2 * Copyright (c) 2006 Oracle. All rights reserved.
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:
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
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.
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
33 #include <linux/kernel.h>
35 #include <linux/device.h>
36 #include <linux/dmapool.h>
37 #include <linux/ratelimit.h>
43 * Convert IB-specific error message to RDS error message and call core
46 static void rds_ib_send_complete(struct rds_message *rm,
48 void (*complete)(struct rds_message *rm, int status))
53 case IB_WC_WR_FLUSH_ERR:
57 notify_status = RDS_RDMA_SUCCESS;
60 case IB_WC_REM_ACCESS_ERR:
61 notify_status = RDS_RDMA_REMOTE_ERROR;
65 notify_status = RDS_RDMA_OTHER_ERROR;
68 complete(rm, notify_status);
71 static void rds_ib_send_unmap_data(struct rds_ib_connection *ic,
72 struct rm_data_op *op,
76 ib_dma_unmap_sg(ic->i_cm_id->device,
77 op->op_sg, op->op_nents,
81 static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic,
82 struct rm_rdma_op *op,
86 ib_dma_unmap_sg(ic->i_cm_id->device,
87 op->op_sg, op->op_nents,
88 op->op_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
92 /* If the user asked for a completion notification on this
93 * message, we can implement three different semantics:
94 * 1. Notify when we received the ACK on the RDS message
95 * that was queued with the RDMA. This provides reliable
96 * notification of RDMA status at the expense of a one-way
98 * 2. Notify when the IB stack gives us the completion event for
100 * 3. Notify when the IB stack gives us the completion event for
101 * the accompanying RDS messages.
102 * Here, we implement approach #3. To implement approach #2,
103 * we would need to take an event for the rdma WR. To implement #1,
104 * don't call rds_rdma_send_complete at all, and fall back to the notify
105 * handling in the ACK processing code.
107 * Note: There's no need to explicitly sync any RDMA buffers using
108 * ib_dma_sync_sg_for_cpu - the completion for the RDMA
109 * operation itself unmapped the RDMA buffers, which takes care
112 rds_ib_send_complete(container_of(op, struct rds_message, rdma),
113 wc_status, rds_rdma_send_complete);
116 rds_stats_add(s_send_rdma_bytes, op->op_bytes);
118 rds_stats_add(s_recv_rdma_bytes, op->op_bytes);
121 static void rds_ib_send_unmap_atomic(struct rds_ib_connection *ic,
122 struct rm_atomic_op *op,
125 /* unmap atomic recvbuf */
127 ib_dma_unmap_sg(ic->i_cm_id->device, op->op_sg, 1,
132 rds_ib_send_complete(container_of(op, struct rds_message, atomic),
133 wc_status, rds_atomic_send_complete);
135 if (op->op_type == RDS_ATOMIC_TYPE_CSWP)
136 rds_ib_stats_inc(s_ib_atomic_cswp);
138 rds_ib_stats_inc(s_ib_atomic_fadd);
142 * Unmap the resources associated with a struct send_work.
144 * Returns the rm for no good reason other than it is unobtainable
145 * other than by switching on wr.opcode, currently, and the caller,
146 * the event handler, needs it.
148 static struct rds_message *rds_ib_send_unmap_op(struct rds_ib_connection *ic,
149 struct rds_ib_send_work *send,
152 struct rds_message *rm = NULL;
154 /* In the error case, wc.opcode sometimes contains garbage */
155 switch (send->s_wr.opcode) {
158 rm = container_of(send->s_op, struct rds_message, data);
159 rds_ib_send_unmap_data(ic, send->s_op, wc_status);
162 case IB_WR_RDMA_WRITE:
163 case IB_WR_RDMA_READ:
165 rm = container_of(send->s_op, struct rds_message, rdma);
166 rds_ib_send_unmap_rdma(ic, send->s_op, wc_status);
169 case IB_WR_ATOMIC_FETCH_AND_ADD:
170 case IB_WR_ATOMIC_CMP_AND_SWP:
172 rm = container_of(send->s_op, struct rds_message, atomic);
173 rds_ib_send_unmap_atomic(ic, send->s_op, wc_status);
177 printk_ratelimited(KERN_NOTICE
178 "RDS/IB: %s: unexpected opcode 0x%x in WR!\n",
179 __func__, send->s_wr.opcode);
183 send->s_wr.opcode = 0xdead;
188 void rds_ib_send_init_ring(struct rds_ib_connection *ic)
190 struct rds_ib_send_work *send;
193 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
198 send->s_wr.wr_id = i;
199 send->s_wr.sg_list = send->s_sge;
200 send->s_wr.ex.imm_data = 0;
202 sge = &send->s_sge[0];
203 sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header));
204 sge->length = sizeof(struct rds_header);
205 sge->lkey = ic->i_mr->lkey;
207 send->s_sge[1].lkey = ic->i_mr->lkey;
211 void rds_ib_send_clear_ring(struct rds_ib_connection *ic)
213 struct rds_ib_send_work *send;
216 for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
217 if (send->s_op && send->s_wr.opcode != 0xdead)
218 rds_ib_send_unmap_op(ic, send, IB_WC_WR_FLUSH_ERR);
223 * The only fast path caller always has a non-zero nr, so we don't
224 * bother testing nr before performing the atomic sub.
226 static void rds_ib_sub_signaled(struct rds_ib_connection *ic, int nr)
228 if ((atomic_sub_return(nr, &ic->i_signaled_sends) == 0) &&
229 waitqueue_active(&rds_ib_ring_empty_wait))
230 wake_up(&rds_ib_ring_empty_wait);
231 BUG_ON(atomic_read(&ic->i_signaled_sends) < 0);
235 * The _oldest/_free ring operations here race cleanly with the alloc/unalloc
236 * operations performed in the send path. As the sender allocs and potentially
237 * unallocs the next free entry in the ring it doesn't alter which is
238 * the next to be freed, which is what this is concerned with.
240 void rds_ib_send_cq_comp_handler(struct ib_cq *cq, void *context)
242 struct rds_connection *conn = context;
243 struct rds_ib_connection *ic = conn->c_transport_data;
244 struct rds_message *rm = NULL;
246 struct rds_ib_send_work *send;
253 rdsdebug("cq %p conn %p\n", cq, conn);
254 rds_ib_stats_inc(s_ib_tx_cq_call);
255 ret = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
257 rdsdebug("ib_req_notify_cq send failed: %d\n", ret);
259 while (ib_poll_cq(cq, 1, &wc) > 0) {
260 rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
261 (unsigned long long)wc.wr_id, wc.status,
262 ib_wc_status_msg(wc.status), wc.byte_len,
263 be32_to_cpu(wc.ex.imm_data));
264 rds_ib_stats_inc(s_ib_tx_cq_event);
266 if (wc.wr_id == RDS_IB_ACK_WR_ID) {
267 if (time_after(jiffies, ic->i_ack_queued + HZ/2))
268 rds_ib_stats_inc(s_ib_tx_stalled);
269 rds_ib_ack_send_complete(ic);
273 oldest = rds_ib_ring_oldest(&ic->i_send_ring);
275 completed = rds_ib_ring_completed(&ic->i_send_ring, wc.wr_id, oldest);
277 for (i = 0; i < completed; i++) {
278 send = &ic->i_sends[oldest];
279 if (send->s_wr.send_flags & IB_SEND_SIGNALED)
282 rm = rds_ib_send_unmap_op(ic, send, wc.status);
284 if (time_after(jiffies, send->s_queued + HZ/2))
285 rds_ib_stats_inc(s_ib_tx_stalled);
288 if (send->s_op == rm->m_final_op) {
289 /* If anyone waited for this message to get flushed out, wake
291 rds_message_unmapped(rm);
297 oldest = (oldest + 1) % ic->i_send_ring.w_nr;
300 rds_ib_ring_free(&ic->i_send_ring, completed);
301 rds_ib_sub_signaled(ic, nr_sig);
304 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) ||
305 test_bit(0, &conn->c_map_queued))
306 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
308 /* We expect errors as the qp is drained during shutdown */
309 if (wc.status != IB_WC_SUCCESS && rds_conn_up(conn)) {
310 rds_ib_conn_error(conn, "send completion on %pI4 had status "
311 "%u (%s), disconnecting and reconnecting\n",
312 &conn->c_faddr, wc.status,
313 ib_wc_status_msg(wc.status));
319 * This is the main function for allocating credits when sending
322 * Conceptually, we have two counters:
323 * - send credits: this tells us how many WRs we're allowed
324 * to submit without overruning the receiver's queue. For
325 * each SEND WR we post, we decrement this by one.
327 * - posted credits: this tells us how many WRs we recently
328 * posted to the receive queue. This value is transferred
329 * to the peer as a "credit update" in a RDS header field.
330 * Every time we transmit credits to the peer, we subtract
331 * the amount of transferred credits from this counter.
333 * It is essential that we avoid situations where both sides have
334 * exhausted their send credits, and are unable to send new credits
335 * to the peer. We achieve this by requiring that we send at least
336 * one credit update to the peer before exhausting our credits.
337 * When new credits arrive, we subtract one credit that is withheld
338 * until we've posted new buffers and are ready to transmit these
339 * credits (see rds_ib_send_add_credits below).
341 * The RDS send code is essentially single-threaded; rds_send_xmit
342 * sets RDS_IN_XMIT to ensure exclusive access to the send ring.
343 * However, the ACK sending code is independent and can race with
346 * In the send path, we need to update the counters for send credits
347 * and the counter of posted buffers atomically - when we use the
348 * last available credit, we cannot allow another thread to race us
349 * and grab the posted credits counter. Hence, we have to use a
350 * spinlock to protect the credit counter, or use atomics.
352 * Spinlocks shared between the send and the receive path are bad,
353 * because they create unnecessary delays. An early implementation
354 * using a spinlock showed a 5% degradation in throughput at some
357 * This implementation avoids spinlocks completely, putting both
358 * counters into a single atomic, and updating that atomic using
359 * atomic_add (in the receive path, when receiving fresh credits),
360 * and using atomic_cmpxchg when updating the two counters.
362 int rds_ib_send_grab_credits(struct rds_ib_connection *ic,
363 u32 wanted, u32 *adv_credits, int need_posted, int max_posted)
365 unsigned int avail, posted, got = 0, advertise;
374 oldval = newval = atomic_read(&ic->i_credits);
375 posted = IB_GET_POST_CREDITS(oldval);
376 avail = IB_GET_SEND_CREDITS(oldval);
378 rdsdebug("wanted=%u credits=%u posted=%u\n",
379 wanted, avail, posted);
381 /* The last credit must be used to send a credit update. */
382 if (avail && !posted)
385 if (avail < wanted) {
386 struct rds_connection *conn = ic->i_cm_id->context;
388 /* Oops, there aren't that many credits left! */
389 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
392 /* Sometimes you get what you want, lalala. */
395 newval -= IB_SET_SEND_CREDITS(got);
398 * If need_posted is non-zero, then the caller wants
399 * the posted regardless of whether any send credits are
402 if (posted && (got || need_posted)) {
403 advertise = min_t(unsigned int, posted, max_posted);
404 newval -= IB_SET_POST_CREDITS(advertise);
407 /* Finally bill everything */
408 if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval)
411 *adv_credits = advertise;
415 void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits)
417 struct rds_ib_connection *ic = conn->c_transport_data;
422 rdsdebug("credits=%u current=%u%s\n",
424 IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)),
425 test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : "");
427 atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits);
428 if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags))
429 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
431 WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384);
433 rds_ib_stats_inc(s_ib_rx_credit_updates);
436 void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted)
438 struct rds_ib_connection *ic = conn->c_transport_data;
443 atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits);
445 /* Decide whether to send an update to the peer now.
446 * If we would send a credit update for every single buffer we
447 * post, we would end up with an ACK storm (ACK arrives,
448 * consumes buffer, we refill the ring, send ACK to remote
449 * advertising the newly posted buffer... ad inf)
451 * Performance pretty much depends on how often we send
452 * credit updates - too frequent updates mean lots of ACKs.
453 * Too infrequent updates, and the peer will run out of
454 * credits and has to throttle.
455 * For the time being, 16 seems to be a good compromise.
457 if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16)
458 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
461 static inline int rds_ib_set_wr_signal_state(struct rds_ib_connection *ic,
462 struct rds_ib_send_work *send,
466 * We want to delay signaling completions just enough to get
467 * the batching benefits but not so much that we create dead time
470 if (ic->i_unsignaled_wrs-- == 0 || notify) {
471 ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
472 send->s_wr.send_flags |= IB_SEND_SIGNALED;
479 * This can be called multiple times for a given message. The first time
480 * we see a message we map its scatterlist into the IB device so that
481 * we can provide that mapped address to the IB scatter gather entries
482 * in the IB work requests. We translate the scatterlist into a series
483 * of work requests that fragment the message. These work requests complete
484 * in order so we pass ownership of the message to the completion handler
485 * once we send the final fragment.
487 * The RDS core uses the c_send_lock to only enter this function once
488 * per connection. This makes sure that the tx ring alloc/unalloc pairs
489 * don't get out of sync and confuse the ring.
491 int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
492 unsigned int hdr_off, unsigned int sg, unsigned int off)
494 struct rds_ib_connection *ic = conn->c_transport_data;
495 struct ib_device *dev = ic->i_cm_id->device;
496 struct rds_ib_send_work *send = NULL;
497 struct rds_ib_send_work *first;
498 struct rds_ib_send_work *prev;
499 struct ib_send_wr *failed_wr;
500 struct scatterlist *scat;
504 u32 credit_alloc = 0;
510 int flow_controlled = 0;
513 BUG_ON(off % RDS_FRAG_SIZE);
514 BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header));
516 /* Do not send cong updates to IB loopback */
518 && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) {
519 rds_cong_map_updated(conn->c_fcong, ~(u64) 0);
520 scat = &rm->data.op_sg[sg];
521 ret = max_t(int, RDS_CONG_MAP_BYTES, scat->length);
522 return sizeof(struct rds_header) + ret;
525 /* FIXME we may overallocate here */
526 if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0)
529 i = ceil(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE);
531 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
532 if (work_alloc == 0) {
533 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
534 rds_ib_stats_inc(s_ib_tx_ring_full);
540 credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT);
541 adv_credits += posted;
542 if (credit_alloc < work_alloc) {
543 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc);
544 work_alloc = credit_alloc;
547 if (work_alloc == 0) {
548 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
549 rds_ib_stats_inc(s_ib_tx_throttle);
555 /* map the message the first time we see it */
556 if (!ic->i_data_op) {
557 if (rm->data.op_nents) {
558 rm->data.op_count = ib_dma_map_sg(dev,
562 rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count);
563 if (rm->data.op_count == 0) {
564 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
565 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
566 ret = -ENOMEM; /* XXX ? */
570 rm->data.op_count = 0;
573 rds_message_addref(rm);
574 rm->data.op_dmasg = 0;
575 rm->data.op_dmaoff = 0;
576 ic->i_data_op = &rm->data;
578 /* Finalize the header */
579 if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags))
580 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED;
581 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
582 rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;
584 /* If it has a RDMA op, tell the peer we did it. This is
585 * used by the peer to release use-once RDMA MRs. */
586 if (rm->rdma.op_active) {
587 struct rds_ext_header_rdma ext_hdr;
589 ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey);
590 rds_message_add_extension(&rm->m_inc.i_hdr,
591 RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr));
593 if (rm->m_rdma_cookie) {
594 rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr,
595 rds_rdma_cookie_key(rm->m_rdma_cookie),
596 rds_rdma_cookie_offset(rm->m_rdma_cookie));
599 /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so
600 * we should not do this unless we have a chance of at least
601 * sticking the header into the send ring. Which is why we
602 * should call rds_ib_ring_alloc first. */
603 rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic));
604 rds_message_make_checksum(&rm->m_inc.i_hdr);
607 * Update adv_credits since we reset the ACK_REQUIRED bit.
610 rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits);
611 adv_credits += posted;
612 BUG_ON(adv_credits > 255);
616 /* Sometimes you want to put a fence between an RDMA
617 * READ and the following SEND.
618 * We could either do this all the time
619 * or when requested by the user. Right now, we let
620 * the application choose.
622 if (rm->rdma.op_active && rm->rdma.op_fence)
623 send_flags = IB_SEND_FENCE;
625 /* Each frag gets a header. Msgs may be 0 bytes */
626 send = &ic->i_sends[pos];
629 scat = &ic->i_data_op->op_sg[rm->data.op_dmasg];
632 unsigned int len = 0;
634 /* Set up the header */
635 send->s_wr.send_flags = send_flags;
636 send->s_wr.opcode = IB_WR_SEND;
637 send->s_wr.num_sge = 1;
638 send->s_wr.next = NULL;
639 send->s_queued = jiffies;
642 send->s_sge[0].addr = ic->i_send_hdrs_dma
643 + (pos * sizeof(struct rds_header));
644 send->s_sge[0].length = sizeof(struct rds_header);
646 memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header));
648 /* Set up the data, if present */
650 && scat != &rm->data.op_sg[rm->data.op_count]) {
651 len = min(RDS_FRAG_SIZE,
652 ib_sg_dma_len(dev, scat) - rm->data.op_dmaoff);
653 send->s_wr.num_sge = 2;
655 send->s_sge[1].addr = ib_sg_dma_address(dev, scat);
656 send->s_sge[1].addr += rm->data.op_dmaoff;
657 send->s_sge[1].length = len;
660 rm->data.op_dmaoff += len;
661 if (rm->data.op_dmaoff == ib_sg_dma_len(dev, scat)) {
664 rm->data.op_dmaoff = 0;
668 rds_ib_set_wr_signal_state(ic, send, 0);
671 * Always signal the last one if we're stopping due to flow control.
673 if (ic->i_flowctl && flow_controlled && i == (work_alloc-1))
674 send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
676 if (send->s_wr.send_flags & IB_SEND_SIGNALED)
679 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
680 &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
682 if (ic->i_flowctl && adv_credits) {
683 struct rds_header *hdr = &ic->i_send_hdrs[pos];
685 /* add credit and redo the header checksum */
686 hdr->h_credit = adv_credits;
687 rds_message_make_checksum(hdr);
689 rds_ib_stats_inc(s_ib_tx_credit_updates);
693 prev->s_wr.next = &send->s_wr;
696 pos = (pos + 1) % ic->i_send_ring.w_nr;
697 send = &ic->i_sends[pos];
700 } while (i < work_alloc
701 && scat != &rm->data.op_sg[rm->data.op_count]);
703 /* Account the RDS header in the number of bytes we sent, but just once.
704 * The caller has no concept of fragmentation. */
706 bytes_sent += sizeof(struct rds_header);
708 /* if we finished the message then send completion owns it */
709 if (scat == &rm->data.op_sg[rm->data.op_count]) {
710 prev->s_op = ic->i_data_op;
711 prev->s_wr.send_flags |= IB_SEND_SOLICITED;
712 if (!(prev->s_wr.send_flags & IB_SEND_SIGNALED)) {
713 ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
714 prev->s_wr.send_flags |= IB_SEND_SIGNALED;
717 ic->i_data_op = NULL;
720 /* Put back wrs & credits we didn't use */
721 if (i < work_alloc) {
722 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
725 if (ic->i_flowctl && i < credit_alloc)
726 rds_ib_send_add_credits(conn, credit_alloc - i);
729 atomic_add(nr_sig, &ic->i_signaled_sends);
731 /* XXX need to worry about failed_wr and partial sends. */
732 failed_wr = &first->s_wr;
733 ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
734 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
735 first, &first->s_wr, ret, failed_wr);
736 BUG_ON(failed_wr != &first->s_wr);
738 printk(KERN_WARNING "RDS/IB: ib_post_send to %pI4 "
739 "returned %d\n", &conn->c_faddr, ret);
740 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
741 rds_ib_sub_signaled(ic, nr_sig);
743 ic->i_data_op = prev->s_op;
747 rds_ib_conn_error(ic->conn, "ib_post_send failed\n");
758 * Issue atomic operation.
759 * A simplified version of the rdma case, we always map 1 SG, and
760 * only 8 bytes, for the return value from the atomic operation.
762 int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op)
764 struct rds_ib_connection *ic = conn->c_transport_data;
765 struct rds_ib_send_work *send = NULL;
766 struct ib_send_wr *failed_wr;
767 struct rds_ib_device *rds_ibdev;
773 rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client);
775 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos);
776 if (work_alloc != 1) {
777 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
778 rds_ib_stats_inc(s_ib_tx_ring_full);
783 /* address of send request in ring */
784 send = &ic->i_sends[pos];
785 send->s_queued = jiffies;
787 if (op->op_type == RDS_ATOMIC_TYPE_CSWP) {
788 send->s_wr.opcode = IB_WR_MASKED_ATOMIC_CMP_AND_SWP;
789 send->s_wr.wr.atomic.compare_add = op->op_m_cswp.compare;
790 send->s_wr.wr.atomic.swap = op->op_m_cswp.swap;
791 send->s_wr.wr.atomic.compare_add_mask = op->op_m_cswp.compare_mask;
792 send->s_wr.wr.atomic.swap_mask = op->op_m_cswp.swap_mask;
794 send->s_wr.opcode = IB_WR_MASKED_ATOMIC_FETCH_AND_ADD;
795 send->s_wr.wr.atomic.compare_add = op->op_m_fadd.add;
796 send->s_wr.wr.atomic.swap = 0;
797 send->s_wr.wr.atomic.compare_add_mask = op->op_m_fadd.nocarry_mask;
798 send->s_wr.wr.atomic.swap_mask = 0;
800 nr_sig = rds_ib_set_wr_signal_state(ic, send, op->op_notify);
801 send->s_wr.num_sge = 1;
802 send->s_wr.next = NULL;
803 send->s_wr.wr.atomic.remote_addr = op->op_remote_addr;
804 send->s_wr.wr.atomic.rkey = op->op_rkey;
806 rds_message_addref(container_of(send->s_op, struct rds_message, atomic));
808 /* map 8 byte retval buffer to the device */
809 ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE);
810 rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret);
812 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
813 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
814 ret = -ENOMEM; /* XXX ? */
818 /* Convert our struct scatterlist to struct ib_sge */
819 send->s_sge[0].addr = ib_sg_dma_address(ic->i_cm_id->device, op->op_sg);
820 send->s_sge[0].length = ib_sg_dma_len(ic->i_cm_id->device, op->op_sg);
821 send->s_sge[0].lkey = ic->i_mr->lkey;
823 rdsdebug("rva %Lx rpa %Lx len %u\n", op->op_remote_addr,
824 send->s_sge[0].addr, send->s_sge[0].length);
827 atomic_add(nr_sig, &ic->i_signaled_sends);
829 failed_wr = &send->s_wr;
830 ret = ib_post_send(ic->i_cm_id->qp, &send->s_wr, &failed_wr);
831 rdsdebug("ic %p send %p (wr %p) ret %d wr %p\n", ic,
832 send, &send->s_wr, ret, failed_wr);
833 BUG_ON(failed_wr != &send->s_wr);
835 printk(KERN_WARNING "RDS/IB: atomic ib_post_send to %pI4 "
836 "returned %d\n", &conn->c_faddr, ret);
837 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
838 rds_ib_sub_signaled(ic, nr_sig);
842 if (unlikely(failed_wr != &send->s_wr)) {
843 printk(KERN_WARNING "RDS/IB: atomic ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
844 BUG_ON(failed_wr != &send->s_wr);
851 int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op)
853 struct rds_ib_connection *ic = conn->c_transport_data;
854 struct rds_ib_send_work *send = NULL;
855 struct rds_ib_send_work *first;
856 struct rds_ib_send_work *prev;
857 struct ib_send_wr *failed_wr;
858 struct scatterlist *scat;
860 u64 remote_addr = op->op_remote_addr;
861 u32 max_sge = ic->rds_ibdev->max_sge;
871 /* map the op the first time we see it */
872 if (!op->op_mapped) {
873 op->op_count = ib_dma_map_sg(ic->i_cm_id->device,
874 op->op_sg, op->op_nents, (op->op_write) ?
875 DMA_TO_DEVICE : DMA_FROM_DEVICE);
876 rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->op_count);
877 if (op->op_count == 0) {
878 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
879 ret = -ENOMEM; /* XXX ? */
887 * Instead of knowing how to return a partial rdma read/write we insist that there
888 * be enough work requests to send the entire message.
890 i = ceil(op->op_count, max_sge);
892 work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
893 if (work_alloc != i) {
894 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
895 rds_ib_stats_inc(s_ib_tx_ring_full);
900 send = &ic->i_sends[pos];
903 scat = &op->op_sg[0];
905 num_sge = op->op_count;
907 for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) {
908 send->s_wr.send_flags = 0;
909 send->s_queued = jiffies;
912 nr_sig += rds_ib_set_wr_signal_state(ic, send, op->op_notify);
914 send->s_wr.opcode = op->op_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ;
915 send->s_wr.wr.rdma.remote_addr = remote_addr;
916 send->s_wr.wr.rdma.rkey = op->op_rkey;
918 if (num_sge > max_sge) {
919 send->s_wr.num_sge = max_sge;
922 send->s_wr.num_sge = num_sge;
925 send->s_wr.next = NULL;
928 prev->s_wr.next = &send->s_wr;
930 for (j = 0; j < send->s_wr.num_sge && scat != &op->op_sg[op->op_count]; j++) {
931 len = ib_sg_dma_len(ic->i_cm_id->device, scat);
932 send->s_sge[j].addr =
933 ib_sg_dma_address(ic->i_cm_id->device, scat);
934 send->s_sge[j].length = len;
935 send->s_sge[j].lkey = ic->i_mr->lkey;
938 rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr);
944 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
945 &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
948 if (++send == &ic->i_sends[ic->i_send_ring.w_nr])
952 /* give a reference to the last op */
953 if (scat == &op->op_sg[op->op_count]) {
955 rds_message_addref(container_of(op, struct rds_message, rdma));
958 if (i < work_alloc) {
959 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
964 atomic_add(nr_sig, &ic->i_signaled_sends);
966 failed_wr = &first->s_wr;
967 ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
968 rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
969 first, &first->s_wr, ret, failed_wr);
970 BUG_ON(failed_wr != &first->s_wr);
972 printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI4 "
973 "returned %d\n", &conn->c_faddr, ret);
974 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
975 rds_ib_sub_signaled(ic, nr_sig);
979 if (unlikely(failed_wr != &first->s_wr)) {
980 printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
981 BUG_ON(failed_wr != &first->s_wr);
989 void rds_ib_xmit_complete(struct rds_connection *conn)
991 struct rds_ib_connection *ic = conn->c_transport_data;
993 /* We may have a pending ACK or window update we were unable
994 * to send previously (due to flow control). Try again. */
995 rds_ib_attempt_ack(ic);