On Thu, 2011-04-07 at 14:26 -0700, Mark Rustad wrote:
> Unsigned serial number comparison is very simple if you simply put the
> difference into a signed integer of the same size and then compare that
> value with zero. All the complexity and confusion fall away.
>
> Signed-off-by: Mark Rustad <mark.d.rustad@xxxxxxxxx>
> ---
> include/scsi/iscsi_proto.h | 21 ++++++++++++---------
> 1 files changed, 12 insertions(+), 9 deletions(-)
>
> diff --git a/include/scsi/iscsi_proto.h b/include/scsi/iscsi_proto.h
> index 0c6c1d6..98ebc3d 100644
> --- a/include/scsi/iscsi_proto.h
> +++ b/include/scsi/iscsi_proto.h
> @@ -35,30 +35,33 @@
> /*
> * Serial Number Arithmetic, 32 bits, RFC1982
> */
> -#define SNA32_CHECK 2147483648UL
>
> static inline int iscsi_sna_lt(u32 n1, u32 n2)
> {
> - return n1 != n2 && ((n1 < n2 && (n2 - n1 < SNA32_CHECK)) ||
> - (n1 > n2 && (n2 - n1 < SNA32_CHECK)));
> + s32 diff = n1 - n2;
> +
> + return diff < 0;
> }
>
> static inline int iscsi_sna_lte(u32 n1, u32 n2)
> {
> - return n1 == n2 || ((n1 < n2 && (n2 - n1 < SNA32_CHECK)) ||
> - (n1 > n2 && (n2 - n1 < SNA32_CHECK)));
> + s32 diff = n1 - n2;
> +
> + return diff <= 0;
> }
>
> static inline int iscsi_sna_gt(u32 n1, u32 n2)
> {
> - return n1 != n2 && (((n1 < n2) && ((n2 - n1) > SNA32_CHECK)) ||
> - ((n1 > n2) && ((n1 - n2) < SNA32_CHECK)));
> + s32 diff = n1 - n2;
> +
> + return diff > 0;
> }
>
> static inline int iscsi_sna_gte(u32 n1, u32 n2)
> {
> - return n1 == n2 || (((n1 < n2) && ((n2 - n1) > SNA32_CHECK)) ||
> - ((n1 > n2) && ((n1 - n2) < SNA32_CHECK)));
> + s32 diff = n1 - n2;
> +
> + return diff >= 0;
> }
Hi Mark,
My apolgies for the delayed response on this patch.
I think this simplification to use s32 for iSCSI Command Serial Number
arithmetic looks perfectly reasonable, and am including this into
lio-core-2.6.git/lio-4.1. Thank you for your contribution!!
Mike, Hannes and Co, do you have any objections here for mainline
Open-iSCSI and iSCSI-Target code for .40 code..?
Best Regards,
--nab
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