v4.19.13 snapshot.
diff --git a/drivers/infiniband/sw/rdmavt/rc.c b/drivers/infiniband/sw/rdmavt/rc.c
new file mode 100644
index 0000000..6131cc5
--- /dev/null
+++ b/drivers/infiniband/sw/rdmavt/rc.c
@@ -0,0 +1,189 @@
+/*
+ * Copyright(c) 2016 Intel Corporation.
+ *
+ * This file is provided under a dual BSD/GPLv2 license. When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * BSD LICENSE
+ *
+ * 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.
+ * - Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <rdma/rdma_vt.h>
+#include <rdma/ib_hdrs.h>
+
+/*
+ * Convert the AETH credit code into the number of credits.
+ */
+static const u16 credit_table[31] = {
+ 0, /* 0 */
+ 1, /* 1 */
+ 2, /* 2 */
+ 3, /* 3 */
+ 4, /* 4 */
+ 6, /* 5 */
+ 8, /* 6 */
+ 12, /* 7 */
+ 16, /* 8 */
+ 24, /* 9 */
+ 32, /* A */
+ 48, /* B */
+ 64, /* C */
+ 96, /* D */
+ 128, /* E */
+ 192, /* F */
+ 256, /* 10 */
+ 384, /* 11 */
+ 512, /* 12 */
+ 768, /* 13 */
+ 1024, /* 14 */
+ 1536, /* 15 */
+ 2048, /* 16 */
+ 3072, /* 17 */
+ 4096, /* 18 */
+ 6144, /* 19 */
+ 8192, /* 1A */
+ 12288, /* 1B */
+ 16384, /* 1C */
+ 24576, /* 1D */
+ 32768 /* 1E */
+};
+
+/**
+ * rvt_compute_aeth - compute the AETH (syndrome + MSN)
+ * @qp: the queue pair to compute the AETH for
+ *
+ * Returns the AETH.
+ */
+__be32 rvt_compute_aeth(struct rvt_qp *qp)
+{
+ u32 aeth = qp->r_msn & IB_MSN_MASK;
+
+ if (qp->ibqp.srq) {
+ /*
+ * Shared receive queues don't generate credits.
+ * Set the credit field to the invalid value.
+ */
+ aeth |= IB_AETH_CREDIT_INVAL << IB_AETH_CREDIT_SHIFT;
+ } else {
+ u32 min, max, x;
+ u32 credits;
+ struct rvt_rwq *wq = qp->r_rq.wq;
+ u32 head;
+ u32 tail;
+
+ /* sanity check pointers before trusting them */
+ head = wq->head;
+ if (head >= qp->r_rq.size)
+ head = 0;
+ tail = wq->tail;
+ if (tail >= qp->r_rq.size)
+ tail = 0;
+ /*
+ * Compute the number of credits available (RWQEs).
+ * There is a small chance that the pair of reads are
+ * not atomic, which is OK, since the fuzziness is
+ * resolved as further ACKs go out.
+ */
+ credits = head - tail;
+ if ((int)credits < 0)
+ credits += qp->r_rq.size;
+ /*
+ * Binary search the credit table to find the code to
+ * use.
+ */
+ min = 0;
+ max = 31;
+ for (;;) {
+ x = (min + max) / 2;
+ if (credit_table[x] == credits)
+ break;
+ if (credit_table[x] > credits) {
+ max = x;
+ } else {
+ if (min == x)
+ break;
+ min = x;
+ }
+ }
+ aeth |= x << IB_AETH_CREDIT_SHIFT;
+ }
+ return cpu_to_be32(aeth);
+}
+EXPORT_SYMBOL(rvt_compute_aeth);
+
+/**
+ * rvt_get_credit - flush the send work queue of a QP
+ * @qp: the qp who's send work queue to flush
+ * @aeth: the Acknowledge Extended Transport Header
+ *
+ * The QP s_lock should be held.
+ */
+void rvt_get_credit(struct rvt_qp *qp, u32 aeth)
+{
+ struct rvt_dev_info *rdi = ib_to_rvt(qp->ibqp.device);
+ u32 credit = (aeth >> IB_AETH_CREDIT_SHIFT) & IB_AETH_CREDIT_MASK;
+
+ lockdep_assert_held(&qp->s_lock);
+ /*
+ * If the credit is invalid, we can send
+ * as many packets as we like. Otherwise, we have to
+ * honor the credit field.
+ */
+ if (credit == IB_AETH_CREDIT_INVAL) {
+ if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT)) {
+ qp->s_flags |= RVT_S_UNLIMITED_CREDIT;
+ if (qp->s_flags & RVT_S_WAIT_SSN_CREDIT) {
+ qp->s_flags &= ~RVT_S_WAIT_SSN_CREDIT;
+ rdi->driver_f.schedule_send(qp);
+ }
+ }
+ } else if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT)) {
+ /* Compute new LSN (i.e., MSN + credit) */
+ credit = (aeth + credit_table[credit]) & IB_MSN_MASK;
+ if (rvt_cmp_msn(credit, qp->s_lsn) > 0) {
+ qp->s_lsn = credit;
+ if (qp->s_flags & RVT_S_WAIT_SSN_CREDIT) {
+ qp->s_flags &= ~RVT_S_WAIT_SSN_CREDIT;
+ rdi->driver_f.schedule_send(qp);
+ }
+ }
+ }
+}
+EXPORT_SYMBOL(rvt_get_credit);