static int vp_request_msix_vectors()

in virtio_pci_common.c [134:206]

• 63 lines of code
• 11 McCabe index (conditional complexity)

static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
				   bool per_vq_vectors, struct irq_affinity *desc)
{
	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
	const char *name = dev_name(&vp_dev->vdev.dev);
	unsigned flags = PCI_IRQ_MSIX;
	unsigned i, v;
	int err = -ENOMEM;

	vp_dev->msix_vectors = nvectors;

	vp_dev->msix_names = kmalloc_array(nvectors,
					   sizeof(*vp_dev->msix_names),
					   GFP_KERNEL);
	if (!vp_dev->msix_names)
		goto error;
	vp_dev->msix_affinity_masks
		= kcalloc(nvectors, sizeof(*vp_dev->msix_affinity_masks),
			  GFP_KERNEL);
	if (!vp_dev->msix_affinity_masks)
		goto error;
	for (i = 0; i < nvectors; ++i)
		if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i],
					GFP_KERNEL))
			goto error;

	if (desc) {
		flags |= PCI_IRQ_AFFINITY;
		desc->pre_vectors++; /* virtio config vector */
	}

	err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors,
					     nvectors, flags, desc);
	if (err < 0)
		goto error;
	vp_dev->msix_enabled = 1;

	/* Set the vector used for configuration */
	v = vp_dev->msix_used_vectors;
	snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
		 "%s-config", name);
	err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
			  vp_config_changed, IRQF_NO_AUTOEN,
			  vp_dev->msix_names[v],
			  vp_dev);
	if (err)
		goto error;
	++vp_dev->msix_used_vectors;

	v = vp_dev->config_vector(vp_dev, v);
	/* Verify we had enough resources to assign the vector */
	if (v == VIRTIO_MSI_NO_VECTOR) {
		err = -EBUSY;
		goto error;
	}

	if (!per_vq_vectors) {
		/* Shared vector for all VQs */
		v = vp_dev->msix_used_vectors;
		snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
			 "%s-virtqueues", name);
		err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
				  vp_vring_interrupt, IRQF_NO_AUTOEN,
				  vp_dev->msix_names[v],
				  vp_dev);
		if (err)
			goto error;
		++vp_dev->msix_used_vectors;
	}
	return 0;
error:
	return err;
}