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>
34 #include <linux/pci.h>
35 #include <linux/dma-mapping.h>
36 #include <rdma/rdma_cm.h>
41 static struct kmem_cache *rds_iw_incoming_slab;
42 static struct kmem_cache *rds_iw_frag_slab;
43 static atomic_t rds_iw_allocation = ATOMIC_INIT(0);
45 static void rds_iw_frag_drop_page(struct rds_page_frag *frag)
47 rdsdebug("frag %p page %p\n", frag, frag->f_page);
48 __free_page(frag->f_page);
52 static void rds_iw_frag_free(struct rds_page_frag *frag)
54 rdsdebug("frag %p page %p\n", frag, frag->f_page);
55 BUG_ON(frag->f_page != NULL);
56 kmem_cache_free(rds_iw_frag_slab, frag);
60 * We map a page at a time. Its fragments are posted in order. This
61 * is called in fragment order as the fragments get send completion events.
62 * Only the last frag in the page performs the unmapping.
64 * It's OK for ring cleanup to call this in whatever order it likes because
65 * DMA is not in flight and so we can unmap while other ring entries still
66 * hold page references in their frags.
68 static void rds_iw_recv_unmap_page(struct rds_iw_connection *ic,
69 struct rds_iw_recv_work *recv)
71 struct rds_page_frag *frag = recv->r_frag;
73 rdsdebug("recv %p frag %p page %p\n", recv, frag, frag->f_page);
75 ib_dma_unmap_page(ic->i_cm_id->device,
77 RDS_FRAG_SIZE, DMA_FROM_DEVICE);
81 void rds_iw_recv_init_ring(struct rds_iw_connection *ic)
83 struct rds_iw_recv_work *recv;
86 for (i = 0, recv = ic->i_recvs; i < ic->i_recv_ring.w_nr; i++, recv++) {
92 recv->r_wr.next = NULL;
94 recv->r_wr.sg_list = recv->r_sge;
95 recv->r_wr.num_sge = RDS_IW_RECV_SGE;
97 sge = rds_iw_data_sge(ic, recv->r_sge);
99 sge->length = RDS_FRAG_SIZE;
102 sge = rds_iw_header_sge(ic, recv->r_sge);
103 sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header));
104 sge->length = sizeof(struct rds_header);
109 static void rds_iw_recv_clear_one(struct rds_iw_connection *ic,
110 struct rds_iw_recv_work *recv)
113 rds_inc_put(&recv->r_iwinc->ii_inc);
114 recv->r_iwinc = NULL;
117 rds_iw_recv_unmap_page(ic, recv);
118 if (recv->r_frag->f_page)
119 rds_iw_frag_drop_page(recv->r_frag);
120 rds_iw_frag_free(recv->r_frag);
125 void rds_iw_recv_clear_ring(struct rds_iw_connection *ic)
129 for (i = 0; i < ic->i_recv_ring.w_nr; i++)
130 rds_iw_recv_clear_one(ic, &ic->i_recvs[i]);
132 if (ic->i_frag.f_page)
133 rds_iw_frag_drop_page(&ic->i_frag);
136 static int rds_iw_recv_refill_one(struct rds_connection *conn,
137 struct rds_iw_recv_work *recv,
138 gfp_t kptr_gfp, gfp_t page_gfp)
140 struct rds_iw_connection *ic = conn->c_transport_data;
145 if (recv->r_iwinc == NULL) {
146 if (!atomic_add_unless(&rds_iw_allocation, 1, rds_iw_sysctl_max_recv_allocation)) {
147 rds_iw_stats_inc(s_iw_rx_alloc_limit);
150 recv->r_iwinc = kmem_cache_alloc(rds_iw_incoming_slab,
152 if (recv->r_iwinc == NULL) {
153 atomic_dec(&rds_iw_allocation);
156 INIT_LIST_HEAD(&recv->r_iwinc->ii_frags);
157 rds_inc_init(&recv->r_iwinc->ii_inc, conn, conn->c_faddr);
160 if (recv->r_frag == NULL) {
161 recv->r_frag = kmem_cache_alloc(rds_iw_frag_slab, kptr_gfp);
162 if (recv->r_frag == NULL)
164 INIT_LIST_HEAD(&recv->r_frag->f_item);
165 recv->r_frag->f_page = NULL;
168 if (ic->i_frag.f_page == NULL) {
169 ic->i_frag.f_page = alloc_page(page_gfp);
170 if (ic->i_frag.f_page == NULL)
172 ic->i_frag.f_offset = 0;
175 dma_addr = ib_dma_map_page(ic->i_cm_id->device,
180 if (ib_dma_mapping_error(ic->i_cm_id->device, dma_addr))
184 * Once we get the RDS_PAGE_LAST_OFF frag then rds_iw_frag_unmap()
185 * must be called on this recv. This happens as completions hit
186 * in order or on connection shutdown.
188 recv->r_frag->f_page = ic->i_frag.f_page;
189 recv->r_frag->f_offset = ic->i_frag.f_offset;
190 recv->r_frag->f_mapped = dma_addr;
192 sge = rds_iw_data_sge(ic, recv->r_sge);
193 sge->addr = dma_addr;
194 sge->length = RDS_FRAG_SIZE;
196 sge = rds_iw_header_sge(ic, recv->r_sge);
197 sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header);
198 sge->length = sizeof(struct rds_header);
200 get_page(recv->r_frag->f_page);
202 if (ic->i_frag.f_offset < RDS_PAGE_LAST_OFF) {
203 ic->i_frag.f_offset += RDS_FRAG_SIZE;
205 put_page(ic->i_frag.f_page);
206 ic->i_frag.f_page = NULL;
207 ic->i_frag.f_offset = 0;
216 * This tries to allocate and post unused work requests after making sure that
217 * they have all the allocations they need to queue received fragments into
218 * sockets. The i_recv_mutex is held here so that ring_alloc and _unalloc
219 * pairs don't go unmatched.
221 * -1 is returned if posting fails due to temporary resource exhaustion.
223 int rds_iw_recv_refill(struct rds_connection *conn, gfp_t kptr_gfp,
224 gfp_t page_gfp, int prefill)
226 struct rds_iw_connection *ic = conn->c_transport_data;
227 struct rds_iw_recv_work *recv;
228 struct ib_recv_wr *failed_wr;
229 unsigned int posted = 0;
233 while ((prefill || rds_conn_up(conn)) &&
234 rds_iw_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
235 if (pos >= ic->i_recv_ring.w_nr) {
236 printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n",
242 recv = &ic->i_recvs[pos];
243 ret = rds_iw_recv_refill_one(conn, recv, kptr_gfp, page_gfp);
249 /* XXX when can this fail? */
250 ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr);
251 rdsdebug("recv %p iwinc %p page %p addr %lu ret %d\n", recv,
252 recv->r_iwinc, recv->r_frag->f_page,
253 (long) recv->r_frag->f_mapped, ret);
255 rds_iw_conn_error(conn, "recv post on "
256 "%pI4 returned %d, disconnecting and "
257 "reconnecting\n", &conn->c_faddr,
266 /* We're doing flow control - update the window. */
267 if (ic->i_flowctl && posted)
268 rds_iw_advertise_credits(conn, posted);
271 rds_iw_ring_unalloc(&ic->i_recv_ring, 1);
275 void rds_iw_inc_purge(struct rds_incoming *inc)
277 struct rds_iw_incoming *iwinc;
278 struct rds_page_frag *frag;
279 struct rds_page_frag *pos;
281 iwinc = container_of(inc, struct rds_iw_incoming, ii_inc);
282 rdsdebug("purging iwinc %p inc %p\n", iwinc, inc);
284 list_for_each_entry_safe(frag, pos, &iwinc->ii_frags, f_item) {
285 list_del_init(&frag->f_item);
286 rds_iw_frag_drop_page(frag);
287 rds_iw_frag_free(frag);
291 void rds_iw_inc_free(struct rds_incoming *inc)
293 struct rds_iw_incoming *iwinc;
295 iwinc = container_of(inc, struct rds_iw_incoming, ii_inc);
297 rds_iw_inc_purge(inc);
298 rdsdebug("freeing iwinc %p inc %p\n", iwinc, inc);
299 BUG_ON(!list_empty(&iwinc->ii_frags));
300 kmem_cache_free(rds_iw_incoming_slab, iwinc);
301 atomic_dec(&rds_iw_allocation);
302 BUG_ON(atomic_read(&rds_iw_allocation) < 0);
305 int rds_iw_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov,
308 struct rds_iw_incoming *iwinc;
309 struct rds_page_frag *frag;
310 struct iovec *iov = first_iov;
311 unsigned long to_copy;
312 unsigned long frag_off = 0;
313 unsigned long iov_off = 0;
318 iwinc = container_of(inc, struct rds_iw_incoming, ii_inc);
319 frag = list_entry(iwinc->ii_frags.next, struct rds_page_frag, f_item);
320 len = be32_to_cpu(inc->i_hdr.h_len);
322 while (copied < size && copied < len) {
323 if (frag_off == RDS_FRAG_SIZE) {
324 frag = list_entry(frag->f_item.next,
325 struct rds_page_frag, f_item);
328 while (iov_off == iov->iov_len) {
333 to_copy = min(iov->iov_len - iov_off, RDS_FRAG_SIZE - frag_off);
334 to_copy = min_t(size_t, to_copy, size - copied);
335 to_copy = min_t(unsigned long, to_copy, len - copied);
337 rdsdebug("%lu bytes to user [%p, %zu] + %lu from frag "
339 to_copy, iov->iov_base, iov->iov_len, iov_off,
340 frag->f_page, frag->f_offset, frag_off);
342 /* XXX needs + offset for multiple recvs per page */
343 ret = rds_page_copy_to_user(frag->f_page,
344 frag->f_offset + frag_off,
345 iov->iov_base + iov_off,
360 /* ic starts out kzalloc()ed */
361 void rds_iw_recv_init_ack(struct rds_iw_connection *ic)
363 struct ib_send_wr *wr = &ic->i_ack_wr;
364 struct ib_sge *sge = &ic->i_ack_sge;
366 sge->addr = ic->i_ack_dma;
367 sge->length = sizeof(struct rds_header);
368 sge->lkey = rds_iw_local_dma_lkey(ic);
372 wr->opcode = IB_WR_SEND;
373 wr->wr_id = RDS_IW_ACK_WR_ID;
374 wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED;
378 * You'd think that with reliable IB connections you wouldn't need to ack
379 * messages that have been received. The problem is that IB hardware generates
380 * an ack message before it has DMAed the message into memory. This creates a
381 * potential message loss if the HCA is disabled for any reason between when it
382 * sends the ack and before the message is DMAed and processed. This is only a
383 * potential issue if another HCA is available for fail-over.
385 * When the remote host receives our ack they'll free the sent message from
386 * their send queue. To decrease the latency of this we always send an ack
387 * immediately after we've received messages.
389 * For simplicity, we only have one ack in flight at a time. This puts
390 * pressure on senders to have deep enough send queues to absorb the latency of
391 * a single ack frame being in flight. This might not be good enough.
393 * This is implemented by have a long-lived send_wr and sge which point to a
394 * statically allocated ack frame. This ack wr does not fall under the ring
395 * accounting that the tx and rx wrs do. The QP attribute specifically makes
396 * room for it beyond the ring size. Send completion notices its special
397 * wr_id and avoids working with the ring in that case.
399 #ifndef KERNEL_HAS_ATOMIC64
400 static void rds_iw_set_ack(struct rds_iw_connection *ic, u64 seq,
405 spin_lock_irqsave(&ic->i_ack_lock, flags);
406 ic->i_ack_next = seq;
408 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
409 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
412 static u64 rds_iw_get_ack(struct rds_iw_connection *ic)
417 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
419 spin_lock_irqsave(&ic->i_ack_lock, flags);
420 seq = ic->i_ack_next;
421 spin_unlock_irqrestore(&ic->i_ack_lock, flags);
426 static void rds_iw_set_ack(struct rds_iw_connection *ic, u64 seq,
429 atomic64_set(&ic->i_ack_next, seq);
431 smp_mb__before_clear_bit();
432 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
436 static u64 rds_iw_get_ack(struct rds_iw_connection *ic)
438 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
439 smp_mb__after_clear_bit();
441 return atomic64_read(&ic->i_ack_next);
446 static void rds_iw_send_ack(struct rds_iw_connection *ic, unsigned int adv_credits)
448 struct rds_header *hdr = ic->i_ack;
449 struct ib_send_wr *failed_wr;
453 seq = rds_iw_get_ack(ic);
455 rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
456 rds_message_populate_header(hdr, 0, 0, 0);
457 hdr->h_ack = cpu_to_be64(seq);
458 hdr->h_credit = adv_credits;
459 rds_message_make_checksum(hdr);
460 ic->i_ack_queued = jiffies;
462 ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr);
464 /* Failed to send. Release the WR, and
467 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
468 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
470 rds_iw_stats_inc(s_iw_ack_send_failure);
471 /* Need to finesse this later. */
474 rds_iw_stats_inc(s_iw_ack_sent);
478 * There are 3 ways of getting acknowledgements to the peer:
479 * 1. We call rds_iw_attempt_ack from the recv completion handler
480 * to send an ACK-only frame.
481 * However, there can be only one such frame in the send queue
482 * at any time, so we may have to postpone it.
483 * 2. When another (data) packet is transmitted while there's
484 * an ACK in the queue, we piggyback the ACK sequence number
485 * on the data packet.
486 * 3. If the ACK WR is done sending, we get called from the
487 * send queue completion handler, and check whether there's
488 * another ACK pending (postponed because the WR was on the
489 * queue). If so, we transmit it.
491 * We maintain 2 variables:
492 * - i_ack_flags, which keeps track of whether the ACK WR
493 * is currently in the send queue or not (IB_ACK_IN_FLIGHT)
494 * - i_ack_next, which is the last sequence number we received
496 * Potentially, send queue and receive queue handlers can run concurrently.
497 * It would be nice to not have to use a spinlock to synchronize things,
498 * but the one problem that rules this out is that 64bit updates are
499 * not atomic on all platforms. Things would be a lot simpler if
500 * we had atomic64 or maybe cmpxchg64 everywhere.
502 * Reconnecting complicates this picture just slightly. When we
503 * reconnect, we may be seeing duplicate packets. The peer
504 * is retransmitting them, because it hasn't seen an ACK for
505 * them. It is important that we ACK these.
507 * ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with
508 * this flag set *MUST* be acknowledged immediately.
512 * When we get here, we're called from the recv queue handler.
513 * Check whether we ought to transmit an ACK.
515 void rds_iw_attempt_ack(struct rds_iw_connection *ic)
517 unsigned int adv_credits;
519 if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
522 if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) {
523 rds_iw_stats_inc(s_iw_ack_send_delayed);
527 /* Can we get a send credit? */
528 if (!rds_iw_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) {
529 rds_iw_stats_inc(s_iw_tx_throttle);
530 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
534 clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
535 rds_iw_send_ack(ic, adv_credits);
539 * We get here from the send completion handler, when the
540 * adapter tells us the ACK frame was sent.
542 void rds_iw_ack_send_complete(struct rds_iw_connection *ic)
544 clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
545 rds_iw_attempt_ack(ic);
549 * This is called by the regular xmit code when it wants to piggyback
550 * an ACK on an outgoing frame.
552 u64 rds_iw_piggyb_ack(struct rds_iw_connection *ic)
554 if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags))
555 rds_iw_stats_inc(s_iw_ack_send_piggybacked);
556 return rds_iw_get_ack(ic);
560 * It's kind of lame that we're copying from the posted receive pages into
561 * long-lived bitmaps. We could have posted the bitmaps and rdma written into
562 * them. But receiving new congestion bitmaps should be a *rare* event, so
563 * hopefully we won't need to invest that complexity in making it more
564 * efficient. By copying we can share a simpler core with TCP which has to
567 static void rds_iw_cong_recv(struct rds_connection *conn,
568 struct rds_iw_incoming *iwinc)
570 struct rds_cong_map *map;
571 unsigned int map_off;
572 unsigned int map_page;
573 struct rds_page_frag *frag;
574 unsigned long frag_off;
575 unsigned long to_copy;
576 unsigned long copied;
577 uint64_t uncongested = 0;
580 /* catch completely corrupt packets */
581 if (be32_to_cpu(iwinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
588 frag = list_entry(iwinc->ii_frags.next, struct rds_page_frag, f_item);
593 while (copied < RDS_CONG_MAP_BYTES) {
597 to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off);
598 BUG_ON(to_copy & 7); /* Must be 64bit aligned. */
600 addr = kmap_atomic(frag->f_page, KM_SOFTIRQ0);
602 src = addr + frag_off;
603 dst = (void *)map->m_page_addrs[map_page] + map_off;
604 for (k = 0; k < to_copy; k += 8) {
605 /* Record ports that became uncongested, ie
606 * bits that changed from 0 to 1. */
607 uncongested |= ~(*src) & *dst;
610 kunmap_atomic(addr, KM_SOFTIRQ0);
615 if (map_off == PAGE_SIZE) {
621 if (frag_off == RDS_FRAG_SIZE) {
622 frag = list_entry(frag->f_item.next,
623 struct rds_page_frag, f_item);
628 /* the congestion map is in little endian order */
629 uncongested = le64_to_cpu(uncongested);
631 rds_cong_map_updated(map, uncongested);
635 * Rings are posted with all the allocations they'll need to queue the
636 * incoming message to the receiving socket so this can't fail.
637 * All fragments start with a header, so we can make sure we're not receiving
638 * garbage, and we can tell a small 8 byte fragment from an ACK frame.
640 struct rds_iw_ack_state {
643 unsigned int ack_required:1;
644 unsigned int ack_next_valid:1;
645 unsigned int ack_recv_valid:1;
648 static void rds_iw_process_recv(struct rds_connection *conn,
649 struct rds_iw_recv_work *recv, u32 byte_len,
650 struct rds_iw_ack_state *state)
652 struct rds_iw_connection *ic = conn->c_transport_data;
653 struct rds_iw_incoming *iwinc = ic->i_iwinc;
654 struct rds_header *ihdr, *hdr;
656 /* XXX shut down the connection if port 0,0 are seen? */
658 rdsdebug("ic %p iwinc %p recv %p byte len %u\n", ic, iwinc, recv,
661 if (byte_len < sizeof(struct rds_header)) {
662 rds_iw_conn_error(conn, "incoming message "
663 "from %pI4 didn't inclue a "
664 "header, disconnecting and "
669 byte_len -= sizeof(struct rds_header);
671 ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs];
673 /* Validate the checksum. */
674 if (!rds_message_verify_checksum(ihdr)) {
675 rds_iw_conn_error(conn, "incoming message "
676 "from %pI4 has corrupted header - "
677 "forcing a reconnect\n",
679 rds_stats_inc(s_recv_drop_bad_checksum);
683 /* Process the ACK sequence which comes with every packet */
684 state->ack_recv = be64_to_cpu(ihdr->h_ack);
685 state->ack_recv_valid = 1;
687 /* Process the credits update if there was one */
689 rds_iw_send_add_credits(conn, ihdr->h_credit);
691 if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && byte_len == 0) {
692 /* This is an ACK-only packet. The fact that it gets
693 * special treatment here is that historically, ACKs
694 * were rather special beasts.
696 rds_iw_stats_inc(s_iw_ack_received);
699 * Usually the frags make their way on to incs and are then freed as
700 * the inc is freed. We don't go that route, so we have to drop the
701 * page ref ourselves. We can't just leave the page on the recv
702 * because that confuses the dma mapping of pages and each recv's use
703 * of a partial page. We can leave the frag, though, it will be
706 * FIXME: Fold this into the code path below.
708 rds_iw_frag_drop_page(recv->r_frag);
713 * If we don't already have an inc on the connection then this
714 * fragment has a header and starts a message.. copy its header
715 * into the inc and save the inc so we can hang upcoming fragments
719 iwinc = recv->r_iwinc;
720 recv->r_iwinc = NULL;
723 hdr = &iwinc->ii_inc.i_hdr;
724 memcpy(hdr, ihdr, sizeof(*hdr));
725 ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);
727 rdsdebug("ic %p iwinc %p rem %u flag 0x%x\n", ic, iwinc,
728 ic->i_recv_data_rem, hdr->h_flags);
730 hdr = &iwinc->ii_inc.i_hdr;
731 /* We can't just use memcmp here; fragments of a
732 * single message may carry different ACKs */
733 if (hdr->h_sequence != ihdr->h_sequence ||
734 hdr->h_len != ihdr->h_len ||
735 hdr->h_sport != ihdr->h_sport ||
736 hdr->h_dport != ihdr->h_dport) {
737 rds_iw_conn_error(conn,
738 "fragment header mismatch; forcing reconnect\n");
743 list_add_tail(&recv->r_frag->f_item, &iwinc->ii_frags);
746 if (ic->i_recv_data_rem > RDS_FRAG_SIZE)
747 ic->i_recv_data_rem -= RDS_FRAG_SIZE;
749 ic->i_recv_data_rem = 0;
752 if (iwinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
753 rds_iw_cong_recv(conn, iwinc);
755 rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr,
756 &iwinc->ii_inc, GFP_ATOMIC,
758 state->ack_next = be64_to_cpu(hdr->h_sequence);
759 state->ack_next_valid = 1;
762 /* Evaluate the ACK_REQUIRED flag *after* we received
763 * the complete frame, and after bumping the next_rx
765 if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) {
766 rds_stats_inc(s_recv_ack_required);
767 state->ack_required = 1;
770 rds_inc_put(&iwinc->ii_inc);
775 * Plucking the oldest entry from the ring can be done concurrently with
776 * the thread refilling the ring. Each ring operation is protected by
777 * spinlocks and the transient state of refilling doesn't change the
778 * recording of which entry is oldest.
780 * This relies on IB only calling one cq comp_handler for each cq so that
781 * there will only be one caller of rds_recv_incoming() per RDS connection.
783 void rds_iw_recv_cq_comp_handler(struct ib_cq *cq, void *context)
785 struct rds_connection *conn = context;
786 struct rds_iw_connection *ic = conn->c_transport_data;
788 rdsdebug("conn %p cq %p\n", conn, cq);
790 rds_iw_stats_inc(s_iw_rx_cq_call);
792 tasklet_schedule(&ic->i_recv_tasklet);
795 static inline void rds_poll_cq(struct rds_iw_connection *ic,
796 struct rds_iw_ack_state *state)
798 struct rds_connection *conn = ic->conn;
800 struct rds_iw_recv_work *recv;
802 while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) {
803 rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n",
804 (unsigned long long)wc.wr_id, wc.status, wc.byte_len,
805 be32_to_cpu(wc.ex.imm_data));
806 rds_iw_stats_inc(s_iw_rx_cq_event);
808 recv = &ic->i_recvs[rds_iw_ring_oldest(&ic->i_recv_ring)];
810 rds_iw_recv_unmap_page(ic, recv);
813 * Also process recvs in connecting state because it is possible
814 * to get a recv completion _before_ the rdmacm ESTABLISHED
815 * event is processed.
817 if (rds_conn_up(conn) || rds_conn_connecting(conn)) {
818 /* We expect errors as the qp is drained during shutdown */
819 if (wc.status == IB_WC_SUCCESS) {
820 rds_iw_process_recv(conn, recv, wc.byte_len, state);
822 rds_iw_conn_error(conn, "recv completion on "
823 "%pI4 had status %u, disconnecting and "
824 "reconnecting\n", &conn->c_faddr,
829 rds_iw_ring_free(&ic->i_recv_ring, 1);
833 void rds_iw_recv_tasklet_fn(unsigned long data)
835 struct rds_iw_connection *ic = (struct rds_iw_connection *) data;
836 struct rds_connection *conn = ic->conn;
837 struct rds_iw_ack_state state = { 0, };
839 rds_poll_cq(ic, &state);
840 ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED);
841 rds_poll_cq(ic, &state);
843 if (state.ack_next_valid)
844 rds_iw_set_ack(ic, state.ack_next, state.ack_required);
845 if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) {
846 rds_send_drop_acked(conn, state.ack_recv, NULL);
847 ic->i_ack_recv = state.ack_recv;
849 if (rds_conn_up(conn))
850 rds_iw_attempt_ack(ic);
852 /* If we ever end up with a really empty receive ring, we're
853 * in deep trouble, as the sender will definitely see RNR
855 if (rds_iw_ring_empty(&ic->i_recv_ring))
856 rds_iw_stats_inc(s_iw_rx_ring_empty);
859 * If the ring is running low, then schedule the thread to refill.
861 if (rds_iw_ring_low(&ic->i_recv_ring))
862 queue_delayed_work(rds_wq, &conn->c_recv_w, 0);
865 int rds_iw_recv(struct rds_connection *conn)
867 struct rds_iw_connection *ic = conn->c_transport_data;
870 rdsdebug("conn %p\n", conn);
873 * If we get a temporary posting failure in this context then
874 * we're really low and we want the caller to back off for a bit.
876 mutex_lock(&ic->i_recv_mutex);
877 if (rds_iw_recv_refill(conn, GFP_KERNEL, GFP_HIGHUSER, 0))
880 rds_iw_stats_inc(s_iw_rx_refill_from_thread);
881 mutex_unlock(&ic->i_recv_mutex);
883 if (rds_conn_up(conn))
884 rds_iw_attempt_ack(ic);
889 int __init rds_iw_recv_init(void)
894 /* Default to 30% of all available RAM for recv memory */
896 rds_iw_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;
898 rds_iw_incoming_slab = kmem_cache_create("rds_iw_incoming",
899 sizeof(struct rds_iw_incoming),
901 if (rds_iw_incoming_slab == NULL)
904 rds_iw_frag_slab = kmem_cache_create("rds_iw_frag",
905 sizeof(struct rds_page_frag),
907 if (rds_iw_frag_slab == NULL)
908 kmem_cache_destroy(rds_iw_incoming_slab);
915 void rds_iw_recv_exit(void)
917 kmem_cache_destroy(rds_iw_incoming_slab);
918 kmem_cache_destroy(rds_iw_frag_slab);