Merge master.kernel.org:/home/rmk/linux-2.6-serial
[pandora-kernel.git] / drivers / infiniband / hw / mthca / mthca_srq.c
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         srq->wqe_shift = long_log2(ds);
209
210         srq->srqn = mthca_alloc(&dev->srq_table.alloc);
211         if (srq->srqn == -1)
212                 return -ENOMEM;
213
214         if (mthca_is_memfree(dev)) {
215                 err = mthca_table_get(dev, dev->srq_table.table, srq->srqn);
216                 if (err)
217                         goto err_out;
218
219                 if (!pd->ibpd.uobject) {
220                         srq->db_index = mthca_alloc_db(dev, MTHCA_DB_TYPE_SRQ,
221                                                        srq->srqn, &srq->db);
222                         if (srq->db_index < 0) {
223                                 err = -ENOMEM;
224                                 goto err_out_icm;
225                         }
226                 }
227         }
228
229         mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
230         if (IS_ERR(mailbox)) {
231                 err = PTR_ERR(mailbox);
232                 goto err_out_db;
233         }
234
235         err = mthca_alloc_srq_buf(dev, pd, srq);
236         if (err)
237                 goto err_out_mailbox;
238
239         spin_lock_init(&srq->lock);
240         atomic_set(&srq->refcount, 1);
241         init_waitqueue_head(&srq->wait);
242
243         if (mthca_is_memfree(dev))
244                 mthca_arbel_init_srq_context(dev, pd, srq, mailbox->buf);
245         else
246                 mthca_tavor_init_srq_context(dev, pd, srq, mailbox->buf);
247
248         err = mthca_SW2HW_SRQ(dev, mailbox, srq->srqn, &status);
249
250         if (err) {
251                 mthca_warn(dev, "SW2HW_SRQ failed (%d)\n", err);
252                 goto err_out_free_buf;
253         }
254         if (status) {
255                 mthca_warn(dev, "SW2HW_SRQ returned status 0x%02x\n",
256                            status);
257                 err = -EINVAL;
258                 goto err_out_free_buf;
259         }
260
261         spin_lock_irq(&dev->srq_table.lock);
262         if (mthca_array_set(&dev->srq_table.srq,
263                             srq->srqn & (dev->limits.num_srqs - 1),
264                             srq)) {
265                 spin_unlock_irq(&dev->srq_table.lock);
266                 goto err_out_free_srq;
267         }
268         spin_unlock_irq(&dev->srq_table.lock);
269
270         mthca_free_mailbox(dev, mailbox);
271
272         srq->first_free = 0;
273         srq->last_free  = srq->max - 1;
274
275         attr->max_wr    = (mthca_is_memfree(dev)) ? srq->max - 1 : srq->max;
276         attr->max_sge   = srq->max_gs;
277
278         return 0;
279
280 err_out_free_srq:
281         err = mthca_HW2SW_SRQ(dev, mailbox, srq->srqn, &status);
282         if (err)
283                 mthca_warn(dev, "HW2SW_SRQ failed (%d)\n", err);
284         else if (status)
285                 mthca_warn(dev, "HW2SW_SRQ returned status 0x%02x\n", status);
286
287 err_out_free_buf:
288         if (!pd->ibpd.uobject)
289                 mthca_free_srq_buf(dev, srq);
290
291 err_out_mailbox:
292         mthca_free_mailbox(dev, mailbox);
293
294 err_out_db:
295         if (!pd->ibpd.uobject && mthca_is_memfree(dev))
296                 mthca_free_db(dev, MTHCA_DB_TYPE_SRQ, srq->db_index);
297
298 err_out_icm:
299         mthca_table_put(dev, dev->srq_table.table, srq->srqn);
300
301 err_out:
302         mthca_free(&dev->srq_table.alloc, srq->srqn);
303
304         return err;
305 }
306
307 void mthca_free_srq(struct mthca_dev *dev, struct mthca_srq *srq)
308 {
309         struct mthca_mailbox *mailbox;
310         int err;
311         u8 status;
312
313         mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
314         if (IS_ERR(mailbox)) {
315                 mthca_warn(dev, "No memory for mailbox to free SRQ.\n");
316                 return;
317         }
318
319         err = mthca_HW2SW_SRQ(dev, mailbox, srq->srqn, &status);
320         if (err)
321                 mthca_warn(dev, "HW2SW_SRQ failed (%d)\n", err);
322         else if (status)
323                 mthca_warn(dev, "HW2SW_SRQ returned status 0x%02x\n", status);
324
325         spin_lock_irq(&dev->srq_table.lock);
326         mthca_array_clear(&dev->srq_table.srq,
327                           srq->srqn & (dev->limits.num_srqs - 1));
328         spin_unlock_irq(&dev->srq_table.lock);
329
330         atomic_dec(&srq->refcount);
331         wait_event(srq->wait, !atomic_read(&srq->refcount));
332
333         if (!srq->ibsrq.uobject) {
334                 mthca_free_srq_buf(dev, srq);
335                 if (mthca_is_memfree(dev))
336                         mthca_free_db(dev, MTHCA_DB_TYPE_SRQ, srq->db_index);
337         }
338
339         mthca_table_put(dev, dev->srq_table.table, srq->srqn);
340         mthca_free(&dev->srq_table.alloc, srq->srqn);
341         mthca_free_mailbox(dev, mailbox);
342 }
343
344 int mthca_modify_srq(struct ib_srq *ibsrq, struct ib_srq_attr *attr,
345                      enum ib_srq_attr_mask attr_mask)
346 {
347         struct mthca_dev *dev = to_mdev(ibsrq->device);
348         struct mthca_srq *srq = to_msrq(ibsrq);
349         int ret;
350         u8 status;
351
352         /* We don't support resizing SRQs (yet?) */
353         if (attr_mask & IB_SRQ_MAX_WR)
354                 return -EINVAL;
355
356         if (attr_mask & IB_SRQ_LIMIT) {
357                 ret = mthca_ARM_SRQ(dev, srq->srqn, attr->srq_limit, &status);
358                 if (ret)
359                         return ret;
360                 if (status)
361                         return -EINVAL;
362         }
363
364         return 0;
365 }
366
367 int mthca_query_srq(struct ib_srq *ibsrq, struct ib_srq_attr *srq_attr)
368 {
369         struct mthca_dev *dev = to_mdev(ibsrq->device);
370         struct mthca_srq *srq = to_msrq(ibsrq);
371         struct mthca_mailbox *mailbox;
372         struct mthca_arbel_srq_context *arbel_ctx;
373         struct mthca_tavor_srq_context *tavor_ctx;
374         u8 status;
375         int err;
376
377         mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
378         if (IS_ERR(mailbox))
379                 return PTR_ERR(mailbox);
380
381         err = mthca_QUERY_SRQ(dev, srq->srqn, mailbox, &status);
382         if (err)
383                 goto out;
384
385         if (mthca_is_memfree(dev)) {
386                 arbel_ctx = mailbox->buf;
387                 srq_attr->srq_limit = be16_to_cpu(arbel_ctx->limit_watermark);
388         } else {
389                 tavor_ctx = mailbox->buf;
390                 srq_attr->srq_limit = be16_to_cpu(tavor_ctx->limit_watermark);
391         }
392
393         srq_attr->max_wr  = (mthca_is_memfree(dev)) ? srq->max - 1 : srq->max;
394         srq_attr->max_sge = srq->max_gs;
395
396 out:
397         mthca_free_mailbox(dev, mailbox);
398
399         return err;
400 }
401
402 void mthca_srq_event(struct mthca_dev *dev, u32 srqn,
403                      enum ib_event_type event_type)
404 {
405         struct mthca_srq *srq;
406         struct ib_event event;
407
408         spin_lock(&dev->srq_table.lock);
409         srq = mthca_array_get(&dev->srq_table.srq, srqn & (dev->limits.num_srqs - 1));
410         if (srq)
411                 atomic_inc(&srq->refcount);
412         spin_unlock(&dev->srq_table.lock);
413
414         if (!srq) {
415                 mthca_warn(dev, "Async event for bogus SRQ %08x\n", srqn);
416                 return;
417         }
418
419         if (!srq->ibsrq.event_handler)
420                 goto out;
421
422         event.device      = &dev->ib_dev;
423         event.event       = event_type;
424         event.element.srq = &srq->ibsrq;
425         srq->ibsrq.event_handler(&event, srq->ibsrq.srq_context);
426
427 out:
428         if (atomic_dec_and_test(&srq->refcount))
429                 wake_up(&srq->wait);
430 }
431
432 /*
433  * This function must be called with IRQs disabled.
434  */
435 void mthca_free_srq_wqe(struct mthca_srq *srq, u32 wqe_addr)
436 {
437         int ind;
438
439         ind = wqe_addr >> srq->wqe_shift;
440
441         spin_lock(&srq->lock);
442
443         if (likely(srq->first_free >= 0))
444                 *wqe_to_link(get_wqe(srq, srq->last_free)) = ind;
445         else
446                 srq->first_free = ind;
447
448         *wqe_to_link(get_wqe(srq, ind)) = -1;
449         srq->last_free = ind;
450
451         spin_unlock(&srq->lock);
452 }
453
454 int mthca_tavor_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
455                               struct ib_recv_wr **bad_wr)
456 {
457         struct mthca_dev *dev = to_mdev(ibsrq->device);
458         struct mthca_srq *srq = to_msrq(ibsrq);
459         __be32 doorbell[2];
460         unsigned long flags;
461         int err = 0;
462         int first_ind;
463         int ind;
464         int next_ind;
465         int nreq;
466         int i;
467         void *wqe;
468         void *prev_wqe;
469
470         spin_lock_irqsave(&srq->lock, flags);
471
472         first_ind = srq->first_free;
473
474         for (nreq = 0; wr; ++nreq, wr = wr->next) {
475                 if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) {
476                         nreq = 0;
477
478                         doorbell[0] = cpu_to_be32(first_ind << srq->wqe_shift);
479                         doorbell[1] = cpu_to_be32(srq->srqn << 8);
480
481                         /*
482                          * Make sure that descriptors are written
483                          * before doorbell is rung.
484                          */
485                         wmb();
486
487                         mthca_write64(doorbell,
488                                       dev->kar + MTHCA_RECEIVE_DOORBELL,
489                                       MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
490
491                         first_ind = srq->first_free;
492                 }
493
494                 ind = srq->first_free;
495
496                 if (ind < 0) {
497                         mthca_err(dev, "SRQ %06x full\n", srq->srqn);
498                         err = -ENOMEM;
499                         *bad_wr = wr;
500                         break;
501                 }
502
503                 wqe       = get_wqe(srq, ind);
504                 next_ind  = *wqe_to_link(wqe);
505
506                 if (next_ind < 0) {
507                         mthca_err(dev, "SRQ %06x full\n", srq->srqn);
508                         err = -ENOMEM;
509                         *bad_wr = wr;
510                         break;
511                 }
512
513                 prev_wqe  = srq->last;
514                 srq->last = wqe;
515
516                 ((struct mthca_next_seg *) wqe)->nda_op = 0;
517                 ((struct mthca_next_seg *) wqe)->ee_nds = 0;
518                 /* flags field will always remain 0 */
519
520                 wqe += sizeof (struct mthca_next_seg);
521
522                 if (unlikely(wr->num_sge > srq->max_gs)) {
523                         err = -EINVAL;
524                         *bad_wr = wr;
525                         srq->last = prev_wqe;
526                         break;
527                 }
528
529                 for (i = 0; i < wr->num_sge; ++i) {
530                         ((struct mthca_data_seg *) wqe)->byte_count =
531                                 cpu_to_be32(wr->sg_list[i].length);
532                         ((struct mthca_data_seg *) wqe)->lkey =
533                                 cpu_to_be32(wr->sg_list[i].lkey);
534                         ((struct mthca_data_seg *) wqe)->addr =
535                                 cpu_to_be64(wr->sg_list[i].addr);
536                         wqe += sizeof (struct mthca_data_seg);
537                 }
538
539                 if (i < srq->max_gs) {
540                         ((struct mthca_data_seg *) wqe)->byte_count = 0;
541                         ((struct mthca_data_seg *) wqe)->lkey = cpu_to_be32(MTHCA_INVAL_LKEY);
542                         ((struct mthca_data_seg *) wqe)->addr = 0;
543                 }
544
545                 ((struct mthca_next_seg *) prev_wqe)->nda_op =
546                         cpu_to_be32((ind << srq->wqe_shift) | 1);
547                 wmb();
548                 ((struct mthca_next_seg *) prev_wqe)->ee_nds =
549                         cpu_to_be32(MTHCA_NEXT_DBD);
550
551                 srq->wrid[ind]  = wr->wr_id;
552                 srq->first_free = next_ind;
553         }
554
555         if (likely(nreq)) {
556                 doorbell[0] = cpu_to_be32(first_ind << srq->wqe_shift);
557                 doorbell[1] = cpu_to_be32((srq->srqn << 8) | nreq);
558
559                 /*
560                  * Make sure that descriptors are written before
561                  * doorbell is rung.
562                  */
563                 wmb();
564
565                 mthca_write64(doorbell,
566                               dev->kar + MTHCA_RECEIVE_DOORBELL,
567                               MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
568         }
569
570         spin_unlock_irqrestore(&srq->lock, flags);
571         return err;
572 }
573
574 int mthca_arbel_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
575                               struct ib_recv_wr **bad_wr)
576 {
577         struct mthca_dev *dev = to_mdev(ibsrq->device);
578         struct mthca_srq *srq = to_msrq(ibsrq);
579         unsigned long flags;
580         int err = 0;
581         int ind;
582         int next_ind;
583         int nreq;
584         int i;
585         void *wqe;
586
587         spin_lock_irqsave(&srq->lock, flags);
588
589         for (nreq = 0; wr; ++nreq, wr = wr->next) {
590                 ind = srq->first_free;
591
592                 if (ind < 0) {
593                         mthca_err(dev, "SRQ %06x full\n", srq->srqn);
594                         err = -ENOMEM;
595                         *bad_wr = wr;
596                         break;
597                 }
598
599                 wqe       = get_wqe(srq, ind);
600                 next_ind  = *wqe_to_link(wqe);
601
602                 if (next_ind < 0) {
603                         mthca_err(dev, "SRQ %06x full\n", srq->srqn);
604                         err = -ENOMEM;
605                         *bad_wr = wr;
606                         break;
607                 }
608
609                 ((struct mthca_next_seg *) wqe)->nda_op =
610                         cpu_to_be32((next_ind << srq->wqe_shift) | 1);
611                 ((struct mthca_next_seg *) wqe)->ee_nds = 0;
612                 /* flags field will always remain 0 */
613
614                 wqe += sizeof (struct mthca_next_seg);
615
616                 if (unlikely(wr->num_sge > srq->max_gs)) {
617                         err = -EINVAL;
618                         *bad_wr = wr;
619                         break;
620                 }
621
622                 for (i = 0; i < wr->num_sge; ++i) {
623                         ((struct mthca_data_seg *) wqe)->byte_count =
624                                 cpu_to_be32(wr->sg_list[i].length);
625                         ((struct mthca_data_seg *) wqe)->lkey =
626                                 cpu_to_be32(wr->sg_list[i].lkey);
627                         ((struct mthca_data_seg *) wqe)->addr =
628                                 cpu_to_be64(wr->sg_list[i].addr);
629                         wqe += sizeof (struct mthca_data_seg);
630                 }
631
632                 if (i < srq->max_gs) {
633                         ((struct mthca_data_seg *) wqe)->byte_count = 0;
634                         ((struct mthca_data_seg *) wqe)->lkey = cpu_to_be32(MTHCA_INVAL_LKEY);
635                         ((struct mthca_data_seg *) wqe)->addr = 0;
636                 }
637
638                 srq->wrid[ind]  = wr->wr_id;
639                 srq->first_free = next_ind;
640         }
641
642         if (likely(nreq)) {
643                 srq->counter += nreq;
644
645                 /*
646                  * Make sure that descriptors are written before
647                  * we write doorbell record.
648                  */
649                 wmb();
650                 *srq->db = cpu_to_be32(srq->counter);
651         }
652
653         spin_unlock_irqrestore(&srq->lock, flags);
654         return err;
655 }
656
657 int __devinit mthca_init_srq_table(struct mthca_dev *dev)
658 {
659         int err;
660
661         if (!(dev->mthca_flags & MTHCA_FLAG_SRQ))
662                 return 0;
663
664         spin_lock_init(&dev->srq_table.lock);
665
666         err = mthca_alloc_init(&dev->srq_table.alloc,
667                                dev->limits.num_srqs,
668                                dev->limits.num_srqs - 1,
669                                dev->limits.reserved_srqs);
670         if (err)
671                 return err;
672
673         err = mthca_array_init(&dev->srq_table.srq,
674                                dev->limits.num_srqs);
675         if (err)
676                 mthca_alloc_cleanup(&dev->srq_table.alloc);
677
678         return err;
679 }
680
681 void __devexit mthca_cleanup_srq_table(struct mthca_dev *dev)
682 {
683         if (!(dev->mthca_flags & MTHCA_FLAG_SRQ))
684                 return;
685
686         mthca_array_cleanup(&dev->srq_table.srq, dev->limits.num_srqs);
687         mthca_alloc_cleanup(&dev->srq_table.alloc);
688 }