| /* |
| * 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 "ib.h" |
| |
| static struct kmem_cache *rds_ib_incoming_slab; |
| static struct kmem_cache *rds_ib_frag_slab; |
| static atomic_t rds_ib_allocation = ATOMIC_INIT(0); |
| |
| void rds_ib_recv_init_ring(struct rds_ib_connection *ic) |
| { |
| struct rds_ib_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_ibinc = 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_IB_RECV_SGE; |
| |
| sge = &recv->r_sge[0]; |
| sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header)); |
| sge->length = sizeof(struct rds_header); |
| sge->lkey = ic->i_mr->lkey; |
| |
| sge = &recv->r_sge[1]; |
| sge->addr = 0; |
| sge->length = RDS_FRAG_SIZE; |
| sge->lkey = ic->i_mr->lkey; |
| } |
| } |
| |
| /* |
| * The entire 'from' list, including the from element itself, is put on |
| * to the tail of the 'to' list. |
| */ |
| static void list_splice_entire_tail(struct list_head *from, |
| struct list_head *to) |
| { |
| struct list_head *from_last = from->prev; |
| |
| list_splice_tail(from_last, to); |
| list_add_tail(from_last, to); |
| } |
| |
| static void rds_ib_cache_xfer_to_ready(struct rds_ib_refill_cache *cache) |
| { |
| struct list_head *tmp; |
| |
| tmp = xchg(&cache->xfer, NULL); |
| if (tmp) { |
| if (cache->ready) |
| list_splice_entire_tail(tmp, cache->ready); |
| else |
| cache->ready = tmp; |
| } |
| } |
| |
| static int rds_ib_recv_alloc_cache(struct rds_ib_refill_cache *cache) |
| { |
| struct rds_ib_cache_head *head; |
| int cpu; |
| |
| cache->percpu = alloc_percpu(struct rds_ib_cache_head); |
| if (!cache->percpu) |
| return -ENOMEM; |
| |
| for_each_possible_cpu(cpu) { |
| head = per_cpu_ptr(cache->percpu, cpu); |
| head->first = NULL; |
| head->count = 0; |
| } |
| cache->xfer = NULL; |
| cache->ready = NULL; |
| |
| return 0; |
| } |
| |
| int rds_ib_recv_alloc_caches(struct rds_ib_connection *ic) |
| { |
| int ret; |
| |
| ret = rds_ib_recv_alloc_cache(&ic->i_cache_incs); |
| if (!ret) { |
| ret = rds_ib_recv_alloc_cache(&ic->i_cache_frags); |
| if (ret) |
| free_percpu(ic->i_cache_incs.percpu); |
| } |
| |
| return ret; |
| } |
| |
| static void rds_ib_cache_splice_all_lists(struct rds_ib_refill_cache *cache, |
| struct list_head *caller_list) |
| { |
| struct rds_ib_cache_head *head; |
| int cpu; |
| |
| for_each_possible_cpu(cpu) { |
| head = per_cpu_ptr(cache->percpu, cpu); |
| if (head->first) { |
| list_splice_entire_tail(head->first, caller_list); |
| head->first = NULL; |
| } |
| } |
| |
| if (cache->ready) { |
| list_splice_entire_tail(cache->ready, caller_list); |
| cache->ready = NULL; |
| } |
| } |
| |
| void rds_ib_recv_free_caches(struct rds_ib_connection *ic) |
| { |
| struct rds_ib_incoming *inc; |
| struct rds_ib_incoming *inc_tmp; |
| struct rds_page_frag *frag; |
| struct rds_page_frag *frag_tmp; |
| LIST_HEAD(list); |
| |
| rds_ib_cache_xfer_to_ready(&ic->i_cache_incs); |
| rds_ib_cache_splice_all_lists(&ic->i_cache_incs, &list); |
| free_percpu(ic->i_cache_incs.percpu); |
| |
| list_for_each_entry_safe(inc, inc_tmp, &list, ii_cache_entry) { |
| list_del(&inc->ii_cache_entry); |
| WARN_ON(!list_empty(&inc->ii_frags)); |
| kmem_cache_free(rds_ib_incoming_slab, inc); |
| } |
| |
| rds_ib_cache_xfer_to_ready(&ic->i_cache_frags); |
| rds_ib_cache_splice_all_lists(&ic->i_cache_frags, &list); |
| free_percpu(ic->i_cache_frags.percpu); |
| |
| list_for_each_entry_safe(frag, frag_tmp, &list, f_cache_entry) { |
| list_del(&frag->f_cache_entry); |
| WARN_ON(!list_empty(&frag->f_item)); |
| kmem_cache_free(rds_ib_frag_slab, frag); |
| } |
| } |
| |
| /* fwd decl */ |
| static void rds_ib_recv_cache_put(struct list_head *new_item, |
| struct rds_ib_refill_cache *cache); |
| static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache); |
| |
| |
| /* Recycle frag and attached recv buffer f_sg */ |
| static void rds_ib_frag_free(struct rds_ib_connection *ic, |
| struct rds_page_frag *frag) |
| { |
| rdsdebug("frag %p page %p\n", frag, sg_page(&frag->f_sg)); |
| |
| rds_ib_recv_cache_put(&frag->f_cache_entry, &ic->i_cache_frags); |
| } |
| |
| /* Recycle inc after freeing attached frags */ |
| void rds_ib_inc_free(struct rds_incoming *inc) |
| { |
| struct rds_ib_incoming *ibinc; |
| struct rds_page_frag *frag; |
| struct rds_page_frag *pos; |
| struct rds_ib_connection *ic = inc->i_conn->c_transport_data; |
| |
| ibinc = container_of(inc, struct rds_ib_incoming, ii_inc); |
| |
| /* Free attached frags */ |
| list_for_each_entry_safe(frag, pos, &ibinc->ii_frags, f_item) { |
| list_del_init(&frag->f_item); |
| rds_ib_frag_free(ic, frag); |
| } |
| BUG_ON(!list_empty(&ibinc->ii_frags)); |
| |
| rdsdebug("freeing ibinc %p inc %p\n", ibinc, inc); |
| rds_ib_recv_cache_put(&ibinc->ii_cache_entry, &ic->i_cache_incs); |
| } |
| |
| static void rds_ib_recv_clear_one(struct rds_ib_connection *ic, |
| struct rds_ib_recv_work *recv) |
| { |
| if (recv->r_ibinc) { |
| rds_inc_put(&recv->r_ibinc->ii_inc); |
| recv->r_ibinc = NULL; |
| } |
| if (recv->r_frag) { |
| ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE); |
| rds_ib_frag_free(ic, recv->r_frag); |
| recv->r_frag = NULL; |
| } |
| } |
| |
| void rds_ib_recv_clear_ring(struct rds_ib_connection *ic) |
| { |
| u32 i; |
| |
| for (i = 0; i < ic->i_recv_ring.w_nr; i++) |
| rds_ib_recv_clear_one(ic, &ic->i_recvs[i]); |
| } |
| |
| static struct rds_ib_incoming *rds_ib_refill_one_inc(struct rds_ib_connection *ic, |
| gfp_t slab_mask) |
| { |
| struct rds_ib_incoming *ibinc; |
| struct list_head *cache_item; |
| int avail_allocs; |
| |
| cache_item = rds_ib_recv_cache_get(&ic->i_cache_incs); |
| if (cache_item) { |
| ibinc = container_of(cache_item, struct rds_ib_incoming, ii_cache_entry); |
| } else { |
| avail_allocs = atomic_add_unless(&rds_ib_allocation, |
| 1, rds_ib_sysctl_max_recv_allocation); |
| if (!avail_allocs) { |
| rds_ib_stats_inc(s_ib_rx_alloc_limit); |
| return NULL; |
| } |
| ibinc = kmem_cache_alloc(rds_ib_incoming_slab, slab_mask); |
| if (!ibinc) { |
| atomic_dec(&rds_ib_allocation); |
| return NULL; |
| } |
| } |
| INIT_LIST_HEAD(&ibinc->ii_frags); |
| rds_inc_init(&ibinc->ii_inc, ic->conn, ic->conn->c_faddr); |
| |
| return ibinc; |
| } |
| |
| static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic, |
| gfp_t slab_mask, gfp_t page_mask) |
| { |
| struct rds_page_frag *frag; |
| struct list_head *cache_item; |
| int ret; |
| |
| cache_item = rds_ib_recv_cache_get(&ic->i_cache_frags); |
| if (cache_item) { |
| frag = container_of(cache_item, struct rds_page_frag, f_cache_entry); |
| } else { |
| frag = kmem_cache_alloc(rds_ib_frag_slab, slab_mask); |
| if (!frag) |
| return NULL; |
| |
| ret = rds_page_remainder_alloc(&frag->f_sg, |
| RDS_FRAG_SIZE, page_mask); |
| if (ret) { |
| kmem_cache_free(rds_ib_frag_slab, frag); |
| return NULL; |
| } |
| } |
| |
| INIT_LIST_HEAD(&frag->f_item); |
| |
| return frag; |
| } |
| |
| static int rds_ib_recv_refill_one(struct rds_connection *conn, |
| struct rds_ib_recv_work *recv, int prefill) |
| { |
| struct rds_ib_connection *ic = conn->c_transport_data; |
| struct ib_sge *sge; |
| int ret = -ENOMEM; |
| gfp_t slab_mask = GFP_NOWAIT; |
| gfp_t page_mask = GFP_NOWAIT; |
| |
| if (prefill) { |
| slab_mask = GFP_KERNEL; |
| page_mask = GFP_HIGHUSER; |
| } |
| |
| if (!ic->i_cache_incs.ready) |
| rds_ib_cache_xfer_to_ready(&ic->i_cache_incs); |
| if (!ic->i_cache_frags.ready) |
| rds_ib_cache_xfer_to_ready(&ic->i_cache_frags); |
| |
| /* |
| * ibinc was taken from recv if recv contained the start of a message. |
| * recvs that were continuations will still have this allocated. |
| */ |
| if (!recv->r_ibinc) { |
| recv->r_ibinc = rds_ib_refill_one_inc(ic, slab_mask); |
| if (!recv->r_ibinc) |
| goto out; |
| } |
| |
| WARN_ON(recv->r_frag); /* leak! */ |
| recv->r_frag = rds_ib_refill_one_frag(ic, slab_mask, page_mask); |
| if (!recv->r_frag) |
| goto out; |
| |
| ret = ib_dma_map_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, |
| 1, DMA_FROM_DEVICE); |
| WARN_ON(ret != 1); |
| |
| sge = &recv->r_sge[0]; |
| sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header); |
| sge->length = sizeof(struct rds_header); |
| |
| sge = &recv->r_sge[1]; |
| sge->addr = sg_dma_address(&recv->r_frag->f_sg); |
| sge->length = sg_dma_len(&recv->r_frag->f_sg); |
| |
| 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. |
| * |
| * -1 is returned if posting fails due to temporary resource exhaustion. |
| */ |
| void rds_ib_recv_refill(struct rds_connection *conn, int prefill) |
| { |
| struct rds_ib_connection *ic = conn->c_transport_data; |
| struct rds_ib_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_ib_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); |
| break; |
| } |
| |
| recv = &ic->i_recvs[pos]; |
| ret = rds_ib_recv_refill_one(conn, recv, prefill); |
| if (ret) { |
| break; |
| } |
| |
| /* XXX when can this fail? */ |
| ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr); |
| rdsdebug("recv %p ibinc %p page %p addr %lu ret %d\n", recv, |
| recv->r_ibinc, sg_page(&recv->r_frag->f_sg), |
| (long) sg_dma_address(&recv->r_frag->f_sg), ret); |
| if (ret) { |
| rds_ib_conn_error(conn, "recv post on " |
| "%pI4 returned %d, disconnecting and " |
| "reconnecting\n", &conn->c_faddr, |
| ret); |
| break; |
| } |
| |
| posted++; |
| } |
| |
| /* We're doing flow control - update the window. */ |
| if (ic->i_flowctl && posted) |
| rds_ib_advertise_credits(conn, posted); |
| |
| if (ret) |
| rds_ib_ring_unalloc(&ic->i_recv_ring, 1); |
| } |
| |
| /* |
| * We want to recycle several types of recv allocations, like incs and frags. |
| * To use this, the *_free() function passes in the ptr to a list_head within |
| * the recyclee, as well as the cache to put it on. |
| * |
| * First, we put the memory on a percpu list. When this reaches a certain size, |
| * We move it to an intermediate non-percpu list in a lockless manner, with some |
| * xchg/compxchg wizardry. |
| * |
| * N.B. Instead of a list_head as the anchor, we use a single pointer, which can |
| * be NULL and xchg'd. The list is actually empty when the pointer is NULL, and |
| * list_empty() will return true with one element is actually present. |
| */ |
| static void rds_ib_recv_cache_put(struct list_head *new_item, |
| struct rds_ib_refill_cache *cache) |
| { |
| unsigned long flags; |
| struct rds_ib_cache_head *chp; |
| struct list_head *old; |
| |
| local_irq_save(flags); |
| |
| chp = per_cpu_ptr(cache->percpu, smp_processor_id()); |
| if (!chp->first) |
| INIT_LIST_HEAD(new_item); |
| else /* put on front */ |
| list_add_tail(new_item, chp->first); |
| chp->first = new_item; |
| chp->count++; |
| |
| if (chp->count < RDS_IB_RECYCLE_BATCH_COUNT) |
| goto end; |
| |
| /* |
| * Return our per-cpu first list to the cache's xfer by atomically |
| * grabbing the current xfer list, appending it to our per-cpu list, |
| * and then atomically returning that entire list back to the |
| * cache's xfer list as long as it's still empty. |
| */ |
| do { |
| old = xchg(&cache->xfer, NULL); |
| if (old) |
| list_splice_entire_tail(old, chp->first); |
| old = cmpxchg(&cache->xfer, NULL, chp->first); |
| } while (old); |
| |
| chp->first = NULL; |
| chp->count = 0; |
| end: |
| local_irq_restore(flags); |
| } |
| |
| static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache) |
| { |
| struct list_head *head = cache->ready; |
| |
| if (head) { |
| if (!list_empty(head)) { |
| cache->ready = head->next; |
| list_del_init(head); |
| } else |
| cache->ready = NULL; |
| } |
| |
| return head; |
| } |
| |
| int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov, |
| size_t size) |
| { |
| struct rds_ib_incoming *ibinc; |
| 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; |
| |
| ibinc = container_of(inc, struct rds_ib_incoming, ii_inc); |
| frag = list_entry(ibinc->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, %u] + %lu\n", |
| to_copy, iov->iov_base, iov->iov_len, iov_off, |
| sg_page(&frag->f_sg), frag->f_sg.offset, frag_off); |
| |
| /* XXX needs + offset for multiple recvs per page */ |
| ret = rds_page_copy_to_user(sg_page(&frag->f_sg), |
| frag->f_sg.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_ib_recv_init_ack(struct rds_ib_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 = ic->i_mr->lkey; |
| |
| wr->sg_list = sge; |
| wr->num_sge = 1; |
| wr->opcode = IB_WR_SEND; |
| wr->wr_id = RDS_IB_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_ib_set_ack(struct rds_ib_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_ib_get_ack(struct rds_ib_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_ib_set_ack(struct rds_ib_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_ib_get_ack(struct rds_ib_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_ib_send_ack(struct rds_ib_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_ib_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_ib_stats_inc(s_ib_ack_send_failure); |
| |
| rds_ib_conn_error(ic->conn, "sending ack failed\n"); |
| } else |
| rds_ib_stats_inc(s_ib_ack_sent); |
| } |
| |
| /* |
| * There are 3 ways of getting acknowledgements to the peer: |
| * 1. We call rds_ib_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_ib_attempt_ack(struct rds_ib_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_ib_stats_inc(s_ib_ack_send_delayed); |
| return; |
| } |
| |
| /* Can we get a send credit? */ |
| if (!rds_ib_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) { |
| rds_ib_stats_inc(s_ib_tx_throttle); |
| clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); |
| return; |
| } |
| |
| clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
| rds_ib_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_ib_ack_send_complete(struct rds_ib_connection *ic) |
| { |
| clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); |
| rds_ib_attempt_ack(ic); |
| } |
| |
| /* |
| * This is called by the regular xmit code when it wants to piggyback |
| * an ACK on an outgoing frame. |
| */ |
| u64 rds_ib_piggyb_ack(struct rds_ib_connection *ic) |
| { |
| if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags)) |
| rds_ib_stats_inc(s_ib_ack_send_piggybacked); |
| return rds_ib_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_ib_cong_recv(struct rds_connection *conn, |
| struct rds_ib_incoming *ibinc) |
| { |
| 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(ibinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES) |
| return; |
| |
| map = conn->c_fcong; |
| map_page = 0; |
| map_off = 0; |
| |
| frag = list_entry(ibinc->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(sg_page(&frag->f_sg), KM_SOFTIRQ0); |
| |
| 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, KM_SOFTIRQ0); |
| |
| 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_ib_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_ib_process_recv(struct rds_connection *conn, |
| struct rds_ib_recv_work *recv, u32 data_len, |
| struct rds_ib_ack_state *state) |
| { |
| struct rds_ib_connection *ic = conn->c_transport_data; |
| struct rds_ib_incoming *ibinc = ic->i_ibinc; |
| struct rds_header *ihdr, *hdr; |
| |
| /* XXX shut down the connection if port 0,0 are seen? */ |
| |
| rdsdebug("ic %p ibinc %p recv %p byte len %u\n", ic, ibinc, recv, |
| data_len); |
| |
| if (data_len < sizeof(struct rds_header)) { |
| rds_ib_conn_error(conn, "incoming message " |
| "from %pI4 didn't inclue a " |
| "header, disconnecting and " |
| "reconnecting\n", |
| &conn->c_faddr); |
| return; |
| } |
| data_len -= sizeof(struct rds_header); |
| |
| ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs]; |
| |
| /* Validate the checksum. */ |
| if (!rds_message_verify_checksum(ihdr)) { |
| rds_ib_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_ib_send_add_credits(conn, ihdr->h_credit); |
| |
| if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && data_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_ib_stats_inc(s_ib_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. |
| * |
| * FIXME: Fold this into the code path below. |
| */ |
| rds_ib_frag_free(ic, recv->r_frag); |
| recv->r_frag = NULL; |
| 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 (!ibinc) { |
| ibinc = recv->r_ibinc; |
| recv->r_ibinc = NULL; |
| ic->i_ibinc = ibinc; |
| |
| hdr = &ibinc->ii_inc.i_hdr; |
| memcpy(hdr, ihdr, sizeof(*hdr)); |
| ic->i_recv_data_rem = be32_to_cpu(hdr->h_len); |
| |
| rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc, |
| ic->i_recv_data_rem, hdr->h_flags); |
| } else { |
| hdr = &ibinc->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_ib_conn_error(conn, |
| "fragment header mismatch; forcing reconnect\n"); |
| return; |
| } |
| } |
| |
| list_add_tail(&recv->r_frag->f_item, &ibinc->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_ibinc = NULL; |
| |
| if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP) |
| rds_ib_cong_recv(conn, ibinc); |
| else { |
| rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr, |
| &ibinc->ii_inc, GFP_ATOMIC, |
| KM_SOFTIRQ0); |
| 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(&ibinc->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_ib_recv_cq_comp_handler(struct ib_cq *cq, void *context) |
| { |
| struct rds_connection *conn = context; |
| struct rds_ib_connection *ic = conn->c_transport_data; |
| |
| rdsdebug("conn %p cq %p\n", conn, cq); |
| |
| rds_ib_stats_inc(s_ib_rx_cq_call); |
| |
| tasklet_schedule(&ic->i_recv_tasklet); |
| } |
| |
| static inline void rds_poll_cq(struct rds_ib_connection *ic, |
| struct rds_ib_ack_state *state) |
| { |
| struct rds_connection *conn = ic->conn; |
| struct ib_wc wc; |
| struct rds_ib_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_ib_stats_inc(s_ib_rx_cq_event); |
| |
| recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)]; |
| |
| ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE); |
| |
| /* |
| * 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_ib_process_recv(conn, recv, wc.byte_len, state); |
| } else { |
| rds_ib_conn_error(conn, "recv completion on " |
| "%pI4 had status %u, disconnecting and " |
| "reconnecting\n", &conn->c_faddr, |
| wc.status); |
| } |
| } |
| |
| rds_ib_ring_free(&ic->i_recv_ring, 1); |
| } |
| } |
| |
| void rds_ib_recv_tasklet_fn(unsigned long data) |
| { |
| struct rds_ib_connection *ic = (struct rds_ib_connection *) data; |
| struct rds_connection *conn = ic->conn; |
| struct rds_ib_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_ib_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_ib_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_ib_ring_empty(&ic->i_recv_ring)) |
| rds_ib_stats_inc(s_ib_rx_ring_empty); |
| |
| if (rds_ib_ring_low(&ic->i_recv_ring)) |
| rds_ib_recv_refill(conn, 0); |
| } |
| |
| int rds_ib_recv(struct rds_connection *conn) |
| { |
| struct rds_ib_connection *ic = conn->c_transport_data; |
| int ret = 0; |
| |
| rdsdebug("conn %p\n", conn); |
| if (rds_conn_up(conn)) |
| rds_ib_attempt_ack(ic); |
| |
| return ret; |
| } |
| |
| int __init rds_ib_recv_init(void) |
| { |
| struct sysinfo si; |
| int ret = -ENOMEM; |
| |
| /* Default to 30% of all available RAM for recv memory */ |
| si_meminfo(&si); |
| rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE; |
| |
| rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming", |
| sizeof(struct rds_ib_incoming), |
| 0, 0, NULL); |
| if (!rds_ib_incoming_slab) |
| goto out; |
| |
| rds_ib_frag_slab = kmem_cache_create("rds_ib_frag", |
| sizeof(struct rds_page_frag), |
| 0, 0, NULL); |
| if (!rds_ib_frag_slab) |
| kmem_cache_destroy(rds_ib_incoming_slab); |
| else |
| ret = 0; |
| out: |
| return ret; |
| } |
| |
| void rds_ib_recv_exit(void) |
| { |
| kmem_cache_destroy(rds_ib_incoming_slab); |
| kmem_cache_destroy(rds_ib_frag_slab); |
| } |