f7530512045d0f0e7584424e020e1e5169909a29
[linux-2.6.git] / drivers / infiniband / hw / ipath / ipath_ruc.c
1 /*
2  * Copyright (c) 2006 QLogic, Inc. All rights reserved.
3  * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *      - Redistributions of source code must retain the above
16  *        copyright notice, this list of conditions and the following
17  *        disclaimer.
18  *
19  *      - Redistributions in binary form must reproduce the above
20  *        copyright notice, this list of conditions and the following
21  *        disclaimer in the documentation and/or other materials
22  *        provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  */
33
34 #include "ipath_verbs.h"
35 #include "ipath_kernel.h"
36
37 /*
38  * Convert the AETH RNR timeout code into the number of milliseconds.
39  */
40 const u32 ib_ipath_rnr_table[32] = {
41         656,                    /* 0 */
42         1,                      /* 1 */
43         1,                      /* 2 */
44         1,                      /* 3 */
45         1,                      /* 4 */
46         1,                      /* 5 */
47         1,                      /* 6 */
48         1,                      /* 7 */
49         1,                      /* 8 */
50         1,                      /* 9 */
51         1,                      /* A */
52         1,                      /* B */
53         1,                      /* C */
54         1,                      /* D */
55         2,                      /* E */
56         2,                      /* F */
57         3,                      /* 10 */
58         4,                      /* 11 */
59         6,                      /* 12 */
60         8,                      /* 13 */
61         11,                     /* 14 */
62         16,                     /* 15 */
63         21,                     /* 16 */
64         31,                     /* 17 */
65         41,                     /* 18 */
66         62,                     /* 19 */
67         82,                     /* 1A */
68         123,                    /* 1B */
69         164,                    /* 1C */
70         246,                    /* 1D */
71         328,                    /* 1E */
72         492                     /* 1F */
73 };
74
75 /**
76  * ipath_insert_rnr_queue - put QP on the RNR timeout list for the device
77  * @qp: the QP
78  *
79  * XXX Use a simple list for now.  We might need a priority
80  * queue if we have lots of QPs waiting for RNR timeouts
81  * but that should be rare.
82  */
83 void ipath_insert_rnr_queue(struct ipath_qp *qp)
84 {
85         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
86         unsigned long flags;
87
88         spin_lock_irqsave(&dev->pending_lock, flags);
89         if (list_empty(&dev->rnrwait))
90                 list_add(&qp->timerwait, &dev->rnrwait);
91         else {
92                 struct list_head *l = &dev->rnrwait;
93                 struct ipath_qp *nqp = list_entry(l->next, struct ipath_qp,
94                                                   timerwait);
95
96                 while (qp->s_rnr_timeout >= nqp->s_rnr_timeout) {
97                         qp->s_rnr_timeout -= nqp->s_rnr_timeout;
98                         l = l->next;
99                         if (l->next == &dev->rnrwait)
100                                 break;
101                         nqp = list_entry(l->next, struct ipath_qp,
102                                          timerwait);
103                 }
104                 list_add(&qp->timerwait, l);
105         }
106         spin_unlock_irqrestore(&dev->pending_lock, flags);
107 }
108
109 static int init_sge(struct ipath_qp *qp, struct ipath_rwqe *wqe)
110 {
111         int user = to_ipd(qp->ibqp.pd)->user;
112         int i, j, ret;
113         struct ib_wc wc;
114
115         qp->r_len = 0;
116         for (i = j = 0; i < wqe->num_sge; i++) {
117                 if (wqe->sg_list[i].length == 0)
118                         continue;
119                 /* Check LKEY */
120                 if ((user && wqe->sg_list[i].lkey == 0) ||
121                     !ipath_lkey_ok(qp, &qp->r_sg_list[j], &wqe->sg_list[i],
122                                    IB_ACCESS_LOCAL_WRITE))
123                         goto bad_lkey;
124                 qp->r_len += wqe->sg_list[i].length;
125                 j++;
126         }
127         qp->r_sge.sge = qp->r_sg_list[0];
128         qp->r_sge.sg_list = qp->r_sg_list + 1;
129         qp->r_sge.num_sge = j;
130         ret = 1;
131         goto bail;
132
133 bad_lkey:
134         wc.wr_id = wqe->wr_id;
135         wc.status = IB_WC_LOC_PROT_ERR;
136         wc.opcode = IB_WC_RECV;
137         wc.vendor_err = 0;
138         wc.byte_len = 0;
139         wc.imm_data = 0;
140         wc.qp_num = qp->ibqp.qp_num;
141         wc.src_qp = 0;
142         wc.wc_flags = 0;
143         wc.pkey_index = 0;
144         wc.slid = 0;
145         wc.sl = 0;
146         wc.dlid_path_bits = 0;
147         wc.port_num = 0;
148         /* Signal solicited completion event. */
149         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc, 1);
150         ret = 0;
151 bail:
152         return ret;
153 }
154
155 /**
156  * ipath_get_rwqe - copy the next RWQE into the QP's RWQE
157  * @qp: the QP
158  * @wr_id_only: update wr_id only, not SGEs
159  *
160  * Return 0 if no RWQE is available, otherwise return 1.
161  *
162  * Can be called from interrupt level.
163  */
164 int ipath_get_rwqe(struct ipath_qp *qp, int wr_id_only)
165 {
166         unsigned long flags;
167         struct ipath_rq *rq;
168         struct ipath_rwq *wq;
169         struct ipath_srq *srq;
170         struct ipath_rwqe *wqe;
171         void (*handler)(struct ib_event *, void *);
172         u32 tail;
173         int ret;
174
175         if (qp->ibqp.srq) {
176                 srq = to_isrq(qp->ibqp.srq);
177                 handler = srq->ibsrq.event_handler;
178                 rq = &srq->rq;
179         } else {
180                 srq = NULL;
181                 handler = NULL;
182                 rq = &qp->r_rq;
183         }
184
185         spin_lock_irqsave(&rq->lock, flags);
186         wq = rq->wq;
187         tail = wq->tail;
188         /* Validate tail before using it since it is user writable. */
189         if (tail >= rq->size)
190                 tail = 0;
191         do {
192                 if (unlikely(tail == wq->head)) {
193                         spin_unlock_irqrestore(&rq->lock, flags);
194                         ret = 0;
195                         goto bail;
196                 }
197                 wqe = get_rwqe_ptr(rq, tail);
198                 if (++tail >= rq->size)
199                         tail = 0;
200         } while (!wr_id_only && !init_sge(qp, wqe));
201         qp->r_wr_id = wqe->wr_id;
202         wq->tail = tail;
203
204         ret = 1;
205         if (handler) {
206                 u32 n;
207
208                 /*
209                  * validate head pointer value and compute
210                  * the number of remaining WQEs.
211                  */
212                 n = wq->head;
213                 if (n >= rq->size)
214                         n = 0;
215                 if (n < tail)
216                         n += rq->size - tail;
217                 else
218                         n -= tail;
219                 if (n < srq->limit) {
220                         struct ib_event ev;
221
222                         srq->limit = 0;
223                         spin_unlock_irqrestore(&rq->lock, flags);
224                         ev.device = qp->ibqp.device;
225                         ev.element.srq = qp->ibqp.srq;
226                         ev.event = IB_EVENT_SRQ_LIMIT_REACHED;
227                         handler(&ev, srq->ibsrq.srq_context);
228                         goto bail;
229                 }
230         }
231         spin_unlock_irqrestore(&rq->lock, flags);
232         qp->r_wrid_valid = 1;
233
234 bail:
235         return ret;
236 }
237
238 /**
239  * ipath_ruc_loopback - handle UC and RC lookback requests
240  * @sqp: the loopback QP
241  *
242  * This is called from ipath_do_uc_send() or ipath_do_rc_send() to
243  * forward a WQE addressed to the same HCA.
244  * Note that although we are single threaded due to the tasklet, we still
245  * have to protect against post_send().  We don't have to worry about
246  * receive interrupts since this is a connected protocol and all packets
247  * will pass through here.
248  */
249 static void ipath_ruc_loopback(struct ipath_qp *sqp)
250 {
251         struct ipath_ibdev *dev = to_idev(sqp->ibqp.device);
252         struct ipath_qp *qp;
253         struct ipath_swqe *wqe;
254         struct ipath_sge *sge;
255         unsigned long flags;
256         struct ib_wc wc;
257         u64 sdata;
258
259         qp = ipath_lookup_qpn(&dev->qp_table, sqp->remote_qpn);
260         if (!qp) {
261                 dev->n_pkt_drops++;
262                 return;
263         }
264
265 again:
266         spin_lock_irqsave(&sqp->s_lock, flags);
267
268         if (!(ib_ipath_state_ops[sqp->state] & IPATH_PROCESS_SEND_OK)) {
269                 spin_unlock_irqrestore(&sqp->s_lock, flags);
270                 goto done;
271         }
272
273         /* Get the next send request. */
274         if (sqp->s_last == sqp->s_head) {
275                 /* Send work queue is empty. */
276                 spin_unlock_irqrestore(&sqp->s_lock, flags);
277                 goto done;
278         }
279
280         /*
281          * We can rely on the entry not changing without the s_lock
282          * being held until we update s_last.
283          */
284         wqe = get_swqe_ptr(sqp, sqp->s_last);
285         spin_unlock_irqrestore(&sqp->s_lock, flags);
286
287         wc.wc_flags = 0;
288         wc.imm_data = 0;
289
290         sqp->s_sge.sge = wqe->sg_list[0];
291         sqp->s_sge.sg_list = wqe->sg_list + 1;
292         sqp->s_sge.num_sge = wqe->wr.num_sge;
293         sqp->s_len = wqe->length;
294         switch (wqe->wr.opcode) {
295         case IB_WR_SEND_WITH_IMM:
296                 wc.wc_flags = IB_WC_WITH_IMM;
297                 wc.imm_data = wqe->wr.imm_data;
298                 /* FALLTHROUGH */
299         case IB_WR_SEND:
300                 if (!ipath_get_rwqe(qp, 0)) {
301                 rnr_nak:
302                         /* Handle RNR NAK */
303                         if (qp->ibqp.qp_type == IB_QPT_UC)
304                                 goto send_comp;
305                         if (sqp->s_rnr_retry == 0) {
306                                 wc.status = IB_WC_RNR_RETRY_EXC_ERR;
307                                 goto err;
308                         }
309                         if (sqp->s_rnr_retry_cnt < 7)
310                                 sqp->s_rnr_retry--;
311                         dev->n_rnr_naks++;
312                         sqp->s_rnr_timeout =
313                                 ib_ipath_rnr_table[sqp->r_min_rnr_timer];
314                         ipath_insert_rnr_queue(sqp);
315                         goto done;
316                 }
317                 break;
318
319         case IB_WR_RDMA_WRITE_WITH_IMM:
320                 wc.wc_flags = IB_WC_WITH_IMM;
321                 wc.imm_data = wqe->wr.imm_data;
322                 if (!ipath_get_rwqe(qp, 1))
323                         goto rnr_nak;
324                 /* FALLTHROUGH */
325         case IB_WR_RDMA_WRITE:
326                 if (wqe->length == 0)
327                         break;
328                 if (unlikely(!ipath_rkey_ok(qp, &qp->r_sge, wqe->length,
329                                             wqe->wr.wr.rdma.remote_addr,
330                                             wqe->wr.wr.rdma.rkey,
331                                             IB_ACCESS_REMOTE_WRITE))) {
332                 acc_err:
333                         wc.status = IB_WC_REM_ACCESS_ERR;
334                 err:
335                         wc.wr_id = wqe->wr.wr_id;
336                         wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
337                         wc.vendor_err = 0;
338                         wc.byte_len = 0;
339                         wc.qp_num = sqp->ibqp.qp_num;
340                         wc.src_qp = sqp->remote_qpn;
341                         wc.pkey_index = 0;
342                         wc.slid = sqp->remote_ah_attr.dlid;
343                         wc.sl = sqp->remote_ah_attr.sl;
344                         wc.dlid_path_bits = 0;
345                         wc.port_num = 0;
346                         ipath_sqerror_qp(sqp, &wc);
347                         goto done;
348                 }
349                 break;
350
351         case IB_WR_RDMA_READ:
352                 if (unlikely(!ipath_rkey_ok(qp, &sqp->s_sge, wqe->length,
353                                             wqe->wr.wr.rdma.remote_addr,
354                                             wqe->wr.wr.rdma.rkey,
355                                             IB_ACCESS_REMOTE_READ)))
356                         goto acc_err;
357                 if (unlikely(!(qp->qp_access_flags &
358                                IB_ACCESS_REMOTE_READ)))
359                         goto acc_err;
360                 qp->r_sge.sge = wqe->sg_list[0];
361                 qp->r_sge.sg_list = wqe->sg_list + 1;
362                 qp->r_sge.num_sge = wqe->wr.num_sge;
363                 break;
364
365         case IB_WR_ATOMIC_CMP_AND_SWP:
366         case IB_WR_ATOMIC_FETCH_AND_ADD:
367                 if (unlikely(!ipath_rkey_ok(qp, &qp->r_sge, sizeof(u64),
368                                             wqe->wr.wr.rdma.remote_addr,
369                                             wqe->wr.wr.rdma.rkey,
370                                             IB_ACCESS_REMOTE_ATOMIC)))
371                         goto acc_err;
372                 /* Perform atomic OP and save result. */
373                 sdata = wqe->wr.wr.atomic.swap;
374                 spin_lock_irqsave(&dev->pending_lock, flags);
375                 qp->r_atomic_data = *(u64 *) qp->r_sge.sge.vaddr;
376                 if (wqe->wr.opcode == IB_WR_ATOMIC_FETCH_AND_ADD)
377                         *(u64 *) qp->r_sge.sge.vaddr =
378                                 qp->r_atomic_data + sdata;
379                 else if (qp->r_atomic_data == wqe->wr.wr.atomic.compare_add)
380                         *(u64 *) qp->r_sge.sge.vaddr = sdata;
381                 spin_unlock_irqrestore(&dev->pending_lock, flags);
382                 *(u64 *) sqp->s_sge.sge.vaddr = qp->r_atomic_data;
383                 goto send_comp;
384
385         default:
386                 goto done;
387         }
388
389         sge = &sqp->s_sge.sge;
390         while (sqp->s_len) {
391                 u32 len = sqp->s_len;
392
393                 if (len > sge->length)
394                         len = sge->length;
395                 BUG_ON(len == 0);
396                 ipath_copy_sge(&qp->r_sge, sge->vaddr, len);
397                 sge->vaddr += len;
398                 sge->length -= len;
399                 sge->sge_length -= len;
400                 if (sge->sge_length == 0) {
401                         if (--sqp->s_sge.num_sge)
402                                 *sge = *sqp->s_sge.sg_list++;
403                 } else if (sge->length == 0 && sge->mr != NULL) {
404                         if (++sge->n >= IPATH_SEGSZ) {
405                                 if (++sge->m >= sge->mr->mapsz)
406                                         break;
407                                 sge->n = 0;
408                         }
409                         sge->vaddr =
410                                 sge->mr->map[sge->m]->segs[sge->n].vaddr;
411                         sge->length =
412                                 sge->mr->map[sge->m]->segs[sge->n].length;
413                 }
414                 sqp->s_len -= len;
415         }
416
417         if (wqe->wr.opcode == IB_WR_RDMA_WRITE ||
418             wqe->wr.opcode == IB_WR_RDMA_READ)
419                 goto send_comp;
420
421         if (wqe->wr.opcode == IB_WR_RDMA_WRITE_WITH_IMM)
422                 wc.opcode = IB_WC_RECV_RDMA_WITH_IMM;
423         else
424                 wc.opcode = IB_WC_RECV;
425         wc.wr_id = qp->r_wr_id;
426         wc.status = IB_WC_SUCCESS;
427         wc.vendor_err = 0;
428         wc.byte_len = wqe->length;
429         wc.qp_num = qp->ibqp.qp_num;
430         wc.src_qp = qp->remote_qpn;
431         /* XXX do we know which pkey matched? Only needed for GSI. */
432         wc.pkey_index = 0;
433         wc.slid = qp->remote_ah_attr.dlid;
434         wc.sl = qp->remote_ah_attr.sl;
435         wc.dlid_path_bits = 0;
436         /* Signal completion event if the solicited bit is set. */
437         ipath_cq_enter(to_icq(qp->ibqp.recv_cq), &wc,
438                        wqe->wr.send_flags & IB_SEND_SOLICITED);
439
440 send_comp:
441         sqp->s_rnr_retry = sqp->s_rnr_retry_cnt;
442
443         if (!test_bit(IPATH_S_SIGNAL_REQ_WR, &sqp->s_flags) ||
444             (wqe->wr.send_flags & IB_SEND_SIGNALED)) {
445                 wc.wr_id = wqe->wr.wr_id;
446                 wc.status = IB_WC_SUCCESS;
447                 wc.opcode = ib_ipath_wc_opcode[wqe->wr.opcode];
448                 wc.vendor_err = 0;
449                 wc.byte_len = wqe->length;
450                 wc.qp_num = sqp->ibqp.qp_num;
451                 wc.src_qp = 0;
452                 wc.pkey_index = 0;
453                 wc.slid = 0;
454                 wc.sl = 0;
455                 wc.dlid_path_bits = 0;
456                 wc.port_num = 0;
457                 ipath_cq_enter(to_icq(sqp->ibqp.send_cq), &wc, 0);
458         }
459
460         /* Update s_last now that we are finished with the SWQE */
461         spin_lock_irqsave(&sqp->s_lock, flags);
462         if (++sqp->s_last >= sqp->s_size)
463                 sqp->s_last = 0;
464         spin_unlock_irqrestore(&sqp->s_lock, flags);
465         goto again;
466
467 done:
468         if (atomic_dec_and_test(&qp->refcount))
469                 wake_up(&qp->wait);
470 }
471
472 static int want_buffer(struct ipath_devdata *dd)
473 {
474         set_bit(IPATH_S_PIOINTBUFAVAIL, &dd->ipath_sendctrl);
475         ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
476                          dd->ipath_sendctrl);
477
478         return 0;
479 }
480
481 /**
482  * ipath_no_bufs_available - tell the layer driver we need buffers
483  * @qp: the QP that caused the problem
484  * @dev: the device we ran out of buffers on
485  *
486  * Called when we run out of PIO buffers.
487  */
488 void ipath_no_bufs_available(struct ipath_qp *qp, struct ipath_ibdev *dev)
489 {
490         unsigned long flags;
491
492         spin_lock_irqsave(&dev->pending_lock, flags);
493         if (list_empty(&qp->piowait))
494                 list_add_tail(&qp->piowait, &dev->piowait);
495         spin_unlock_irqrestore(&dev->pending_lock, flags);
496         /*
497          * Note that as soon as want_buffer() is called and
498          * possibly before it returns, ipath_ib_piobufavail()
499          * could be called.  If we are still in the tasklet function,
500          * tasklet_hi_schedule() will not call us until the next time
501          * tasklet_hi_schedule() is called.
502          * We clear the tasklet flag now since we are committing to return
503          * from the tasklet function.
504          */
505         clear_bit(IPATH_S_BUSY, &qp->s_flags);
506         tasklet_unlock(&qp->s_task);
507         want_buffer(dev->dd);
508         dev->n_piowait++;
509 }
510
511 /**
512  * ipath_post_ruc_send - post RC and UC sends
513  * @qp: the QP to post on
514  * @wr: the work request to send
515  */
516 int ipath_post_ruc_send(struct ipath_qp *qp, struct ib_send_wr *wr)
517 {
518         struct ipath_swqe *wqe;
519         unsigned long flags;
520         u32 next;
521         int i, j;
522         int acc;
523         int ret;
524
525         /*
526          * Don't allow RDMA reads or atomic operations on UC or
527          * undefined operations.
528          * Make sure buffer is large enough to hold the result for atomics.
529          */
530         if (qp->ibqp.qp_type == IB_QPT_UC) {
531                 if ((unsigned) wr->opcode >= IB_WR_RDMA_READ) {
532                         ret = -EINVAL;
533                         goto bail;
534                 }
535         } else if ((unsigned) wr->opcode > IB_WR_ATOMIC_FETCH_AND_ADD) {
536                 ret = -EINVAL;
537                 goto bail;
538         } else if (wr->opcode >= IB_WR_ATOMIC_CMP_AND_SWP &&
539                    (wr->num_sge == 0 ||
540                     wr->sg_list[0].length < sizeof(u64) ||
541                     wr->sg_list[0].addr & (sizeof(u64) - 1))) {
542                 ret = -EINVAL;
543                 goto bail;
544         }
545         /* IB spec says that num_sge == 0 is OK. */
546         if (wr->num_sge > qp->s_max_sge) {
547                 ret = -ENOMEM;
548                 goto bail;
549         }
550         spin_lock_irqsave(&qp->s_lock, flags);
551         next = qp->s_head + 1;
552         if (next >= qp->s_size)
553                 next = 0;
554         if (next == qp->s_last) {
555                 spin_unlock_irqrestore(&qp->s_lock, flags);
556                 ret = -EINVAL;
557                 goto bail;
558         }
559
560         wqe = get_swqe_ptr(qp, qp->s_head);
561         wqe->wr = *wr;
562         wqe->ssn = qp->s_ssn++;
563         wqe->sg_list[0].mr = NULL;
564         wqe->sg_list[0].vaddr = NULL;
565         wqe->sg_list[0].length = 0;
566         wqe->sg_list[0].sge_length = 0;
567         wqe->length = 0;
568         acc = wr->opcode >= IB_WR_RDMA_READ ? IB_ACCESS_LOCAL_WRITE : 0;
569         for (i = 0, j = 0; i < wr->num_sge; i++) {
570                 if (to_ipd(qp->ibqp.pd)->user && wr->sg_list[i].lkey == 0) {
571                         spin_unlock_irqrestore(&qp->s_lock, flags);
572                         ret = -EINVAL;
573                         goto bail;
574                 }
575                 if (wr->sg_list[i].length == 0)
576                         continue;
577                 if (!ipath_lkey_ok(qp, &wqe->sg_list[j], &wr->sg_list[i],
578                                    acc)) {
579                         spin_unlock_irqrestore(&qp->s_lock, flags);
580                         ret = -EINVAL;
581                         goto bail;
582                 }
583                 wqe->length += wr->sg_list[i].length;
584                 j++;
585         }
586         wqe->wr.num_sge = j;
587         qp->s_head = next;
588         spin_unlock_irqrestore(&qp->s_lock, flags);
589
590         ipath_do_ruc_send((unsigned long) qp);
591
592         ret = 0;
593
594 bail:
595         return ret;
596 }
597
598 /**
599  * ipath_make_grh - construct a GRH header
600  * @dev: a pointer to the ipath device
601  * @hdr: a pointer to the GRH header being constructed
602  * @grh: the global route address to send to
603  * @hwords: the number of 32 bit words of header being sent
604  * @nwords: the number of 32 bit words of data being sent
605  *
606  * Return the size of the header in 32 bit words.
607  */
608 u32 ipath_make_grh(struct ipath_ibdev *dev, struct ib_grh *hdr,
609                    struct ib_global_route *grh, u32 hwords, u32 nwords)
610 {
611         hdr->version_tclass_flow =
612                 cpu_to_be32((6 << 28) |
613                             (grh->traffic_class << 20) |
614                             grh->flow_label);
615         hdr->paylen = cpu_to_be16((hwords - 2 + nwords + SIZE_OF_CRC) << 2);
616         /* next_hdr is defined by C8-7 in ch. 8.4.1 */
617         hdr->next_hdr = 0x1B;
618         hdr->hop_limit = grh->hop_limit;
619         /* The SGID is 32-bit aligned. */
620         hdr->sgid.global.subnet_prefix = dev->gid_prefix;
621         hdr->sgid.global.interface_id = dev->dd->ipath_guid;
622         hdr->dgid = grh->dgid;
623
624         /* GRH header size in 32-bit words. */
625         return sizeof(struct ib_grh) / sizeof(u32);
626 }
627
628 /**
629  * ipath_do_ruc_send - perform a send on an RC or UC QP
630  * @data: contains a pointer to the QP
631  *
632  * Process entries in the send work queue until credit or queue is
633  * exhausted.  Only allow one CPU to send a packet per QP (tasklet).
634  * Otherwise, after we drop the QP s_lock, two threads could send
635  * packets out of order.
636  */
637 void ipath_do_ruc_send(unsigned long data)
638 {
639         struct ipath_qp *qp = (struct ipath_qp *)data;
640         struct ipath_ibdev *dev = to_idev(qp->ibqp.device);
641         unsigned long flags;
642         u16 lrh0;
643         u32 nwords;
644         u32 extra_bytes;
645         u32 bth0;
646         u32 bth2;
647         u32 pmtu = ib_mtu_enum_to_int(qp->path_mtu);
648         struct ipath_other_headers *ohdr;
649
650         if (test_and_set_bit(IPATH_S_BUSY, &qp->s_flags))
651                 goto bail;
652
653         if (unlikely(qp->remote_ah_attr.dlid == dev->dd->ipath_lid)) {
654                 ipath_ruc_loopback(qp);
655                 goto clear;
656         }
657
658         ohdr = &qp->s_hdr.u.oth;
659         if (qp->remote_ah_attr.ah_flags & IB_AH_GRH)
660                 ohdr = &qp->s_hdr.u.l.oth;
661
662 again:
663         /* Check for a constructed packet to be sent. */
664         if (qp->s_hdrwords != 0) {
665                 /*
666                  * If no PIO bufs are available, return.  An interrupt will
667                  * call ipath_ib_piobufavail() when one is available.
668                  */
669                 if (ipath_verbs_send(dev->dd, qp->s_hdrwords,
670                                      (u32 *) &qp->s_hdr, qp->s_cur_size,
671                                      qp->s_cur_sge)) {
672                         ipath_no_bufs_available(qp, dev);
673                         goto bail;
674                 }
675                 dev->n_unicast_xmit++;
676                 /* Record that we sent the packet and s_hdr is empty. */
677                 qp->s_hdrwords = 0;
678         }
679
680         /*
681          * The lock is needed to synchronize between setting
682          * qp->s_ack_state, resend timer, and post_send().
683          */
684         spin_lock_irqsave(&qp->s_lock, flags);
685
686         /* Sending responses has higher priority over sending requests. */
687         if (qp->s_ack_state != IB_OPCODE_RC_ACKNOWLEDGE &&
688             (bth0 = ipath_make_rc_ack(qp, ohdr, pmtu)) != 0)
689                 bth2 = qp->s_ack_psn++ & IPATH_PSN_MASK;
690         else if (!((qp->ibqp.qp_type == IB_QPT_RC) ?
691                    ipath_make_rc_req(qp, ohdr, pmtu, &bth0, &bth2) :
692                    ipath_make_uc_req(qp, ohdr, pmtu, &bth0, &bth2))) {
693                 /*
694                  * Clear the busy bit before unlocking to avoid races with
695                  * adding new work queue items and then failing to process
696                  * them.
697                  */
698                 clear_bit(IPATH_S_BUSY, &qp->s_flags);
699                 spin_unlock_irqrestore(&qp->s_lock, flags);
700                 goto bail;
701         }
702
703         spin_unlock_irqrestore(&qp->s_lock, flags);
704
705         /* Construct the header. */
706         extra_bytes = (4 - qp->s_cur_size) & 3;
707         nwords = (qp->s_cur_size + extra_bytes) >> 2;
708         lrh0 = IPATH_LRH_BTH;
709         if (unlikely(qp->remote_ah_attr.ah_flags & IB_AH_GRH)) {
710                 qp->s_hdrwords += ipath_make_grh(dev, &qp->s_hdr.u.l.grh,
711                                                  &qp->remote_ah_attr.grh,
712                                                  qp->s_hdrwords, nwords);
713                 lrh0 = IPATH_LRH_GRH;
714         }
715         lrh0 |= qp->remote_ah_attr.sl << 4;
716         qp->s_hdr.lrh[0] = cpu_to_be16(lrh0);
717         qp->s_hdr.lrh[1] = cpu_to_be16(qp->remote_ah_attr.dlid);
718         qp->s_hdr.lrh[2] = cpu_to_be16(qp->s_hdrwords + nwords +
719                                        SIZE_OF_CRC);
720         qp->s_hdr.lrh[3] = cpu_to_be16(dev->dd->ipath_lid);
721         bth0 |= ipath_get_pkey(dev->dd, qp->s_pkey_index);
722         bth0 |= extra_bytes << 20;
723         ohdr->bth[0] = cpu_to_be32(bth0);
724         ohdr->bth[1] = cpu_to_be32(qp->remote_qpn);
725         ohdr->bth[2] = cpu_to_be32(bth2);
726
727         /* Check for more work to do. */
728         goto again;
729
730 clear:
731         clear_bit(IPATH_S_BUSY, &qp->s_flags);
732 bail:
733         return;
734 }