Michael> this one's wrong. nreq will overflow into bit 8. You
Michael> want to put 0 there since we know nreq is 256:
Michael> doorbell[1] = cpu_to_be32(qp->qpn << 8);
Thanks, fixed both places.
Michael> I know I did it differently, but I now think its better
Michael> to replace nreq with MTHCA_TAVOR_MAX_WQES_PER_RECV_DB in
Michael> the line above since wmb should prevent gcc from knowing
Michael> the value of nreq here or storing it in a register.
Good idea.
How's this:
--- infiniband/hw/mthca/mthca_srq.c (revision 3989)
+++ infiniband/hw/mthca/mthca_srq.c (working copy)
@@ -414,6 +414,7 @@ int mthca_tavor_post_srq_recv(struct ib_
{
struct mthca_dev *dev = to_mdev(ibsrq->device);
struct mthca_srq *srq = to_msrq(ibsrq);
+ __be32 doorbell[2];
unsigned long flags;
int err = 0;
int first_ind;
@@ -429,6 +430,25 @@ int mthca_tavor_post_srq_recv(struct ib_
first_ind = srq->first_free;
for (nreq = 0; wr; ++nreq, wr = wr->next) {
+ if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) {
+ nreq = 0;
+
+ doorbell[0] = cpu_to_be32(first_ind << srq->wqe_shift);
+ doorbell[1] = cpu_to_be32(srq->srqn << 8);
+
+ /*
+ * Make sure that descriptors are written
+ * before doorbell is rung.
+ */
+ wmb();
+
+ mthca_write64(doorbell,
+ dev->kar + MTHCA_RECEIVE_DOORBELL,
+
MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
+
+ first_ind = srq->first_free;
+ }
+
ind = srq->first_free;
if (ind < 0) {
@@ -491,8 +511,6 @@ int mthca_tavor_post_srq_recv(struct ib_
}
if (likely(nreq)) {
- __be32 doorbell[2];
-
doorbell[0] = cpu_to_be32(first_ind << srq->wqe_shift);
doorbell[1] = cpu_to_be32((srq->srqn << 8) | nreq);
--- infiniband/hw/mthca/mthca_wqe.h (revision 3989)
+++ infiniband/hw/mthca/mthca_wqe.h (working copy)
@@ -49,7 +49,8 @@ enum {
};
enum {
- MTHCA_INVAL_LKEY = 0x100
+ MTHCA_INVAL_LKEY = 0x100,
+ MTHCA_TAVOR_MAX_WQES_PER_RECV_DB = 256
};
struct mthca_next_seg {
--- infiniband/hw/mthca/mthca_qp.c (revision 4003)
+++ infiniband/hw/mthca/mthca_qp.c (working copy)
@@ -1705,6 +1705,7 @@ int mthca_tavor_post_receive(struct ib_q
{
struct mthca_dev *dev = to_mdev(ibqp->device);
struct mthca_qp *qp = to_mqp(ibqp);
+ __be32 doorbell[2];
unsigned long flags;
int err = 0;
int nreq;
@@ -1722,6 +1723,22 @@ int mthca_tavor_post_receive(struct ib_q
ind = qp->rq.next_ind;
for (nreq = 0; wr; ++nreq, wr = wr->next) {
+ if (unlikely(nreq == MTHCA_TAVOR_MAX_WQES_PER_RECV_DB)) {
+ nreq = 0;
+
+ doorbell[0] = cpu_to_be32((qp->rq.next_ind <<
qp->rq.wqe_shift) | size0);
+ doorbell[1] = cpu_to_be32(qp->qpn << 8);
+
+ wmb();
+
+ mthca_write64(doorbell,
+ dev->kar + MTHCA_RECEIVE_DOORBELL,
+
MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
+
+ qp->rq.head += MTHCA_TAVOR_MAX_WQES_PER_RECV_DB;
+ size0 = 0;
+ }
+
if (mthca_wq_overflow(&qp->rq, nreq, qp->ibqp.recv_cq)) {
mthca_err(dev, "RQ %06x full (%u head, %u tail,"
" %d max, %d nreq)\n", qp->qpn,
@@ -1779,8 +1796,6 @@ int mthca_tavor_post_receive(struct ib_q
out:
if (likely(nreq)) {
- __be32 doorbell[2];
-
doorbell[0] = cpu_to_be32((qp->rq.next_ind << qp->rq.wqe_shift)
| size0);
doorbell[1] = cpu_to_be32((qp->qpn << 8) | nreq);
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