| Message ID | 1479479809-10798-2-git-send-email-andrew.boyer@dell.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 11/18/2016 4:36 PM, Andrew Boyer wrote: > A simple userspace application might poll the CQ, find a completion, > and then attempt to post a new WQE to the SQ. A spurious error can > occur if the userspace application detects a full SQ in the instant > before the kernel is able to advance the SQ consumer pointer. > > This is noticeable when using single-entry SQs with ibv_rc_pingpong() > if lots of kernel and userspace library debugging is enabled. > > Signed-off-by: Andrew Boyer <andrew.boyer@dell.com> > --- > drivers/infiniband/sw/rxe/rxe_comp.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c > index 6c5e29d..d46c49b 100644 > --- a/drivers/infiniband/sw/rxe/rxe_comp.c > +++ b/drivers/infiniband/sw/rxe/rxe_comp.c > @@ -420,11 +420,12 @@ static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe) > (wqe->wr.send_flags & IB_SEND_SIGNALED) || > (qp->req.state == QP_STATE_ERROR)) { > make_send_cqe(qp, wqe, &cqe); > + advance_consumer(qp->sq.queue); > rxe_cq_post(qp->scq, &cqe, 0); > + } else { > + advance_consumer(qp->sq.queue); > } > > - advance_consumer(qp->sq.queue); > - > /* > * we completed something so let req run again > * if it is trying to fence > Reviewed-by: Yonatan Cohen <yonatanc@mellanox.com> -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c index 6c5e29d..d46c49b 100644 --- a/drivers/infiniband/sw/rxe/rxe_comp.c +++ b/drivers/infiniband/sw/rxe/rxe_comp.c @@ -420,11 +420,12 @@ static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe) (wqe->wr.send_flags & IB_SEND_SIGNALED) || (qp->req.state == QP_STATE_ERROR)) { make_send_cqe(qp, wqe, &cqe); + advance_consumer(qp->sq.queue); rxe_cq_post(qp->scq, &cqe, 0); + } else { + advance_consumer(qp->sq.queue); } - advance_consumer(qp->sq.queue); - /* * we completed something so let req run again * if it is trying to fence
A simple userspace application might poll the CQ, find a completion, and then attempt to post a new WQE to the SQ. A spurious error can occur if the userspace application detects a full SQ in the instant before the kernel is able to advance the SQ consumer pointer. This is noticeable when using single-entry SQs with ibv_rc_pingpong() if lots of kernel and userspace library debugging is enabled. Signed-off-by: Andrew Boyer <andrew.boyer@dell.com> --- drivers/infiniband/sw/rxe/rxe_comp.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)