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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Wed, 29 Mar 2023 10:41:13 -0700
Message-ID: <CAKwvOdk0wgGrMLrebTcHU078Kjtgb_xR3ghnEgQeS3PxgxNzag@mail.gmail.com>
Subject: Re: [PATCH net-next] net: ethernet: ti: Fix format specifier in netcp_create_interface()
To:     Nathan Chancellor <nathan@kernel.org>
Cc:     davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com, trix@redhat.com, razor@blackwall.org,
        kerneljasonxing@gmail.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        patches@lists.linux.dev
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On Wed, Mar 29, 2023 at 10:10=E2=80=AFAM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> Because integer literals in C are signed, the cast is necessary to
> avoid the format specifier from warning about the wrong signedness.
> It would be preferable to have a `U` suffix on the literal value, then
> the cast would be unnecessary.
>
> Untested:
> ```
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 494a23a976b0..67cb6bfc4056 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -349,7 +349,7 @@ struct sk_buff;
>  # define CONFIG_MAX_SKB_FRAGS 17
>  #endif
>
> -#define MAX_SKB_FRAGS CONFIG_MAX_SKB_FRAGS
> +#define MAX_SKB_FRAGS CONFIG_MAX_SKB_FRAGS ## U

Or rather this trick.
https://godbolt.org/z/81aPxf39b
I forget what that's called (it's not xmacros); we definitely have a
macro for that in the kernel.

--=20
Thanks,
~Nick Desaulniers