Invalid comparison function

[yugr]

bs_cmp (from options.c) is passed to qsort to compare bssplit structures. But it does not satisfy qsort symmetry requirement i.e.
bs_cmp(a, b) != - bs_cmp(b, a)
This triggers UB at runtime and may cause qsort to fail to sort the array.

The fix should be as simple as replacing the current code with

  return (int)bsp1->perc - (int)->bsp2->perc;

[yugr]

The problem was found when running Phoronix under SortChecker tool (https://github.com/yugr/sortcheck).

[axboe]

Indeed, should return int difference. Fix committed.