On Fri, Jun 20, 2025 at 09:10:03AM -0600, Caleb Sander Mateos wrote: > Currently, UBLK_IO_REGISTER_IO_BUF and UBLK_IO_UNREGISTER_IO_BUF are > only permitted on the ublk_io's daemon task. But this restriction is > unnecessary. ublk_register_io_buf() calls __ublk_check_and_get_req() to > look up the request from the tagset and atomically take a reference on > the request without accessing the ublk_io. ublk_unregister_io_buf() > doesn't use the q_id or tag at all. > > So allow these opcodes even on tasks other than io->task. > > Handle UBLK_IO_UNREGISTER_IO_BUF before obtaining the ubq and io since > the buffer index being unregistered is not necessarily related to the > specified q_id and tag. > > Add a feature flag UBLK_F_BUF_REG_OFF_DAEMON that userspace can use to > determine whether the kernel supports off-daemon buffer registration. > > Suggested-by: Ming Lei <ming.lei@xxxxxxxxxx> > Signed-off-by: Caleb Sander Mateos <csander@xxxxxxxxxxxxxxx> Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> Thanks, Ming
