On Mon, Oct 18, 2021 at 8:34 AM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > LGTM, thanks for the patch! I guess this would be the first > "interesting" case this warning has found in kernel sources? The patch looks obviously correct (tm), but I'm not convinced that the warning is actually all that interesting. The thing is, using bitwise operators for booleans is _exactly_ the same as using logical ones as long as there are no side effects. In fact, any compiler worth its salt will already convert some cases between the two as an optimization just as part of code generation. Of course, that "as long as there are no side effects" is the big thing - then the short-circuiting of the actual logical operations clearly matters. But that wasn't actually the case in this situation (or in the kvm situation elsewhere). So in both of these cases, the difference between "|" and "||" ends up purely being a hint to the compiler. In this case, even if there are no side effects, it's clearly pointless to do the second strlencmp() if the first one already matched, and the "||" is unquestionably the right hint (and honestly, most compilers probably wouldn't even be able to tell "no side effects" because it's a fairly complex expression - but since it's inlined and uses compiler intrinsics, the compiler _might_ actually be able to see that the two are equivalent). But no, I don't think that warning is very interesting. In fact, the warning might be overall detrimental, in case the hints were intentional (like the kvm case - although I'm not convinced the kvm hinting was actually meaningful). Linus