Function wake

vmm/src/uffd.rs:187–201

Wake threads waiting on a fault in the given range without copying data. Needed after UFFDIO_COPY returns EEXIST: the page was already resolved by a concurrent fault, but any additional threads blocked on that page may not have been woken.

(fd: BorrowedFd<'_>, addr: u64, len: u64)

/// by a concurrent fault, but any additional threads blocked on that page
/// may not have been woken.
pub(crate) fn wake(fd: BorrowedFd<'_>, addr: u64, len: u64) -> Result<(), Error> {
    let mut range = UffdioRange { start: addr, len };
    // SAFETY: `range` is a valid, correctly-sized struct for this ioctl.
    let ret = unsafe {
        libc::ioctl(
            fd.as_raw_fd(),
            userfaultfd::UFFDIO_WAKE as libc::Ioctl,
            &mut range,
        )
    };
    if ret < 0 {
        return Err(Error::last_os_error());
    }
    Ok(())
}