Sent out a review for this. IMO even without multiple use sites, the static inline helper method seems cleaner to me. I'm ok if we don't want it, but I really do think it would make our lives easier.Without CONFIG_FUSE_PASSTHROUGH, fuse/passthrough.c is compiled out, so the check cannot be moved into fuse_backing_* we'd need inline helpers that return -EOPNOTSUPP when CONFIG_FUSE_PASSTHROUGH is not defined. I don't mind, but I am not sure this is justified (yet).
