Re: [PATCH] RDMA/siw: Add missing Kconfig selections

[Jason Gunthorpe <jgg@nvidia.com>]

On Wed, Aug 31, 2022 at 12:30:48PM -0400, Tom Talpey wrote:
> The SoftiWARP Kconfig is missing "select" for CRYPTO and CRYPTO_CRC32C.
> 
> In addition, it improperly "depends on" LIBCRC32C, this should be a
> "select", similar to net/sctp and others. As a dependency, SIW fails
> to appear in generic configurations.
> 
> Signed-off-by: Tom Talpey <tom@talpey.com>
> ---
>  drivers/infiniband/sw/siw/Kconfig | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/sw/siw/Kconfig
> b/drivers/infiniband/sw/siw/Kconfig
> index 1b5105cbabae..81b70a3eeb87 100644
> --- a/drivers/infiniband/sw/siw/Kconfig
> +++ b/drivers/infiniband/sw/siw/Kconfig
> @@ -1,7 +1,10 @@
>  config RDMA_SIW
>         tristate "Software RDMA over TCP/IP (iWARP) driver"
> -       depends on INET && INFINIBAND && LIBCRC32C
> +       depends on INET && INFINIBAND
>         depends on INFINIBAND_VIRT_DMA
> +       select LIBCRC32C
> +       select CRYPTO
> +       select CRYPTO_CRC32C

This is against the kconfig instructions Documentation/kbuild/kconfig-language.rst:

  Note:
        select should be used with care. select will force
        a symbol to a value without visiting the dependencies.
        By abusing select you are able to select a symbol FOO even
        if FOO depends on BAR that is not set.
        In general use select only for non-visible symbols
        (no prompts anywhere) and for symbols with no dependencies.
        That will limit the usefulness but on the other hand avoid
        the illegal configurations all over.

None of them meet that criteria even though other places do abuse
select like this as well.

It looked fine to me the way it was, you are supposed to have to
select libcrc32c manually to make siw appear, and it already brings in
the other symbols.

Jason