On Fri, Dec 12 2014, Mark Brown broonie@kernel.org wrote:
On Tue, Dec 09, 2014 at 10:53:41PM +0100, Rasmus Villemoes wrote:
if (a->reg != b->reg) return a->reg - b->reg;
- if (a->dapm != b->dapm)
return (unsigned long)a->dapm - (unsigned long)b->dapm;
- if (a->dapm < b->dapm)
return -1;- if (a->dapm > b->dapm)
return 1;If we're worrying about standards conformance type stuff here this is also buggy since it's out of spec to compare pointers that are not part of the same array like this. Casting to uintptr_t is a better fix here.
I'm not worrying about standards conformance. Casting pointers to and from [unsigned] long is done everywhere in the kernel, and that's fine. But subtracting ints or longs and using the sign of the result for comparison is simply wrong. See acbbe6fbb2 (kcmp: fix standard comparison bug) for the long story. In this case the narrowing (when BITS_PER_LONG==64) of the result from long to int just makes it even more wrong.
Rasmus