xref: /openbmc/linux/net/smc/smc_wr.c (revision 63705da3)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Shared Memory Communications over RDMA (SMC-R) and RoCE
4  *
5  * Work Requests exploiting Infiniband API
6  *
7  * Work requests (WR) of type ib_post_send or ib_post_recv respectively
8  * are submitted to either RC SQ or RC RQ respectively
9  * (reliably connected send/receive queue)
10  * and become work queue entries (WQEs).
11  * While an SQ WR/WQE is pending, we track it until transmission completion.
12  * Through a send or receive completion queue (CQ) respectively,
13  * we get completion queue entries (CQEs) [aka work completions (WCs)].
14  * Since the CQ callback is called from IRQ context, we split work by using
15  * bottom halves implemented by tasklets.
16  *
17  * SMC uses this to exchange LLC (link layer control)
18  * and CDC (connection data control) messages.
19  *
20  * Copyright IBM Corp. 2016
21  *
22  * Author(s):  Steffen Maier <maier@linux.vnet.ibm.com>
23  */
24 
25 #include <linux/atomic.h>
26 #include <linux/hashtable.h>
27 #include <linux/wait.h>
28 #include <rdma/ib_verbs.h>
29 #include <asm/div64.h>
30 
31 #include "smc.h"
32 #include "smc_wr.h"
33 
34 #define SMC_WR_MAX_POLL_CQE 10	/* max. # of compl. queue elements in 1 poll */
35 
36 #define SMC_WR_RX_HASH_BITS 4
37 static DEFINE_HASHTABLE(smc_wr_rx_hash, SMC_WR_RX_HASH_BITS);
38 static DEFINE_SPINLOCK(smc_wr_rx_hash_lock);
39 
40 struct smc_wr_tx_pend {	/* control data for a pending send request */
41 	u64			wr_id;		/* work request id sent */
42 	smc_wr_tx_handler	handler;
43 	enum ib_wc_status	wc_status;	/* CQE status */
44 	struct smc_link		*link;
45 	u32			idx;
46 	struct smc_wr_tx_pend_priv priv;
47 	u8			compl_requested;
48 };
49 
50 /******************************** send queue *********************************/
51 
52 /*------------------------------- completion --------------------------------*/
53 
54 /* returns true if at least one tx work request is pending on the given link */
55 static inline bool smc_wr_is_tx_pend(struct smc_link *link)
56 {
57 	if (find_first_bit(link->wr_tx_mask, link->wr_tx_cnt) !=
58 							link->wr_tx_cnt) {
59 		return true;
60 	}
61 	return false;
62 }
63 
64 /* wait till all pending tx work requests on the given link are completed */
65 int smc_wr_tx_wait_no_pending_sends(struct smc_link *link)
66 {
67 	if (wait_event_timeout(link->wr_tx_wait, !smc_wr_is_tx_pend(link),
68 			       SMC_WR_TX_WAIT_PENDING_TIME))
69 		return 0;
70 	else /* timeout */
71 		return -EPIPE;
72 }
73 
74 static inline int smc_wr_tx_find_pending_index(struct smc_link *link, u64 wr_id)
75 {
76 	u32 i;
77 
78 	for (i = 0; i < link->wr_tx_cnt; i++) {
79 		if (link->wr_tx_pends[i].wr_id == wr_id)
80 			return i;
81 	}
82 	return link->wr_tx_cnt;
83 }
84 
85 static inline void smc_wr_tx_process_cqe(struct ib_wc *wc)
86 {
87 	struct smc_wr_tx_pend pnd_snd;
88 	struct smc_link *link;
89 	u32 pnd_snd_idx;
90 	int i;
91 
92 	link = wc->qp->qp_context;
93 
94 	if (wc->opcode == IB_WC_REG_MR) {
95 		if (wc->status)
96 			link->wr_reg_state = FAILED;
97 		else
98 			link->wr_reg_state = CONFIRMED;
99 		smc_wr_wakeup_reg_wait(link);
100 		return;
101 	}
102 
103 	pnd_snd_idx = smc_wr_tx_find_pending_index(link, wc->wr_id);
104 	if (pnd_snd_idx == link->wr_tx_cnt) {
105 		if (link->lgr->smc_version != SMC_V2 ||
106 		    link->wr_tx_v2_pend->wr_id != wc->wr_id)
107 			return;
108 		link->wr_tx_v2_pend->wc_status = wc->status;
109 		memcpy(&pnd_snd, link->wr_tx_v2_pend, sizeof(pnd_snd));
110 		/* clear the full struct smc_wr_tx_pend including .priv */
111 		memset(link->wr_tx_v2_pend, 0,
112 		       sizeof(*link->wr_tx_v2_pend));
113 		memset(link->lgr->wr_tx_buf_v2, 0,
114 		       sizeof(*link->lgr->wr_tx_buf_v2));
115 	} else {
116 		link->wr_tx_pends[pnd_snd_idx].wc_status = wc->status;
117 		if (link->wr_tx_pends[pnd_snd_idx].compl_requested)
118 			complete(&link->wr_tx_compl[pnd_snd_idx]);
119 		memcpy(&pnd_snd, &link->wr_tx_pends[pnd_snd_idx],
120 		       sizeof(pnd_snd));
121 		/* clear the full struct smc_wr_tx_pend including .priv */
122 		memset(&link->wr_tx_pends[pnd_snd_idx], 0,
123 		       sizeof(link->wr_tx_pends[pnd_snd_idx]));
124 		memset(&link->wr_tx_bufs[pnd_snd_idx], 0,
125 		       sizeof(link->wr_tx_bufs[pnd_snd_idx]));
126 		if (!test_and_clear_bit(pnd_snd_idx, link->wr_tx_mask))
127 			return;
128 	}
129 
130 	if (wc->status) {
131 		for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
132 			/* clear full struct smc_wr_tx_pend including .priv */
133 			memset(&link->wr_tx_pends[i], 0,
134 			       sizeof(link->wr_tx_pends[i]));
135 			memset(&link->wr_tx_bufs[i], 0,
136 			       sizeof(link->wr_tx_bufs[i]));
137 			clear_bit(i, link->wr_tx_mask);
138 		}
139 		if (link->lgr->smc_version == SMC_V2) {
140 			memset(link->wr_tx_v2_pend, 0,
141 			       sizeof(*link->wr_tx_v2_pend));
142 			memset(link->lgr->wr_tx_buf_v2, 0,
143 			       sizeof(*link->lgr->wr_tx_buf_v2));
144 		}
145 		/* terminate link */
146 		smcr_link_down_cond_sched(link);
147 	}
148 	if (pnd_snd.handler)
149 		pnd_snd.handler(&pnd_snd.priv, link, wc->status);
150 	wake_up(&link->wr_tx_wait);
151 }
152 
153 static void smc_wr_tx_tasklet_fn(struct tasklet_struct *t)
154 {
155 	struct smc_ib_device *dev = from_tasklet(dev, t, send_tasklet);
156 	struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
157 	int i = 0, rc;
158 	int polled = 0;
159 
160 again:
161 	polled++;
162 	do {
163 		memset(&wc, 0, sizeof(wc));
164 		rc = ib_poll_cq(dev->roce_cq_send, SMC_WR_MAX_POLL_CQE, wc);
165 		if (polled == 1) {
166 			ib_req_notify_cq(dev->roce_cq_send,
167 					 IB_CQ_NEXT_COMP |
168 					 IB_CQ_REPORT_MISSED_EVENTS);
169 		}
170 		if (!rc)
171 			break;
172 		for (i = 0; i < rc; i++)
173 			smc_wr_tx_process_cqe(&wc[i]);
174 	} while (rc > 0);
175 	if (polled == 1)
176 		goto again;
177 }
178 
179 void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
180 {
181 	struct smc_ib_device *dev = (struct smc_ib_device *)cq_context;
182 
183 	tasklet_schedule(&dev->send_tasklet);
184 }
185 
186 /*---------------------------- request submission ---------------------------*/
187 
188 static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
189 {
190 	*idx = link->wr_tx_cnt;
191 	if (!smc_link_usable(link))
192 		return -ENOLINK;
193 	for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
194 		if (!test_and_set_bit(*idx, link->wr_tx_mask))
195 			return 0;
196 	}
197 	*idx = link->wr_tx_cnt;
198 	return -EBUSY;
199 }
200 
201 /**
202  * smc_wr_tx_get_free_slot() - returns buffer for message assembly,
203  *			and sets info for pending transmit tracking
204  * @link:		Pointer to smc_link used to later send the message.
205  * @handler:		Send completion handler function pointer.
206  * @wr_buf:		Out value returns pointer to message buffer.
207  * @wr_rdma_buf:	Out value returns pointer to rdma work request.
208  * @wr_pend_priv:	Out value returns pointer serving as handler context.
209  *
210  * Return: 0 on success, or -errno on error.
211  */
212 int smc_wr_tx_get_free_slot(struct smc_link *link,
213 			    smc_wr_tx_handler handler,
214 			    struct smc_wr_buf **wr_buf,
215 			    struct smc_rdma_wr **wr_rdma_buf,
216 			    struct smc_wr_tx_pend_priv **wr_pend_priv)
217 {
218 	struct smc_link_group *lgr = smc_get_lgr(link);
219 	struct smc_wr_tx_pend *wr_pend;
220 	u32 idx = link->wr_tx_cnt;
221 	struct ib_send_wr *wr_ib;
222 	u64 wr_id;
223 	int rc;
224 
225 	*wr_buf = NULL;
226 	*wr_pend_priv = NULL;
227 	if (in_softirq() || lgr->terminating) {
228 		rc = smc_wr_tx_get_free_slot_index(link, &idx);
229 		if (rc)
230 			return rc;
231 	} else {
232 		rc = wait_event_interruptible_timeout(
233 			link->wr_tx_wait,
234 			!smc_link_usable(link) ||
235 			lgr->terminating ||
236 			(smc_wr_tx_get_free_slot_index(link, &idx) != -EBUSY),
237 			SMC_WR_TX_WAIT_FREE_SLOT_TIME);
238 		if (!rc) {
239 			/* timeout - terminate link */
240 			smcr_link_down_cond_sched(link);
241 			return -EPIPE;
242 		}
243 		if (idx == link->wr_tx_cnt)
244 			return -EPIPE;
245 	}
246 	wr_id = smc_wr_tx_get_next_wr_id(link);
247 	wr_pend = &link->wr_tx_pends[idx];
248 	wr_pend->wr_id = wr_id;
249 	wr_pend->handler = handler;
250 	wr_pend->link = link;
251 	wr_pend->idx = idx;
252 	wr_ib = &link->wr_tx_ibs[idx];
253 	wr_ib->wr_id = wr_id;
254 	*wr_buf = &link->wr_tx_bufs[idx];
255 	if (wr_rdma_buf)
256 		*wr_rdma_buf = &link->wr_tx_rdmas[idx];
257 	*wr_pend_priv = &wr_pend->priv;
258 	return 0;
259 }
260 
261 int smc_wr_tx_get_v2_slot(struct smc_link *link,
262 			  smc_wr_tx_handler handler,
263 			  struct smc_wr_v2_buf **wr_buf,
264 			  struct smc_wr_tx_pend_priv **wr_pend_priv)
265 {
266 	struct smc_wr_tx_pend *wr_pend;
267 	struct ib_send_wr *wr_ib;
268 	u64 wr_id;
269 
270 	if (link->wr_tx_v2_pend->idx == link->wr_tx_cnt)
271 		return -EBUSY;
272 
273 	*wr_buf = NULL;
274 	*wr_pend_priv = NULL;
275 	wr_id = smc_wr_tx_get_next_wr_id(link);
276 	wr_pend = link->wr_tx_v2_pend;
277 	wr_pend->wr_id = wr_id;
278 	wr_pend->handler = handler;
279 	wr_pend->link = link;
280 	wr_pend->idx = link->wr_tx_cnt;
281 	wr_ib = link->wr_tx_v2_ib;
282 	wr_ib->wr_id = wr_id;
283 	*wr_buf = link->lgr->wr_tx_buf_v2;
284 	*wr_pend_priv = &wr_pend->priv;
285 	return 0;
286 }
287 
288 int smc_wr_tx_put_slot(struct smc_link *link,
289 		       struct smc_wr_tx_pend_priv *wr_pend_priv)
290 {
291 	struct smc_wr_tx_pend *pend;
292 
293 	pend = container_of(wr_pend_priv, struct smc_wr_tx_pend, priv);
294 	if (pend->idx < link->wr_tx_cnt) {
295 		u32 idx = pend->idx;
296 
297 		/* clear the full struct smc_wr_tx_pend including .priv */
298 		memset(&link->wr_tx_pends[idx], 0,
299 		       sizeof(link->wr_tx_pends[idx]));
300 		memset(&link->wr_tx_bufs[idx], 0,
301 		       sizeof(link->wr_tx_bufs[idx]));
302 		test_and_clear_bit(idx, link->wr_tx_mask);
303 		wake_up(&link->wr_tx_wait);
304 		return 1;
305 	} else if (link->lgr->smc_version == SMC_V2 &&
306 		   pend->idx == link->wr_tx_cnt) {
307 		/* Large v2 buffer */
308 		memset(&link->wr_tx_v2_pend, 0,
309 		       sizeof(link->wr_tx_v2_pend));
310 		memset(&link->lgr->wr_tx_buf_v2, 0,
311 		       sizeof(link->lgr->wr_tx_buf_v2));
312 		return 1;
313 	}
314 
315 	return 0;
316 }
317 
318 /* Send prepared WR slot via ib_post_send.
319  * @priv: pointer to smc_wr_tx_pend_priv identifying prepared message buffer
320  */
321 int smc_wr_tx_send(struct smc_link *link, struct smc_wr_tx_pend_priv *priv)
322 {
323 	struct smc_wr_tx_pend *pend;
324 	int rc;
325 
326 	ib_req_notify_cq(link->smcibdev->roce_cq_send,
327 			 IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
328 	pend = container_of(priv, struct smc_wr_tx_pend, priv);
329 	rc = ib_post_send(link->roce_qp, &link->wr_tx_ibs[pend->idx], NULL);
330 	if (rc) {
331 		smc_wr_tx_put_slot(link, priv);
332 		smcr_link_down_cond_sched(link);
333 	}
334 	return rc;
335 }
336 
337 int smc_wr_tx_v2_send(struct smc_link *link, struct smc_wr_tx_pend_priv *priv,
338 		      int len)
339 {
340 	int rc;
341 
342 	link->wr_tx_v2_ib->sg_list[0].length = len;
343 	ib_req_notify_cq(link->smcibdev->roce_cq_send,
344 			 IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
345 	rc = ib_post_send(link->roce_qp, link->wr_tx_v2_ib, NULL);
346 	if (rc) {
347 		smc_wr_tx_put_slot(link, priv);
348 		smcr_link_down_cond_sched(link);
349 	}
350 	return rc;
351 }
352 
353 /* Send prepared WR slot via ib_post_send and wait for send completion
354  * notification.
355  * @priv: pointer to smc_wr_tx_pend_priv identifying prepared message buffer
356  */
357 int smc_wr_tx_send_wait(struct smc_link *link, struct smc_wr_tx_pend_priv *priv,
358 			unsigned long timeout)
359 {
360 	struct smc_wr_tx_pend *pend;
361 	int rc;
362 
363 	pend = container_of(priv, struct smc_wr_tx_pend, priv);
364 	pend->compl_requested = 1;
365 	init_completion(&link->wr_tx_compl[pend->idx]);
366 
367 	rc = smc_wr_tx_send(link, priv);
368 	if (rc)
369 		return rc;
370 	/* wait for completion by smc_wr_tx_process_cqe() */
371 	rc = wait_for_completion_interruptible_timeout(
372 					&link->wr_tx_compl[pend->idx], timeout);
373 	if (rc <= 0)
374 		rc = -ENODATA;
375 	if (rc > 0)
376 		rc = 0;
377 	return rc;
378 }
379 
380 /* Register a memory region and wait for result. */
381 int smc_wr_reg_send(struct smc_link *link, struct ib_mr *mr)
382 {
383 	int rc;
384 
385 	ib_req_notify_cq(link->smcibdev->roce_cq_send,
386 			 IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
387 	link->wr_reg_state = POSTED;
388 	link->wr_reg.wr.wr_id = (u64)(uintptr_t)mr;
389 	link->wr_reg.mr = mr;
390 	link->wr_reg.key = mr->rkey;
391 	rc = ib_post_send(link->roce_qp, &link->wr_reg.wr, NULL);
392 	if (rc)
393 		return rc;
394 
395 	atomic_inc(&link->wr_reg_refcnt);
396 	rc = wait_event_interruptible_timeout(link->wr_reg_wait,
397 					      (link->wr_reg_state != POSTED),
398 					      SMC_WR_REG_MR_WAIT_TIME);
399 	if (atomic_dec_and_test(&link->wr_reg_refcnt))
400 		wake_up_all(&link->wr_reg_wait);
401 	if (!rc) {
402 		/* timeout - terminate link */
403 		smcr_link_down_cond_sched(link);
404 		return -EPIPE;
405 	}
406 	if (rc == -ERESTARTSYS)
407 		return -EINTR;
408 	switch (link->wr_reg_state) {
409 	case CONFIRMED:
410 		rc = 0;
411 		break;
412 	case FAILED:
413 		rc = -EIO;
414 		break;
415 	case POSTED:
416 		rc = -EPIPE;
417 		break;
418 	}
419 	return rc;
420 }
421 
422 void smc_wr_tx_dismiss_slots(struct smc_link *link, u8 wr_tx_hdr_type,
423 			     smc_wr_tx_filter filter,
424 			     smc_wr_tx_dismisser dismisser,
425 			     unsigned long data)
426 {
427 	struct smc_wr_tx_pend_priv *tx_pend;
428 	struct smc_wr_rx_hdr *wr_tx;
429 	int i;
430 
431 	for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
432 		wr_tx = (struct smc_wr_rx_hdr *)&link->wr_tx_bufs[i];
433 		if (wr_tx->type != wr_tx_hdr_type)
434 			continue;
435 		tx_pend = &link->wr_tx_pends[i].priv;
436 		if (filter(tx_pend, data))
437 			dismisser(tx_pend);
438 	}
439 }
440 
441 /****************************** receive queue ********************************/
442 
443 int smc_wr_rx_register_handler(struct smc_wr_rx_handler *handler)
444 {
445 	struct smc_wr_rx_handler *h_iter;
446 	int rc = 0;
447 
448 	spin_lock(&smc_wr_rx_hash_lock);
449 	hash_for_each_possible(smc_wr_rx_hash, h_iter, list, handler->type) {
450 		if (h_iter->type == handler->type) {
451 			rc = -EEXIST;
452 			goto out_unlock;
453 		}
454 	}
455 	hash_add(smc_wr_rx_hash, &handler->list, handler->type);
456 out_unlock:
457 	spin_unlock(&smc_wr_rx_hash_lock);
458 	return rc;
459 }
460 
461 /* Demultiplex a received work request based on the message type to its handler.
462  * Relies on smc_wr_rx_hash having been completely filled before any IB WRs,
463  * and not being modified any more afterwards so we don't need to lock it.
464  */
465 static inline void smc_wr_rx_demultiplex(struct ib_wc *wc)
466 {
467 	struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
468 	struct smc_wr_rx_handler *handler;
469 	struct smc_wr_rx_hdr *wr_rx;
470 	u64 temp_wr_id;
471 	u32 index;
472 
473 	if (wc->byte_len < sizeof(*wr_rx))
474 		return; /* short message */
475 	temp_wr_id = wc->wr_id;
476 	index = do_div(temp_wr_id, link->wr_rx_cnt);
477 	wr_rx = (struct smc_wr_rx_hdr *)&link->wr_rx_bufs[index];
478 	hash_for_each_possible(smc_wr_rx_hash, handler, list, wr_rx->type) {
479 		if (handler->type == wr_rx->type)
480 			handler->handler(wc, wr_rx);
481 	}
482 }
483 
484 static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num)
485 {
486 	struct smc_link *link;
487 	int i;
488 
489 	for (i = 0; i < num; i++) {
490 		link = wc[i].qp->qp_context;
491 		if (wc[i].status == IB_WC_SUCCESS) {
492 			link->wr_rx_tstamp = jiffies;
493 			smc_wr_rx_demultiplex(&wc[i]);
494 			smc_wr_rx_post(link); /* refill WR RX */
495 		} else {
496 			/* handle status errors */
497 			switch (wc[i].status) {
498 			case IB_WC_RETRY_EXC_ERR:
499 			case IB_WC_RNR_RETRY_EXC_ERR:
500 			case IB_WC_WR_FLUSH_ERR:
501 				smcr_link_down_cond_sched(link);
502 				break;
503 			default:
504 				smc_wr_rx_post(link); /* refill WR RX */
505 				break;
506 			}
507 		}
508 	}
509 }
510 
511 static void smc_wr_rx_tasklet_fn(struct tasklet_struct *t)
512 {
513 	struct smc_ib_device *dev = from_tasklet(dev, t, recv_tasklet);
514 	struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
515 	int polled = 0;
516 	int rc;
517 
518 again:
519 	polled++;
520 	do {
521 		memset(&wc, 0, sizeof(wc));
522 		rc = ib_poll_cq(dev->roce_cq_recv, SMC_WR_MAX_POLL_CQE, wc);
523 		if (polled == 1) {
524 			ib_req_notify_cq(dev->roce_cq_recv,
525 					 IB_CQ_SOLICITED_MASK
526 					 | IB_CQ_REPORT_MISSED_EVENTS);
527 		}
528 		if (!rc)
529 			break;
530 		smc_wr_rx_process_cqes(&wc[0], rc);
531 	} while (rc > 0);
532 	if (polled == 1)
533 		goto again;
534 }
535 
536 void smc_wr_rx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
537 {
538 	struct smc_ib_device *dev = (struct smc_ib_device *)cq_context;
539 
540 	tasklet_schedule(&dev->recv_tasklet);
541 }
542 
543 int smc_wr_rx_post_init(struct smc_link *link)
544 {
545 	u32 i;
546 	int rc = 0;
547 
548 	for (i = 0; i < link->wr_rx_cnt; i++)
549 		rc = smc_wr_rx_post(link);
550 	return rc;
551 }
552 
553 /***************************** init, exit, misc ******************************/
554 
555 void smc_wr_remember_qp_attr(struct smc_link *lnk)
556 {
557 	struct ib_qp_attr *attr = &lnk->qp_attr;
558 	struct ib_qp_init_attr init_attr;
559 
560 	memset(attr, 0, sizeof(*attr));
561 	memset(&init_attr, 0, sizeof(init_attr));
562 	ib_query_qp(lnk->roce_qp, attr,
563 		    IB_QP_STATE |
564 		    IB_QP_CUR_STATE |
565 		    IB_QP_PKEY_INDEX |
566 		    IB_QP_PORT |
567 		    IB_QP_QKEY |
568 		    IB_QP_AV |
569 		    IB_QP_PATH_MTU |
570 		    IB_QP_TIMEOUT |
571 		    IB_QP_RETRY_CNT |
572 		    IB_QP_RNR_RETRY |
573 		    IB_QP_RQ_PSN |
574 		    IB_QP_ALT_PATH |
575 		    IB_QP_MIN_RNR_TIMER |
576 		    IB_QP_SQ_PSN |
577 		    IB_QP_PATH_MIG_STATE |
578 		    IB_QP_CAP |
579 		    IB_QP_DEST_QPN,
580 		    &init_attr);
581 
582 	lnk->wr_tx_cnt = min_t(size_t, SMC_WR_BUF_CNT,
583 			       lnk->qp_attr.cap.max_send_wr);
584 	lnk->wr_rx_cnt = min_t(size_t, SMC_WR_BUF_CNT * 3,
585 			       lnk->qp_attr.cap.max_recv_wr);
586 }
587 
588 static void smc_wr_init_sge(struct smc_link *lnk)
589 {
590 	int sges_per_buf = (lnk->lgr->smc_version == SMC_V2) ? 2 : 1;
591 	u32 i;
592 
593 	for (i = 0; i < lnk->wr_tx_cnt; i++) {
594 		lnk->wr_tx_sges[i].addr =
595 			lnk->wr_tx_dma_addr + i * SMC_WR_BUF_SIZE;
596 		lnk->wr_tx_sges[i].length = SMC_WR_TX_SIZE;
597 		lnk->wr_tx_sges[i].lkey = lnk->roce_pd->local_dma_lkey;
598 		lnk->wr_tx_rdma_sges[i].tx_rdma_sge[0].wr_tx_rdma_sge[0].lkey =
599 			lnk->roce_pd->local_dma_lkey;
600 		lnk->wr_tx_rdma_sges[i].tx_rdma_sge[0].wr_tx_rdma_sge[1].lkey =
601 			lnk->roce_pd->local_dma_lkey;
602 		lnk->wr_tx_rdma_sges[i].tx_rdma_sge[1].wr_tx_rdma_sge[0].lkey =
603 			lnk->roce_pd->local_dma_lkey;
604 		lnk->wr_tx_rdma_sges[i].tx_rdma_sge[1].wr_tx_rdma_sge[1].lkey =
605 			lnk->roce_pd->local_dma_lkey;
606 		lnk->wr_tx_ibs[i].next = NULL;
607 		lnk->wr_tx_ibs[i].sg_list = &lnk->wr_tx_sges[i];
608 		lnk->wr_tx_ibs[i].num_sge = 1;
609 		lnk->wr_tx_ibs[i].opcode = IB_WR_SEND;
610 		lnk->wr_tx_ibs[i].send_flags =
611 			IB_SEND_SIGNALED | IB_SEND_SOLICITED;
612 		lnk->wr_tx_rdmas[i].wr_tx_rdma[0].wr.opcode = IB_WR_RDMA_WRITE;
613 		lnk->wr_tx_rdmas[i].wr_tx_rdma[1].wr.opcode = IB_WR_RDMA_WRITE;
614 		lnk->wr_tx_rdmas[i].wr_tx_rdma[0].wr.sg_list =
615 			lnk->wr_tx_rdma_sges[i].tx_rdma_sge[0].wr_tx_rdma_sge;
616 		lnk->wr_tx_rdmas[i].wr_tx_rdma[1].wr.sg_list =
617 			lnk->wr_tx_rdma_sges[i].tx_rdma_sge[1].wr_tx_rdma_sge;
618 	}
619 
620 	if (lnk->lgr->smc_version == SMC_V2) {
621 		lnk->wr_tx_v2_sge->addr = lnk->wr_tx_v2_dma_addr;
622 		lnk->wr_tx_v2_sge->length = SMC_WR_BUF_V2_SIZE;
623 		lnk->wr_tx_v2_sge->lkey = lnk->roce_pd->local_dma_lkey;
624 
625 		lnk->wr_tx_v2_ib->next = NULL;
626 		lnk->wr_tx_v2_ib->sg_list = lnk->wr_tx_v2_sge;
627 		lnk->wr_tx_v2_ib->num_sge = 1;
628 		lnk->wr_tx_v2_ib->opcode = IB_WR_SEND;
629 		lnk->wr_tx_v2_ib->send_flags =
630 			IB_SEND_SIGNALED | IB_SEND_SOLICITED;
631 	}
632 
633 	/* With SMC-Rv2 there can be messages larger than SMC_WR_TX_SIZE.
634 	 * Each ib_recv_wr gets 2 sges, the second one is a spillover buffer
635 	 * and the same buffer for all sges. When a larger message arrived then
636 	 * the content of the first small sge is copied to the beginning of
637 	 * the larger spillover buffer, allowing easy data mapping.
638 	 */
639 	for (i = 0; i < lnk->wr_rx_cnt; i++) {
640 		int x = i * sges_per_buf;
641 
642 		lnk->wr_rx_sges[x].addr =
643 			lnk->wr_rx_dma_addr + i * SMC_WR_BUF_SIZE;
644 		lnk->wr_rx_sges[x].length = SMC_WR_TX_SIZE;
645 		lnk->wr_rx_sges[x].lkey = lnk->roce_pd->local_dma_lkey;
646 		if (lnk->lgr->smc_version == SMC_V2) {
647 			lnk->wr_rx_sges[x + 1].addr =
648 					lnk->wr_rx_v2_dma_addr + SMC_WR_TX_SIZE;
649 			lnk->wr_rx_sges[x + 1].length =
650 					SMC_WR_BUF_V2_SIZE - SMC_WR_TX_SIZE;
651 			lnk->wr_rx_sges[x + 1].lkey =
652 					lnk->roce_pd->local_dma_lkey;
653 		}
654 		lnk->wr_rx_ibs[i].next = NULL;
655 		lnk->wr_rx_ibs[i].sg_list = &lnk->wr_rx_sges[x];
656 		lnk->wr_rx_ibs[i].num_sge = sges_per_buf;
657 	}
658 	lnk->wr_reg.wr.next = NULL;
659 	lnk->wr_reg.wr.num_sge = 0;
660 	lnk->wr_reg.wr.send_flags = IB_SEND_SIGNALED;
661 	lnk->wr_reg.wr.opcode = IB_WR_REG_MR;
662 	lnk->wr_reg.access = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE;
663 }
664 
665 void smc_wr_free_link(struct smc_link *lnk)
666 {
667 	struct ib_device *ibdev;
668 
669 	if (!lnk->smcibdev)
670 		return;
671 	ibdev = lnk->smcibdev->ibdev;
672 
673 	smc_wr_wakeup_reg_wait(lnk);
674 	smc_wr_wakeup_tx_wait(lnk);
675 
676 	if (smc_wr_tx_wait_no_pending_sends(lnk))
677 		memset(lnk->wr_tx_mask, 0,
678 		       BITS_TO_LONGS(SMC_WR_BUF_CNT) *
679 						sizeof(*lnk->wr_tx_mask));
680 	wait_event(lnk->wr_reg_wait, (!atomic_read(&lnk->wr_reg_refcnt)));
681 	wait_event(lnk->wr_tx_wait, (!atomic_read(&lnk->wr_tx_refcnt)));
682 
683 	if (lnk->wr_rx_dma_addr) {
684 		ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
685 				    SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
686 				    DMA_FROM_DEVICE);
687 		lnk->wr_rx_dma_addr = 0;
688 	}
689 	if (lnk->wr_rx_v2_dma_addr) {
690 		ib_dma_unmap_single(ibdev, lnk->wr_rx_v2_dma_addr,
691 				    SMC_WR_BUF_V2_SIZE,
692 				    DMA_FROM_DEVICE);
693 		lnk->wr_rx_v2_dma_addr = 0;
694 	}
695 	if (lnk->wr_tx_dma_addr) {
696 		ib_dma_unmap_single(ibdev, lnk->wr_tx_dma_addr,
697 				    SMC_WR_BUF_SIZE * lnk->wr_tx_cnt,
698 				    DMA_TO_DEVICE);
699 		lnk->wr_tx_dma_addr = 0;
700 	}
701 	if (lnk->wr_tx_v2_dma_addr) {
702 		ib_dma_unmap_single(ibdev, lnk->wr_tx_v2_dma_addr,
703 				    SMC_WR_BUF_V2_SIZE,
704 				    DMA_TO_DEVICE);
705 		lnk->wr_tx_v2_dma_addr = 0;
706 	}
707 }
708 
709 void smc_wr_free_lgr_mem(struct smc_link_group *lgr)
710 {
711 	if (lgr->smc_version < SMC_V2)
712 		return;
713 
714 	kfree(lgr->wr_rx_buf_v2);
715 	lgr->wr_rx_buf_v2 = NULL;
716 	kfree(lgr->wr_tx_buf_v2);
717 	lgr->wr_tx_buf_v2 = NULL;
718 }
719 
720 void smc_wr_free_link_mem(struct smc_link *lnk)
721 {
722 	kfree(lnk->wr_tx_v2_ib);
723 	lnk->wr_tx_v2_ib = NULL;
724 	kfree(lnk->wr_tx_v2_sge);
725 	lnk->wr_tx_v2_sge = NULL;
726 	kfree(lnk->wr_tx_v2_pend);
727 	lnk->wr_tx_v2_pend = NULL;
728 	kfree(lnk->wr_tx_compl);
729 	lnk->wr_tx_compl = NULL;
730 	kfree(lnk->wr_tx_pends);
731 	lnk->wr_tx_pends = NULL;
732 	kfree(lnk->wr_tx_mask);
733 	lnk->wr_tx_mask = NULL;
734 	kfree(lnk->wr_tx_sges);
735 	lnk->wr_tx_sges = NULL;
736 	kfree(lnk->wr_tx_rdma_sges);
737 	lnk->wr_tx_rdma_sges = NULL;
738 	kfree(lnk->wr_rx_sges);
739 	lnk->wr_rx_sges = NULL;
740 	kfree(lnk->wr_tx_rdmas);
741 	lnk->wr_tx_rdmas = NULL;
742 	kfree(lnk->wr_rx_ibs);
743 	lnk->wr_rx_ibs = NULL;
744 	kfree(lnk->wr_tx_ibs);
745 	lnk->wr_tx_ibs = NULL;
746 	kfree(lnk->wr_tx_bufs);
747 	lnk->wr_tx_bufs = NULL;
748 	kfree(lnk->wr_rx_bufs);
749 	lnk->wr_rx_bufs = NULL;
750 }
751 
752 int smc_wr_alloc_lgr_mem(struct smc_link_group *lgr)
753 {
754 	if (lgr->smc_version < SMC_V2)
755 		return 0;
756 
757 	lgr->wr_rx_buf_v2 = kzalloc(SMC_WR_BUF_V2_SIZE, GFP_KERNEL);
758 	if (!lgr->wr_rx_buf_v2)
759 		return -ENOMEM;
760 	lgr->wr_tx_buf_v2 = kzalloc(SMC_WR_BUF_V2_SIZE, GFP_KERNEL);
761 	if (!lgr->wr_tx_buf_v2) {
762 		kfree(lgr->wr_rx_buf_v2);
763 		return -ENOMEM;
764 	}
765 	return 0;
766 }
767 
768 int smc_wr_alloc_link_mem(struct smc_link *link)
769 {
770 	int sges_per_buf = link->lgr->smc_version == SMC_V2 ? 2 : 1;
771 
772 	/* allocate link related memory */
773 	link->wr_tx_bufs = kcalloc(SMC_WR_BUF_CNT, SMC_WR_BUF_SIZE, GFP_KERNEL);
774 	if (!link->wr_tx_bufs)
775 		goto no_mem;
776 	link->wr_rx_bufs = kcalloc(SMC_WR_BUF_CNT * 3, SMC_WR_BUF_SIZE,
777 				   GFP_KERNEL);
778 	if (!link->wr_rx_bufs)
779 		goto no_mem_wr_tx_bufs;
780 	link->wr_tx_ibs = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_ibs[0]),
781 				  GFP_KERNEL);
782 	if (!link->wr_tx_ibs)
783 		goto no_mem_wr_rx_bufs;
784 	link->wr_rx_ibs = kcalloc(SMC_WR_BUF_CNT * 3,
785 				  sizeof(link->wr_rx_ibs[0]),
786 				  GFP_KERNEL);
787 	if (!link->wr_rx_ibs)
788 		goto no_mem_wr_tx_ibs;
789 	link->wr_tx_rdmas = kcalloc(SMC_WR_BUF_CNT,
790 				    sizeof(link->wr_tx_rdmas[0]),
791 				    GFP_KERNEL);
792 	if (!link->wr_tx_rdmas)
793 		goto no_mem_wr_rx_ibs;
794 	link->wr_tx_rdma_sges = kcalloc(SMC_WR_BUF_CNT,
795 					sizeof(link->wr_tx_rdma_sges[0]),
796 					GFP_KERNEL);
797 	if (!link->wr_tx_rdma_sges)
798 		goto no_mem_wr_tx_rdmas;
799 	link->wr_tx_sges = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_sges[0]),
800 				   GFP_KERNEL);
801 	if (!link->wr_tx_sges)
802 		goto no_mem_wr_tx_rdma_sges;
803 	link->wr_rx_sges = kcalloc(SMC_WR_BUF_CNT * 3,
804 				   sizeof(link->wr_rx_sges[0]) * sges_per_buf,
805 				   GFP_KERNEL);
806 	if (!link->wr_rx_sges)
807 		goto no_mem_wr_tx_sges;
808 	link->wr_tx_mask = kcalloc(BITS_TO_LONGS(SMC_WR_BUF_CNT),
809 				   sizeof(*link->wr_tx_mask),
810 				   GFP_KERNEL);
811 	if (!link->wr_tx_mask)
812 		goto no_mem_wr_rx_sges;
813 	link->wr_tx_pends = kcalloc(SMC_WR_BUF_CNT,
814 				    sizeof(link->wr_tx_pends[0]),
815 				    GFP_KERNEL);
816 	if (!link->wr_tx_pends)
817 		goto no_mem_wr_tx_mask;
818 	link->wr_tx_compl = kcalloc(SMC_WR_BUF_CNT,
819 				    sizeof(link->wr_tx_compl[0]),
820 				    GFP_KERNEL);
821 	if (!link->wr_tx_compl)
822 		goto no_mem_wr_tx_pends;
823 
824 	if (link->lgr->smc_version == SMC_V2) {
825 		link->wr_tx_v2_ib = kzalloc(sizeof(*link->wr_tx_v2_ib),
826 					    GFP_KERNEL);
827 		if (!link->wr_tx_v2_ib)
828 			goto no_mem_tx_compl;
829 		link->wr_tx_v2_sge = kzalloc(sizeof(*link->wr_tx_v2_sge),
830 					     GFP_KERNEL);
831 		if (!link->wr_tx_v2_sge)
832 			goto no_mem_v2_ib;
833 		link->wr_tx_v2_pend = kzalloc(sizeof(*link->wr_tx_v2_pend),
834 					      GFP_KERNEL);
835 		if (!link->wr_tx_v2_pend)
836 			goto no_mem_v2_sge;
837 	}
838 	return 0;
839 
840 no_mem_v2_sge:
841 	kfree(link->wr_tx_v2_sge);
842 no_mem_v2_ib:
843 	kfree(link->wr_tx_v2_ib);
844 no_mem_tx_compl:
845 	kfree(link->wr_tx_compl);
846 no_mem_wr_tx_pends:
847 	kfree(link->wr_tx_pends);
848 no_mem_wr_tx_mask:
849 	kfree(link->wr_tx_mask);
850 no_mem_wr_rx_sges:
851 	kfree(link->wr_rx_sges);
852 no_mem_wr_tx_sges:
853 	kfree(link->wr_tx_sges);
854 no_mem_wr_tx_rdma_sges:
855 	kfree(link->wr_tx_rdma_sges);
856 no_mem_wr_tx_rdmas:
857 	kfree(link->wr_tx_rdmas);
858 no_mem_wr_rx_ibs:
859 	kfree(link->wr_rx_ibs);
860 no_mem_wr_tx_ibs:
861 	kfree(link->wr_tx_ibs);
862 no_mem_wr_rx_bufs:
863 	kfree(link->wr_rx_bufs);
864 no_mem_wr_tx_bufs:
865 	kfree(link->wr_tx_bufs);
866 no_mem:
867 	return -ENOMEM;
868 }
869 
870 void smc_wr_remove_dev(struct smc_ib_device *smcibdev)
871 {
872 	tasklet_kill(&smcibdev->recv_tasklet);
873 	tasklet_kill(&smcibdev->send_tasklet);
874 }
875 
876 void smc_wr_add_dev(struct smc_ib_device *smcibdev)
877 {
878 	tasklet_setup(&smcibdev->recv_tasklet, smc_wr_rx_tasklet_fn);
879 	tasklet_setup(&smcibdev->send_tasklet, smc_wr_tx_tasklet_fn);
880 }
881 
882 int smc_wr_create_link(struct smc_link *lnk)
883 {
884 	struct ib_device *ibdev = lnk->smcibdev->ibdev;
885 	int rc = 0;
886 
887 	smc_wr_tx_set_wr_id(&lnk->wr_tx_id, 0);
888 	lnk->wr_rx_id = 0;
889 	lnk->wr_rx_dma_addr = ib_dma_map_single(
890 		ibdev, lnk->wr_rx_bufs,	SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
891 		DMA_FROM_DEVICE);
892 	if (ib_dma_mapping_error(ibdev, lnk->wr_rx_dma_addr)) {
893 		lnk->wr_rx_dma_addr = 0;
894 		rc = -EIO;
895 		goto out;
896 	}
897 	if (lnk->lgr->smc_version == SMC_V2) {
898 		lnk->wr_rx_v2_dma_addr = ib_dma_map_single(ibdev,
899 			lnk->lgr->wr_rx_buf_v2, SMC_WR_BUF_V2_SIZE,
900 			DMA_FROM_DEVICE);
901 		if (ib_dma_mapping_error(ibdev, lnk->wr_rx_v2_dma_addr)) {
902 			lnk->wr_rx_v2_dma_addr = 0;
903 			rc = -EIO;
904 			goto dma_unmap;
905 		}
906 		lnk->wr_tx_v2_dma_addr = ib_dma_map_single(ibdev,
907 			lnk->lgr->wr_tx_buf_v2, SMC_WR_BUF_V2_SIZE,
908 			DMA_TO_DEVICE);
909 		if (ib_dma_mapping_error(ibdev, lnk->wr_tx_v2_dma_addr)) {
910 			lnk->wr_tx_v2_dma_addr = 0;
911 			rc = -EIO;
912 			goto dma_unmap;
913 		}
914 	}
915 	lnk->wr_tx_dma_addr = ib_dma_map_single(
916 		ibdev, lnk->wr_tx_bufs,	SMC_WR_BUF_SIZE * lnk->wr_tx_cnt,
917 		DMA_TO_DEVICE);
918 	if (ib_dma_mapping_error(ibdev, lnk->wr_tx_dma_addr)) {
919 		rc = -EIO;
920 		goto dma_unmap;
921 	}
922 	smc_wr_init_sge(lnk);
923 	memset(lnk->wr_tx_mask, 0,
924 	       BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
925 	init_waitqueue_head(&lnk->wr_tx_wait);
926 	atomic_set(&lnk->wr_tx_refcnt, 0);
927 	init_waitqueue_head(&lnk->wr_reg_wait);
928 	atomic_set(&lnk->wr_reg_refcnt, 0);
929 	return rc;
930 
931 dma_unmap:
932 	if (lnk->wr_rx_v2_dma_addr) {
933 		ib_dma_unmap_single(ibdev, lnk->wr_rx_v2_dma_addr,
934 				    SMC_WR_BUF_V2_SIZE,
935 				    DMA_FROM_DEVICE);
936 		lnk->wr_rx_v2_dma_addr = 0;
937 	}
938 	if (lnk->wr_tx_v2_dma_addr) {
939 		ib_dma_unmap_single(ibdev, lnk->wr_tx_v2_dma_addr,
940 				    SMC_WR_BUF_V2_SIZE,
941 				    DMA_TO_DEVICE);
942 		lnk->wr_tx_v2_dma_addr = 0;
943 	}
944 	ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
945 			    SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
946 			    DMA_FROM_DEVICE);
947 	lnk->wr_rx_dma_addr = 0;
948 out:
949 	return rc;
950 }
951