netdev - RE: [PATCH 5/6] alx: fix MAC address alignment problem

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Date:	Fri, 21 Jun 2013 09:38:09 +0100
From:	"David Laight" <David.Laight@...LAB.COM>
To:	"Johannes Berg" <johannes@...solutions.net>,
	<netdev@...r.kernel.org>
Cc:	<ben@...adent.org.uk>
Subject: RE: [PATCH 5/6] alx: fix MAC address alignment problem

> In two places, parts of MAC addresses are used as u32/u16
> values. This can cause alignment problems, use put_unaligned
> and get_unaligned to fix this.

I suspect they are always 16bit aligned, so 16bit accesses
would be ok - rather than using byte accesses.
However I wouldn't know how to request this with the available
definitions....

	David

...
>  	/* addr should be big-endian */
> -	*(__be32 *)(addr + 2) = cpu_to_be32(mac0);
> -	*(__be16 *)addr = cpu_to_be16(mac1);
> +	put_unaligned(cpu_to_be32(mac0), (__be32 *)(addr + 2));
> +	put_unaligned(cpu_to_be16(mac1), (__be16 *)addr);
...
> -	val = be32_to_cpu(*(__be32 *)(addr + 2));
> +	val = be32_to_cpu(get_unaligned((__be32 *)(addr + 2)));
>  	alx_write_mem32(hw, ALX_STAD0, val);
> -	val = be16_to_cpu(*(__be16 *)addr);
> +	val = be16_to_cpu(get_unaligned((__be16 *)addr));
>  	alx_write_mem32(hw, ALX_STAD1, val);


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