From 561e5d48968be22fc71af6a0e13af6edae595dbe Mon Sep 17 00:00:00 2001 From: Sinan Kaya Date: Tue, 13 Mar 2018 23:20:24 -0400 Subject: RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs Code includes wmb() followed by writel() in multiple places. writel() already has a barrier on some architectures like arm64. This ends up CPU observing two barriers back to back before executing the register write. Since code already has an explicit barrier call, changing writel() to writel_relaxed(). Signed-off-by: Sinan Kaya Signed-off-by: Jason Gunthorpe --- drivers/infiniband/hw/qedr/verbs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/infiniband') diff --git a/drivers/infiniband/hw/qedr/verbs.c b/drivers/infiniband/hw/qedr/verbs.c index 875b17272d65..b61a395f89de 100644 --- a/drivers/infiniband/hw/qedr/verbs.c +++ b/drivers/infiniband/hw/qedr/verbs.c @@ -1870,7 +1870,7 @@ static int qedr_update_qp_state(struct qedr_dev *dev, if (rdma_protocol_roce(&dev->ibdev, 1)) { wmb(); - writel(qp->rq.db_data.raw, qp->rq.db); + writel_relaxed(qp->rq.db_data.raw, qp->rq.db); /* Make sure write takes effect */ mmiowb(); } @@ -3257,7 +3257,7 @@ int qedr_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr, * redundant doorbell. */ wmb(); - writel(qp->sq.db_data.raw, qp->sq.db); + writel_relaxed(qp->sq.db_data.raw, qp->sq.db); /* Make sure write sticks */ mmiowb(); -- cgit v1.2.3-59-g8ed1b