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Subject: Re: [RFC 1/2] Unified UUID/GUID definition
From: Joe Perches <joe@perches.com>
To: Huang Ying <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Steven Whitehouse <swhiteho@redhat.com>,
       Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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Date: Wed, 14 Oct 2009 00:01:11 -0700
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On Wed, 2009-10-14 at 14:30 +0800, Huang Ying wrote:
> There are many different UUID/GUID definitions in kernel, such as that
> in EFI, many file systems, some drivers, etc. Every kernel components
> need UUID/GUID has its own definition. This patch provides a unified
> definition for UUID/GUID.
> 
> UUID is defined via typedef. This makes that UUID appears more like a
> preliminary type, and makes the data type explicit (comparing with
> implicit "u8 uuid[16]").
> 
> The binary representation of UUID/GUID can be little-endian (used by
> EFI, etc) or big-endian (defined by RFC4122), so both is defined.
[]
> +typedef struct {
> +	__u8 b[16];
> +} uuid_le;
> +
> +typedef struct {
> +	__u8 b[16];
> +} uuid_be;

I thought you originally suggested something like:

typedef union {
	u8 b[16];
	struct {
		__be32 time_low;
		__be16 time_mid;
		__be16 time_hi_and_version;
		u8 clock_seq_hi;
		u8 clock_seq_low;
		u8 node[6];
	} v1;
} uuid_be;

typedef union {
	u8 b[16];
	struct {
		__le32 time_low;
		__le16 time_mid;
		__le16 time_hi_and_version;
		u8 clock_seq_hi;
		u8 clock_seq_low;
		u8 node[6];
	} v1;
} uuid_le;