On Fri, Aug 22, 2008 at 01:36:06PM -0700, Luck, Tony wrote:
> > How about long instead of int. int leaves us with the possibility that
> > something else will expect 8 byte alignment.
>
> How about this?
>
> Align __cmd to ward off kernel unaligned access consoles messages on
> ia64 (and perhaps make an almost imperceptible performance improvement
> on other architectures that can handle unaligned access, but do so
> more slowly than aligned accesses).
That's probably the best solution for now. Testing...
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
>
> ---
>
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index e61f22b..a493a4b 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -211,7 +211,7 @@ struct request {
> * when request is used as a packet command carrier
> */
> unsigned short cmd_len;
> - unsigned char __cmd[BLK_MAX_CDB];
> + unsigned char __cmd[BLK_MAX_CDB] __attribute__((aligned(8)));
> unsigned char *cmd;
>
> unsigned int data_len;
--
Regards/Gruss,
Boris.
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