On Tue, Jul 21, 2020 at 7:34 AM Christoph Hellwig <hch@xxxxxx> wrote: > > On Tue, Jul 21, 2020 at 07:31:02AM -0700, Andy Lutomirski wrote: > > > What do you mean with "properly wired up". Do you really want to spread > > > ->compat_foo methods everywhere, including read and write? I found > > > in_compat_syscall() a lot small and easier to maintain than all the > > > separate compat cruft. > > > > I was imagining using a flag. Some of the net code uses > > MSG_CMSG_COMPAT for this purpose. > > Killing that nightmarish monster is what actually got me into looking > io_uring and starting this thread. I agree that MSG_CMSG_COMPAT is nasty, but I think the concept is sound -- rather than tracking whether we're compat by using a different function or a per-thread variable, actually explicitly tracking the mode seems sensible. If we're going to play in_compat_syscall() games, let's please make io_uring_enter() return -EINVAL if in_compat_syscall() != ctx->compat. --Andy
