linux-kernel - Re: [PATCH] lib/uuid.c: eliminate uuid_[bl]e

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Message-ID: <1464730604.14627.66.camel@perches.com>
Date:	Tue, 31 May 2016 14:36:44 -0700
From:	Joe Perches <joe@...ches.com>
To:	George Spelvin <linux@...encehorizons.net>,
	andriy.shevchenko@...ux.intel.com
Cc:	akpm@...ux-foundation.org, bbjorn@...k.no,
	linux-kernel@...r.kernel.org, tytso@....edu
Subject: Re: [PATCH] lib/uuid.c: eliminate uuid_[bl]e_index arrays

On Tue, 2016-05-31 at 16:31 -0400, George Spelvin wrote:
> Here's a patch implementing the suggestion I made earlier.  This reduces
> code size, data size, and run time for input and output of UUIDs.
[]
> diff --git a/lib/uuid.c b/lib/uuid.c
[]
> @@ -97,32 +97,28 @@ bool uuid_is_valid(const char *uuid)
>  }
>  EXPORT_SYMBOL(uuid_is_valid);
>  
> -static int __uuid_to_bin(const char *uuid, __u8 b[16], const u8 ei[16])
> +static int __uuid_to_bin(const char uuid[36], __u8 b[16], const u8 si[16])

Functions with sized array arguments are generally undesired.

Linus once wrote: (http://comments.gmane.org/gmane.linux.kernel/2031400)

    array arguments in C don't
    actually exist. Sadly, compilers accept it for various bad historical
    reasons, and silently turn it into just a pointer argument. There are
    arguments for them, but they are from weak minds.

Perhaps this would be better using simple pointers and without the __

static int __uuid_to_bin(const char *uuid, u8 *b, const u8 *si)