Implemented linux ionice funtionality

ionice.go

@@ -0,0 +1,17 @@
+package main
+
+func PrioToClass(prio uint32) uint32 {
+	return prio >> IOPRIO_CLASS_SHIFT
+}
+
+func PrioToClassdata(prio uint32) uint32 {
+	return prio & IOPRIO_PRIO_MASK
+}
+
+func ClassAndClassdataToPrio(class uint32, classdata uint32) uint32 {
+	return ((class) << IOPRIO_CLASS_SHIFT) | classdata
+}
+
+func PrioToClassAndClassdata(prio uint32) (uint32, uint32) {
+	return PrioToClass(prio), PrioToClassdata(prio)
+}