xref: /openbmc/linux/net/smc/smc_wr.c (revision df687341)
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 };
48 
49 /******************************** send queue *********************************/
50 
51 /*------------------------------- completion --------------------------------*/
52 
53 static inline int smc_wr_tx_find_pending_index(struct smc_link *link, u64 wr_id)
54 {
55 	u32 i;
56 
57 	for (i = 0; i < link->wr_tx_cnt; i++) {
58 		if (link->wr_tx_pends[i].wr_id == wr_id)
59 			return i;
60 	}
61 	return link->wr_tx_cnt;
62 }
63 
64 static inline void smc_wr_tx_process_cqe(struct ib_wc *wc)
65 {
66 	struct smc_wr_tx_pend pnd_snd;
67 	struct smc_link *link;
68 	u32 pnd_snd_idx;
69 	int i;
70 
71 	link = wc->qp->qp_context;
72 
73 	if (wc->opcode == IB_WC_REG_MR) {
74 		if (wc->status)
75 			link->wr_reg_state = FAILED;
76 		else
77 			link->wr_reg_state = CONFIRMED;
78 		wake_up(&link->wr_reg_wait);
79 		return;
80 	}
81 
82 	pnd_snd_idx = smc_wr_tx_find_pending_index(link, wc->wr_id);
83 	if (pnd_snd_idx == link->wr_tx_cnt)
84 		return;
85 	link->wr_tx_pends[pnd_snd_idx].wc_status = wc->status;
86 	memcpy(&pnd_snd, &link->wr_tx_pends[pnd_snd_idx], sizeof(pnd_snd));
87 	/* clear the full struct smc_wr_tx_pend including .priv */
88 	memset(&link->wr_tx_pends[pnd_snd_idx], 0,
89 	       sizeof(link->wr_tx_pends[pnd_snd_idx]));
90 	memset(&link->wr_tx_bufs[pnd_snd_idx], 0,
91 	       sizeof(link->wr_tx_bufs[pnd_snd_idx]));
92 	if (!test_and_clear_bit(pnd_snd_idx, link->wr_tx_mask))
93 		return;
94 	if (wc->status) {
95 		for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
96 			/* clear full struct smc_wr_tx_pend including .priv */
97 			memset(&link->wr_tx_pends[i], 0,
98 			       sizeof(link->wr_tx_pends[i]));
99 			memset(&link->wr_tx_bufs[i], 0,
100 			       sizeof(link->wr_tx_bufs[i]));
101 			clear_bit(i, link->wr_tx_mask);
102 		}
103 		/* terminate connections of this link group abnormally */
104 		smc_lgr_terminate(smc_get_lgr(link));
105 	}
106 	if (pnd_snd.handler)
107 		pnd_snd.handler(&pnd_snd.priv, link, wc->status);
108 	wake_up(&link->wr_tx_wait);
109 }
110 
111 static void smc_wr_tx_tasklet_fn(unsigned long data)
112 {
113 	struct smc_ib_device *dev = (struct smc_ib_device *)data;
114 	struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
115 	int i = 0, rc;
116 	int polled = 0;
117 
118 again:
119 	polled++;
120 	do {
121 		memset(&wc, 0, sizeof(wc));
122 		rc = ib_poll_cq(dev->roce_cq_send, SMC_WR_MAX_POLL_CQE, wc);
123 		if (polled == 1) {
124 			ib_req_notify_cq(dev->roce_cq_send,
125 					 IB_CQ_NEXT_COMP |
126 					 IB_CQ_REPORT_MISSED_EVENTS);
127 		}
128 		if (!rc)
129 			break;
130 		for (i = 0; i < rc; i++)
131 			smc_wr_tx_process_cqe(&wc[i]);
132 	} while (rc > 0);
133 	if (polled == 1)
134 		goto again;
135 }
136 
137 void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
138 {
139 	struct smc_ib_device *dev = (struct smc_ib_device *)cq_context;
140 
141 	tasklet_schedule(&dev->send_tasklet);
142 }
143 
144 /*---------------------------- request submission ---------------------------*/
145 
146 static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
147 {
148 	*idx = link->wr_tx_cnt;
149 	for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
150 		if (!test_and_set_bit(*idx, link->wr_tx_mask))
151 			return 0;
152 	}
153 	*idx = link->wr_tx_cnt;
154 	return -EBUSY;
155 }
156 
157 /**
158  * smc_wr_tx_get_free_slot() - returns buffer for message assembly,
159  *			and sets info for pending transmit tracking
160  * @link:		Pointer to smc_link used to later send the message.
161  * @handler:		Send completion handler function pointer.
162  * @wr_buf:		Out value returns pointer to message buffer.
163  * @wr_pend_priv:	Out value returns pointer serving as handler context.
164  *
165  * Return: 0 on success, or -errno on error.
166  */
167 int smc_wr_tx_get_free_slot(struct smc_link *link,
168 			    smc_wr_tx_handler handler,
169 			    struct smc_wr_buf **wr_buf,
170 			    struct smc_wr_tx_pend_priv **wr_pend_priv)
171 {
172 	struct smc_wr_tx_pend *wr_pend;
173 	u32 idx = link->wr_tx_cnt;
174 	struct ib_send_wr *wr_ib;
175 	u64 wr_id;
176 	int rc;
177 
178 	*wr_buf = NULL;
179 	*wr_pend_priv = NULL;
180 	if (in_softirq()) {
181 		rc = smc_wr_tx_get_free_slot_index(link, &idx);
182 		if (rc)
183 			return rc;
184 	} else {
185 		rc = wait_event_timeout(
186 			link->wr_tx_wait,
187 			link->state == SMC_LNK_INACTIVE ||
188 			(smc_wr_tx_get_free_slot_index(link, &idx) != -EBUSY),
189 			SMC_WR_TX_WAIT_FREE_SLOT_TIME);
190 		if (!rc) {
191 			/* timeout - terminate connections */
192 			smc_lgr_terminate(smc_get_lgr(link));
193 			return -EPIPE;
194 		}
195 		if (idx == link->wr_tx_cnt)
196 			return -EPIPE;
197 	}
198 	wr_id = smc_wr_tx_get_next_wr_id(link);
199 	wr_pend = &link->wr_tx_pends[idx];
200 	wr_pend->wr_id = wr_id;
201 	wr_pend->handler = handler;
202 	wr_pend->link = link;
203 	wr_pend->idx = idx;
204 	wr_ib = &link->wr_tx_ibs[idx];
205 	wr_ib->wr_id = wr_id;
206 	*wr_buf = &link->wr_tx_bufs[idx];
207 	*wr_pend_priv = &wr_pend->priv;
208 	return 0;
209 }
210 
211 int smc_wr_tx_put_slot(struct smc_link *link,
212 		       struct smc_wr_tx_pend_priv *wr_pend_priv)
213 {
214 	struct smc_wr_tx_pend *pend;
215 
216 	pend = container_of(wr_pend_priv, struct smc_wr_tx_pend, priv);
217 	if (pend->idx < link->wr_tx_cnt) {
218 		u32 idx = pend->idx;
219 
220 		/* clear the full struct smc_wr_tx_pend including .priv */
221 		memset(&link->wr_tx_pends[pend->idx], 0,
222 		       sizeof(link->wr_tx_pends[pend->idx]));
223 		memset(&link->wr_tx_bufs[pend->idx], 0,
224 		       sizeof(link->wr_tx_bufs[pend->idx]));
225 		test_and_clear_bit(idx, link->wr_tx_mask);
226 		return 1;
227 	}
228 
229 	return 0;
230 }
231 
232 /* Send prepared WR slot via ib_post_send.
233  * @priv: pointer to smc_wr_tx_pend_priv identifying prepared message buffer
234  */
235 int smc_wr_tx_send(struct smc_link *link, struct smc_wr_tx_pend_priv *priv)
236 {
237 	struct smc_wr_tx_pend *pend;
238 	int rc;
239 
240 	ib_req_notify_cq(link->smcibdev->roce_cq_send,
241 			 IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
242 	pend = container_of(priv, struct smc_wr_tx_pend, priv);
243 	rc = ib_post_send(link->roce_qp, &link->wr_tx_ibs[pend->idx], NULL);
244 	if (rc) {
245 		smc_wr_tx_put_slot(link, priv);
246 		smc_lgr_terminate(smc_get_lgr(link));
247 	}
248 	return rc;
249 }
250 
251 /* Register a memory region and wait for result. */
252 int smc_wr_reg_send(struct smc_link *link, struct ib_mr *mr)
253 {
254 	int rc;
255 
256 	ib_req_notify_cq(link->smcibdev->roce_cq_send,
257 			 IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
258 	link->wr_reg_state = POSTED;
259 	link->wr_reg.wr.wr_id = (u64)(uintptr_t)mr;
260 	link->wr_reg.mr = mr;
261 	link->wr_reg.key = mr->rkey;
262 	rc = ib_post_send(link->roce_qp, &link->wr_reg.wr, NULL);
263 	if (rc)
264 		return rc;
265 
266 	rc = wait_event_interruptible_timeout(link->wr_reg_wait,
267 					      (link->wr_reg_state != POSTED),
268 					      SMC_WR_REG_MR_WAIT_TIME);
269 	if (!rc) {
270 		/* timeout - terminate connections */
271 		smc_lgr_terminate(smc_get_lgr(link));
272 		return -EPIPE;
273 	}
274 	if (rc == -ERESTARTSYS)
275 		return -EINTR;
276 	switch (link->wr_reg_state) {
277 	case CONFIRMED:
278 		rc = 0;
279 		break;
280 	case FAILED:
281 		rc = -EIO;
282 		break;
283 	case POSTED:
284 		rc = -EPIPE;
285 		break;
286 	}
287 	return rc;
288 }
289 
290 void smc_wr_tx_dismiss_slots(struct smc_link *link, u8 wr_tx_hdr_type,
291 			     smc_wr_tx_filter filter,
292 			     smc_wr_tx_dismisser dismisser,
293 			     unsigned long data)
294 {
295 	struct smc_wr_tx_pend_priv *tx_pend;
296 	struct smc_wr_rx_hdr *wr_tx;
297 	int i;
298 
299 	for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
300 		wr_tx = (struct smc_wr_rx_hdr *)&link->wr_tx_bufs[i];
301 		if (wr_tx->type != wr_tx_hdr_type)
302 			continue;
303 		tx_pend = &link->wr_tx_pends[i].priv;
304 		if (filter(tx_pend, data))
305 			dismisser(tx_pend);
306 	}
307 }
308 
309 /****************************** receive queue ********************************/
310 
311 int smc_wr_rx_register_handler(struct smc_wr_rx_handler *handler)
312 {
313 	struct smc_wr_rx_handler *h_iter;
314 	int rc = 0;
315 
316 	spin_lock(&smc_wr_rx_hash_lock);
317 	hash_for_each_possible(smc_wr_rx_hash, h_iter, list, handler->type) {
318 		if (h_iter->type == handler->type) {
319 			rc = -EEXIST;
320 			goto out_unlock;
321 		}
322 	}
323 	hash_add(smc_wr_rx_hash, &handler->list, handler->type);
324 out_unlock:
325 	spin_unlock(&smc_wr_rx_hash_lock);
326 	return rc;
327 }
328 
329 /* Demultiplex a received work request based on the message type to its handler.
330  * Relies on smc_wr_rx_hash having been completely filled before any IB WRs,
331  * and not being modified any more afterwards so we don't need to lock it.
332  */
333 static inline void smc_wr_rx_demultiplex(struct ib_wc *wc)
334 {
335 	struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
336 	struct smc_wr_rx_handler *handler;
337 	struct smc_wr_rx_hdr *wr_rx;
338 	u64 temp_wr_id;
339 	u32 index;
340 
341 	if (wc->byte_len < sizeof(*wr_rx))
342 		return; /* short message */
343 	temp_wr_id = wc->wr_id;
344 	index = do_div(temp_wr_id, link->wr_rx_cnt);
345 	wr_rx = (struct smc_wr_rx_hdr *)&link->wr_rx_bufs[index];
346 	hash_for_each_possible(smc_wr_rx_hash, handler, list, wr_rx->type) {
347 		if (handler->type == wr_rx->type)
348 			handler->handler(wc, wr_rx);
349 	}
350 }
351 
352 static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num)
353 {
354 	struct smc_link *link;
355 	int i;
356 
357 	for (i = 0; i < num; i++) {
358 		link = wc[i].qp->qp_context;
359 		if (wc[i].status == IB_WC_SUCCESS) {
360 			link->wr_rx_tstamp = jiffies;
361 			smc_wr_rx_demultiplex(&wc[i]);
362 			smc_wr_rx_post(link); /* refill WR RX */
363 		} else {
364 			/* handle status errors */
365 			switch (wc[i].status) {
366 			case IB_WC_RETRY_EXC_ERR:
367 			case IB_WC_RNR_RETRY_EXC_ERR:
368 			case IB_WC_WR_FLUSH_ERR:
369 				/* terminate connections of this link group
370 				 * abnormally
371 				 */
372 				smc_lgr_terminate(smc_get_lgr(link));
373 				break;
374 			default:
375 				smc_wr_rx_post(link); /* refill WR RX */
376 				break;
377 			}
378 		}
379 	}
380 }
381 
382 static void smc_wr_rx_tasklet_fn(unsigned long data)
383 {
384 	struct smc_ib_device *dev = (struct smc_ib_device *)data;
385 	struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
386 	int polled = 0;
387 	int rc;
388 
389 again:
390 	polled++;
391 	do {
392 		memset(&wc, 0, sizeof(wc));
393 		rc = ib_poll_cq(dev->roce_cq_recv, SMC_WR_MAX_POLL_CQE, wc);
394 		if (polled == 1) {
395 			ib_req_notify_cq(dev->roce_cq_recv,
396 					 IB_CQ_SOLICITED_MASK
397 					 | IB_CQ_REPORT_MISSED_EVENTS);
398 		}
399 		if (!rc)
400 			break;
401 		smc_wr_rx_process_cqes(&wc[0], rc);
402 	} while (rc > 0);
403 	if (polled == 1)
404 		goto again;
405 }
406 
407 void smc_wr_rx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
408 {
409 	struct smc_ib_device *dev = (struct smc_ib_device *)cq_context;
410 
411 	tasklet_schedule(&dev->recv_tasklet);
412 }
413 
414 int smc_wr_rx_post_init(struct smc_link *link)
415 {
416 	u32 i;
417 	int rc = 0;
418 
419 	for (i = 0; i < link->wr_rx_cnt; i++)
420 		rc = smc_wr_rx_post(link);
421 	return rc;
422 }
423 
424 /***************************** init, exit, misc ******************************/
425 
426 void smc_wr_remember_qp_attr(struct smc_link *lnk)
427 {
428 	struct ib_qp_attr *attr = &lnk->qp_attr;
429 	struct ib_qp_init_attr init_attr;
430 
431 	memset(attr, 0, sizeof(*attr));
432 	memset(&init_attr, 0, sizeof(init_attr));
433 	ib_query_qp(lnk->roce_qp, attr,
434 		    IB_QP_STATE |
435 		    IB_QP_CUR_STATE |
436 		    IB_QP_PKEY_INDEX |
437 		    IB_QP_PORT |
438 		    IB_QP_QKEY |
439 		    IB_QP_AV |
440 		    IB_QP_PATH_MTU |
441 		    IB_QP_TIMEOUT |
442 		    IB_QP_RETRY_CNT |
443 		    IB_QP_RNR_RETRY |
444 		    IB_QP_RQ_PSN |
445 		    IB_QP_ALT_PATH |
446 		    IB_QP_MIN_RNR_TIMER |
447 		    IB_QP_SQ_PSN |
448 		    IB_QP_PATH_MIG_STATE |
449 		    IB_QP_CAP |
450 		    IB_QP_DEST_QPN,
451 		    &init_attr);
452 
453 	lnk->wr_tx_cnt = min_t(size_t, SMC_WR_BUF_CNT,
454 			       lnk->qp_attr.cap.max_send_wr);
455 	lnk->wr_rx_cnt = min_t(size_t, SMC_WR_BUF_CNT * 3,
456 			       lnk->qp_attr.cap.max_recv_wr);
457 }
458 
459 static void smc_wr_init_sge(struct smc_link *lnk)
460 {
461 	u32 i;
462 
463 	for (i = 0; i < lnk->wr_tx_cnt; i++) {
464 		lnk->wr_tx_sges[i].addr =
465 			lnk->wr_tx_dma_addr + i * SMC_WR_BUF_SIZE;
466 		lnk->wr_tx_sges[i].length = SMC_WR_TX_SIZE;
467 		lnk->wr_tx_sges[i].lkey = lnk->roce_pd->local_dma_lkey;
468 		lnk->wr_tx_ibs[i].next = NULL;
469 		lnk->wr_tx_ibs[i].sg_list = &lnk->wr_tx_sges[i];
470 		lnk->wr_tx_ibs[i].num_sge = 1;
471 		lnk->wr_tx_ibs[i].opcode = IB_WR_SEND;
472 		lnk->wr_tx_ibs[i].send_flags =
473 			IB_SEND_SIGNALED | IB_SEND_SOLICITED;
474 	}
475 	for (i = 0; i < lnk->wr_rx_cnt; i++) {
476 		lnk->wr_rx_sges[i].addr =
477 			lnk->wr_rx_dma_addr + i * SMC_WR_BUF_SIZE;
478 		lnk->wr_rx_sges[i].length = SMC_WR_BUF_SIZE;
479 		lnk->wr_rx_sges[i].lkey = lnk->roce_pd->local_dma_lkey;
480 		lnk->wr_rx_ibs[i].next = NULL;
481 		lnk->wr_rx_ibs[i].sg_list = &lnk->wr_rx_sges[i];
482 		lnk->wr_rx_ibs[i].num_sge = 1;
483 	}
484 	lnk->wr_reg.wr.next = NULL;
485 	lnk->wr_reg.wr.num_sge = 0;
486 	lnk->wr_reg.wr.send_flags = IB_SEND_SIGNALED;
487 	lnk->wr_reg.wr.opcode = IB_WR_REG_MR;
488 	lnk->wr_reg.access = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE;
489 }
490 
491 void smc_wr_free_link(struct smc_link *lnk)
492 {
493 	struct ib_device *ibdev;
494 
495 	memset(lnk->wr_tx_mask, 0,
496 	       BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
497 
498 	if (!lnk->smcibdev)
499 		return;
500 	ibdev = lnk->smcibdev->ibdev;
501 
502 	if (lnk->wr_rx_dma_addr) {
503 		ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
504 				    SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
505 				    DMA_FROM_DEVICE);
506 		lnk->wr_rx_dma_addr = 0;
507 	}
508 	if (lnk->wr_tx_dma_addr) {
509 		ib_dma_unmap_single(ibdev, lnk->wr_tx_dma_addr,
510 				    SMC_WR_BUF_SIZE * lnk->wr_tx_cnt,
511 				    DMA_TO_DEVICE);
512 		lnk->wr_tx_dma_addr = 0;
513 	}
514 }
515 
516 void smc_wr_free_link_mem(struct smc_link *lnk)
517 {
518 	kfree(lnk->wr_tx_pends);
519 	lnk->wr_tx_pends = NULL;
520 	kfree(lnk->wr_tx_mask);
521 	lnk->wr_tx_mask = NULL;
522 	kfree(lnk->wr_tx_sges);
523 	lnk->wr_tx_sges = NULL;
524 	kfree(lnk->wr_rx_sges);
525 	lnk->wr_rx_sges = NULL;
526 	kfree(lnk->wr_rx_ibs);
527 	lnk->wr_rx_ibs = NULL;
528 	kfree(lnk->wr_tx_ibs);
529 	lnk->wr_tx_ibs = NULL;
530 	kfree(lnk->wr_tx_bufs);
531 	lnk->wr_tx_bufs = NULL;
532 	kfree(lnk->wr_rx_bufs);
533 	lnk->wr_rx_bufs = NULL;
534 }
535 
536 int smc_wr_alloc_link_mem(struct smc_link *link)
537 {
538 	/* allocate link related memory */
539 	link->wr_tx_bufs = kcalloc(SMC_WR_BUF_CNT, SMC_WR_BUF_SIZE, GFP_KERNEL);
540 	if (!link->wr_tx_bufs)
541 		goto no_mem;
542 	link->wr_rx_bufs = kcalloc(SMC_WR_BUF_CNT * 3, SMC_WR_BUF_SIZE,
543 				   GFP_KERNEL);
544 	if (!link->wr_rx_bufs)
545 		goto no_mem_wr_tx_bufs;
546 	link->wr_tx_ibs = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_ibs[0]),
547 				  GFP_KERNEL);
548 	if (!link->wr_tx_ibs)
549 		goto no_mem_wr_rx_bufs;
550 	link->wr_rx_ibs = kcalloc(SMC_WR_BUF_CNT * 3,
551 				  sizeof(link->wr_rx_ibs[0]),
552 				  GFP_KERNEL);
553 	if (!link->wr_rx_ibs)
554 		goto no_mem_wr_tx_ibs;
555 	link->wr_tx_sges = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_sges[0]),
556 				   GFP_KERNEL);
557 	if (!link->wr_tx_sges)
558 		goto no_mem_wr_rx_ibs;
559 	link->wr_rx_sges = kcalloc(SMC_WR_BUF_CNT * 3,
560 				   sizeof(link->wr_rx_sges[0]),
561 				   GFP_KERNEL);
562 	if (!link->wr_rx_sges)
563 		goto no_mem_wr_tx_sges;
564 	link->wr_tx_mask = kcalloc(BITS_TO_LONGS(SMC_WR_BUF_CNT),
565 				   sizeof(*link->wr_tx_mask),
566 				   GFP_KERNEL);
567 	if (!link->wr_tx_mask)
568 		goto no_mem_wr_rx_sges;
569 	link->wr_tx_pends = kcalloc(SMC_WR_BUF_CNT,
570 				    sizeof(link->wr_tx_pends[0]),
571 				    GFP_KERNEL);
572 	if (!link->wr_tx_pends)
573 		goto no_mem_wr_tx_mask;
574 	return 0;
575 
576 no_mem_wr_tx_mask:
577 	kfree(link->wr_tx_mask);
578 no_mem_wr_rx_sges:
579 	kfree(link->wr_rx_sges);
580 no_mem_wr_tx_sges:
581 	kfree(link->wr_tx_sges);
582 no_mem_wr_rx_ibs:
583 	kfree(link->wr_rx_ibs);
584 no_mem_wr_tx_ibs:
585 	kfree(link->wr_tx_ibs);
586 no_mem_wr_rx_bufs:
587 	kfree(link->wr_rx_bufs);
588 no_mem_wr_tx_bufs:
589 	kfree(link->wr_tx_bufs);
590 no_mem:
591 	return -ENOMEM;
592 }
593 
594 void smc_wr_remove_dev(struct smc_ib_device *smcibdev)
595 {
596 	tasklet_kill(&smcibdev->recv_tasklet);
597 	tasklet_kill(&smcibdev->send_tasklet);
598 }
599 
600 void smc_wr_add_dev(struct smc_ib_device *smcibdev)
601 {
602 	tasklet_init(&smcibdev->recv_tasklet, smc_wr_rx_tasklet_fn,
603 		     (unsigned long)smcibdev);
604 	tasklet_init(&smcibdev->send_tasklet, smc_wr_tx_tasklet_fn,
605 		     (unsigned long)smcibdev);
606 }
607 
608 int smc_wr_create_link(struct smc_link *lnk)
609 {
610 	struct ib_device *ibdev = lnk->smcibdev->ibdev;
611 	int rc = 0;
612 
613 	smc_wr_tx_set_wr_id(&lnk->wr_tx_id, 0);
614 	lnk->wr_rx_id = 0;
615 	lnk->wr_rx_dma_addr = ib_dma_map_single(
616 		ibdev, lnk->wr_rx_bufs,	SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
617 		DMA_FROM_DEVICE);
618 	if (ib_dma_mapping_error(ibdev, lnk->wr_rx_dma_addr)) {
619 		lnk->wr_rx_dma_addr = 0;
620 		rc = -EIO;
621 		goto out;
622 	}
623 	lnk->wr_tx_dma_addr = ib_dma_map_single(
624 		ibdev, lnk->wr_tx_bufs,	SMC_WR_BUF_SIZE * lnk->wr_tx_cnt,
625 		DMA_TO_DEVICE);
626 	if (ib_dma_mapping_error(ibdev, lnk->wr_tx_dma_addr)) {
627 		rc = -EIO;
628 		goto dma_unmap;
629 	}
630 	smc_wr_init_sge(lnk);
631 	memset(lnk->wr_tx_mask, 0,
632 	       BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
633 	init_waitqueue_head(&lnk->wr_tx_wait);
634 	init_waitqueue_head(&lnk->wr_reg_wait);
635 	return rc;
636 
637 dma_unmap:
638 	ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
639 			    SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
640 			    DMA_FROM_DEVICE);
641 	lnk->wr_rx_dma_addr = 0;
642 out:
643 	return rc;
644 }
645