IB/mthca: fix posting of send lists of length >= 255 on mem-free HCAs
On mem-free HCAs, when posting a long list of send requests, a
doorbell must be rung every 255 requests. Add code to handle this.
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/hw/mthca/mthca_qp.c b/drivers/infiniband/hw/mthca/mthca_qp.c
index f9c8eb9..7450550 100644
--- a/drivers/infiniband/hw/mthca/mthca_qp.c
+++ b/drivers/infiniband/hw/mthca/mthca_qp.c
@@ -1822,6 +1822,7 @@
{
struct mthca_dev *dev = to_mdev(ibqp->device);
struct mthca_qp *qp = to_mqp(ibqp);
+ __be32 doorbell[2];
void *wqe;
void *prev_wqe;
unsigned long flags;
@@ -1841,6 +1842,34 @@
ind = qp->sq.head & (qp->sq.max - 1);
for (nreq = 0; wr; ++nreq, wr = wr->next) {
+ if (unlikely(nreq == MTHCA_ARBEL_MAX_WQES_PER_SEND_DB)) {
+ nreq = 0;
+
+ doorbell[0] = cpu_to_be32((MTHCA_ARBEL_MAX_WQES_PER_SEND_DB << 24) |
+ ((qp->sq.head & 0xffff) << 8) |
+ f0 | op0);
+ doorbell[1] = cpu_to_be32((qp->qpn << 8) | size0);
+
+ qp->sq.head += MTHCA_ARBEL_MAX_WQES_PER_SEND_DB;
+ size0 = 0;
+
+ /*
+ * Make sure that descriptors are written before
+ * doorbell record.
+ */
+ wmb();
+ *qp->sq.db = cpu_to_be32(qp->sq.head & 0xffff);
+
+ /*
+ * Make sure doorbell record is written before we
+ * write MMIO send doorbell.
+ */
+ wmb();
+ mthca_write64(doorbell,
+ dev->kar + MTHCA_SEND_DOORBELL,
+ MTHCA_GET_DOORBELL_LOCK(&dev->doorbell_lock));
+ }
+
if (mthca_wq_overflow(&qp->sq, nreq, qp->ibqp.send_cq)) {
mthca_err(dev, "SQ %06x full (%u head, %u tail,"
" %d max, %d nreq)\n", qp->qpn,
@@ -2017,8 +2046,6 @@
out:
if (likely(nreq)) {
- __be32 doorbell[2];
-
doorbell[0] = cpu_to_be32((nreq << 24) |
((qp->sq.head & 0xffff) << 8) |
f0 | op0);