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

[sashiko-bot@kernel.org]

> 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.

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