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authorSinan Kaya <okaya@codeaurora.org>2018-03-20 05:47:44 +0300
committerJason Gunthorpe <jgg@mellanox.com>2018-03-21 22:51:41 +0300
commit97d82a48d7a7eca6f20b100ae19811134509406e (patch)
treec748fec9d12b873df810c1cf787bdc94b625c7d3 /drivers/infiniband/hw/mlx4
parent185899ee8d00460a305e07ed2df178dbf7455227 (diff)
downloadlinux-97d82a48d7a7eca6f20b100ae19811134509406e.tar.xz
IB/mlx4: Eliminate duplicate barriers on weakly-ordered archs
Code includes wmb() followed by writel(). 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> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'drivers/infiniband/hw/mlx4')
-rw-r--r--drivers/infiniband/hw/mlx4/qp.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/infiniband/hw/mlx4/qp.c b/drivers/infiniband/hw/mlx4/qp.c
index 04efc05fb531..523028e944ed 100644
--- a/drivers/infiniband/hw/mlx4/qp.c
+++ b/drivers/infiniband/hw/mlx4/qp.c
@@ -3894,8 +3894,8 @@ out:
*/
wmb();
- writel(qp->doorbell_qpn,
- to_mdev(ibqp->device)->uar_map + MLX4_SEND_DOORBELL);
+ writel_relaxed(qp->doorbell_qpn,
+ to_mdev(ibqp->device)->uar_map + MLX4_SEND_DOORBELL);
/*
* Make sure doorbells don't leak out of SQ spinlock