void vfio_pci_intx_mask(struct vfio_pci_device *vdev)
{
	struct pci_dev *pdev = vdev->pdev;
	unsigned long flags;

	spin_lock_irqsave(&vdev->irqlock, flags);

	/*
	 * Masking can come from interrupt, ioctl, or config space
	 * via INTx disable.  The latter means this can get called
	 * even when not using intx delivery.  In this case, just
	 * try to have the physical bit follow the virtual bit.
	 */
	if (unlikely(!is_intx(vdev))) {
		if (vdev->pci_2_3)
			pci_intx(pdev, 0);
	} else if (!vdev->ctx[0].masked) {
		/*
		 * Can't use check_and_mask here because we always want to
		 * mask, not just when something is pending.
		 */
		if (vdev->pci_2_3)
			pci_intx(pdev, 0);
		else
			disable_irq_nosync(pdev->irq);

		vdev->ctx[0].masked = true;
	}

	spin_unlock_irqrestore(&vdev->irqlock, flags);
}

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.