/* * Copyright (c) 2006 Oracle. All rights reserved. * * This software is available to you under a choice of one of two * licenses. You may choose to be licensed under the terms of the GNU * General Public License (GPL) Version 2, available from the file * COPYING in the main directory of this source tree, or the * OpenIB.org BSD license below: * * Redistribution and use in source and binary forms, with or * without modification, are permitted provided that the following * conditions are met: * * - Redistributions of source code must retain the above * copyright notice, this list of conditions and the following * disclaimer. * * - Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials * provided with the distribution. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. * */ #include <linux/kernel.h> #include <linux/slab.h> #include <linux/pci.h> #include <linux/dma-mapping.h> #include <rdma/rdma_cm.h> #include "rds.h" #include "iw.h" static struct kmem_cache *rds_iw_incoming_slab; static struct kmem_cache *rds_iw_frag_slab; static atomic_t rds_iw_allocation = ATOMIC_INIT(0); static void rds_iw_frag_drop_page(struct rds_page_frag *frag) { rdsdebug("frag %p page %p\n", frag, frag->f_page); __free_page(frag->f_page); frag->f_page = NULL; } static void rds_iw_frag_free(struct rds_page_frag *frag) { rdsdebug("frag %p page %p\n", frag, frag->f_page); BUG_ON(frag->f_page); kmem_cache_free(rds_iw_frag_slab, frag); } /* * We map a page at a time. Its fragments are posted in order. This * is called in fragment order as the fragments get send completion events. * Only the last frag in the page performs the unmapping. * * It's OK for ring cleanup to call this in whatever order it likes because * DMA is not in flight and so we can unmap while other ring entries still * hold page references in their frags. */ static void rds_iw_recv_unmap_page(struct rds_iw_connection *ic, struct rds_iw_recv_work *recv) { struct rds_page_frag *frag = recv->r_frag; rdsdebug("recv %p frag %p page %p\n", recv, frag, frag->f_page); if (frag->f_mapped) ib_dma_unmap_page(ic->i_cm_id->device, frag->f_mapped, RDS_FRAG_SIZE, DMA_FROM_DEVICE); frag->f_mapped = 0; } void rds_iw_recv_init_ring(struct rds_iw_connection *ic) { struct rds_iw_recv_work *recv; u32 i; for (i = 0, recv = ic->i_recvs; i < ic->i_recv_ring.w_nr; i++, recv++) { struct ib_sge *sge; recv->r_iwinc = NULL; recv->r_frag = NULL; recv->r_wr.next = NULL; recv->r_wr.wr_id = i; recv->r_wr.sg_list = recv->r_sge; recv->r_wr.num_sge = RDS_IW_RECV_SGE; sge = rds_iw_data_sge(ic, recv->r_sge); sge->addr = 0; sge->length = RDS_FRAG_SIZE; sge->lkey = 0; sge = rds_iw_header_sge(ic, recv->r_sge); sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header)); sge->length = sizeof(struct rds_header); sge->lkey = 0; } } static void rds_iw_recv_clear_one(struct rds_iw_connection *ic, struct rds_iw_recv_work *recv) { if (recv->r_iwinc) { rds_inc_put(&recv->r_iwinc->ii_inc); recv->r_iwinc = NULL; } if (recv->r_frag) { rds_iw_recv_unmap_page(ic, recv); if (recv->r_frag->f_page) rds_iw_frag_drop_page(recv->r_frag); rds_iw_frag_free(recv->r_frag); recv->r_frag = NULL; } } void rds_iw_recv_clear_ring(struct rds_iw_connection *ic) { u32 i; for (i = 0; i < ic->i_recv_ring.w_nr; i++) rds_iw_recv_clear_one(ic, &ic->i_recvs[i]); if (ic->i_frag.f_page) rds_iw_frag_drop_page(&ic->i_frag); } static int rds_iw_recv_refill_one(struct rds_connection *conn, struct rds_iw_recv_work *recv, gfp_t kptr_gfp, gfp_t page_gfp) { struct rds_iw_connection *ic = conn->c_transport_data; dma_addr_t dma_addr; struct ib_sge *sge; int ret = -ENOMEM; if (!recv->r_iwinc) { if (!atomic_add_unless(&rds_iw_allocation, 1, rds_iw_sysctl_max_recv_allocation)) { rds_iw_stats_inc(s_iw_rx_alloc_limit); goto out; } recv->r_iwinc = kmem_cache_alloc(rds_iw_incoming_slab, kptr_gfp); if (!recv->r_iwinc) { atomic_dec(&rds_iw_allocation); goto out; } INIT_LIST_HEAD(&recv->r_iwinc->ii_frags); rds_inc_init(&recv->r_iwinc->ii_inc, conn, conn->c_faddr); } if (!recv->r_frag) { recv->r_frag = kmem_cache_alloc(rds_iw_frag_slab, kptr_gfp); if (!recv->r_frag) goto out; INIT_LIST_HEAD(&recv->r_frag->f_item); recv->r_frag->f_page = NULL; } if (!ic->i_frag.f_page) { ic->i_frag.f_page = alloc_page(page_gfp); if (!ic->i_frag.f_page) goto out; ic->i_frag.f_offset = 0; } dma_addr = ib_dma_map_page(ic->i_cm_id->device, ic->i_frag.f_page, ic->i_frag.f_offset, RDS_FRAG_SIZE, DMA_FROM_DEVICE); if (ib_dma_mapping_error(ic->i_cm_id->device, dma_addr)) goto out; /* * Once we get the RDS_PAGE_LAST_OFF frag then rds_iw_frag_unmap() * must be called on this recv. This happens as completions hit * in order or on connection shutdown. */ recv->r_frag->f_page = ic->i_frag.f_page; recv->r_frag->f_offset = ic->i_frag.f_offset; recv->r_frag->f_mapped = dma_addr; sge = rds_iw_data_sge(ic, recv->r_sge); sge->addr = dma_addr; sge->length = RDS_FRAG_SIZE; sge = rds_iw_header_sge(ic, recv->r_sge); sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header); sge->length = sizeof(struct rds_header); get_page(recv->r_frag->f_page); if (ic->i_frag.f_offset < RDS_PAGE_LAST_OFF) { ic->i_frag.f_offset += RDS_FRAG_SIZE; } else { put_page(ic->i_frag.f_page); ic->i_frag.f_page = NULL; ic->i_frag.f_offset = 0; } ret = 0; out: return ret; } /* * This tries to allocate and post unused work requests after making sure that * they have all the allocations they need to queue received fragments into * sockets. The i_recv_mutex is held here so that ring_alloc and _unalloc * pairs don't go unmatched. * * -1 is returned if posting fails due to temporary resource exhaustion. */ int rds_iw_recv_refill(struct rds_connection *conn, gfp_t kptr_gfp, gfp_t page_gfp, int prefill) { struct rds_iw_connection *ic = conn->c_transport_data; struct rds_iw_recv_work *recv; struct ib_recv_wr *failed_wr; unsigned int posted = 0; int ret = 0; u32 pos; while ((prefill || rds_conn_up(conn)) && rds_iw_ring_alloc(&ic->i_recv_ring, 1, &pos)) { if (pos >= ic->i_recv_ring.w_nr) { printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n", pos); ret = -EINVAL; break; } recv = &ic->i_recvs[pos]; ret = rds_iw_recv_refill_one(conn, recv, kptr_gfp, page_gfp); if (ret) { ret = -1; break; } /* XXX when can this fail? */ ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr); rdsdebug("recv %p iwinc %p page %p addr %lu ret %d\n", recv, recv->r_iwinc, recv->r_frag->f_page, (long) recv->r_frag->f_mapped, ret); if (ret) { rds_iw_conn_error(conn, "recv post on " "%pI4 returned %d, disconnecting and " "reconnecting\n", &conn->c_faddr, ret); ret = -1; break; } posted++; } /* We're doing flow control - update the window. */ if (ic->i_flowctl && posted) rds_iw_advertise_credits(conn, posted); if (ret) rds_iw_ring_unalloc(&ic->i_recv_ring, 1); return ret; } static void rds_iw_inc_purge(struct rds_incoming *inc) { struct rds_iw_incoming *iwinc; struct rds_page_frag *frag; struct rds_page_frag *pos; iwinc = container_of(inc, struct rds_iw_incoming, ii_inc); rdsdebug("purging iwinc %p inc %p\n", iwinc, inc); list_for_each_entry_safe(frag, pos, &iwinc->ii_frags, f_item) { list_del_init(&frag->f_item); rds_iw_frag_drop_page(frag); rds_iw_frag_free(frag); } } void rds_iw_inc_free(struct rds_incoming *inc) { struct rds_iw_incoming *iwinc; iwinc = container_of(inc, struct rds_iw_incoming, ii_inc); rds_iw_inc_purge(inc); rdsdebug("freeing iwinc %p inc %p\n", iwinc, inc); BUG_ON(!list_empty(&iwinc->ii_frags)); kmem_cache_free(rds_iw_incoming_slab, iwinc); atomic_dec(&rds_iw_allocation); BUG_ON(atomic_read(&rds_iw_allocation) < 0); } int rds_iw_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov, size_t size) { struct rds_iw_incoming *iwinc; struct rds_page_frag *frag; struct iovec *iov = first_iov; unsigned long to_copy; unsigned long frag_off = 0; unsigned long iov_off = 0; int copied = 0; int ret; u32 len; iwinc = container_of(inc, struct rds_iw_incoming, ii_inc); frag = list_entry(iwinc->ii_frags.next, struct rds_page_frag, f_item); len = be32_to_cpu(inc->i_hdr.h_len); while (copied < size && copied < len) { if (frag_off == RDS_FRAG_SIZE) { frag = list_entry(frag->f_item.next, struct rds_page_frag, f_item); frag_off = 0; } while (iov_off == iov->iov_len) { iov_off = 0; iov++; } to_copy = min(iov->iov_len - iov_off, RDS_FRAG_SIZE - frag_off); to_copy = min_t(size_t, to_copy, size - copied); to_copy = min_t(unsigned long, to_copy, len - copied); rdsdebug("%lu bytes to user [%p, %zu] + %lu from frag " "[%p, %lu] + %lu\n", to_copy, iov->iov_base, iov->iov_len, iov_off, frag->f_page, frag->f_offset, frag_off); /* XXX needs + offset for multiple recvs per page */ ret = rds_page_copy_to_user(frag->f_page, frag->f_offset + frag_off, iov->iov_base + iov_off, to_copy); if (ret) { copied = ret; break; } iov_off += to_copy; frag_off += to_copy; copied += to_copy; } return copied; } /* ic starts out kzalloc()ed */ void rds_iw_recv_init_ack(struct rds_iw_connection *ic) { struct ib_send_wr *wr = &ic->i_ack_wr; struct ib_sge *sge = &ic->i_ack_sge; sge->addr = ic->i_ack_dma; sge->length = sizeof(struct rds_header); sge->lkey = rds_iw_local_dma_lkey(ic); wr->sg_list = sge; wr->num_sge = 1; wr->opcode = IB_WR_SEND; wr->wr_id = RDS_IW_ACK_WR_ID; wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED; } /* * You'd think that with reliable IB connections you wouldn't need to ack * messages that have been received. The problem is that IB hardware generates * an ack message before it has DMAed the message into memory. This creates a * potential message loss if the HCA is disabled for any reason between when it * sends the ack and before the message is DMAed and processed. This is only a * potential issue if another HCA is available for fail-over. * * When the remote host receives our ack they'll free the sent message from * their send queue. To decrease the latency of this we always send an ack * immediately after we've received messages. * * For simplicity, we only have one ack in flight at a time. This puts * pressure on senders to have deep enough send queues to absorb the latency of * a single ack frame being in flight. This might not be good enough. * * This is implemented by have a long-lived send_wr and sge which point to a * statically allocated ack frame. This ack wr does not fall under the ring * accounting that the tx and rx wrs do. The QP attribute specifically makes * room for it beyond the ring size. Send completion notices its special * wr_id and avoids working with the ring in that case. */ #ifndef KERNEL_HAS_ATOMIC64 static void rds_iw_set_ack(struct rds_iw_connection *ic, u64 seq, int ack_required) { unsigned long flags; spin_lock_irqsave(&ic->i_ack_lock, flags); ic->i_ack_next = seq; if (ack_required) set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); spin_unlock_irqrestore(&ic->i_ack_lock, flags); } static u64 rds_iw_get_ack(struct rds_iw_connection *ic) { unsigned long flags; u64 seq; clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); spin_lock_irqsave(&ic->i_ack_lock, flags); seq = ic->i_ack_next; spin_unlock_irqrestore(&ic->i_ack_lock, flags); return seq; } #else static void rds_iw_set_ack(struct rds_iw_connection *ic, u64 seq, int ack_required) { atomic64_set(&ic->i_ack_next, seq); if (ack_required) { smp_mb__before_clear_bit(); set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); } } static u64 rds_iw_get_ack(struct rds_iw_connection *ic) { clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); smp_mb__after_clear_bit(); return atomic64_read(&ic->i_ack_next); } #endif static void rds_iw_send_ack(struct rds_iw_connection *ic, unsigned int adv_credits) { struct rds_header *hdr = ic->i_ack; struct ib_send_wr *failed_wr; u64 seq; int ret; seq = rds_iw_get_ack(ic); rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq); rds_message_populate_header(hdr, 0, 0, 0); hdr->h_ack = cpu_to_be64(seq); hdr->h_credit = adv_credits; rds_message_make_checksum(hdr); ic->i_ack_queued = jiffies; ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr); if (unlikely(ret)) { /* Failed to send. Release the WR, and * force another ACK. */ clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); rds_iw_stats_inc(s_iw_ack_send_failure); rds_iw_conn_error(ic->conn, "sending ack failed\n"); } else rds_iw_stats_inc(s_iw_ack_sent); } /* * There are 3 ways of getting acknowledgements to the peer: * 1. We call rds_iw_attempt_ack from the recv completion handler * to send an ACK-only frame. * However, there can be only one such frame in the send queue * at any time, so we may have to postpone it. * 2. When another (data) packet is transmitted while there's * an ACK in the queue, we piggyback the ACK sequence number * on the data packet. * 3. If the ACK WR is done sending, we get called from the * send queue completion handler, and check whether there's * another ACK pending (postponed because the WR was on the * queue). If so, we transmit it. * * We maintain 2 variables: * - i_ack_flags, which keeps track of whether the ACK WR * is currently in the send queue or not (IB_ACK_IN_FLIGHT) * - i_ack_next, which is the last sequence number we received * * Potentially, send queue and receive queue handlers can run concurrently. * It would be nice to not have to use a spinlock to synchronize things, * but the one problem that rules this out is that 64bit updates are * not atomic on all platforms. Things would be a lot simpler if * we had atomic64 or maybe cmpxchg64 everywhere. * * Reconnecting complicates this picture just slightly. When we * reconnect, we may be seeing duplicate packets. The peer * is retransmitting them, because it hasn't seen an ACK for * them. It is important that we ACK these. * * ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with * this flag set *MUST* be acknowledged immediately. */ /* * When we get here, we're called from the recv queue handler. * Check whether we ought to transmit an ACK. */ void rds_iw_attempt_ack(struct rds_iw_connection *ic) { unsigned int adv_credits; if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags)) return; if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) { rds_iw_stats_inc(s_iw_ack_send_delayed); return; } /* Can we get a send credit? */ if (!rds_iw_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) { rds_iw_stats_inc(s_iw_tx_throttle); clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); return; } clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); rds_iw_send_ack(ic, adv_credits); } /* * We get here from the send completion handler, when the * adapter tells us the ACK frame was sent. */ void rds_iw_ack_send_complete(struct rds_iw_connection *ic) { clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); rds_iw_attempt_ack(ic); } /* * This is called by the regular xmit code when it wants to piggyback * an ACK on an outgoing frame. */ u64 rds_iw_piggyb_ack(struct rds_iw_connection *ic) { if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags)) rds_iw_stats_inc(s_iw_ack_send_piggybacked); return rds_iw_get_ack(ic); } /* * It's kind of lame that we're copying from the posted receive pages into * long-lived bitmaps. We could have posted the bitmaps and rdma written into * them. But receiving new congestion bitmaps should be a *rare* event, so * hopefully we won't need to invest that complexity in making it more * efficient. By copying we can share a simpler core with TCP which has to * copy. */ static void rds_iw_cong_recv(struct rds_connection *conn, struct rds_iw_incoming *iwinc) { struct rds_cong_map *map; unsigned int map_off; unsigned int map_page; struct rds_page_frag *frag; unsigned long frag_off; unsigned long to_copy; unsigned long copied; uint64_t uncongested = 0; void *addr; /* catch completely corrupt packets */ if (be32_to_cpu(iwinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES) return; map = conn->c_fcong; map_page = 0; map_off = 0; frag = list_entry(iwinc->ii_frags.next, struct rds_page_frag, f_item); frag_off = 0; copied = 0; while (copied < RDS_CONG_MAP_BYTES) { uint64_t *src, *dst; unsigned int k; to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off); BUG_ON(to_copy & 7); /* Must be 64bit aligned. */ addr = kmap_atomic(frag->f_page); src = addr + frag_off; dst = (void *)map->m_page_addrs[map_page] + map_off; for (k = 0; k < to_copy; k += 8) { /* Record ports that became uncongested, ie * bits that changed from 0 to 1. */ uncongested |= ~(*src) & *dst; *dst++ = *src++; } kunmap_atomic(addr); copied += to_copy; map_off += to_copy; if (map_off == PAGE_SIZE) { map_off = 0; map_page++; } frag_off += to_copy; if (frag_off == RDS_FRAG_SIZE) { frag = list_entry(frag->f_item.next, struct rds_page_frag, f_item); frag_off = 0; } } /* the congestion map is in little endian order */ uncongested = le64_to_cpu(uncongested); rds_cong_map_updated(map, uncongested); } /* * Rings are posted with all the allocations they'll need to queue the * incoming message to the receiving socket so this can't fail. * All fragments start with a header, so we can make sure we're not receiving * garbage, and we can tell a small 8 byte fragment from an ACK frame. */ struct rds_iw_ack_state { u64 ack_next; u64 ack_recv; unsigned int ack_required:1; unsigned int ack_next_valid:1; unsigned int ack_recv_valid:1; }; static void rds_iw_process_recv(struct rds_connection *conn, struct rds_iw_recv_work *recv, u32 byte_len, struct rds_iw_ack_state *state) { struct rds_iw_connection *ic = conn->c_transport_data; struct rds_iw_incoming *iwinc = ic->i_iwinc; struct rds_header *ihdr, *hdr; /* XXX shut down the connection if port 0,0 are seen? */ rdsdebug("ic %p iwinc %p recv %p byte len %u\n", ic, iwinc, recv, byte_len); if (byte_len < sizeof(struct rds_header)) { rds_iw_conn_error(conn, "incoming message " "from %pI4 didn't include a " "header, disconnecting and " "reconnecting\n", &conn->c_faddr); return; } byte_len -= sizeof(struct rds_header); ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs]; /* Validate the checksum. */ if (!rds_message_verify_checksum(ihdr)) { rds_iw_conn_error(conn, "incoming message " "from %pI4 has corrupted header - " "forcing a reconnect\n", &conn->c_faddr); rds_stats_inc(s_recv_drop_bad_checksum); return; } /* Process the ACK sequence which comes with every packet */ state->ack_recv = be64_to_cpu(ihdr->h_ack); state->ack_recv_valid = 1; /* Process the credits update if there was one */ if (ihdr->h_credit) rds_iw_send_add_credits(conn, ihdr->h_credit); if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && byte_len == 0) { /* This is an ACK-only packet. The fact that it gets * special treatment here is that historically, ACKs * were rather special beasts. */ rds_iw_stats_inc(s_iw_ack_received); /* * Usually the frags make their way on to incs and are then freed as * the inc is freed. We don't go that route, so we have to drop the * page ref ourselves. We can't just leave the page on the recv * because that confuses the dma mapping of pages and each recv's use * of a partial page. We can leave the frag, though, it will be * reused. * * FIXME: Fold this into the code path below. */ rds_iw_frag_drop_page(recv->r_frag); return; } /* * If we don't already have an inc on the connection then this * fragment has a header and starts a message.. copy its header * into the inc and save the inc so we can hang upcoming fragments * off its list. */ if (!iwinc) { iwinc = recv->r_iwinc; recv->r_iwinc = NULL; ic->i_iwinc = iwinc; hdr = &iwinc->ii_inc.i_hdr; memcpy(hdr, ihdr, sizeof(*hdr)); ic->i_recv_data_rem = be32_to_cpu(hdr->h_len); rdsdebug("ic %p iwinc %p rem %u flag 0x%x\n", ic, iwinc, ic->i_recv_data_rem, hdr->h_flags); } else { hdr = &iwinc->ii_inc.i_hdr; /* We can't just use memcmp here; fragments of a * single message may carry different ACKs */ if (hdr->h_sequence != ihdr->h_sequence || hdr->h_len != ihdr->h_len || hdr->h_sport != ihdr->h_sport || hdr->h_dport != ihdr->h_dport) { rds_iw_conn_error(conn, "fragment header mismatch; forcing reconnect\n"); return; } } list_add_tail(&recv->r_frag->f_item, &iwinc->ii_frags); recv->r_frag = NULL; if (ic->i_recv_data_rem > RDS_FRAG_SIZE) ic->i_recv_data_rem -= RDS_FRAG_SIZE; else { ic->i_recv_data_rem = 0; ic->i_iwinc = NULL; if (iwinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP) rds_iw_cong_recv(conn, iwinc); else { rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr, &iwinc->ii_inc, GFP_ATOMIC); state->ack_next = be64_to_cpu(hdr->h_sequence); state->ack_next_valid = 1; } /* Evaluate the ACK_REQUIRED flag *after* we received * the complete frame, and after bumping the next_rx * sequence. */ if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) { rds_stats_inc(s_recv_ack_required); state->ack_required = 1; } rds_inc_put(&iwinc->ii_inc); } } /* * Plucking the oldest entry from the ring can be done concurrently with * the thread refilling the ring. Each ring operation is protected by * spinlocks and the transient state of refilling doesn't change the * recording of which entry is oldest. * * This relies on IB only calling one cq comp_handler for each cq so that * there will only be one caller of rds_recv_incoming() per RDS connection. */ void rds_iw_recv_cq_comp_handler(struct ib_cq *cq, void *context) { struct rds_connection *conn = context; struct rds_iw_connection *ic = conn->c_transport_data; rdsdebug("conn %p cq %p\n", conn, cq); rds_iw_stats_inc(s_iw_rx_cq_call); tasklet_schedule(&ic->i_recv_tasklet); } static inline void rds_poll_cq(struct rds_iw_connection *ic, struct rds_iw_ack_state *state) { struct rds_connection *conn = ic->conn; struct ib_wc wc; struct rds_iw_recv_work *recv; while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) { rdsdebug("wc wr_id 0x%llx status %u byte_len %u imm_data %u\n", (unsigned long long)wc.wr_id, wc.status, wc.byte_len, be32_to_cpu(wc.ex.imm_data)); rds_iw_stats_inc(s_iw_rx_cq_event); recv = &ic->i_recvs[rds_iw_ring_oldest(&ic->i_recv_ring)]; rds_iw_recv_unmap_page(ic, recv); /* * Also process recvs in connecting state because it is possible * to get a recv completion _before_ the rdmacm ESTABLISHED * event is processed. */ if (rds_conn_up(conn) || rds_conn_connecting(conn)) { /* We expect errors as the qp is drained during shutdown */ if (wc.status == IB_WC_SUCCESS) { rds_iw_process_recv(conn, recv, wc.byte_len, state); } else { rds_iw_conn_error(conn, "recv completion on " "%pI4 had status %u, disconnecting and " "reconnecting\n", &conn->c_faddr, wc.status); } } rds_iw_ring_free(&ic->i_recv_ring, 1); } } void rds_iw_recv_tasklet_fn(unsigned long data) { struct rds_iw_connection *ic = (struct rds_iw_connection *) data; struct rds_connection *conn = ic->conn; struct rds_iw_ack_state state = { 0, }; rds_poll_cq(ic, &state); ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED); rds_poll_cq(ic, &state); if (state.ack_next_valid) rds_iw_set_ack(ic, state.ack_next, state.ack_required); if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) { rds_send_drop_acked(conn, state.ack_recv, NULL); ic->i_ack_recv = state.ack_recv; } if (rds_conn_up(conn)) rds_iw_attempt_ack(ic); /* If we ever end up with a really empty receive ring, we're * in deep trouble, as the sender will definitely see RNR * timeouts. */ if (rds_iw_ring_empty(&ic->i_recv_ring)) rds_iw_stats_inc(s_iw_rx_ring_empty); /* * If the ring is running low, then schedule the thread to refill. */ if (rds_iw_ring_low(&ic->i_recv_ring)) queue_delayed_work(rds_wq, &conn->c_recv_w, 0); } int rds_iw_recv(struct rds_connection *conn) { struct rds_iw_connection *ic = conn->c_transport_data; int ret = 0; rdsdebug("conn %p\n", conn); /* * If we get a temporary posting failure in this context then * we're really low and we want the caller to back off for a bit. */ mutex_lock(&ic->i_recv_mutex); if (rds_iw_recv_refill(conn, GFP_KERNEL, GFP_HIGHUSER, 0)) ret = -ENOMEM; else rds_iw_stats_inc(s_iw_rx_refill_from_thread); mutex_unlock(&ic->i_recv_mutex); if (rds_conn_up(conn)) rds_iw_attempt_ack(ic); return ret; } int rds_iw_recv_init(void) { struct sysinfo si; int ret = -ENOMEM; /* Default to 30% of all available RAM for recv memory */ si_meminfo(&si); rds_iw_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE; rds_iw_incoming_slab = kmem_cache_create("rds_iw_incoming", sizeof(struct rds_iw_incoming), 0, 0, NULL); if (!rds_iw_incoming_slab) goto out; rds_iw_frag_slab = kmem_cache_create("rds_iw_frag", sizeof(struct rds_page_frag), 0, 0, NULL); if (!rds_iw_frag_slab) kmem_cache_destroy(rds_iw_incoming_slab); else ret = 0; out: return ret; } void rds_iw_recv_exit(void) { kmem_cache_destroy(rds_iw_incoming_slab); kmem_cache_destroy(rds_iw_frag_slab); }