Re: [PATCH for-next v2] RDMA/efa: Add EFA query MR support

[Leon Romanovsky <leon@kernel.org>]

On Thu, Dec 07, 2023 at 02:27:48PM +0000, Michael Margolin wrote:
> Add EFA driver uapi definitions and register a new query MR method that
> currently returns the physical PCI buses' IDs the device is using to
> reach the MR. Update admin definitions and efa-abi accordingly.
> 
> Reviewed-by: Anas Mousa <anasmous@amazon.com>
> Reviewed-by: Firas Jahjah <firasj@amazon.com>
> Signed-off-by: Michael Margolin <mrgolin@amazon.com>
> ---
>  drivers/infiniband/hw/efa/efa.h               |  5 +-
>  .../infiniband/hw/efa/efa_admin_cmds_defs.h   | 31 ++++++++
>  drivers/infiniband/hw/efa/efa_com_cmd.c       |  6 ++
>  drivers/infiniband/hw/efa/efa_com_cmd.h       |  4 +
>  drivers/infiniband/hw/efa/efa_main.c          |  5 ++
>  drivers/infiniband/hw/efa/efa_verbs.c         | 77 +++++++++++++++++++
>  include/uapi/rdma/efa-abi.h                   | 19 +++++
>  7 files changed, 146 insertions(+), 1 deletion(-)

<...>

> +	/*
> +	 * Mask indicating which fields have valid values
> +	 * 0 : recv_pci_bus_id
> +	 * 1 : rdma_read_pci_bus_id
> +	 * 2 : rdma_recv_pci_bus_id
> +	 */
> +	u8 validity;

<...>

>  #define EFA_GID_SIZE 16
> +#define EFA_INVALID_PCI_BUS_ID 0xffff

Is 0xffff value guaranteed by PCI subsystem to be invalid? Why don't you
provide "validity" field to userspace instead?

Thanks