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From: Gerd Bayer <gbayer@linux.ibm.com>
To: Saeed Mahameed <saeedm@nvidia.com>,
	Leon Romanovsky <leon@kernel.org>,
	Tariq Toukan <tariqt@nvidia.com>, Mark Bloch <mbloch@nvidia.com>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Bjorn Helgaas <bhelgaas@google.com>
Cc: Jay Cornwall <Jay.Cornwall@amd.com>,
	Felix Kuehling <Felix.Kuehling@amd.com>,
	Niklas Schnelle <schnelle@linux.ibm.com>,
	Alexander Schmidt <alexs@linux.ibm.com>,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
	linux-kernel@vger.kernel.org, Gerd Bayer <gbayer@linux.ibm.com>
Subject: [PATCH RFC 1/2] net/mlx5: Request PCIe AtomicOps enabled for all 3 sizes
Date: Wed, 05 Nov 2025 18:55:13 +0100	[thread overview]
Message-ID: <20251105-mlxatomics-v1-1-10c71649e08d@linux.ibm.com> (raw)
In-Reply-To: <20251105-mlxatomics-v1-0-10c71649e08d@linux.ibm.com>

Pass fully populated capability bit-mask requesting support for all 3
sizes of AtomicOps at once when attempting to enable AtomicOps for PCI
function.

When called individually, pci_enable_atomic_ops_to_root() may enable the
device to send requests as soon as one size is supported. According to
PCIe Spec 7.0 Section 6.15.3.1 support of 32-bit and 64-bit AtomicOps
completer capabilities are tied together for root-ports. Only the
128-bit/CAS completer capabilities is an optional feature, but still we
might end up end up enabling AtomicOps despite 128-bit/CAS is not
supported at the root-port.

Signed-off-by: Gerd Bayer <gbayer@linux.ibm.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/main.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index 70c156591b0ba9c61dd99818043003e50e177590..69152a9dae2be07e023fa42fd9ef010c8b255c4c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -934,9 +934,9 @@ static int mlx5_pci_init(struct mlx5_core_dev *dev, struct pci_dev *pdev,
 		goto err_clr_master;
 	}
 
-	if (pci_enable_atomic_ops_to_root(pdev, PCI_EXP_DEVCAP2_ATOMIC_COMP32) &&
-	    pci_enable_atomic_ops_to_root(pdev, PCI_EXP_DEVCAP2_ATOMIC_COMP64) &&
-	    pci_enable_atomic_ops_to_root(pdev, PCI_EXP_DEVCAP2_ATOMIC_COMP128))
+	if (pci_enable_atomic_ops_to_root(pdev, PCI_EXP_DEVCAP2_ATOMIC_COMP32 |
+						PCI_EXP_DEVCAP2_ATOMIC_COMP64 |
+						PCI_EXP_DEVCAP2_ATOMIC_COMP128))
 		mlx5_core_dbg(dev, "Enabling pci atomics failed\n");
 
 	dev->iseg_base = dev->bar_addr;

-- 
2.48.1


  reply	other threads:[~2025-11-05 17:56 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-05 17:55 [PATCH RFC 0/2] mlx5/pci: Fix enablement of PCIe AtomicOp Requests Gerd Bayer
2025-11-05 17:55 ` Gerd Bayer [this message]
2025-11-05 17:55 ` [PATCH RFC 2/2] ib/mlx5: Request PCIe AtomicOps enabled for all 3 sizes Gerd Bayer
2025-11-06 10:19   ` Leon Romanovsky
2025-11-06 12:16     ` Gerd Bayer
2025-11-06 13:14       ` Leon Romanovsky

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