v4.19.13 snapshot.
diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c
new file mode 100644
index 0000000..2dcb555
--- /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);
+}