From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: George Spelvin <linux@sciencehorizons.net>
Cc: bjorn@mork.no, linux-kernel@vger.kernel.org,
matt@codeblueprint.co.uk, rv@rasmusvillemoes.dk
Subject: Re: [PATCH v2 3/2] lib/uuid.c: Silence an unchecked return value warning
Date: Sun, 05 Jun 2016 17:21:04 +0300 [thread overview]
Message-ID: <1465136464.1767.57.camel@linux.intel.com> (raw)
In-Reply-To: <20160604131622.28377.qmail@ns.sciencehorizons.net>
On Sat, 2016-06-04 at 09:16 -0400, George Spelvin wrote:
> Andy Shevchenko pointed out that __uuid_to_bin doesn't need to check
> the return value from hex2bin(), because the preceding uuid_is_valid()
> check already took care of that.
>
> But hex2bin() is declared __must_check, so checking anyway is the
> simplest way to silence the warning.
>
> This cancels a small fraction of the the space savings, but not all:
>
> vs. previous patch vs. before patch series
> Before After Delta Percent Orig. Delta
> Percent
> x86-32 90 96 +6 6.7% 122 -
> 26 -21.3%
> x86-64 90 96 +6 6.7% 127 -31
> -24.4%
> arm 92 104 +12 13.0% 116 -12
> -10.3%
> thumb 50 62 +12 24.0% 100 -38
> -38.0%
> arm64 116 124 +8 6.9% 148 -24
> -16.2%
>
> Signed-off-by: George Spelvin <linux@sciencehorizons.net>
> ---
> lib/uuid.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/lib/uuid.c b/lib/uuid.c
> index 93945915..1a6dbbd2 100644
> --- a/lib/uuid.c
> +++ b/lib/uuid.c
> @@ -104,7 +104,8 @@ static int __uuid_to_bin(const char uuid[36], __u8
> b[16], const u8 pos[16])
> return -EINVAL;
>
> for (i = 0; i < 16; i++)
> - hex2bin(b + i, uuid + pos[i], 1);
> + if (hex2bin(b + i, uuid + pos[i], 1) < 0)
> + return -EINVAL;
Which I against of. Please, use normal hex_to_bin() calls here.
Compiler will inline it anyway, but at least will not do second check
for nothing.
>
> return 0;
> }
--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
next prev parent reply other threads:[~2016-06-05 14:19 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1464952090.1767.34.camel@linux.intel.com>
2016-06-04 5:13 ` [PATCH v2 0/2] Clean up and shrink uuid input & output George Spelvin
2016-06-04 5:14 ` [PATCH v2 1/2] lib/vsprintf.c: Simplify uuid_string() George Spelvin
2016-06-05 14:22 ` Andy Shevchenko
2016-06-05 19:57 ` George Spelvin
2016-06-04 5:14 ` [PATCH v2 2/2] lib/uuid.c: eliminate uuid_[bl]e_index arrays George Spelvin
2016-06-04 5:42 ` kbuild test robot
2016-06-04 16:29 ` Joe Perches
2016-06-04 21:57 ` George Spelvin
2016-06-05 14:19 ` Andy Shevchenko
2016-06-05 15:34 ` Joe Perches
2016-06-05 16:15 ` Andy Shevchenko
2016-06-04 13:16 ` [PATCH v2 3/2] lib/uuid.c: Silence an unchecked return value warning George Spelvin
2016-06-05 14:21 ` Andy Shevchenko [this message]
2016-06-05 19:25 ` George Spelvin
2016-06-06 8:24 ` Andy Shevchenko
2016-06-07 16:43 ` George Spelvin
2016-06-07 17:13 ` Joe Perches
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