Hi, As you remember, splice(2) needs two fds, and it's a bit of a pain finding a place for the second REQ_F_FIXED_FILE flag. So, I was thinking, can we use the last (i.e. sign) bit to mark an fd as fixed? A lot of userspace programs consider any negative result of open() as an error, so it's more or less safe to reuse it. e.g. fill_sqe(fd) // is not fixed fill_sqe(buf_idx | LAST_BIT) // fixed file -- Pavel Begunkov
