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RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs

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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 <okaya@codeaurora.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Sinan Kaya 2018-03-13 23:20:24 -04:00 committed by Jason Gunthorpe
parent 7b48221cf4
commit 561e5d4896
1 changed files with 2 additions and 2 deletions
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4
drivers/infiniband/hw/qedr/verbs.c
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@ -1870,7 +1870,7 @@ static int qedr_update_qp_state(struct qedr_dev *dev,
if (rdma_protocol_roce(&dev->ibdev, 1)) { if (rdma_protocol_roce(&dev->ibdev, 1)) {
wmb(); 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 */ /* Make sure write takes effect */
mmiowb(); mmiowb();
} }
@ -3257,7 +3257,7 @@ int qedr_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
* redundant doorbell. * redundant doorbell.
*/ */
wmb(); wmb();
writel(qp->sq.db_data.raw, qp->sq.db); writel_relaxed(qp->sq.db_data.raw, qp->sq.db);
/* Make sure write sticks */ /* Make sure write sticks */
mmiowb(); mmiowb();