Peter sent an RFC out about a year ago <https://lore.kernel.org/lkml/YHbBBuVFNnI4kjj3@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/>, but after a spirited discussion it looks like we lost track of things. IIRC there was broad consensus on this being the way to go, but there was a lot of discussion so I wasn't sure. Given that it's been a year, I figured it'd be best to just send this out again formatted a bit more explicitly as a patch. This has had almost no testing (just a build test on RISC-V defconfig), but I wanted to send it out largely as-is because I didn't have a SOB from Peter on the code. I had sent around something sort of similar in spirit, but this looks completely re-written. Just to play it safe I wanted to send out almost exactly as it was posted. I'd probably rename this tspinlock and tspinlock_types, as the mis-match kind of makes my eyes go funny, but I don't really care that much. I'll also go through the other ports and see if there's any more candidates, I seem to remember there having been more than just OpenRISC but it's been a while. I'm in no big rush for this and given the complex HW dependencies I think it's best to target it for 5.19, that'd give us a full merge window for folks to test/benchmark it on their systems to make sure it's OK. RISC-V has a forward progress guarantee so we should be safe, but these can always trip things up.
