userfaultfd

/*
 * userfaultfd_wake may be used in combination with the
 * UFFDIO_*_MODE_DONTWAKE to wakeup userfaults in batches.
 */
static int userfaultfd_wake(struct userfaultfd_ctx *ctx,
                unsigned long arg)
{
    int ret;
    struct uffdio_range uffdio_wake;
    struct userfaultfd_wake_range range;
    const void __user *buf = (void __user *)arg;
 
    ret = -EFAULT;
    if (copy_from_user(&uffdio_wake, buf, sizeof(uffdio_wake)))
        goto out;
 
    ret = validate_range(ctx->mm, &uffdio_wake.start, uffdio_wake.len);
    if (ret)
        goto out;
 
    range.start = uffdio_wake.start;
    range.len = uffdio_wake.len;
 
    /*
     * len == 0 means wake all and we don't want to wake all here,
     * so check it again to be sure.
     */
    VM_BUG_ON(!range.len);
 
    wake_userfault(ctx, &range);
    ret = 0;
 
out:
    return ret;
}
函数源码
