What does “do { … } while (0)” do exactly in kernel code? [duplicate]

Answer 1

Looks like it's there just for scoping. It's similar to:

if (true)
{
    // Do stuff.
}

edit

I don't see it in your example, but it's possible that one of those function calls is actually a macro, in which case there's one key difference between do/while(0) and if(true), which is that the former allows continue and break.