On Thu, Mar 17, 2022 at 12:25 AM Palmer Dabbelt <palmer@xxxxxxxxxxxx> wrote: > > 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. This all looks good to me, feel free to merge the asm-generic bits through the riscv tree. Regarding the naming, my preference would be to just use this version in place of the (currently useless) asm-generic/spinlock.h, and just naming it arch_spin_lock() etc. This way, converting an architecture to the generic ticket lock can be done simply by removing its custom asm/spinlock.h. Or it could stay with the current name, but then have a new asm-generic/spinlock.h that just includes both asm/ticket_lock.h and asm/qrwlock.h. Arnd
