Why selunlock unlocks in the inverse order of sellock?
func sellock(scases []scase, lockorder []uint16) {
var c *hchan
for _, o := range lockorder {
c0 := scases[o].c
if c0 != nil && c0 != c {
c = c0
lock(&c.lock)
}
}
}
func selunlock(scases []scase, lockorder []uint16) {
for i := len(scases) - 1; i >= 0; i-- {
c := scases[lockorder[i]].c
if c == nil {
break
}
if i > 0 && c == scases[lockorder[i-1]].c {
continue // will unlock it on the next iteration
}
unlock(&c.lock)
}
}