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From: Nick Desaulniers <ndesaulniers@google.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-arch <linux-arch@vger.kernel.org>,
	Ralf Baechle <ralf@linux-mips.org>,
	Paul Burton <paul.burton@mips.com>,
	James Hogan <jhogan@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Deepa Dinamani <deepa.kernel@gmail.com>,
	Christian Brauner <christian@brauner.io>,
	"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
	linux-mips@vger.kernel.org
Subject: Re: [PATCH] signal: fix building with clang
Date: Thu, 7 Mar 2019 10:41:57 -0800	[thread overview]
Message-ID: <CAKwvOdkEuK04iqdrGR1CaHGc-3zCAS+tGnvfN8R0+j728TTPtQ@mail.gmail.com> (raw)
In-Reply-To: <20190307164647.GC25101@redhat.com>

On Thu, Mar 7, 2019 at 8:46 AM Oleg Nesterov <oleg@redhat.com> wrote:
>
> On 03/07, Arnd Bergmann wrote:
> >
> > We could use % everywhere,
>
> Yes.
>
> But again, why not simply use the "for (;;)" loops? Why we can't kill the
> supid switch(_NSIG_WORDS) tricks altogether?
>
> Oleg.
>
> --- x/include/linux/signal.h
> +++ x/include/linux/signal.h
> @@ -121,26 +121,9 @@
>  #define _SIG_SET_BINOP(name, op)                                       \
>  static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
>  {                                                                      \
> -       unsigned long a0, a1, a2, a3, b0, b1, b2, b3;                   \
> -                                                                       \
> -       switch (_NSIG_WORDS) {                                          \
> -       case 4:                                                         \
> -               a3 = a->sig[3]; a2 = a->sig[2];                         \
> -               b3 = b->sig[3]; b2 = b->sig[2];                         \
> -               r->sig[3] = op(a3, b3);                                 \
> -               r->sig[2] = op(a2, b2);                                 \
> -               /* fall through */                                      \
> -       case 2:                                                         \
> -               a1 = a->sig[1]; b1 = b->sig[1];                         \
> -               r->sig[1] = op(a1, b1);                                 \
> -               /* fall through */                                      \
> -       case 1:                                                         \
> -               a0 = a->sig[0]; b0 = b->sig[0];                         \
> -               r->sig[0] = op(a0, b0);                                 \
> -               break;                                                  \
> -       default:                                                        \
> -               BUILD_BUG();                                            \
> -       }                                                               \
> +       int i;                                                          \
> +       for (i = 0; i < ARRAY_SIZE(r->sig); ++i)                        \
> +               r->sig[i] = op(a->sig[i], b->sig[i]);                   \
>  }
>
>  #define _sig_or(x,y)   ((x) | (y))
>

That looks much cleaner IMO.
-- 
Thanks,
~Nick Desaulniers

  reply	other threads:[~2019-03-07 18:42 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-07  9:11 [PATCH] signal: fix building with clang Arnd Bergmann
2019-03-07 10:03 ` Christian Brauner
2019-03-07 15:28 ` Oleg Nesterov
2019-03-07 15:37   ` Arnd Bergmann
2019-03-07 16:46     ` Oleg Nesterov
2019-03-07 18:41       ` Nick Desaulniers [this message]
2019-03-07 21:45       ` Arnd Bergmann
2019-03-08  0:22         ` Nick Desaulniers
2019-03-08  0:27           ` Joe Perches
2019-03-08 21:09             ` Nick Desaulniers

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