On 10/31/24 8:12 PM, Ming Lei wrote: > On Thu, Oct 31, 2024 at 03:22:18PM -0600, Jens Axboe wrote: >> In hindsight everything is clearer, but it probably should've been known >> that 8 bits of ->flags would run out sooner than later. Rather than >> gobble up the last bit for a random use case, add a bit that controls >> whether or not ->personality is used as a flags2 argument. If that is >> the case, then there's a new IOSQE2_PERSONALITY flag that tells io_uring >> which personality field to read. >> >> While this isn't the prettiest, it does allow extending with 15 extra >> flags, and retains being able to use personality with any kind of >> command. The exception is uring cmd, where personality2 will overlap >> with the space set aside for SQE128. If they really need that, then that > > The space is the 1st `short` for uring_cmd, instead of SQE128 only. > > Also it is overlapped with ->optval and ->addr3, so just wondering why not > use ->__pad2? > > Another ways is to use __pad2 for sqe2_flags for non-uring_cmd, and for > uring_cmd, use its top 16 as sqe2_flags, this way does work, but it is > just a bit ugly to use. Agree, __pad2 is the better place, we don't want it overlapping with add3/optval. -- Jens Axboe
