[PATCH net] net/mlx4: always create the eth and ib auxiliary devices

[PATCH net] net/mlx4: always create the eth and ib auxiliary devices

[Peter Morrow]

Since commit 7d22b1cb9d84 ("mlx4: Connect the infiniband part to the
auxiliary bus"), mlx4_core creates the "ib" auxiliary device only for
an IB port or a device that advertises IBoE. Before it, each mlx4
interface was offered every device and decided in its own add callback.
mlx4_ib_add() accepted Ethernet ports without IBoE and registered them
for raw packet QPs only.

ConnectX-3 VFs on Azure have an Ethernet port and no IBoE, so since
v6.6 they get no RDMA device. DPDK's mlx4 PMD, which needs only raw
packet QPs, then cannot open them:

  net_mlx4: cannot access device, is mlx4_ib loaded?

Restore the old behaviour by creating both auxiliary devices for every
device and letting mlx4_en and mlx4_ib decide in probe, as their add
callbacks did. mlx4_ib_probe() returns -ENODEV when there are no usable
ports, and mlx4_en_probe() binds a device without Ethernet ports but
creates no netdevs, as mlx4_en_add() did.

Tested on 6.12.111 on an Azure VM with two ConnectX-3 VFs: each gets an
eth and an ib auxiliary device, and DPDK attaches both VFs and passes
traffic through them.

Fixes: 7d22b1cb9d84 ("mlx4: Connect the infiniband part to the auxiliary bus")
Closes: https://lore.kernel.org/r/20261014133951.3219055-1-pdmorrow@gmail.com
Suggested-by: Leon Romanovsky <leon@kernel.org>
Assisted-by: LLM
Signed-off-by: Peter Morrow <pdmorrow@gmail.com>
---
 drivers/net/ethernet/mellanox/mlx4/intf.c | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/intf.c b/drivers/net/ethernet/mellanox/mlx4/intf.c
index 82e467c..31860b4 100644
--- a/drivers/net/ethernet/mellanox/mlx4/intf.c
+++ b/drivers/net/ethernet/mellanox/mlx4/intf.c
@@ -43,23 +43,12 @@ static DEFINE_IDA(mlx4_adev_ida);
 
 static bool is_eth_supported(struct mlx4_dev *dev)
 {
-	for (int port = 1; port <= dev->caps.num_ports; port++)
-		if (dev->caps.port_type[port] == MLX4_PORT_TYPE_ETH)
-			return true;
-
-	return false;
+	return true;
 }
 
 static bool is_ib_supported(struct mlx4_dev *dev)
 {
-	for (int port = 1; port <= dev->caps.num_ports; port++)
-		if (dev->caps.port_type[port] == MLX4_PORT_TYPE_IB)
-			return true;
-
-	if (dev->caps.flags & MLX4_DEV_CAP_FLAG_IBOE)
-		return true;
-
-	return false;
+	return true;
 }
 
 static const struct mlx4_adev_device {
-- 
2.47.3

Re: [PATCH net] net/mlx4: always create the eth and ib auxiliary devices

[sashiko-bot]

> Since commit 7d22b1cb9d84 ("mlx4: Connect the infiniband part to the
> auxiliary bus"), mlx4_core creates the "ib" auxiliary device only for
> an IB port or a device that advertises IBoE. Before it, each mlx4
> interface was offered every device and decided in its own add callback.
> mlx4_ib_add() accepted Ethernet ports without IBoE and registered them
> for raw packet QPs only.
> 
> ConnectX-3 VFs on Azure have an Ethernet port and no IBoE, so since
> v6.6 they get no RDMA device. DPDK's mlx4 PMD, which needs only raw
> packet QPs, then cannot open them:
> 
>   net_mlx4: cannot access device, is mlx4_ib loaded?
> 
> Restore the old behaviour by creating both auxiliary devices for every
> device and letting mlx4_en and mlx4_ib decide in probe, as their add
> callbacks did. mlx4_ib_probe() returns -ENODEV when there are no usable
> ports, and mlx4_en_probe() binds a device without Ethernet ports but
> creates no netdevs, as mlx4_en_add() did.
> 
> Tested on 6.12.111 on an Azure VM with two ConnectX-3 VFs: each gets an
> eth and an ib auxiliary device, and DPDK attaches both VFs and passes
> traffic through them.
> 
> Fixes: 7d22b1cb9d84 ("mlx4: Connect the infiniband part to the auxiliary bus")
> Closes: https://lore.kernel.org/r/20261014133951.3219055-1-pdmorrow@gmail.com
> Suggested-by: Leon Romanovsky <leon@kernel.org>
> Assisted-by: LLM
> Signed-off-by: Peter Morrow <pdmorrow@gmail.com>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261020164239.3808903-1-pdmorrow@gmail.com?part=1