xref: /linux/drivers/infiniband/hw/mthca/mthca_srq.c (revision de2fe5e07d58424bc286fff3fd3c1b0bf933cd58)
1 /*
2  * Copyright (c) 2005 Cisco Systems. All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *      - Redistributions of source code must retain the above
15  *        copyright notice, this list of conditions and the following
16  *        disclaimer.
17  *
18  *      - Redistributions in binary form must reproduce the above
19  *        copyright notice, this list of conditions and the following
20  *        disclaimer in the documentation and/or other materials
21  *        provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  *
32  * $Id: mthca_srq.c 3047 2005-08-10 03:59:35Z roland $
33  */
34 
35 #include <linux/slab.h>
36 #include <linux/string.h>
37 
38 #include "mthca_dev.h"
39 #include "mthca_cmd.h"
40 #include "mthca_memfree.h"
41 #include "mthca_wqe.h"
42 
43 enum {
44 	MTHCA_MAX_DIRECT_SRQ_SIZE = 4 * PAGE_SIZE
45 };
46 
47 struct mthca_tavor_srq_context {
48 	__be64 wqe_base_ds;	/* low 6 bits is descriptor size */
49 	__be32 state_pd;
50 	__be32 lkey;
51 	__be32 uar;
52 	__be16 limit_watermark;
53 	__be16 wqe_cnt;
54 	u32    reserved[2];
55 };
56 
57 struct mthca_arbel_srq_context {
58 	__be32 state_logsize_srqn;
59 	__be32 lkey;
60 	__be32 db_index;
61 	__be32 logstride_usrpage;
62 	__be64 wqe_base;
63 	__be32 eq_pd;
64 	__be16 limit_watermark;
65 	__be16 wqe_cnt;
66 	u16    reserved1;
67 	__be16 wqe_counter;
68 	u32    reserved2[3];
69 };
70 
71 static void *get_wqe(struct mthca_srq *srq, int n)
72 {
73 	if (srq->is_direct)
74 		return srq->queue.direct.buf + (n << srq->wqe_shift);
75 	else
76 		return srq->queue.page_list[(n << srq->wqe_shift) >> PAGE_SHIFT].buf +
77 			((n << srq->wqe_shift) & (PAGE_SIZE - 1));
78 }
79 
80 /*
81  * Return a pointer to the location within a WQE that we're using as a
82  * link when the WQE is in the free list.  We use the imm field
83  * because in the Tavor case, posting a WQE may overwrite the next
84  * segment of the previous WQE, but a receive WQE will never touch the
85  * imm field.  This avoids corrupting our free list if the previous
86  * WQE has already completed and been put on the free list when we
87  * post the next WQE.
88  */
89 static inline int *wqe_to_link(void *wqe)
90 {
91 	return (int *) (wqe + offsetof(struct mthca_next_seg, imm));
92 }
93 
94 static void mthca_tavor_init_srq_context(struct mthca_dev *dev,
95 					 struct mthca_pd *pd,
96 					 struct mthca_srq *srq,
97 					 struct mthca_tavor_srq_context *context)
98 {
99 	memset(context, 0, sizeof *context);
100 
101 	context->wqe_base_ds = cpu_to_be64(1 << (srq->wqe_shift - 4));
102 	context->state_pd    = cpu_to_be32(pd->pd_num);
103 	context->lkey        = cpu_to_be32(srq->mr.ibmr.lkey);
104 
105 	if (pd->ibpd.uobject)
106 		context->uar =
107 			cpu_to_be32(to_mucontext(pd->ibpd.uobject->context)->uar.index);
108 	else
109 		context->uar = cpu_to_be32(dev->driver_uar.index);
110 }
111 
112 static void mthca_arbel_init_srq_context(struct mthca_dev *dev,
113 					 struct mthca_pd *pd,
114 					 struct mthca_srq *srq,
115 					 struct mthca_arbel_srq_context *context)
116 {
117 	int logsize;
118 
119 	memset(context, 0, sizeof *context);
120 
121 	logsize = long_log2(srq->max) + srq->wqe_shift;
122 	context->state_logsize_srqn = cpu_to_be32(logsize << 24 | srq->srqn);
123 	context->lkey = cpu_to_be32(srq->mr.ibmr.lkey);
124 	context->db_index = cpu_to_be32(srq->db_index);
125 	context->logstride_usrpage = cpu_to_be32((srq->wqe_shift - 4) << 29);
126 	if (pd->ibpd.uobject)
127 		context->logstride_usrpage |=
128 			cpu_to_be32(to_mucontext(pd->ibpd.uobject->context)->uar.index);
129 	else
130 		context->logstride_usrpage |= cpu_to_be32(dev->driver_uar.index);
131 	context->eq_pd = cpu_to_be32(MTHCA_EQ_ASYNC << 24 | pd->pd_num);
132 }
133 
134 static void mthca_free_srq_buf(struct mthca_dev *dev, struct mthca_srq *srq)
135 {
136 	mthca_buf_free(dev, srq->max << srq->wqe_shift, &srq->queue,
137 		       srq->is_direct, &srq->mr);
138 	kfree(srq->wrid);
139 }
140 
141 static int mthca_alloc_srq_buf(struct mthca_dev *dev, struct mthca_pd *pd,
142 			       struct mthca_srq *srq)
143 {
144 	struct mthca_data_seg *scatter;
145 	void *wqe;
146 	int err;
147 	int i;
148 
149 	if (pd->ibpd.uobject)
150 		return 0;
151 
152 	srq->wrid = kmalloc(srq->max * sizeof (u64), GFP_KERNEL);
153 	if (!srq->wrid)
154 		return -ENOMEM;
155 
156 	err = mthca_buf_alloc(dev, srq->max << srq->wqe_shift,
157 			      MTHCA_MAX_DIRECT_SRQ_SIZE,
158 			      &srq->queue, &srq->is_direct, pd, 1, &srq->mr);
159 	if (err) {
160 		kfree(srq->wrid);
161 		return err;
162 	}
163 
164 	/*
165 	 * Now initialize the SRQ buffer so that all of the WQEs are
166 	 * linked into the list of free WQEs.  In addition, set the
167 	 * scatter list L_Keys to the sentry value of 0x100.
168 	 */
169 	for (i = 0; i < srq->max; ++i) {
170 		wqe = get_wqe(srq, i);
171 
172 		*wqe_to_link(wqe) = i < srq->max - 1 ? i + 1 : -1;
173 
174 		for (scatter = wqe + sizeof (struct mthca_next_seg);
175 		     (void *) scatter < wqe + (1 << srq->wqe_shift);
176 		     ++scatter)
177 			scatter->lkey = cpu_to_be32(MTHCA_INVAL_LKEY);
178 	}
179 
180 	srq->last = get_wqe(srq, srq->max - 1);
181 
182 	return 0;
183 }
184 
185 int mthca_alloc_srq(struct mthca_dev *dev, struct mthca_pd *pd,
186 		    struct ib_srq_attr *attr, struct mthca_srq *srq)
187 {
188 	struct mthca_mailbox *mailbox;
189 	u8 status;
190 	int ds;
191 	int err;
192 
193 	/* Sanity check SRQ size before proceeding */
194 	if (attr->max_wr  > dev->limits.max_srq_wqes ||
195 	    attr->max_sge > dev->limits.max_sg)
196 		return -EINVAL;
197 
198 	srq->max      = attr->max_wr;
199 	srq->max_gs   = attr->max_sge;
200 	srq->counter  = 0;
201 
202 	if (mthca_is_memfree(dev))
203 		srq->max = roundup_pow_of_two(srq->max + 1);
204 
205 	ds = max(64UL,
206 		 roundup_pow_of_two(sizeof (struct mthca_next_seg) +
207 				    srq->max_gs * sizeof (struct mthca_data_seg)));
208 
209 	if (!mthca_is_memfree(dev) && (ds > dev->limits.max_desc_sz))
210 		return -EINVAL;
211 
212 	srq->wqe_shift = long_log2(ds);
213 
214 	srq->srqn = mthca_alloc(&dev->srq_table.alloc);
215 	if (srq->srqn == -1)
216 		return -ENOMEM;
217 
218 	if (mthca_is_memfree(dev)) {
219 		err = mthca_table_get(dev, dev->srq_table.table, srq->srqn);
220 		if (err)
221 			goto err_out;
222 
223 		if (!pd->ibpd.uobject) {
224 			srq->db_index = mthca_alloc_db(dev, MTHCA_DB_TYPE_SRQ,
225 						       srq->srqn, &srq->db);
226 			if (srq->db_index < 0) {
227 				err = -ENOMEM;
228 				goto err_out_icm;
229 			}
230 		}
231 	}
232 
233 	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
234 	if (IS_ERR(mailbox)) {
235 		err = PTR_ERR(mailbox);
236 		goto err_out_db;
237 	}
238 
239 	err = mthca_alloc_srq_buf(dev, pd, srq);
240 	if (err)
241 		goto err_out_mailbox;
242 
243 	spin_lock_init(&srq->lock);
244 	atomic_set(&srq->refcount, 1);
245 	init_waitqueue_head(&srq->wait);
246 
247 	if (mthca_is_memfree(dev))
248 		mthca_arbel_init_srq_context(dev, pd, srq, mailbox->buf);
249 	else
250 		mthca_tavor_init_srq_context(dev, pd, srq, mailbox->buf);
251 
252 	err = mthca_SW2HW_SRQ(dev, mailbox, srq->srqn, &status);
253 
254 	if (err) {
255 		mthca_warn(dev, "SW2HW_SRQ failed (%d)\n", err);
256 		goto err_out_free_buf;
257 	}
258 	if (status) {
259 		mthca_warn(dev, "SW2HW_SRQ returned status 0x%02x\n",
260 			   status);
261 		err = -EINVAL;
262 		goto err_out_free_buf;
263 	}
264 
265 	spin_lock_irq(&dev->srq_table.lock);
266 	if (mthca_array_set(&dev->srq_table.srq,
267 			    srq->srqn & (dev->limits.num_srqs - 1),
268 			    srq)) {
269 		spin_unlock_irq(&dev->srq_table.lock);
270 		goto err_out_free_srq;
271 	}
272 	spin_unlock_irq(&dev->srq_table.lock);
273 
274 	mthca_free_mailbox(dev, mailbox);
275 
276 	srq->first_free = 0;
277 	srq->last_free  = srq->max - 1;
278 
279 	attr->max_wr    = (mthca_is_memfree(dev)) ? srq->max - 1 : srq->max;
280 	attr->max_sge   = srq->max_gs;
281 
282 	return 0;
283 
284 err_out_free_srq:
285 	err = mthca_HW2SW_SRQ(dev, mailbox, srq->srqn, &status);
286 	if (err)
287 		mthca_warn(dev, "HW2SW_SRQ failed (%d)\n", err);
288 	else if (status)
289 		mthca_warn(dev, "HW2SW_SRQ returned status 0x%02x\n", status);
290 
291 err_out_free_buf:
292 	if (!pd->ibpd.uobject)
293 		mthca_free_srq_buf(dev, srq);
294 
295 err_out_mailbox:
296 	mthca_free_mailbox(dev, mailbox);
297 
298 err_out_db:
299 	if (!pd->ibpd.uobject && mthca_is_memfree(dev))
300 		mthca_free_db(dev, MTHCA_DB_TYPE_SRQ, srq->db_index);
301 
302 err_out_icm:
303 	mthca_table_put(dev, dev->srq_table.table, srq->srqn);
304 
305 err_out:
306 	mthca_free(&dev->srq_table.alloc, srq->srqn);
307 
308 	return err;
309 }
310 
311 void mthca_free_srq(struct mthca_dev *dev, struct mthca_srq *srq)
312 {
313 	struct mthca_mailbox *mailbox;
314 	int err;
315 	u8 status;
316 
317 	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
318 	if (IS_ERR(mailbox)) {
319 		mthca_warn(dev, "No memory for mailbox to free SRQ.\n");
320 		return;
321 	}
322 
323 	err = mthca_HW2SW_SRQ(dev, mailbox, srq->srqn, &status);
324 	if (err)
325 		mthca_warn(dev, "HW2SW_SRQ failed (%d)\n", err);
326 	else if (status)
327 		mthca_warn(dev, "HW2SW_SRQ returned status 0x%02x\n", status);
328 
329 	spin_lock_irq(&dev->srq_table.lock);
330 	mthca_array_clear(&dev->srq_table.srq,
331 			  srq->srqn & (dev->limits.num_srqs - 1));
332 	spin_unlock_irq(&dev->srq_table.lock);
333 
334 	atomic_dec(&srq->refcount);
335 	wait_event(srq->wait, !atomic_read(&srq->refcount));
336 
337 	if (!srq->ibsrq.uobject) {
338 		mthca_free_srq_buf(dev, srq);
339 		if (mthca_is_memfree(dev))
340 			mthca_free_db(dev, MTHCA_DB_TYPE_SRQ, srq->db_index);
341 	}
342 
343 	mthca_table_put(dev, dev->srq_table.table, srq->srqn);
344 	mthca_free(&dev->srq_table.alloc, srq->srqn);
345 	mthca_free_mailbox(dev, mailbox);
346 }
347 
348 int mthca_modify_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr,
349 		     enum ib_srq_attr_mask attr_mask)
350 {
351 	struct mthca_dev *dev = to_mdev(ibsrq->device);
352 	struct mthca_srq *srq = to_msrq(ibsrq);
353 	int ret;
354 	u8 status;
355 
356 	/* We don't support resizing SRQs (yet?) */
357 	if (attr_mask & IB_SRQ_MAX_WR)
358 		return -EINVAL;
359 
360 	if (attr_mask & IB_SRQ_LIMIT) {
361 		if (attr->srq_limit > srq->max)
362 			return -EINVAL;
363 		ret = mthca_ARM_SRQ(dev, srq->srqn, attr->srq_limit, &status);
364 		if (ret)
365 			return ret;
366 		if (status)
367 			return -EINVAL;
368 	}
369 
370 	return 0;
371 }
372 
373 int mthca_query_srq(struct ib_srq *ibsrq, struct ib_srq_attr *srq_attr)
374 {
375 	struct mthca_dev *dev = to_mdev(ibsrq->device);
376 	struct mthca_srq *srq = to_msrq(ibsrq);
377 	struct mthca_mailbox *mailbox;
378 	struct mthca_arbel_srq_context *arbel_ctx;
379 	struct mthca_tavor_srq_context *tavor_ctx;
380 	u8 status;
381 	int err;
382 
383 	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
384 	if (IS_ERR(mailbox))
385 		return PTR_ERR(mailbox);
386 
387 	err = mthca_QUERY_SRQ(dev, srq->srqn, mailbox, &status);
388 	if (err)
389 		goto out;
390 
391 	if (mthca_is_memfree(dev)) {
392 		arbel_ctx = mailbox->buf;
393 		srq_attr->srq_limit = be16_to_cpu(arbel_ctx->limit_watermark);
394 	} else {
395 		tavor_ctx = mailbox->buf;
396 		srq_attr->srq_limit = be16_to_cpu(tavor_ctx->limit_watermark);
397 	}
398 
399 	srq_attr->max_wr  = (mthca_is_memfree(dev)) ? srq->max - 1 : srq->max;
400 	srq_attr->max_sge = srq->max_gs;
401 
402 out:
403 	mthca_free_mailbox(dev, mailbox);
404 
405 	return err;
406 }
407 
408 void mthca_srq_event(struct mthca_dev *dev, u32 srqn,
409 		     enum ib_event_type event_type)
410 {
411 	struct mthca_srq *srq;
412 	struct ib_event event;
413 
414 	spin_lock(&dev->srq_table.lock);
415 	srq = mthca_array_get(&dev->srq_table.srq, srqn & (dev->limits.num_srqs - 1));
416 	if (srq)
417 		atomic_inc(&srq->refcount);
418 	spin_unlock(&dev->srq_table.lock);
419 
420 	if (!srq) {
421 		mthca_warn(dev, "Async event for bogus SRQ %08x\n", srqn);
422 		return;
423 	}
424 
425 	if (!srq->ibsrq.event_handler)
426 		goto out;
427 
428 	event.device      = &dev->ib_dev;
429 	event.event       = event_type;
430 	event.element.srq = &srq->ibsrq;
431 	srq->ibsrq.event_handler(&event, srq->ibsrq.srq_context);
432 
433 out:
434 	if (atomic_dec_and_test(&srq->refcount))
435 		wake_up(&srq->wait);
436 }
437 
438 /*
439  * This function must be called with IRQs disabled.
440  */
441 void mthca_free_srq_wqe(struct mthca_srq *srq, u32 wqe_addr)
442 {
443 	int ind;
444 
445 	ind = wqe_addr >> srq->wqe_shift;
446 
447 	spin_lock(&srq->lock);
448 
449 	if (likely(srq->first_free >= 0))
450 		*wqe_to_link(get_wqe(srq, srq->last_free)) = ind;
451 	else
452 		srq->first_free = ind;
453 
454 	*wqe_to_link(get_wqe(srq, ind)) = -1;
455 	srq->last_free = ind;
456 
457 	spin_unlock(&srq->lock);
458 }
459 
460 int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
461 			      struct ib_recv_wr **bad_wr)
462 {
463 	struct mthca_dev *dev = to_mdev(ibsrq->device);
464 	struct mthca_srq *srq = to_msrq(ibsrq);
465 	__be32 doorbell[2];
466 	unsigned long flags;
467 	int err = 0;
468 	int first_ind;
469 	int ind;
470 	int next_ind;
471 	int nreq;
472 	int i;
473 	void *wqe;
474 	void *prev_wqe;
475 
476 	spin_lock_irqsave(&srq->lock, flags);
477 
478 	first_ind = srq->first_free;
479 
480 	for (nreq = 0; wr; ++nreq, wr = wr->next) {
481 		if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) {
482 			nreq = 0;
483 
484 			doorbell[0] = cpu_to_be32(first_ind << srq->wqe_shift);
485 			doorbell[1] = cpu_to_be32(srq->srqn << 8);
486 
487 			/*
488 			 * Make sure that descriptors are written
489 			 * before doorbell is rung.
490 			 */
491 			wmb();
492 
493 			mthca_write64(doorbell,
494 				      dev->kar + MTHCA_RECEIVE_DOORBELL,
495 				      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
496 
497 			first_ind = srq->first_free;
498 		}
499 
500 		ind = srq->first_free;
501 
502 		if (ind < 0) {
503 			mthca_err(dev, "SRQ %06x full\n", srq->srqn);
504 			err = -ENOMEM;
505 			*bad_wr = wr;
506 			break;
507 		}
508 
509 		wqe       = get_wqe(srq, ind);
510 		next_ind  = *wqe_to_link(wqe);
511 
512 		if (next_ind < 0) {
513 			mthca_err(dev, "SRQ %06x full\n", srq->srqn);
514 			err = -ENOMEM;
515 			*bad_wr = wr;
516 			break;
517 		}
518 
519 		prev_wqe  = srq->last;
520 		srq->last = wqe;
521 
522 		((struct mthca_next_seg *) wqe)->nda_op = 0;
523 		((struct mthca_next_seg *) wqe)->ee_nds = 0;
524 		/* flags field will always remain 0 */
525 
526 		wqe += sizeof (struct mthca_next_seg);
527 
528 		if (unlikely(wr->num_sge > srq->max_gs)) {
529 			err = -EINVAL;
530 			*bad_wr = wr;
531 			srq->last = prev_wqe;
532 			break;
533 		}
534 
535 		for (i = 0; i < wr->num_sge; ++i) {
536 			((struct mthca_data_seg *) wqe)->byte_count =
537 				cpu_to_be32(wr->sg_list[i].length);
538 			((struct mthca_data_seg *) wqe)->lkey =
539 				cpu_to_be32(wr->sg_list[i].lkey);
540 			((struct mthca_data_seg *) wqe)->addr =
541 				cpu_to_be64(wr->sg_list[i].addr);
542 			wqe += sizeof (struct mthca_data_seg);
543 		}
544 
545 		if (i < srq->max_gs) {
546 			((struct mthca_data_seg *) wqe)->byte_count = 0;
547 			((struct mthca_data_seg *) wqe)->lkey = cpu_to_be32(MTHCA_INVAL_LKEY);
548 			((struct mthca_data_seg *) wqe)->addr = 0;
549 		}
550 
551 		((struct mthca_next_seg *) prev_wqe)->nda_op =
552 			cpu_to_be32((ind << srq->wqe_shift) | 1);
553 		wmb();
554 		((struct mthca_next_seg *) prev_wqe)->ee_nds =
555 			cpu_to_be32(MTHCA_NEXT_DBD);
556 
557 		srq->wrid[ind]  = wr->wr_id;
558 		srq->first_free = next_ind;
559 	}
560 
561 	if (likely(nreq)) {
562 		doorbell[0] = cpu_to_be32(first_ind << srq->wqe_shift);
563 		doorbell[1] = cpu_to_be32((srq->srqn << 8) | nreq);
564 
565 		/*
566 		 * Make sure that descriptors are written before
567 		 * doorbell is rung.
568 		 */
569 		wmb();
570 
571 		mthca_write64(doorbell,
572 			      dev->kar + MTHCA_RECEIVE_DOORBELL,
573 			      MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
574 	}
575 
576 	spin_unlock_irqrestore(&srq->lock, flags);
577 	return err;
578 }
579 
580 int mthca_arbel_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
581 			      struct ib_recv_wr **bad_wr)
582 {
583 	struct mthca_dev *dev = to_mdev(ibsrq->device);
584 	struct mthca_srq *srq = to_msrq(ibsrq);
585 	unsigned long flags;
586 	int err = 0;
587 	int ind;
588 	int next_ind;
589 	int nreq;
590 	int i;
591 	void *wqe;
592 
593 	spin_lock_irqsave(&srq->lock, flags);
594 
595 	for (nreq = 0; wr; ++nreq, wr = wr->next) {
596 		ind = srq->first_free;
597 
598 		if (ind < 0) {
599 			mthca_err(dev, "SRQ %06x full\n", srq->srqn);
600 			err = -ENOMEM;
601 			*bad_wr = wr;
602 			break;
603 		}
604 
605 		wqe       = get_wqe(srq, ind);
606 		next_ind  = *wqe_to_link(wqe);
607 
608 		if (next_ind < 0) {
609 			mthca_err(dev, "SRQ %06x full\n", srq->srqn);
610 			err = -ENOMEM;
611 			*bad_wr = wr;
612 			break;
613 		}
614 
615 		((struct mthca_next_seg *) wqe)->nda_op =
616 			cpu_to_be32((next_ind << srq->wqe_shift) | 1);
617 		((struct mthca_next_seg *) wqe)->ee_nds = 0;
618 		/* flags field will always remain 0 */
619 
620 		wqe += sizeof (struct mthca_next_seg);
621 
622 		if (unlikely(wr->num_sge > srq->max_gs)) {
623 			err = -EINVAL;
624 			*bad_wr = wr;
625 			break;
626 		}
627 
628 		for (i = 0; i < wr->num_sge; ++i) {
629 			((struct mthca_data_seg *) wqe)->byte_count =
630 				cpu_to_be32(wr->sg_list[i].length);
631 			((struct mthca_data_seg *) wqe)->lkey =
632 				cpu_to_be32(wr->sg_list[i].lkey);
633 			((struct mthca_data_seg *) wqe)->addr =
634 				cpu_to_be64(wr->sg_list[i].addr);
635 			wqe += sizeof (struct mthca_data_seg);
636 		}
637 
638 		if (i < srq->max_gs) {
639 			((struct mthca_data_seg *) wqe)->byte_count = 0;
640 			((struct mthca_data_seg *) wqe)->lkey = cpu_to_be32(MTHCA_INVAL_LKEY);
641 			((struct mthca_data_seg *) wqe)->addr = 0;
642 		}
643 
644 		srq->wrid[ind]  = wr->wr_id;
645 		srq->first_free = next_ind;
646 	}
647 
648 	if (likely(nreq)) {
649 		srq->counter += nreq;
650 
651 		/*
652 		 * Make sure that descriptors are written before
653 		 * we write doorbell record.
654 		 */
655 		wmb();
656 		*srq->db = cpu_to_be32(srq->counter);
657 	}
658 
659 	spin_unlock_irqrestore(&srq->lock, flags);
660 	return err;
661 }
662 
663 int __devinit mthca_init_srq_table(struct mthca_dev *dev)
664 {
665 	int err;
666 
667 	if (!(dev->mthca_flags & MTHCA_FLAG_SRQ))
668 		return 0;
669 
670 	spin_lock_init(&dev->srq_table.lock);
671 
672 	err = mthca_alloc_init(&dev->srq_table.alloc,
673 			       dev->limits.num_srqs,
674 			       dev->limits.num_srqs - 1,
675 			       dev->limits.reserved_srqs);
676 	if (err)
677 		return err;
678 
679 	err = mthca_array_init(&dev->srq_table.srq,
680 			       dev->limits.num_srqs);
681 	if (err)
682 		mthca_alloc_cleanup(&dev->srq_table.alloc);
683 
684 	return err;
685 }
686 
687 void mthca_cleanup_srq_table(struct mthca_dev *dev)
688 {
689 	if (!(dev->mthca_flags & MTHCA_FLAG_SRQ))
690 		return;
691 
692 	mthca_array_cleanup(&dev->srq_table.srq, dev->limits.num_srqs);
693 	mthca_alloc_cleanup(&dev->srq_table.alloc);
694 }
695