	},
1826 	{
1827 		.handler	= smc_llc_rx_handler,
1828 		.type		= SMC_LLC_ADD_LINK
1829 	},
1830 	{
1831 		.handler	= smc_llc_rx_handler,
1832 		.type		= SMC_LLC_ADD_LINK_CONT
1833 	},
1834 	{
1835 		.handler	= smc_llc_rx_handler,
1836 		.type		= SMC_LLC_DELETE_LINK
1837 	},
1838 	{
1839 		.handler	= smc_llc_rx_handler,
1840 		.type		= SMC_LLC_CONFIRM_RKEY
1841 	},
1842 	{
1843 		.handler	= smc_llc_rx_handler,
1844 		.type		= SMC_LLC_CONFIRM_RKEY_CONT
1845 	},
1846 	{
1847 		.handler	= smc_llc_rx_handler,
1848 		.type		= SMC_LLC_DELETE_RKEY
1849 	},
1850 	{
1851 		.handler	= NULL,
1852 	}
1853 };
1854 
1855 int __init smc_llc_init(void)
1856 {
1857 	struct smc_wr_rx_handler *handler;
1858 	int rc = 0;
1859 
1860 	for (handler = smc_llc_rx_handlers; handler->handler; handler++) {
1861 		INIT_HLIST_NODE(&handler->list);
1862 		rc = smc_wr_rx_register_handler(handler);
1863 		if (rc)
1864 			break;
1865 	}
1866 	return rc;
1867 }
1868