From: Jason Gunthorpe <jgg@nvidia.com>
Date: Fri, 29 Jul 2022 13:33:38 -0300
Subject: IB/mlx5: Call io_stop_wc() after writing to WC MMIO
Patch-mainline: v6.1-rc1
Git-commit: 19d6214ad6dfffda1a5bdc2b34ea75ba45a1a60a
References: jsc#PED-1552

This new function is defined only on ARM and serves to guarantee a barrier
in the WC operation. The barrier means that another run of this loop will
not combine with the stores this loop created.

On x86 this is happening implicitly because of the spin_unlock().

Link: https://lore.kernel.org/r/0-v1-c5dade92f363+11-mlx5_io_stop_wc_jgg@nvidia.com
Suggested-by: Pavel Shamis <Pavel.Shamis@arm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/hw/mlx5/mem.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/infiniband/hw/mlx5/mem.c
+++ b/drivers/infiniband/hw/mlx5/mem.c
@@ -152,6 +152,7 @@ static int post_send_nop(struct mlx5_ib_
 	for (i = 0; i < 8; i++)
 		mlx5_write64(&mmio_wqe[i * 2],
 			     bf->bfreg->map + bf->offset + i * 8);
+	io_stop_wc();
 
 	bf->offset ^= bf->buf_size;