linux-kernel - [PATCH rdma-next v2 5/5] RDMA/mlx5: Reorder calls to pcie_relaxed_ordering

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Date:   Tue, 15 Feb 2022 19:55:33 +0200
From:   Leon Romanovsky <leon@...nel.org>
To:     Jason Gunthorpe <jgg@...dia.com>
Cc:     Aharon Landau <aharonl@...dia.com>, linux-kernel@...r.kernel.org,
        linux-rdma@...r.kernel.org
Subject: [PATCH rdma-next v2 5/5] RDMA/mlx5: Reorder calls to pcie_relaxed_ordering_enabled()

From: Aharon Landau <aharonl@...dia.com>

The mkc is the key for the mkey cache, hence, created in each attempt to
get a cache mkey, while pcie_relaxed_ordering_enabled() is called during
the setting of the mkc, but used only for cases where
IB_ACCESS_RELAXED_ORDERING is set.

pcie_relaxed_ordering_enabled() is an expensive call (26 us). Reorder the
code so the driver will call it only when it is needed.

Signed-off-by: Aharon Landau <aharonl@...dia.com>
Signed-off-by: Leon Romanovsky <leonro@...dia.com>
---
 drivers/infiniband/hw/mlx5/mr.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index eb14ea4bcbba..eab7921eb91f 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -68,7 +68,6 @@ static void set_mkc_access_pd_addr_fields(void *mkc, int acc, u64 start_addr,
 					  struct ib_pd *pd)
 {
 	struct mlx5_ib_dev *dev = to_mdev(pd->device);
-	bool ro_pci_enabled = pcie_relaxed_ordering_enabled(dev->mdev->pdev);
 
 	MLX5_SET(mkc, mkc, a, !!(acc & IB_ACCESS_REMOTE_ATOMIC));
 	MLX5_SET(mkc, mkc, rw, !!(acc & IB_ACCESS_REMOTE_WRITE));
@@ -76,12 +75,13 @@ static void set_mkc_access_pd_addr_fields(void *mkc, int acc, u64 start_addr,
 	MLX5_SET(mkc, mkc, lw, !!(acc & IB_ACCESS_LOCAL_WRITE));
 	MLX5_SET(mkc, mkc, lr, 1);
 
-	if (MLX5_CAP_GEN(dev->mdev, relaxed_ordering_write))
-		MLX5_SET(mkc, mkc, relaxed_ordering_write,
-			 (acc & IB_ACCESS_RELAXED_ORDERING) && ro_pci_enabled);
-	if (MLX5_CAP_GEN(dev->mdev, relaxed_ordering_read))
-		MLX5_SET(mkc, mkc, relaxed_ordering_read,
-			 (acc & IB_ACCESS_RELAXED_ORDERING) && ro_pci_enabled);
+	if ((acc & IB_ACCESS_RELAXED_ORDERING) &&
+	    pcie_relaxed_ordering_enabled(dev->mdev->pdev)) {
+		if (MLX5_CAP_GEN(dev->mdev, relaxed_ordering_write))
+			MLX5_SET(mkc, mkc, relaxed_ordering_write, 1);
+		if (MLX5_CAP_GEN(dev->mdev, relaxed_ordering_read))
+			MLX5_SET(mkc, mkc, relaxed_ordering_read, 1);
+	}
 
 	MLX5_SET(mkc, mkc, pd, to_mpd(pd)->pdn);
 	MLX5_SET(mkc, mkc, qpn, 0xffffff);
-- 
2.35.1