From: Andrew Morton <akpm@linux-foundation.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Andrzej Hajda <a.hajda@samsung.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
open list <linux-kernel@vger.kernel.org>,
Bob Peterson <rpeterso@redhat.com>
Subject: Re: [PATCH v3] err.h: allow IS_ERR_VALUE to handle properly more types
Date: Thu, 4 Feb 2016 10:59:31 -0800 [thread overview]
Message-ID: <20160204105931.7422c17d0bd1b92a387d97c9@linux-foundation.org> (raw)
In-Reply-To: <13351313.c4ZqBbQEld@wuerfel>
On Thu, 04 Feb 2016 13:40:38 +0100 Arnd Bergmann <arnd@arndb.de> wrote:
> diff --git a/include/linux/err.h b/include/linux/err.h
> index b7d4a9ff6342..bd4936a2c352 100644
> --- a/include/linux/err.h
> +++ b/include/linux/err.h
> @@ -18,9 +18,7 @@
>
> #ifndef __ASSEMBLY__
>
> -#define IS_ERR_VALUE(x) ((typeof(x))(-1) <= 0 \
> - ? unlikely((x) <= -1) \
> - : unlikely((x) >= (typeof(x))-MAX_ERRNO))
> +#define IS_ERR_VALUE(x) (unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO))
>
> static inline void * __must_check ERR_PTR(long error)
> {
>
>
> I'm not sure if the cast to 'unsigned long long' might cause less
> efficient code to be generated by gcc. I would hope that it is smart
> enough to not actually extend shorter variables to 64 bit before
> doing the comparison but I have not checked yet.
I did a quick test with i386 on drivers/nvmem/core.o. The patch takes
the text size from 9098 bytes to 9133. That file has 11 instances of
IS_ERR_VALUE().
next prev parent reply other threads:[~2016-02-04 18:59 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-07 14:58 [PATCH] " Andrzej Hajda
2016-01-07 15:48 ` kbuild test robot
2016-01-28 8:27 ` [PATCH v2] " Andrzej Hajda
2016-02-02 6:23 ` Andrew Morton
2016-02-02 8:22 ` Andrzej Hajda
2016-02-03 0:33 ` Andrew Morton
2016-02-03 10:53 ` Andrzej Hajda
2016-02-03 13:15 ` [PATCH v3] " Andrzej Hajda
2016-02-04 12:40 ` Arnd Bergmann
2016-02-04 14:44 ` Andrzej Hajda
2016-02-04 15:00 ` Arnd Bergmann
2016-02-04 15:10 ` Arnd Bergmann
2016-02-04 18:59 ` Andrew Morton [this message]
2016-02-05 10:52 ` Arnd Bergmann
2016-02-08 8:45 ` Andrzej Hajda
2016-02-08 12:01 ` Arnd Bergmann
2016-02-09 1:44 ` Al Viro
2016-02-09 8:42 ` Andrzej Hajda
2016-02-10 21:01 ` Arnd Bergmann
2016-02-11 7:00 ` Andrzej Hajda
2016-02-11 16:39 ` Arnd Bergmann
2016-02-12 14:45 ` Andrzej Hajda
2016-02-11 21:14 ` Al Viro
2016-02-04 23:37 ` Rasmus Villemoes
2016-02-10 15:16 ` Guenter Roeck
2016-01-15 13:45 ` [PATCH] " Andrzej Hajda
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