RDMA/cxgb4: CQ size must be IQ size - 2

We need 1 extra entry for the status page and 1 to always have 1 free
entry to detect when the queue is full.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --git a/drivers/infiniband/hw/cxgb4/cq.c b/drivers/infiniband/hw/cxgb4/cq.c
index fb1aafcc294f1be1f85a6790b2bce0c340e35e0e..46ac00f728f3c623cd4fa6e6e1aebe4a332cb016 100644 (file)
--- a/drivers/infiniband/hw/cxgb4/cq.c
+++ b/drivers/infiniband/hw/cxgb4/cq.c
@@ -780,6 +780,9 @@ struct ib_cq *c4iw_create_cq(struct ib_device *ibdev, int entries,
        /* account for the status page. */
        entries++;
 
+       /* IQ needs one extra entry to differentiate full vs empty. */
+       entries++;
+
        /*
         * entries must be multiple of 16 for HW.
         */
@@ -801,7 +804,7 @@ struct ib_cq *c4iw_create_cq(struct ib_device *ibdev, int entries,
 
        chp->rhp = rhp;
        chp->cq.size--;                         /* status page */
-       chp->ibcq.cqe = chp->cq.size;
+       chp->ibcq.cqe = chp->cq.size - 1;
        spin_lock_init(&chp->lock);
        atomic_set(&chp->refcnt, 1);
        init_waitqueue_head(&chp->wait);