diff options
Diffstat (limited to '')
| -rw-r--r-- | net/rds/ib_send.c | 992 |
1 files changed, 992 insertions, 0 deletions
diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c new file mode 100644 index 000000000..2dcb555e6 --- /dev/null +++ b/net/rds/ib_send.c @@ -0,0 +1,992 @@ +/* + * Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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/in.h> +#include <linux/device.h> +#include <linux/dmapool.h> +#include <linux/ratelimit.h> + +#include "rds_single_path.h" +#include "rds.h" +#include "ib.h" + +/* + * Convert IB-specific error message to RDS error message and call core + * completion handler. + */ +static void rds_ib_send_complete(struct rds_message *rm, + int wc_status, + void (*complete)(struct rds_message *rm, int status)) +{ + int notify_status; + + switch (wc_status) { + case IB_WC_WR_FLUSH_ERR: + return; + + case IB_WC_SUCCESS: + notify_status = RDS_RDMA_SUCCESS; + break; + + case IB_WC_REM_ACCESS_ERR: + notify_status = RDS_RDMA_REMOTE_ERROR; + break; + + default: + notify_status = RDS_RDMA_OTHER_ERROR; + break; + } + complete(rm, notify_status); +} + +static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic, + struct rm_rdma_op *op, + int wc_status) +{ + if (op->op_mapped) { + ib_dma_unmap_sg(ic->i_cm_id->device, + op->op_sg, op->op_nents, + op->op_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); + op->op_mapped = 0; + } + + /* If the user asked for a completion notification on this + * message, we can implement three different semantics: + * 1. Notify when we received the ACK on the RDS message + * that was queued with the RDMA. This provides reliable + * notification of RDMA status at the expense of a one-way + * packet delay. + * 2. Notify when the IB stack gives us the completion event for + * the RDMA operation. + * 3. Notify when the IB stack gives us the completion event for + * the accompanying RDS messages. + * Here, we implement approach #3. To implement approach #2, + * we would need to take an event for the rdma WR. To implement #1, + * don't call rds_rdma_send_complete at all, and fall back to the notify + * handling in the ACK processing code. + * + * Note: There's no need to explicitly sync any RDMA buffers using + * ib_dma_sync_sg_for_cpu - the completion for the RDMA + * operation itself unmapped the RDMA buffers, which takes care + * of synching. + */ + rds_ib_send_complete(container_of(op, struct rds_message, rdma), + wc_status, rds_rdma_send_complete); + + if (op->op_write) + rds_stats_add(s_send_rdma_bytes, op->op_bytes); + else + rds_stats_add(s_recv_rdma_bytes, op->op_bytes); +} + +static void rds_ib_send_unmap_atomic(struct rds_ib_connection *ic, + struct rm_atomic_op *op, + int wc_status) +{ + /* unmap atomic recvbuf */ + if (op->op_mapped) { + ib_dma_unmap_sg(ic->i_cm_id->device, op->op_sg, 1, + DMA_FROM_DEVICE); + op->op_mapped = 0; + } + + rds_ib_send_complete(container_of(op, struct rds_message, atomic), + wc_status, rds_atomic_send_complete); + + if (op->op_type == RDS_ATOMIC_TYPE_CSWP) + rds_ib_stats_inc(s_ib_atomic_cswp); + else + rds_ib_stats_inc(s_ib_atomic_fadd); +} + +static void rds_ib_send_unmap_data(struct rds_ib_connection *ic, + struct rm_data_op *op, + int wc_status) +{ + struct rds_message *rm = container_of(op, struct rds_message, data); + + if (op->op_nents) + ib_dma_unmap_sg(ic->i_cm_id->device, + op->op_sg, op->op_nents, + DMA_TO_DEVICE); + + if (rm->rdma.op_active && rm->data.op_notify) + rds_ib_send_unmap_rdma(ic, &rm->rdma, wc_status); +} + +/* + * Unmap the resources associated with a struct send_work. + * + * Returns the rm for no good reason other than it is unobtainable + * other than by switching on wr.opcode, currently, and the caller, + * the event handler, needs it. + */ +static struct rds_message *rds_ib_send_unmap_op(struct rds_ib_connection *ic, + struct rds_ib_send_work *send, + int wc_status) +{ + struct rds_message *rm = NULL; + + /* In the error case, wc.opcode sometimes contains garbage */ + switch (send->s_wr.opcode) { + case IB_WR_SEND: + if (send->s_op) { + rm = container_of(send->s_op, struct rds_message, data); + rds_ib_send_unmap_data(ic, send->s_op, wc_status); + } + break; + case IB_WR_RDMA_WRITE: + case IB_WR_RDMA_READ: + if (send->s_op) { + rm = container_of(send->s_op, struct rds_message, rdma); + rds_ib_send_unmap_rdma(ic, send->s_op, wc_status); + } + break; + case IB_WR_ATOMIC_FETCH_AND_ADD: + case IB_WR_ATOMIC_CMP_AND_SWP: + if (send->s_op) { + rm = container_of(send->s_op, struct rds_message, atomic); + rds_ib_send_unmap_atomic(ic, send->s_op, wc_status); + } + break; + default: + printk_ratelimited(KERN_NOTICE + "RDS/IB: %s: unexpected opcode 0x%x in WR!\n", + __func__, send->s_wr.opcode); + break; + } + + send->s_wr.opcode = 0xdead; + + return rm; +} + +void rds_ib_send_init_ring(struct rds_ib_connection *ic) +{ + struct rds_ib_send_work *send; + u32 i; + + for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { + struct ib_sge *sge; + + send->s_op = NULL; + + send->s_wr.wr_id = i; + send->s_wr.sg_list = send->s_sge; + send->s_wr.ex.imm_data = 0; + + sge = &send->s_sge[0]; + sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header)); + sge->length = sizeof(struct rds_header); + sge->lkey = ic->i_pd->local_dma_lkey; + + send->s_sge[1].lkey = ic->i_pd->local_dma_lkey; + } +} + +void rds_ib_send_clear_ring(struct rds_ib_connection *ic) +{ + struct rds_ib_send_work *send; + u32 i; + + for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { + if (send->s_op && send->s_wr.opcode != 0xdead) + rds_ib_send_unmap_op(ic, send, IB_WC_WR_FLUSH_ERR); + } +} + +/* + * The only fast path caller always has a non-zero nr, so we don't + * bother testing nr before performing the atomic sub. + */ +static void rds_ib_sub_signaled(struct rds_ib_connection *ic, int nr) +{ + if ((atomic_sub_return(nr, &ic->i_signaled_sends) == 0) && + waitqueue_active(&rds_ib_ring_empty_wait)) + wake_up(&rds_ib_ring_empty_wait); + BUG_ON(atomic_read(&ic->i_signaled_sends) < 0); +} + +/* + * The _oldest/_free ring operations here race cleanly with the alloc/unalloc + * operations performed in the send path. As the sender allocs and potentially + * unallocs the next free entry in the ring it doesn't alter which is + * the next to be freed, which is what this is concerned with. + */ +void rds_ib_send_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc) +{ + struct rds_message *rm = NULL; + struct rds_connection *conn = ic->conn; + struct rds_ib_send_work *send; + u32 completed; + u32 oldest; + u32 i = 0; + int nr_sig = 0; + + + rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n", + (unsigned long long)wc->wr_id, wc->status, + ib_wc_status_msg(wc->status), wc->byte_len, + be32_to_cpu(wc->ex.imm_data)); + rds_ib_stats_inc(s_ib_tx_cq_event); + + if (wc->wr_id == RDS_IB_ACK_WR_ID) { + if (time_after(jiffies, ic->i_ack_queued + HZ / 2)) + rds_ib_stats_inc(s_ib_tx_stalled); + rds_ib_ack_send_complete(ic); + return; + } + + oldest = rds_ib_ring_oldest(&ic->i_send_ring); + + completed = rds_ib_ring_completed(&ic->i_send_ring, wc->wr_id, oldest); + + for (i = 0; i < completed; i++) { + send = &ic->i_sends[oldest]; + if (send->s_wr.send_flags & IB_SEND_SIGNALED) + nr_sig++; + + rm = rds_ib_send_unmap_op(ic, send, wc->status); + + if (time_after(jiffies, send->s_queued + HZ / 2)) + rds_ib_stats_inc(s_ib_tx_stalled); + + if (send->s_op) { + if (send->s_op == rm->m_final_op) { + /* If anyone waited for this message to get + * flushed out, wake them up now + */ + rds_message_unmapped(rm); + } + rds_message_put(rm); + send->s_op = NULL; + } + + oldest = (oldest + 1) % ic->i_send_ring.w_nr; + } + + rds_ib_ring_free(&ic->i_send_ring, completed); + rds_ib_sub_signaled(ic, nr_sig); + nr_sig = 0; + + if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) || + test_bit(0, &conn->c_map_queued)) + queue_delayed_work(rds_wq, &conn->c_send_w, 0); + + /* We expect errors as the qp is drained during shutdown */ + if (wc->status != IB_WC_SUCCESS && rds_conn_up(conn)) { + rds_ib_conn_error(conn, "send completion on <%pI6c,%pI6c> had status %u (%s), disconnecting and reconnecting\n", + &conn->c_laddr, &conn->c_faddr, wc->status, + ib_wc_status_msg(wc->status)); + } +} + +/* + * This is the main function for allocating credits when sending + * messages. + * + * Conceptually, we have two counters: + * - send credits: this tells us how many WRs we're allowed + * to submit without overruning the receiver's queue. For + * each SEND WR we post, we decrement this by one. + * + * - posted credits: this tells us how many WRs we recently + * posted to the receive queue. This value is transferred + * to the peer as a "credit update" in a RDS header field. + * Every time we transmit credits to the peer, we subtract + * the amount of transferred credits from this counter. + * + * It is essential that we avoid situations where both sides have + * exhausted their send credits, and are unable to send new credits + * to the peer. We achieve this by requiring that we send at least + * one credit update to the peer before exhausting our credits. + * When new credits arrive, we subtract one credit that is withheld + * until we've posted new buffers and are ready to transmit these + * credits (see rds_ib_send_add_credits below). + * + * The RDS send code is essentially single-threaded; rds_send_xmit + * sets RDS_IN_XMIT to ensure exclusive access to the send ring. + * However, the ACK sending code is independent and can race with + * message SENDs. + * + * In the send path, we need to update the counters for send credits + * and the counter of posted buffers atomically - when we use the + * last available credit, we cannot allow another thread to race us + * and grab the posted credits counter. Hence, we have to use a + * spinlock to protect the credit counter, or use atomics. + * + * Spinlocks shared between the send and the receive path are bad, + * because they create unnecessary delays. An early implementation + * using a spinlock showed a 5% degradation in throughput at some + * loads. + * + * This implementation avoids spinlocks completely, putting both + * counters into a single atomic, and updating that atomic using + * atomic_add (in the receive path, when receiving fresh credits), + * and using atomic_cmpxchg when updating the two counters. + */ +int rds_ib_send_grab_credits(struct rds_ib_connection *ic, + u32 wanted, u32 *adv_credits, int need_posted, int max_posted) +{ + unsigned int avail, posted, got = 0, advertise; + long oldval, newval; + + *adv_credits = 0; + if (!ic->i_flowctl) + return wanted; + +try_again: + advertise = 0; + oldval = newval = atomic_read(&ic->i_credits); + posted = IB_GET_POST_CREDITS(oldval); + avail = IB_GET_SEND_CREDITS(oldval); + + rdsdebug("wanted=%u credits=%u posted=%u\n", + wanted, avail, posted); + + /* The last credit must be used to send a credit update. */ + if (avail && !posted) + avail--; + + if (avail < wanted) { + struct rds_connection *conn = ic->i_cm_id->context; + + /* Oops, there aren't that many credits left! */ + set_bit(RDS_LL_SEND_FULL, &conn->c_flags); + got = avail; + } else { + /* Sometimes you get what you want, lalala. */ + got = wanted; + } + newval -= IB_SET_SEND_CREDITS(got); + + /* + * If need_posted is non-zero, then the caller wants + * the posted regardless of whether any send credits are + * available. + */ + if (posted && (got || need_posted)) { + advertise = min_t(unsigned int, posted, max_posted); + newval -= IB_SET_POST_CREDITS(advertise); + } + + /* Finally bill everything */ + if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval) + goto try_again; + + *adv_credits = advertise; + return got; +} + +void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits) +{ + struct rds_ib_connection *ic = conn->c_transport_data; + + if (credits == 0) + return; + + rdsdebug("credits=%u current=%u%s\n", + credits, + IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)), + test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : ""); + + atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits); + if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags)) + queue_delayed_work(rds_wq, &conn->c_send_w, 0); + + WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384); + + rds_ib_stats_inc(s_ib_rx_credit_updates); +} + +void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted) +{ + struct rds_ib_connection *ic = conn->c_transport_data; + + if (posted == 0) + return; + + atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits); + + /* Decide whether to send an update to the peer now. + * If we would send a credit update for every single buffer we + * post, we would end up with an ACK storm (ACK arrives, + * consumes buffer, we refill the ring, send ACK to remote + * advertising the newly posted buffer... ad inf) + * + * Performance pretty much depends on how often we send + * credit updates - too frequent updates mean lots of ACKs. + * Too infrequent updates, and the peer will run out of + * credits and has to throttle. + * For the time being, 16 seems to be a good compromise. + */ + if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16) + set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); +} + +static inline int rds_ib_set_wr_signal_state(struct rds_ib_connection *ic, + struct rds_ib_send_work *send, + bool notify) +{ + /* + * We want to delay signaling completions just enough to get + * the batching benefits but not so much that we create dead time + * on the wire. + */ + if (ic->i_unsignaled_wrs-- == 0 || notify) { + ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs; + send->s_wr.send_flags |= IB_SEND_SIGNALED; + return 1; + } + return 0; +} + +/* + * This can be called multiple times for a given message. The first time + * we see a message we map its scatterlist into the IB device so that + * we can provide that mapped address to the IB scatter gather entries + * in the IB work requests. We translate the scatterlist into a series + * of work requests that fragment the message. These work requests complete + * in order so we pass ownership of the message to the completion handler + * once we send the final fragment. + * + * The RDS core uses the c_send_lock to only enter this function once + * per connection. This makes sure that the tx ring alloc/unalloc pairs + * don't get out of sync and confuse the ring. + */ +int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm, + unsigned int hdr_off, unsigned int sg, unsigned int off) +{ + struct rds_ib_connection *ic = conn->c_transport_data; + struct ib_device *dev = ic->i_cm_id->device; + struct rds_ib_send_work *send = NULL; + struct rds_ib_send_work *first; + struct rds_ib_send_work *prev; + const struct ib_send_wr *failed_wr; + struct scatterlist *scat; + u32 pos; + u32 i; + u32 work_alloc; + u32 credit_alloc = 0; + u32 posted; + u32 adv_credits = 0; + int send_flags = 0; + int bytes_sent = 0; + int ret; + int flow_controlled = 0; + int nr_sig = 0; + + BUG_ON(off % RDS_FRAG_SIZE); + BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header)); + + /* Do not send cong updates to IB loopback */ + if (conn->c_loopback + && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { + rds_cong_map_updated(conn->c_fcong, ~(u64) 0); + scat = &rm->data.op_sg[sg]; + ret = max_t(int, RDS_CONG_MAP_BYTES, scat->length); + return sizeof(struct rds_header) + ret; + } + + /* FIXME we may overallocate here */ + if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) + i = 1; + else + i = ceil(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE); + + work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); + if (work_alloc == 0) { + set_bit(RDS_LL_SEND_FULL, &conn->c_flags); + rds_ib_stats_inc(s_ib_tx_ring_full); + ret = -ENOMEM; + goto out; + } + + if (ic->i_flowctl) { + credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT); + adv_credits += posted; + if (credit_alloc < work_alloc) { + rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc); + work_alloc = credit_alloc; + flow_controlled = 1; + } + if (work_alloc == 0) { + set_bit(RDS_LL_SEND_FULL, &conn->c_flags); + rds_ib_stats_inc(s_ib_tx_throttle); + ret = -ENOMEM; + goto out; + } + } + + /* map the message the first time we see it */ + if (!ic->i_data_op) { + if (rm->data.op_nents) { + rm->data.op_count = ib_dma_map_sg(dev, + rm->data.op_sg, + rm->data.op_nents, + DMA_TO_DEVICE); + rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count); + if (rm->data.op_count == 0) { + rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); + rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); + ret = -ENOMEM; /* XXX ? */ + goto out; + } + } else { + rm->data.op_count = 0; + } + + rds_message_addref(rm); + rm->data.op_dmasg = 0; + rm->data.op_dmaoff = 0; + ic->i_data_op = &rm->data; + + /* Finalize the header */ + if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags)) + rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED; + if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) + rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED; + + /* If it has a RDMA op, tell the peer we did it. This is + * used by the peer to release use-once RDMA MRs. */ + if (rm->rdma.op_active) { + struct rds_ext_header_rdma ext_hdr; + + ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey); + rds_message_add_extension(&rm->m_inc.i_hdr, + RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr)); + } + if (rm->m_rdma_cookie) { + rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr, + rds_rdma_cookie_key(rm->m_rdma_cookie), + rds_rdma_cookie_offset(rm->m_rdma_cookie)); + } + + /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so + * we should not do this unless we have a chance of at least + * sticking the header into the send ring. Which is why we + * should call rds_ib_ring_alloc first. */ + rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic)); + rds_message_make_checksum(&rm->m_inc.i_hdr); + + /* + * Update adv_credits since we reset the ACK_REQUIRED bit. + */ + if (ic->i_flowctl) { + rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits); + adv_credits += posted; + BUG_ON(adv_credits > 255); + } + } + + /* Sometimes you want to put a fence between an RDMA + * READ and the following SEND. + * We could either do this all the time + * or when requested by the user. Right now, we let + * the application choose. + */ + if (rm->rdma.op_active && rm->rdma.op_fence) + send_flags = IB_SEND_FENCE; + + /* Each frag gets a header. Msgs may be 0 bytes */ + send = &ic->i_sends[pos]; + first = send; + prev = NULL; + scat = &ic->i_data_op->op_sg[rm->data.op_dmasg]; + i = 0; + do { + unsigned int len = 0; + + /* Set up the header */ + send->s_wr.send_flags = send_flags; + send->s_wr.opcode = IB_WR_SEND; + send->s_wr.num_sge = 1; + send->s_wr.next = NULL; + send->s_queued = jiffies; + send->s_op = NULL; + + send->s_sge[0].addr = ic->i_send_hdrs_dma + + (pos * sizeof(struct rds_header)); + send->s_sge[0].length = sizeof(struct rds_header); + + memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header)); + + /* Set up the data, if present */ + if (i < work_alloc + && scat != &rm->data.op_sg[rm->data.op_count]) { + len = min(RDS_FRAG_SIZE, + ib_sg_dma_len(dev, scat) - rm->data.op_dmaoff); + send->s_wr.num_sge = 2; + + send->s_sge[1].addr = ib_sg_dma_address(dev, scat); + send->s_sge[1].addr += rm->data.op_dmaoff; + send->s_sge[1].length = len; + + bytes_sent += len; + rm->data.op_dmaoff += len; + if (rm->data.op_dmaoff == ib_sg_dma_len(dev, scat)) { + scat++; + rm->data.op_dmasg++; + rm->data.op_dmaoff = 0; + } + } + + rds_ib_set_wr_signal_state(ic, send, false); + + /* + * Always signal the last one if we're stopping due to flow control. + */ + if (ic->i_flowctl && flow_controlled && i == (work_alloc - 1)) { + rds_ib_set_wr_signal_state(ic, send, true); + send->s_wr.send_flags |= IB_SEND_SOLICITED; + } + + if (send->s_wr.send_flags & IB_SEND_SIGNALED) + nr_sig++; + + rdsdebug("send %p wr %p num_sge %u next %p\n", send, + &send->s_wr, send->s_wr.num_sge, send->s_wr.next); + + if (ic->i_flowctl && adv_credits) { + struct rds_header *hdr = &ic->i_send_hdrs[pos]; + + /* add credit and redo the header checksum */ + hdr->h_credit = adv_credits; + rds_message_make_checksum(hdr); + adv_credits = 0; + rds_ib_stats_inc(s_ib_tx_credit_updates); + } + + if (prev) + prev->s_wr.next = &send->s_wr; + prev = send; + + pos = (pos + 1) % ic->i_send_ring.w_nr; + send = &ic->i_sends[pos]; + i++; + + } while (i < work_alloc + && scat != &rm->data.op_sg[rm->data.op_count]); + + /* Account the RDS header in the number of bytes we sent, but just once. + * The caller has no concept of fragmentation. */ + if (hdr_off == 0) + bytes_sent += sizeof(struct rds_header); + + /* if we finished the message then send completion owns it */ + if (scat == &rm->data.op_sg[rm->data.op_count]) { + prev->s_op = ic->i_data_op; + prev->s_wr.send_flags |= IB_SEND_SOLICITED; + if (!(prev->s_wr.send_flags & IB_SEND_SIGNALED)) + nr_sig += rds_ib_set_wr_signal_state(ic, prev, true); + ic->i_data_op = NULL; + } + + /* Put back wrs & credits we didn't use */ + if (i < work_alloc) { + rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); + work_alloc = i; + } + if (ic->i_flowctl && i < credit_alloc) + rds_ib_send_add_credits(conn, credit_alloc - i); + + if (nr_sig) + atomic_add(nr_sig, &ic->i_signaled_sends); + + /* XXX need to worry about failed_wr and partial sends. */ + failed_wr = &first->s_wr; + ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr); + rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, + first, &first->s_wr, ret, failed_wr); + BUG_ON(failed_wr != &first->s_wr); + if (ret) { + printk(KERN_WARNING "RDS/IB: ib_post_send to %pI6c " + "returned %d\n", &conn->c_faddr, ret); + rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); + rds_ib_sub_signaled(ic, nr_sig); + if (prev->s_op) { + ic->i_data_op = prev->s_op; + prev->s_op = NULL; + } + + rds_ib_conn_error(ic->conn, "ib_post_send failed\n"); + goto out; + } + + ret = bytes_sent; +out: + BUG_ON(adv_credits); + return ret; +} + +/* + * Issue atomic operation. + * A simplified version of the rdma case, we always map 1 SG, and + * only 8 bytes, for the return value from the atomic operation. + */ +int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op) +{ + struct rds_ib_connection *ic = conn->c_transport_data; + struct rds_ib_send_work *send = NULL; + const struct ib_send_wr *failed_wr; + u32 pos; + u32 work_alloc; + int ret; + int nr_sig = 0; + + work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos); + if (work_alloc != 1) { + rds_ib_stats_inc(s_ib_tx_ring_full); + ret = -ENOMEM; + goto out; + } + + /* address of send request in ring */ + send = &ic->i_sends[pos]; + send->s_queued = jiffies; + + if (op->op_type == RDS_ATOMIC_TYPE_CSWP) { + send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_CMP_AND_SWP; + send->s_atomic_wr.compare_add = op->op_m_cswp.compare; + send->s_atomic_wr.swap = op->op_m_cswp.swap; + send->s_atomic_wr.compare_add_mask = op->op_m_cswp.compare_mask; + send->s_atomic_wr.swap_mask = op->op_m_cswp.swap_mask; + } else { /* FADD */ + send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_FETCH_AND_ADD; + send->s_atomic_wr.compare_add = op->op_m_fadd.add; + send->s_atomic_wr.swap = 0; + send->s_atomic_wr.compare_add_mask = op->op_m_fadd.nocarry_mask; + send->s_atomic_wr.swap_mask = 0; + } + send->s_wr.send_flags = 0; + nr_sig = rds_ib_set_wr_signal_state(ic, send, op->op_notify); + send->s_atomic_wr.wr.num_sge = 1; + send->s_atomic_wr.wr.next = NULL; + send->s_atomic_wr.remote_addr = op->op_remote_addr; + send->s_atomic_wr.rkey = op->op_rkey; + send->s_op = op; + rds_message_addref(container_of(send->s_op, struct rds_message, atomic)); + + /* map 8 byte retval buffer to the device */ + ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE); + rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret); + if (ret != 1) { + rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); + rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); + ret = -ENOMEM; /* XXX ? */ + goto out; + } + + /* Convert our struct scatterlist to struct ib_sge */ + send->s_sge[0].addr = ib_sg_dma_address(ic->i_cm_id->device, op->op_sg); + send->s_sge[0].length = ib_sg_dma_len(ic->i_cm_id->device, op->op_sg); + send->s_sge[0].lkey = ic->i_pd->local_dma_lkey; + + rdsdebug("rva %Lx rpa %Lx len %u\n", op->op_remote_addr, + send->s_sge[0].addr, send->s_sge[0].length); + + if (nr_sig) + atomic_add(nr_sig, &ic->i_signaled_sends); + + failed_wr = &send->s_atomic_wr.wr; + ret = ib_post_send(ic->i_cm_id->qp, &send->s_atomic_wr.wr, &failed_wr); + rdsdebug("ic %p send %p (wr %p) ret %d wr %p\n", ic, + send, &send->s_atomic_wr, ret, failed_wr); + BUG_ON(failed_wr != &send->s_atomic_wr.wr); + if (ret) { + printk(KERN_WARNING "RDS/IB: atomic ib_post_send to %pI6c " + "returned %d\n", &conn->c_faddr, ret); + rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); + rds_ib_sub_signaled(ic, nr_sig); + goto out; + } + + if (unlikely(failed_wr != &send->s_atomic_wr.wr)) { + printk(KERN_WARNING "RDS/IB: atomic ib_post_send() rc=%d, but failed_wqe updated!\n", ret); + BUG_ON(failed_wr != &send->s_atomic_wr.wr); + } + +out: + return ret; +} + +int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op) +{ + struct rds_ib_connection *ic = conn->c_transport_data; + struct rds_ib_send_work *send = NULL; + struct rds_ib_send_work *first; + struct rds_ib_send_work *prev; + const struct ib_send_wr *failed_wr; + struct scatterlist *scat; + unsigned long len; + u64 remote_addr = op->op_remote_addr; + u32 max_sge = ic->rds_ibdev->max_sge; + u32 pos; + u32 work_alloc; + u32 i; + u32 j; + int sent; + int ret; + int num_sge; + int nr_sig = 0; + + /* map the op the first time we see it */ + if (!op->op_mapped) { + op->op_count = ib_dma_map_sg(ic->i_cm_id->device, + op->op_sg, op->op_nents, (op->op_write) ? + DMA_TO_DEVICE : DMA_FROM_DEVICE); + rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->op_count); + if (op->op_count == 0) { + rds_ib_stats_inc(s_ib_tx_sg_mapping_failure); + ret = -ENOMEM; /* XXX ? */ + goto out; + } + + op->op_mapped = 1; + } + + /* + * Instead of knowing how to return a partial rdma read/write we insist that there + * be enough work requests to send the entire message. + */ + i = ceil(op->op_count, max_sge); + + work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos); + if (work_alloc != i) { + rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); + rds_ib_stats_inc(s_ib_tx_ring_full); + ret = -ENOMEM; + goto out; + } + + send = &ic->i_sends[pos]; + first = send; + prev = NULL; + scat = &op->op_sg[0]; + sent = 0; + num_sge = op->op_count; + + for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) { + send->s_wr.send_flags = 0; + send->s_queued = jiffies; + send->s_op = NULL; + + nr_sig += rds_ib_set_wr_signal_state(ic, send, op->op_notify); + + send->s_wr.opcode = op->op_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ; + send->s_rdma_wr.remote_addr = remote_addr; + send->s_rdma_wr.rkey = op->op_rkey; + + if (num_sge > max_sge) { + send->s_rdma_wr.wr.num_sge = max_sge; + num_sge -= max_sge; + } else { + send->s_rdma_wr.wr.num_sge = num_sge; + } + + send->s_rdma_wr.wr.next = NULL; + + if (prev) + prev->s_rdma_wr.wr.next = &send->s_rdma_wr.wr; + + for (j = 0; j < send->s_rdma_wr.wr.num_sge && + scat != &op->op_sg[op->op_count]; j++) { + len = ib_sg_dma_len(ic->i_cm_id->device, scat); + send->s_sge[j].addr = + ib_sg_dma_address(ic->i_cm_id->device, scat); + send->s_sge[j].length = len; + send->s_sge[j].lkey = ic->i_pd->local_dma_lkey; + + sent += len; + rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr); + + remote_addr += len; + scat++; + } + + rdsdebug("send %p wr %p num_sge %u next %p\n", send, + &send->s_rdma_wr.wr, + send->s_rdma_wr.wr.num_sge, + send->s_rdma_wr.wr.next); + + prev = send; + if (++send == &ic->i_sends[ic->i_send_ring.w_nr]) + send = ic->i_sends; + } + + /* give a reference to the last op */ + if (scat == &op->op_sg[op->op_count]) { + prev->s_op = op; + rds_message_addref(container_of(op, struct rds_message, rdma)); + } + + if (i < work_alloc) { + rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i); + work_alloc = i; + } + + if (nr_sig) + atomic_add(nr_sig, &ic->i_signaled_sends); + + failed_wr = &first->s_rdma_wr.wr; + ret = ib_post_send(ic->i_cm_id->qp, &first->s_rdma_wr.wr, &failed_wr); + rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic, + first, &first->s_rdma_wr.wr, ret, failed_wr); + BUG_ON(failed_wr != &first->s_rdma_wr.wr); + if (ret) { + printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI6c " + "returned %d\n", &conn->c_faddr, ret); + rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc); + rds_ib_sub_signaled(ic, nr_sig); + goto out; + } + + if (unlikely(failed_wr != &first->s_rdma_wr.wr)) { + printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret); + BUG_ON(failed_wr != &first->s_rdma_wr.wr); + } + + +out: + return ret; +} + +void rds_ib_xmit_path_complete(struct rds_conn_path *cp) +{ + struct rds_connection *conn = cp->cp_conn; + struct rds_ib_connection *ic = conn->c_transport_data; + + /* We may have a pending ACK or window update we were unable + * to send previously (due to flow control). Try again. */ + rds_ib_attempt_ack(ic); +} |