/* * 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/in.h> #include <linux/device.h> #include <linux/dmapool.h> #include <linux/ratelimit.h> #include "rds.h" #include "iw.h" static void rds_iw_send_rdma_complete(struct rds_message *rm, int wc_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; } rds_rdma_send_complete(rm, notify_status); } static void rds_iw_send_unmap_rdma(struct rds_iw_connection *ic, struct rm_rdma_op *op) { 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; } } static void rds_iw_send_unmap_rm(struct rds_iw_connection *ic, struct rds_iw_send_work *send, int wc_status) { struct rds_message *rm = send->s_rm; rdsdebug("ic %p send %p rm %p\n", ic, send, rm); ib_dma_unmap_sg(ic->i_cm_id->device, rm->data.op_sg, rm->data.op_nents, DMA_TO_DEVICE); if (rm->rdma.op_active) { rds_iw_send_unmap_rdma(ic, &rm->rdma); /* 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, * call rds_rdma_send_complete from the cq_handler. 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_iw_send_rdma_complete(rm, wc_status); if (rm->rdma.op_write) rds_stats_add(s_send_rdma_bytes, rm->rdma.op_bytes); else rds_stats_add(s_recv_rdma_bytes, rm->rdma.op_bytes); } /* If anyone waited for this message to get flushed out, wake * them up now */ rds_message_unmapped(rm); rds_message_put(rm); send->s_rm = NULL; } void rds_iw_send_init_ring(struct rds_iw_connection *ic) { struct rds_iw_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_rm = NULL; send->s_op = NULL; send->s_mapping = NULL; send->s_wr.next = NULL; send->s_wr.wr_id = i; send->s_wr.sg_list = send->s_sge; send->s_wr.num_sge = 1; send->s_wr.opcode = IB_WR_SEND; send->s_wr.send_flags = 0; send->s_wr.ex.imm_data = 0; sge = rds_iw_data_sge(ic, send->s_sge); sge->lkey = 0; sge = rds_iw_header_sge(ic, send->s_sge); sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header)); sge->length = sizeof(struct rds_header); sge->lkey = 0; send->s_mr = ib_alloc_fast_reg_mr(ic->i_pd, fastreg_message_size); if (IS_ERR(send->s_mr)) { printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_mr failed\n"); break; } send->s_page_list = ib_alloc_fast_reg_page_list( ic->i_cm_id->device, fastreg_message_size); if (IS_ERR(send->s_page_list)) { printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_page_list failed\n"); break; } } } void rds_iw_send_clear_ring(struct rds_iw_connection *ic) { struct rds_iw_send_work *send; u32 i; for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) { BUG_ON(!send->s_mr); ib_dereg_mr(send->s_mr); BUG_ON(!send->s_page_list); ib_free_fast_reg_page_list(send->s_page_list); if (send->s_wr.opcode == 0xdead) continue; if (send->s_rm) rds_iw_send_unmap_rm(ic, send, IB_WC_WR_FLUSH_ERR); if (send->s_op) rds_iw_send_unmap_rdma(ic, send->s_op); } } /* * 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_iw_send_cq_comp_handler(struct ib_cq *cq, void *context) { struct rds_connection *conn = context; struct rds_iw_connection *ic = conn->c_transport_data; struct ib_wc wc; struct rds_iw_send_work *send; u32 completed; u32 oldest; u32 i; int ret; rdsdebug("cq %p conn %p\n", cq, conn); rds_iw_stats_inc(s_iw_tx_cq_call); ret = ib_req_notify_cq(cq, IB_CQ_NEXT_COMP); if (ret) rdsdebug("ib_req_notify_cq send failed: %d\n", ret); while (ib_poll_cq(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_tx_cq_event); if (wc.status != IB_WC_SUCCESS) { printk(KERN_ERR "WC Error: status = %d opcode = %d\n", wc.status, wc.opcode); break; } if (wc.opcode == IB_WC_LOCAL_INV && wc.wr_id == RDS_IW_LOCAL_INV_WR_ID) { ic->i_fastreg_posted = 0; continue; } if (wc.opcode == IB_WC_FAST_REG_MR && wc.wr_id == RDS_IW_FAST_REG_WR_ID) { ic->i_fastreg_posted = 1; continue; } if (wc.wr_id == RDS_IW_ACK_WR_ID) { if (time_after(jiffies, ic->i_ack_queued + HZ/2)) rds_iw_stats_inc(s_iw_tx_stalled); rds_iw_ack_send_complete(ic); continue; } oldest = rds_iw_ring_oldest(&ic->i_send_ring); completed = rds_iw_ring_completed(&ic->i_send_ring, wc.wr_id, oldest); for (i = 0; i < completed; i++) { send = &ic->i_sends[oldest]; /* In the error case, wc.opcode sometimes contains garbage */ switch (send->s_wr.opcode) { case IB_WR_SEND: if (send->s_rm) rds_iw_send_unmap_rm(ic, send, wc.status); break; case IB_WR_FAST_REG_MR: case IB_WR_RDMA_WRITE: case IB_WR_RDMA_READ: case IB_WR_RDMA_READ_WITH_INV: /* Nothing to be done - the SG list will be unmapped * when the SEND completes. */ break; default: printk_ratelimited(KERN_NOTICE "RDS/IW: %s: unexpected opcode 0x%x in WR!\n", __func__, send->s_wr.opcode); break; } send->s_wr.opcode = 0xdead; send->s_wr.num_sge = 1; if (time_after(jiffies, send->s_queued + HZ/2)) rds_iw_stats_inc(s_iw_tx_stalled); /* If a RDMA operation produced an error, signal this right * away. If we don't, the subsequent SEND that goes with this * RDMA will be canceled with ERR_WFLUSH, and the application * never learn that the RDMA failed. */ if (unlikely(wc.status == IB_WC_REM_ACCESS_ERR && send->s_op)) { struct rds_message *rm; rm = rds_send_get_message(conn, send->s_op); if (rm) rds_iw_send_rdma_complete(rm, wc.status); } oldest = (oldest + 1) % ic->i_send_ring.w_nr; } rds_iw_ring_free(&ic->i_send_ring, completed); 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_iw_conn_error(conn, "send completion on %pI4 " "had status %u, disconnecting and reconnecting\n", &conn->c_faddr, 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_iw_send_add_credits below). * * The RDS send code is essentially single-threaded; rds_send_xmit * grabs c_send_lock 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_iw_send_grab_credits(struct rds_iw_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_iw_send_add_credits(struct rds_connection *conn, unsigned int credits) { struct rds_iw_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_iw_stats_inc(s_iw_rx_credit_updates); } void rds_iw_advertise_credits(struct rds_connection *conn, unsigned int posted) { struct rds_iw_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 void rds_iw_xmit_populate_wr(struct rds_iw_connection *ic, struct rds_iw_send_work *send, unsigned int pos, unsigned long buffer, unsigned int length, int send_flags) { struct ib_sge *sge; WARN_ON(pos != send - ic->i_sends); send->s_wr.send_flags = send_flags; send->s_wr.opcode = IB_WR_SEND; send->s_wr.num_sge = 2; send->s_wr.next = NULL; send->s_queued = jiffies; send->s_op = NULL; if (length != 0) { sge = rds_iw_data_sge(ic, send->s_sge); sge->addr = buffer; sge->length = length; sge->lkey = rds_iw_local_dma_lkey(ic); sge = rds_iw_header_sge(ic, send->s_sge); } else { /* We're sending a packet with no payload. There is only * one SGE */ send->s_wr.num_sge = 1; sge = &send->s_sge[0]; } sge->addr = ic->i_send_hdrs_dma + (pos * sizeof(struct rds_header)); sge->length = sizeof(struct rds_header); sge->lkey = rds_iw_local_dma_lkey(ic); } /* * 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_iw_xmit(struct rds_connection *conn, struct rds_message *rm, unsigned int hdr_off, unsigned int sg, unsigned int off) { struct rds_iw_connection *ic = conn->c_transport_data; struct ib_device *dev = ic->i_cm_id->device; struct rds_iw_send_work *send = NULL; struct rds_iw_send_work *first; struct rds_iw_send_work *prev; struct ib_send_wr *failed_wr; struct scatterlist *scat; u32 pos; u32 i; u32 work_alloc; u32 credit_alloc; u32 posted; u32 adv_credits = 0; int send_flags = 0; int sent; int ret; int flow_controlled = 0; BUG_ON(off % RDS_FRAG_SIZE); BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header)); /* Fastreg support */ if (rds_rdma_cookie_key(rm->m_rdma_cookie) && !ic->i_fastreg_posted) { ret = -EAGAIN; goto out; } /* 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_iw_ring_alloc(&ic->i_send_ring, i, &pos); if (work_alloc == 0) { set_bit(RDS_LL_SEND_FULL, &conn->c_flags); rds_iw_stats_inc(s_iw_tx_ring_full); ret = -ENOMEM; goto out; } credit_alloc = work_alloc; if (ic->i_flowctl) { credit_alloc = rds_iw_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT); adv_credits += posted; if (credit_alloc < work_alloc) { rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc); work_alloc = credit_alloc; flow_controlled++; } if (work_alloc == 0) { set_bit(RDS_LL_SEND_FULL, &conn->c_flags); rds_iw_stats_inc(s_iw_tx_throttle); ret = -ENOMEM; goto out; } } /* map the message the first time we see it */ if (!ic->i_rm) { /* printk(KERN_NOTICE "rds_iw_xmit prep msg dport=%u flags=0x%x len=%d\n", be16_to_cpu(rm->m_inc.i_hdr.h_dport), rm->m_inc.i_hdr.h_flags, be32_to_cpu(rm->m_inc.i_hdr.h_len)); */ 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_iw_stats_inc(s_iw_tx_sg_mapping_failure); rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc); ret = -ENOMEM; /* XXX ? */ goto out; } } else { rm->data.op_count = 0; } ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs; ic->i_unsignaled_bytes = rds_iw_sysctl_max_unsig_bytes; rds_message_addref(rm); ic->i_rm = rm; /* 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_iw_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_iw_ring_alloc first. */ rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_iw_piggyb_ack(ic)); rds_message_make_checksum(&rm->m_inc.i_hdr); /* * Update adv_credits since we reset the ACK_REQUIRED bit. */ rds_iw_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits); adv_credits += posted; BUG_ON(adv_credits > 255); } send = &ic->i_sends[pos]; first = send; prev = NULL; scat = &rm->data.op_sg[sg]; sent = 0; i = 0; /* 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; /* * We could be copying the header into the unused tail of the page. * That would need to be changed in the future when those pages might * be mapped userspace pages or page cache pages. So instead we always * use a second sge and our long-lived ring of mapped headers. We send * the header after the data so that the data payload can be aligned on * the receiver. */ /* handle a 0-len message */ if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0) { rds_iw_xmit_populate_wr(ic, send, pos, 0, 0, send_flags); goto add_header; } /* if there's data reference it with a chain of work reqs */ for (; i < work_alloc && scat != &rm->data.op_sg[rm->data.op_count]; i++) { unsigned int len; send = &ic->i_sends[pos]; len = min(RDS_FRAG_SIZE, ib_sg_dma_len(dev, scat) - off); rds_iw_xmit_populate_wr(ic, send, pos, ib_sg_dma_address(dev, scat) + off, len, send_flags); /* * 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) { ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs; send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; } ic->i_unsignaled_bytes -= len; if (ic->i_unsignaled_bytes <= 0) { ic->i_unsignaled_bytes = rds_iw_sysctl_max_unsig_bytes; send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; } /* * Always signal the last one if we're stopping due to flow control. */ if (flow_controlled && i == (work_alloc-1)) send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; rdsdebug("send %p wr %p num_sge %u next %p\n", send, &send->s_wr, send->s_wr.num_sge, send->s_wr.next); sent += len; off += len; if (off == ib_sg_dma_len(dev, scat)) { scat++; off = 0; } add_header: /* Tack on the header after the data. The header SGE should already * have been set up to point to the right header buffer. */ memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header)); if (0) { struct rds_header *hdr = &ic->i_send_hdrs[pos]; printk(KERN_NOTICE "send WR dport=%u flags=0x%x len=%d\n", be16_to_cpu(hdr->h_dport), hdr->h_flags, be32_to_cpu(hdr->h_len)); } if (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_iw_stats_inc(s_iw_tx_credit_updates); } if (prev) prev->s_wr.next = &send->s_wr; prev = send; pos = (pos + 1) % ic->i_send_ring.w_nr; } /* 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) 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_rm = ic->i_rm; prev->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED; ic->i_rm = NULL; } if (i < work_alloc) { rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - i); work_alloc = i; } if (ic->i_flowctl && i < credit_alloc) rds_iw_send_add_credits(conn, credit_alloc - i); /* 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/IW: ib_post_send to %pI4 " "returned %d\n", &conn->c_faddr, ret); rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc); if (prev->s_rm) { ic->i_rm = prev->s_rm; prev->s_rm = NULL; } goto out; } ret = sent; out: BUG_ON(adv_credits); return ret; } static void rds_iw_build_send_fastreg(struct rds_iw_device *rds_iwdev, struct rds_iw_connection *ic, struct rds_iw_send_work *send, int nent, int len, u64 sg_addr) { BUG_ON(nent > send->s_page_list->max_page_list_len); /* * Perform a WR for the fast_reg_mr. Each individual page * in the sg list is added to the fast reg page list and placed * inside the fast_reg_mr WR. */ send->s_wr.opcode = IB_WR_FAST_REG_MR; send->s_wr.wr.fast_reg.length = len; send->s_wr.wr.fast_reg.rkey = send->s_mr->rkey; send->s_wr.wr.fast_reg.page_list = send->s_page_list; send->s_wr.wr.fast_reg.page_list_len = nent; send->s_wr.wr.fast_reg.page_shift = PAGE_SHIFT; send->s_wr.wr.fast_reg.access_flags = IB_ACCESS_REMOTE_WRITE; send->s_wr.wr.fast_reg.iova_start = sg_addr; ib_update_fast_reg_key(send->s_mr, send->s_remap_count++); } int rds_iw_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op) { struct rds_iw_connection *ic = conn->c_transport_data; struct rds_iw_send_work *send = NULL; struct rds_iw_send_work *first; struct rds_iw_send_work *prev; struct ib_send_wr *failed_wr; struct rds_iw_device *rds_iwdev; struct scatterlist *scat; unsigned long len; u64 remote_addr = op->op_remote_addr; u32 pos, fr_pos; u32 work_alloc; u32 i; u32 j; int sent; int ret; int num_sge; rds_iwdev = ib_get_client_data(ic->i_cm_id->device, &rds_iw_client); /* map the message 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_iw_stats_inc(s_iw_tx_sg_mapping_failure); ret = -ENOMEM; /* XXX ? */ goto out; } op->op_mapped = 1; } if (!op->op_write) { /* Alloc space on the send queue for the fastreg */ work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, 1, &fr_pos); if (work_alloc != 1) { rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc); rds_iw_stats_inc(s_iw_tx_ring_full); ret = -ENOMEM; goto out; } } /* * 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, rds_iwdev->max_sge); work_alloc = rds_iw_ring_alloc(&ic->i_send_ring, i, &pos); if (work_alloc != i) { rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc); rds_iw_stats_inc(s_iw_tx_ring_full); ret = -ENOMEM; goto out; } send = &ic->i_sends[pos]; if (!op->op_write) { first = prev = &ic->i_sends[fr_pos]; } else { 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; /* * 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) { ic->i_unsignaled_wrs = rds_iw_sysctl_max_unsig_wrs; send->s_wr.send_flags = IB_SEND_SIGNALED; } /* To avoid the need to have the plumbing to invalidate the fastreg_mr used * for local access after RDS is finished with it, using * IB_WR_RDMA_READ_WITH_INV will invalidate it after the read has completed. */ if (op->op_write) send->s_wr.opcode = IB_WR_RDMA_WRITE; else send->s_wr.opcode = IB_WR_RDMA_READ_WITH_INV; send->s_wr.wr.rdma.remote_addr = remote_addr; send->s_wr.wr.rdma.rkey = op->op_rkey; send->s_op = op; if (num_sge > rds_iwdev->max_sge) { send->s_wr.num_sge = rds_iwdev->max_sge; num_sge -= rds_iwdev->max_sge; } else send->s_wr.num_sge = num_sge; send->s_wr.next = NULL; if (prev) prev->s_wr.next = &send->s_wr; for (j = 0; j < send->s_wr.num_sge && scat != &op->op_sg[op->op_count]; j++) { len = ib_sg_dma_len(ic->i_cm_id->device, scat); if (send->s_wr.opcode == IB_WR_RDMA_READ_WITH_INV) send->s_page_list->page_list[j] = ib_sg_dma_address(ic->i_cm_id->device, scat); else { 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 = rds_iw_local_dma_lkey(ic); } sent += len; rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr); remote_addr += len; scat++; } if (send->s_wr.opcode == IB_WR_RDMA_READ_WITH_INV) { send->s_wr.num_sge = 1; send->s_sge[0].addr = conn->c_xmit_rm->m_rs->rs_user_addr; send->s_sge[0].length = conn->c_xmit_rm->m_rs->rs_user_bytes; send->s_sge[0].lkey = ic->i_sends[fr_pos].s_mr->lkey; } rdsdebug("send %p wr %p num_sge %u next %p\n", send, &send->s_wr, send->s_wr.num_sge, send->s_wr.next); prev = send; if (++send == &ic->i_sends[ic->i_send_ring.w_nr]) send = ic->i_sends; } /* if we finished the message then send completion owns it */ if (scat == &op->op_sg[op->op_count]) first->s_wr.send_flags = IB_SEND_SIGNALED; if (i < work_alloc) { rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc - i); work_alloc = i; } /* On iWARP, local memory access by a remote system (ie, RDMA Read) is not * recommended. Putting the lkey on the wire is a security hole, as it can * allow for memory access to all of memory on the remote system. Some * adapters do not allow using the lkey for this at all. To bypass this use a * fastreg_mr (or possibly a dma_mr) */ if (!op->op_write) { rds_iw_build_send_fastreg(rds_iwdev, ic, &ic->i_sends[fr_pos], op->op_count, sent, conn->c_xmit_rm->m_rs->rs_user_addr); work_alloc++; } 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/IW: rdma ib_post_send to %pI4 " "returned %d\n", &conn->c_faddr, ret); rds_iw_ring_unalloc(&ic->i_send_ring, work_alloc); goto out; } out: return ret; } void rds_iw_xmit_complete(struct rds_connection *conn) { struct rds_iw_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_iw_attempt_ack(ic); }