diff options
Diffstat (limited to 'drivers/infiniband/sw/rdmavt/rc.c')
| -rw-r--r-- | drivers/infiniband/sw/rdmavt/rc.c | 43 |
1 files changed, 23 insertions, 20 deletions
diff --git a/drivers/infiniband/sw/rdmavt/rc.c b/drivers/infiniband/sw/rdmavt/rc.c index 44cc7ee1b321..890d7b760d2e 100644 --- a/drivers/infiniband/sw/rdmavt/rc.c +++ b/drivers/infiniband/sw/rdmavt/rc.c @@ -107,27 +107,30 @@ __be32 rvt_compute_aeth(struct rvt_qp *qp) u32 head; u32 tail; - /* sanity check pointers before trusting them */ - if (qp->ip) { - head = RDMA_READ_UAPI_ATOMIC(qp->r_rq.wq->head); - tail = RDMA_READ_UAPI_ATOMIC(qp->r_rq.wq->tail); - } else { - head = READ_ONCE(qp->r_rq.kwq->head); - tail = READ_ONCE(qp->r_rq.kwq->tail); + credits = READ_ONCE(qp->r_rq.kwq->count); + if (credits == 0) { + /* sanity check pointers before trusting them */ + if (qp->ip) { + head = RDMA_READ_UAPI_ATOMIC(qp->r_rq.wq->head); + tail = RDMA_READ_UAPI_ATOMIC(qp->r_rq.wq->tail); + } else { + head = READ_ONCE(qp->r_rq.kwq->head); + tail = READ_ONCE(qp->r_rq.kwq->tail); + } + if (head >= qp->r_rq.size) + head = 0; + 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; } - if (head >= qp->r_rq.size) - head = 0; - 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. |