xref: /openbmc/linux/net/smc/smc_wr.c (revision 09c434b8)
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_rdma_buf:	Out value returns pointer to rdma work request.
164  * @wr_pend_priv:	Out value returns pointer serving as handler context.
165  *
166  * Return: 0 on success, or -errno on error.
167  */
168 int smc_wr_tx_get_free_slot(struct smc_link *link,
169 			    smc_wr_tx_handler handler,
170 			    struct smc_wr_buf **wr_buf,
171 			    struct smc_rdma_wr **wr_rdma_buf,
172 			    struct smc_wr_tx_pend_priv **wr_pend_priv)
173 {
174 	struct smc_wr_tx_pend *wr_pend;
175 	u32 idx = link->wr_tx_cnt;
176 	struct ib_send_wr *wr_ib;
177 	u64 wr_id;
178 	int rc;
179 
180 	*wr_buf = NULL;
181 	*wr_pend_priv = NULL;
182 	if (in_softirq()) {
183 		rc = smc_wr_tx_get_free_slot_index(link, &idx);
184 		if (rc)
185 			return rc;
186 	} else {
187 		rc = wait_event_timeout(
188 			link->wr_tx_wait,
189 			link->state == SMC_LNK_INACTIVE ||
190 			(smc_wr_tx_get_free_slot_index(link, &idx) != -EBUSY),
191 			SMC_WR_TX_WAIT_FREE_SLOT_TIME);
192 		if (!rc) {
193 			/* timeout - terminate connections */
194 			smc_lgr_terminate(smc_get_lgr(link));
195 			return -EPIPE;
196 		}
197 		if (idx == link->wr_tx_cnt)
198 			return -EPIPE;
199 	}
200 	wr_id = smc_wr_tx_get_next_wr_id(link);
201 	wr_pend = &link->wr_tx_pends[idx];
202 	wr_pend->wr_id = wr_id;
203 	wr_pend->handler = handler;
204 	wr_pend->link = link;
205 	wr_pend->idx = idx;
206 	wr_ib = &link->wr_tx_ibs[idx];
207 	wr_ib->wr_id = wr_id;
208 	*wr_buf = &link->wr_tx_bufs[idx];
209 	if (wr_rdma_buf)
210 		*wr_rdma_buf = &link->wr_tx_rdmas[idx];
211 	*wr_pend_priv = &wr_pend->priv;
212 	return 0;
213 }
214 
215 int smc_wr_tx_put_slot(struct smc_link *link,
216 		       struct smc_wr_tx_pend_priv *wr_pend_priv)
217 {
218 	struct smc_wr_tx_pend *pend;
219 
220 	pend = container_of(wr_pend_priv, struct smc_wr_tx_pend, priv);
221 	if (pend->idx < link->wr_tx_cnt) {
222 		u32 idx = pend->idx;
223 
224 		/* clear the full struct smc_wr_tx_pend including .priv */
225 		memset(&link->wr_tx_pends[idx], 0,
226 		       sizeof(link->wr_tx_pends[idx]));
227 		memset(&link->wr_tx_bufs[idx], 0,
228 		       sizeof(link->wr_tx_bufs[idx]));
229 		test_and_clear_bit(idx, link->wr_tx_mask);
230 		return 1;
231 	}
232 
233 	return 0;
234 }
235 
236 /* Send prepared WR slot via ib_post_send.
237  * @priv: pointer to smc_wr_tx_pend_priv identifying prepared message buffer
238  */
239 int smc_wr_tx_send(struct smc_link *link, struct smc_wr_tx_pend_priv *priv)
240 {
241 	struct smc_wr_tx_pend *pend;
242 	int rc;
243 
244 	ib_req_notify_cq(link->smcibdev->roce_cq_send,
245 			 IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
246 	pend = container_of(priv, struct smc_wr_tx_pend, priv);
247 	rc = ib_post_send(link->roce_qp, &link->wr_tx_ibs[pend->idx], NULL);
248 	if (rc) {
249 		smc_wr_tx_put_slot(link, priv);
250 		smc_lgr_terminate(smc_get_lgr(link));
251 	}
252 	return rc;
253 }
254 
255 /* Register a memory region and wait for result. */
256 int smc_wr_reg_send(struct smc_link *link, struct ib_mr *mr)
257 {
258 	int rc;
259 
260 	ib_req_notify_cq(link->smcibdev->roce_cq_send,
261 			 IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS);
262 	link->wr_reg_state = POSTED;
263 	link->wr_reg.wr.wr_id = (u64)(uintptr_t)mr;
264 	link->wr_reg.mr = mr;
265 	link->wr_reg.key = mr->rkey;
266 	rc = ib_post_send(link->roce_qp, &link->wr_reg.wr, NULL);
267 	if (rc)
268 		return rc;
269 
270 	rc = wait_event_interruptible_timeout(link->wr_reg_wait,
271 					      (link->wr_reg_state != POSTED),
272 					      SMC_WR_REG_MR_WAIT_TIME);
273 	if (!rc) {
274 		/* timeout - terminate connections */
275 		smc_lgr_terminate(smc_get_lgr(link));
276 		return -EPIPE;
277 	}
278 	if (rc == -ERESTARTSYS)
279 		return -EINTR;
280 	switch (link->wr_reg_state) {
281 	case CONFIRMED:
282 		rc = 0;
283 		break;
284 	case FAILED:
285 		rc = -EIO;
286 		break;
287 	case POSTED:
288 		rc = -EPIPE;
289 		break;
290 	}
291 	return rc;
292 }
293 
294 void smc_wr_tx_dismiss_slots(struct smc_link *link, u8 wr_tx_hdr_type,
295 			     smc_wr_tx_filter filter,
296 			     smc_wr_tx_dismisser dismisser,
297 			     unsigned long data)
298 {
299 	struct smc_wr_tx_pend_priv *tx_pend;
300 	struct smc_wr_rx_hdr *wr_tx;
301 	int i;
302 
303 	for_each_set_bit(i, link->wr_tx_mask, link->wr_tx_cnt) {
304 		wr_tx = (struct smc_wr_rx_hdr *)&link->wr_tx_bufs[i];
305 		if (wr_tx->type != wr_tx_hdr_type)
306 			continue;
307 		tx_pend = &link->wr_tx_pends[i].priv;
308 		if (filter(tx_pend, data))
309 			dismisser(tx_pend);
310 	}
311 }
312 
313 /****************************** receive queue ********************************/
314 
315 int smc_wr_rx_register_handler(struct smc_wr_rx_handler *handler)
316 {
317 	struct smc_wr_rx_handler *h_iter;
318 	int rc = 0;
319 
320 	spin_lock(&smc_wr_rx_hash_lock);
321 	hash_for_each_possible(smc_wr_rx_hash, h_iter, list, handler->type) {
322 		if (h_iter->type == handler->type) {
323 			rc = -EEXIST;
324 			goto out_unlock;
325 		}
326 	}
327 	hash_add(smc_wr_rx_hash, &handler->list, handler->type);
328 out_unlock:
329 	spin_unlock(&smc_wr_rx_hash_lock);
330 	return rc;
331 }
332 
333 /* Demultiplex a received work request based on the message type to its handler.
334  * Relies on smc_wr_rx_hash having been completely filled before any IB WRs,
335  * and not being modified any more afterwards so we don't need to lock it.
336  */
337 static inline void smc_wr_rx_demultiplex(struct ib_wc *wc)
338 {
339 	struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
340 	struct smc_wr_rx_handler *handler;
341 	struct smc_wr_rx_hdr *wr_rx;
342 	u64 temp_wr_id;
343 	u32 index;
344 
345 	if (wc->byte_len < sizeof(*wr_rx))
346 		return; /* short message */
347 	temp_wr_id = wc->wr_id;
348 	index = do_div(temp_wr_id, link->wr_rx_cnt);
349 	wr_rx = (struct smc_wr_rx_hdr *)&link->wr_rx_bufs[index];
350 	hash_for_each_possible(smc_wr_rx_hash, handler, list, wr_rx->type) {
351 		if (handler->type == wr_rx->type)
352 			handler->handler(wc, wr_rx);
353 	}
354 }
355 
356 static inline void smc_wr_rx_process_cqes(struct ib_wc wc[], int num)
357 {
358 	struct smc_link *link;
359 	int i;
360 
361 	for (i = 0; i < num; i++) {
362 		link = wc[i].qp->qp_context;
363 		if (wc[i].status == IB_WC_SUCCESS) {
364 			link->wr_rx_tstamp = jiffies;
365 			smc_wr_rx_demultiplex(&wc[i]);
366 			smc_wr_rx_post(link); /* refill WR RX */
367 		} else {
368 			/* handle status errors */
369 			switch (wc[i].status) {
370 			case IB_WC_RETRY_EXC_ERR:
371 			case IB_WC_RNR_RETRY_EXC_ERR:
372 			case IB_WC_WR_FLUSH_ERR:
373 				/* terminate connections of this link group
374 				 * abnormally
375 				 */
376 				smc_lgr_terminate(smc_get_lgr(link));
377 				break;
378 			default:
379 				smc_wr_rx_post(link); /* refill WR RX */
380 				break;
381 			}
382 		}
383 	}
384 }
385 
386 static void smc_wr_rx_tasklet_fn(unsigned long data)
387 {
388 	struct smc_ib_device *dev = (struct smc_ib_device *)data;
389 	struct ib_wc wc[SMC_WR_MAX_POLL_CQE];
390 	int polled = 0;
391 	int rc;
392 
393 again:
394 	polled++;
395 	do {
396 		memset(&wc, 0, sizeof(wc));
397 		rc = ib_poll_cq(dev->roce_cq_recv, SMC_WR_MAX_POLL_CQE, wc);
398 		if (polled == 1) {
399 			ib_req_notify_cq(dev->roce_cq_recv,
400 					 IB_CQ_SOLICITED_MASK
401 					 | IB_CQ_REPORT_MISSED_EVENTS);
402 		}
403 		if (!rc)
404 			break;
405 		smc_wr_rx_process_cqes(&wc[0], rc);
406 	} while (rc > 0);
407 	if (polled == 1)
408 		goto again;
409 }
410 
411 void smc_wr_rx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
412 {
413 	struct smc_ib_device *dev = (struct smc_ib_device *)cq_context;
414 
415 	tasklet_schedule(&dev->recv_tasklet);
416 }
417 
418 int smc_wr_rx_post_init(struct smc_link *link)
419 {
420 	u32 i;
421 	int rc = 0;
422 
423 	for (i = 0; i < link->wr_rx_cnt; i++)
424 		rc = smc_wr_rx_post(link);
425 	return rc;
426 }
427 
428 /***************************** init, exit, misc ******************************/
429 
430 void smc_wr_remember_qp_attr(struct smc_link *lnk)
431 {
432 	struct ib_qp_attr *attr = &lnk->qp_attr;
433 	struct ib_qp_init_attr init_attr;
434 
435 	memset(attr, 0, sizeof(*attr));
436 	memset(&init_attr, 0, sizeof(init_attr));
437 	ib_query_qp(lnk->roce_qp, attr,
438 		    IB_QP_STATE |
439 		    IB_QP_CUR_STATE |
440 		    IB_QP_PKEY_INDEX |
441 		    IB_QP_PORT |
442 		    IB_QP_QKEY |
443 		    IB_QP_AV |
444 		    IB_QP_PATH_MTU |
445 		    IB_QP_TIMEOUT |
446 		    IB_QP_RETRY_CNT |
447 		    IB_QP_RNR_RETRY |
448 		    IB_QP_RQ_PSN |
449 		    IB_QP_ALT_PATH |
450 		    IB_QP_MIN_RNR_TIMER |
451 		    IB_QP_SQ_PSN |
452 		    IB_QP_PATH_MIG_STATE |
453 		    IB_QP_CAP |
454 		    IB_QP_DEST_QPN,
455 		    &init_attr);
456 
457 	lnk->wr_tx_cnt = min_t(size_t, SMC_WR_BUF_CNT,
458 			       lnk->qp_attr.cap.max_send_wr);
459 	lnk->wr_rx_cnt = min_t(size_t, SMC_WR_BUF_CNT * 3,
460 			       lnk->qp_attr.cap.max_recv_wr);
461 }
462 
463 static void smc_wr_init_sge(struct smc_link *lnk)
464 {
465 	u32 i;
466 
467 	for (i = 0; i < lnk->wr_tx_cnt; i++) {
468 		lnk->wr_tx_sges[i].addr =
469 			lnk->wr_tx_dma_addr + i * SMC_WR_BUF_SIZE;
470 		lnk->wr_tx_sges[i].length = SMC_WR_TX_SIZE;
471 		lnk->wr_tx_sges[i].lkey = lnk->roce_pd->local_dma_lkey;
472 		lnk->wr_tx_rdma_sges[i].tx_rdma_sge[0].wr_tx_rdma_sge[0].lkey =
473 			lnk->roce_pd->local_dma_lkey;
474 		lnk->wr_tx_rdma_sges[i].tx_rdma_sge[0].wr_tx_rdma_sge[1].lkey =
475 			lnk->roce_pd->local_dma_lkey;
476 		lnk->wr_tx_rdma_sges[i].tx_rdma_sge[1].wr_tx_rdma_sge[0].lkey =
477 			lnk->roce_pd->local_dma_lkey;
478 		lnk->wr_tx_rdma_sges[i].tx_rdma_sge[1].wr_tx_rdma_sge[1].lkey =
479 			lnk->roce_pd->local_dma_lkey;
480 		lnk->wr_tx_ibs[i].next = NULL;
481 		lnk->wr_tx_ibs[i].sg_list = &lnk->wr_tx_sges[i];
482 		lnk->wr_tx_ibs[i].num_sge = 1;
483 		lnk->wr_tx_ibs[i].opcode = IB_WR_SEND;
484 		lnk->wr_tx_ibs[i].send_flags =
485 			IB_SEND_SIGNALED | IB_SEND_SOLICITED;
486 		lnk->wr_tx_rdmas[i].wr_tx_rdma[0].wr.opcode = IB_WR_RDMA_WRITE;
487 		lnk->wr_tx_rdmas[i].wr_tx_rdma[1].wr.opcode = IB_WR_RDMA_WRITE;
488 		lnk->wr_tx_rdmas[i].wr_tx_rdma[0].wr.sg_list =
489 			lnk->wr_tx_rdma_sges[i].tx_rdma_sge[0].wr_tx_rdma_sge;
490 		lnk->wr_tx_rdmas[i].wr_tx_rdma[1].wr.sg_list =
491 			lnk->wr_tx_rdma_sges[i].tx_rdma_sge[1].wr_tx_rdma_sge;
492 	}
493 	for (i = 0; i < lnk->wr_rx_cnt; i++) {
494 		lnk->wr_rx_sges[i].addr =
495 			lnk->wr_rx_dma_addr + i * SMC_WR_BUF_SIZE;
496 		lnk->wr_rx_sges[i].length = SMC_WR_BUF_SIZE;
497 		lnk->wr_rx_sges[i].lkey = lnk->roce_pd->local_dma_lkey;
498 		lnk->wr_rx_ibs[i].next = NULL;
499 		lnk->wr_rx_ibs[i].sg_list = &lnk->wr_rx_sges[i];
500 		lnk->wr_rx_ibs[i].num_sge = 1;
501 	}
502 	lnk->wr_reg.wr.next = NULL;
503 	lnk->wr_reg.wr.num_sge = 0;
504 	lnk->wr_reg.wr.send_flags = IB_SEND_SIGNALED;
505 	lnk->wr_reg.wr.opcode = IB_WR_REG_MR;
506 	lnk->wr_reg.access = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE;
507 }
508 
509 void smc_wr_free_link(struct smc_link *lnk)
510 {
511 	struct ib_device *ibdev;
512 
513 	memset(lnk->wr_tx_mask, 0,
514 	       BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
515 
516 	if (!lnk->smcibdev)
517 		return;
518 	ibdev = lnk->smcibdev->ibdev;
519 
520 	if (lnk->wr_rx_dma_addr) {
521 		ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
522 				    SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
523 				    DMA_FROM_DEVICE);
524 		lnk->wr_rx_dma_addr = 0;
525 	}
526 	if (lnk->wr_tx_dma_addr) {
527 		ib_dma_unmap_single(ibdev, lnk->wr_tx_dma_addr,
528 				    SMC_WR_BUF_SIZE * lnk->wr_tx_cnt,
529 				    DMA_TO_DEVICE);
530 		lnk->wr_tx_dma_addr = 0;
531 	}
532 }
533 
534 void smc_wr_free_link_mem(struct smc_link *lnk)
535 {
536 	kfree(lnk->wr_tx_pends);
537 	lnk->wr_tx_pends = NULL;
538 	kfree(lnk->wr_tx_mask);
539 	lnk->wr_tx_mask = NULL;
540 	kfree(lnk->wr_tx_sges);
541 	lnk->wr_tx_sges = NULL;
542 	kfree(lnk->wr_tx_rdma_sges);
543 	lnk->wr_tx_rdma_sges = NULL;
544 	kfree(lnk->wr_rx_sges);
545 	lnk->wr_rx_sges = NULL;
546 	kfree(lnk->wr_tx_rdmas);
547 	lnk->wr_tx_rdmas = NULL;
548 	kfree(lnk->wr_rx_ibs);
549 	lnk->wr_rx_ibs = NULL;
550 	kfree(lnk->wr_tx_ibs);
551 	lnk->wr_tx_ibs = NULL;
552 	kfree(lnk->wr_tx_bufs);
553 	lnk->wr_tx_bufs = NULL;
554 	kfree(lnk->wr_rx_bufs);
555 	lnk->wr_rx_bufs = NULL;
556 }
557 
558 int smc_wr_alloc_link_mem(struct smc_link *link)
559 {
560 	/* allocate link related memory */
561 	link->wr_tx_bufs = kcalloc(SMC_WR_BUF_CNT, SMC_WR_BUF_SIZE, GFP_KERNEL);
562 	if (!link->wr_tx_bufs)
563 		goto no_mem;
564 	link->wr_rx_bufs = kcalloc(SMC_WR_BUF_CNT * 3, SMC_WR_BUF_SIZE,
565 				   GFP_KERNEL);
566 	if (!link->wr_rx_bufs)
567 		goto no_mem_wr_tx_bufs;
568 	link->wr_tx_ibs = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_ibs[0]),
569 				  GFP_KERNEL);
570 	if (!link->wr_tx_ibs)
571 		goto no_mem_wr_rx_bufs;
572 	link->wr_rx_ibs = kcalloc(SMC_WR_BUF_CNT * 3,
573 				  sizeof(link->wr_rx_ibs[0]),
574 				  GFP_KERNEL);
575 	if (!link->wr_rx_ibs)
576 		goto no_mem_wr_tx_ibs;
577 	link->wr_tx_rdmas = kcalloc(SMC_WR_BUF_CNT,
578 				    sizeof(link->wr_tx_rdmas[0]),
579 				    GFP_KERNEL);
580 	if (!link->wr_tx_rdmas)
581 		goto no_mem_wr_rx_ibs;
582 	link->wr_tx_rdma_sges = kcalloc(SMC_WR_BUF_CNT,
583 					sizeof(link->wr_tx_rdma_sges[0]),
584 					GFP_KERNEL);
585 	if (!link->wr_tx_rdma_sges)
586 		goto no_mem_wr_tx_rdmas;
587 	link->wr_tx_sges = kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_sges[0]),
588 				   GFP_KERNEL);
589 	if (!link->wr_tx_sges)
590 		goto no_mem_wr_tx_rdma_sges;
591 	link->wr_rx_sges = kcalloc(SMC_WR_BUF_CNT * 3,
592 				   sizeof(link->wr_rx_sges[0]),
593 				   GFP_KERNEL);
594 	if (!link->wr_rx_sges)
595 		goto no_mem_wr_tx_sges;
596 	link->wr_tx_mask = kcalloc(BITS_TO_LONGS(SMC_WR_BUF_CNT),
597 				   sizeof(*link->wr_tx_mask),
598 				   GFP_KERNEL);
599 	if (!link->wr_tx_mask)
600 		goto no_mem_wr_rx_sges;
601 	link->wr_tx_pends = kcalloc(SMC_WR_BUF_CNT,
602 				    sizeof(link->wr_tx_pends[0]),
603 				    GFP_KERNEL);
604 	if (!link->wr_tx_pends)
605 		goto no_mem_wr_tx_mask;
606 	return 0;
607 
608 no_mem_wr_tx_mask:
609 	kfree(link->wr_tx_mask);
610 no_mem_wr_rx_sges:
611 	kfree(link->wr_rx_sges);
612 no_mem_wr_tx_sges:
613 	kfree(link->wr_tx_sges);
614 no_mem_wr_tx_rdma_sges:
615 	kfree(link->wr_tx_rdma_sges);
616 no_mem_wr_tx_rdmas:
617 	kfree(link->wr_tx_rdmas);
618 no_mem_wr_rx_ibs:
619 	kfree(link->wr_rx_ibs);
620 no_mem_wr_tx_ibs:
621 	kfree(link->wr_tx_ibs);
622 no_mem_wr_rx_bufs:
623 	kfree(link->wr_rx_bufs);
624 no_mem_wr_tx_bufs:
625 	kfree(link->wr_tx_bufs);
626 no_mem:
627 	return -ENOMEM;
628 }
629 
630 void smc_wr_remove_dev(struct smc_ib_device *smcibdev)
631 {
632 	tasklet_kill(&smcibdev->recv_tasklet);
633 	tasklet_kill(&smcibdev->send_tasklet);
634 }
635 
636 void smc_wr_add_dev(struct smc_ib_device *smcibdev)
637 {
638 	tasklet_init(&smcibdev->recv_tasklet, smc_wr_rx_tasklet_fn,
639 		     (unsigned long)smcibdev);
640 	tasklet_init(&smcibdev->send_tasklet, smc_wr_tx_tasklet_fn,
641 		     (unsigned long)smcibdev);
642 }
643 
644 int smc_wr_create_link(struct smc_link *lnk)
645 {
646 	struct ib_device *ibdev = lnk->smcibdev->ibdev;
647 	int rc = 0;
648 
649 	smc_wr_tx_set_wr_id(&lnk->wr_tx_id, 0);
650 	lnk->wr_rx_id = 0;
651 	lnk->wr_rx_dma_addr = ib_dma_map_single(
652 		ibdev, lnk->wr_rx_bufs,	SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
653 		DMA_FROM_DEVICE);
654 	if (ib_dma_mapping_error(ibdev, lnk->wr_rx_dma_addr)) {
655 		lnk->wr_rx_dma_addr = 0;
656 		rc = -EIO;
657 		goto out;
658 	}
659 	lnk->wr_tx_dma_addr = ib_dma_map_single(
660 		ibdev, lnk->wr_tx_bufs,	SMC_WR_BUF_SIZE * lnk->wr_tx_cnt,
661 		DMA_TO_DEVICE);
662 	if (ib_dma_mapping_error(ibdev, lnk->wr_tx_dma_addr)) {
663 		rc = -EIO;
664 		goto dma_unmap;
665 	}
666 	smc_wr_init_sge(lnk);
667 	memset(lnk->wr_tx_mask, 0,
668 	       BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
669 	init_waitqueue_head(&lnk->wr_tx_wait);
670 	init_waitqueue_head(&lnk->wr_reg_wait);
671 	return rc;
672 
673 dma_unmap:
674 	ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
675 			    SMC_WR_BUF_SIZE * lnk->wr_rx_cnt,
676 			    DMA_FROM_DEVICE);
677 	lnk->wr_rx_dma_addr = 0;
678 out:
679 	return rc;
680 }
681