MD RAID10: Improve redundancy of RAID10 'far' and 'offset' algorithms

Neil,

I've changed the way 'far' and 'offset' algorithms are done to reflect your latest suggestions. The case where there were a non-multiple of 'far_copies' devices in the array was the tricky issue we were dealing with. I've separated my patch into two - one dealing with the multiple-of-far_copies case and the other dealing with the non-multiple case.

I had to make some adjustments to the dm-raid patch that includes the new 'far' and 'offset' algorithms and I've included that revised patch in this set.

[PATCH 1 of 4]MD RAID10: Minor non-functional code changes
[PATCH 2 of 4]MD RAID10: Improve redundancy for 'far' and 'offset' algorithms (part 1) [PATCH 3 of 4]MD RAID10: Improve redundancy for 'far' and 'offset' algorithms (part 2) [PATCH 4 of 4]DM RAID: Add support for MD's RAID10 "far" and "offset" algorithms

Thanks,
brassow