Re: [PATCH v3] nfs: remove incorrect fallthrough label

[Nick Desaulniers]

Hello maintainers,
Would you mind please picking up this patch?  KernelCI has been
erroring for over a week without it.

On Thu, Sep 17, 2020 at 2:45 PM Nick Desaulniers
<ndesaulniers@xxxxxxxxxx> wrote:
>
> There is no case after the default from which to fallthrough to. Clang
> will error in this case (unhelpfully without context, see link below)
> and GCC will with -Wswitch-unreachable.
>
> The previous commit should have just replaced the comment with a break
> statement.
>
> If we consider implicit fallthrough to be a design mistake of C, then
> all case statements should be terminated with one of the following
> statements:
> * break
> * continue
> * return
> * fallthrough
> * goto
> * (call of function with __attribute__(__noreturn__))
>
> Fixes: 2a1390c95a69 ("nfs: Convert to use the preferred fallthrough macro")
> Link: https://bugs.llvm.org/show_bug.cgi?id=47539
> Acked-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
> Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
> Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
> Suggested-by: Joe Perches <joe@xxxxxxxxxxx>
> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> ---
> Changes v3:
> * update the commit message as per Joe.
> * collect tags.
>
> Changes v2:
> * add break rather than no terminating statement as per Joe.
> * add Joe's suggested by tag.
> * add blurb about acceptable terminal statements.
>
>  fs/nfs/super.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index d20326ee0475..eb2401079b04 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -889,7 +889,7 @@ static struct nfs_server *nfs_try_mount_request(struct fs_context *fc)
>                 default:
>                         if (rpcauth_get_gssinfo(flavor, &info) != 0)
>                                 continue;
> -                       fallthrough;
> +                       break;
>                 }
>                 dfprintk(MOUNT, "NFS: attempting to use auth flavor %u\n", flavor);
>                 ctx->selected_flavor = flavor;
> --
> 2.28.0.681.g6f77f65b4e-goog
>


-- 
Thanks,
~Nick Desaulniers