From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <shemminger@vyatta.com>
Subject: Re: [PATCH 1/2] net: Enable 64-bit net device statistics on 32-bit
 architectures
Date: Thu, 3 Jun 2010 11:47:38 -0700
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Cc: David Miller <davem@davemloft.net>, Arnd Bergmann <arnd@arndb.de>,
	netdev@vger.kernel.org, linux-net-drivers@solarflare.com
To: Ben Hutchings <bhutchings@solarflare.com>
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On Thu, 03 Jun 2010 18:39:04 +0100
Ben Hutchings <bhutchings@solarflare.com> wrote:

> #if BITS_PER_LONG == 64
> +#define NET_DEVICE_STATS_DEFINE(name)	u64 name
> +#define RTNL_LINK_STATS64_READ(stats, name)				\
> +	ACCESS_ONCE((stats)->name)
> +#define RTNL_LINK_STATS64_READ_OFFSET(stats, offset)			\
> +	ACCESS_ONCE((const u64 *)((const u8 *)(stats) + (offset)))
> +#define RTNL_LINK_STATS64_READ32(stats, name)				\
> +	((u32)ACCESS_ONCE((stats)->name))
> +#else
> +#if defined(__LITTLE_ENDIAN)
> +#define NET_DEVICE_STATS_DEFINE(name)	u32 name, pad_ ## name
> +#define RTNL_LINK_STATS64_READ_OFFSET(stats, offset)			\
> +	(ACCESS_ONCE(*(const u32 *)((const u8 *)(stats) + (offset))) |	\
> +	 (u64)(*(const u32 *)((const u8 *)(stats) + (offset) + 4)) << 32)
> +#define RTNL_LINK_STATS64_READ32(stats, name)				\
> +	(((const volatile u32 *)&(stats)->name)[0])
> +#else
> +#define NET_DEVICE_STATS_DEFINE(name)	u32 pad_ ## name, name
> +#define RTNL_LINK_STATS64_READ_OFFSET(stats, offset)			\
> +	((u64)(*(const u32 *)((const u8 *)(stats) + (offset))) << 32 |	\
> +	 ACCESS_ONCE(*(const u32 *)((const u8 *)(stats) + (offset) + 4)))
> +#define RTNL_LINK_STATS64_READ32(stats, name)				\
> +	(((const volatile u32 *)&(stats)->name)[1])
> +#endif
> +#define RTNL_LINK_STATS64_READ(stats, name)				\
> +	RTNL_LINK_STATS64_READ_OFFSET(					\
> +		stats, offsetof(struct rtnl_link_stats64, name))
> +#endif

Macros... with multiple casts. Gack

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