On Thu, 08 Dec 2022, "Vivi, Rodrigo" <rodrigo.vivi@xxxxxxxxx> wrote: > On Thu, 2022-12-08 at 14:32 +0200, Jani Nikula wrote: >> On Thu, 08 Dec 2022, Andrzej Hajda <andrzej.hajda@xxxxxxxxx> wrote: >> > Simplify the code. >> >> Personally, I absolutely hate fetch_and_zero(). >> >> I understand the point, but there are two main traps: >> >> First, the name implies atomicity, which there is none at all. >> >> Second, the name implies it's part of a kernel core header, which it >> isn't, and this just amplifies the first point. >> >> It's surprising and misleading, and those are not things I like about >> interfaces in the kernel. >> >> I would not like to see this proliferate. If fetch_and_zero() was >> atomic >> *and* part of a core kernel header, it would be a different matter. >> But >> I don't think that's going to happen, exactly because it won't be >> atomic >> and the name implies it is. > > +1 here. > > Please let's go the other way around and try to kill macros like this. > > we either kill or we ensure this gets accepted in the core kernel > libraries. Agreed. I'd be fine with either: 1) Get something like this accepted in core kernel headers: #define fetch_and_zero(ptr) xchg(ptr, 0) 2) Do this in i915: @@ expression E; @@ - fetch_and_zero(E) + xchg(E, 0) BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center
