forked from mirrors/linux
virtio_pci: use shared interrupts for virtqueues
This lets IRQ layer handle dispatching IRQs to separate handlers for the case where we don't have per-VQ MSI-X vectors, and allows us to greatly simplify the code based on the assumption that we always have interrupt vector 0 (legacy INTx or config interrupt for MSI-X) available, and any other interrupt is request/freed throught the VQ, even if the actual interrupt line might be shared in some cases. This allows removing a great deal of variables keeping track of the interrupt state in struct virtio_pci_device, as we can now simply walk the list of VQs and deal with per-VQ interrupt handlers there, and only treat vector 0 special. Additionally clean up the VQ allocation code to properly unwind on error instead of having a single global cleanup label, which is error prone, and in this case also leads to more code. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Christoph Hellwig
Michael S. Tsirkin
parent
5c34d002dc
commit
07ec51480b
2 changed files with 106 additions and 145 deletions
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@ -33,10 +33,8 @@ void vp_synchronize_vectors(struct virtio_device *vdev)
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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int i;
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if (vp_dev->intx_enabled)
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synchronize_irq(vp_dev->pci_dev->irq);
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for (i = 0; i < vp_dev->msix_vectors; ++i)
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synchronize_irq(pci_irq_vector(vp_dev->pci_dev, 0));
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for (i = 1; i < vp_dev->msix_vectors; i++)
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synchronize_irq(pci_irq_vector(vp_dev->pci_dev, i));
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}
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@ -99,77 +97,10 @@ static irqreturn_t vp_interrupt(int irq, void *opaque)
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return vp_vring_interrupt(irq, opaque);
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}
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static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors,
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bool per_vq_vectors)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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const char *name = dev_name(&vp_dev->vdev.dev);
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unsigned i, v;
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int err = -ENOMEM;
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vp_dev->msix_vectors = nvectors;
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vp_dev->msix_names = kmalloc(nvectors * sizeof *vp_dev->msix_names,
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GFP_KERNEL);
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if (!vp_dev->msix_names)
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goto error;
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vp_dev->msix_affinity_masks
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= kzalloc(nvectors * sizeof *vp_dev->msix_affinity_masks,
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GFP_KERNEL);
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if (!vp_dev->msix_affinity_masks)
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goto error;
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for (i = 0; i < nvectors; ++i)
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if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i],
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GFP_KERNEL))
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goto error;
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err = pci_alloc_irq_vectors(vp_dev->pci_dev, nvectors, nvectors,
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PCI_IRQ_MSIX);
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if (err < 0)
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goto error;
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vp_dev->msix_enabled = 1;
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/* Set the vector used for configuration */
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v = vp_dev->msix_used_vectors;
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snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
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"%s-config", name);
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err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
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vp_config_changed, 0, vp_dev->msix_names[v],
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vp_dev);
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if (err)
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goto error;
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++vp_dev->msix_used_vectors;
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v = vp_dev->config_vector(vp_dev, v);
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/* Verify we had enough resources to assign the vector */
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if (v == VIRTIO_MSI_NO_VECTOR) {
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err = -EBUSY;
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goto error;
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}
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if (!per_vq_vectors) {
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/* Shared vector for all VQs */
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v = vp_dev->msix_used_vectors;
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snprintf(vp_dev->msix_names[v], sizeof *vp_dev->msix_names,
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"%s-virtqueues", name);
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err = request_irq(pci_irq_vector(vp_dev->pci_dev, v),
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vp_vring_interrupt, 0, vp_dev->msix_names[v],
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vp_dev);
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if (err)
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goto error;
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++vp_dev->msix_used_vectors;
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}
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return 0;
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error:
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return err;
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}
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/* the config->del_vqs() implementation */
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void vp_del_vqs(struct virtio_device *vdev)
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static void vp_remove_vqs(struct virtio_device *vdev)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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struct virtqueue *vq, *n;
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int i;
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list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
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if (vp_dev->msix_vector_map) {
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@ -181,35 +112,33 @@ void vp_del_vqs(struct virtio_device *vdev)
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}
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vp_dev->del_vq(vq);
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}
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}
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if (vp_dev->intx_enabled) {
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free_irq(vp_dev->pci_dev->irq, vp_dev);
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vp_dev->intx_enabled = 0;
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}
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/* the config->del_vqs() implementation */
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void vp_del_vqs(struct virtio_device *vdev)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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int i;
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for (i = 0; i < vp_dev->msix_used_vectors; ++i)
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free_irq(pci_irq_vector(vp_dev->pci_dev, i), vp_dev);
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if (WARN_ON_ONCE(list_empty_careful(&vdev->vqs)))
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return;
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for (i = 0; i < vp_dev->msix_vectors; i++)
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if (vp_dev->msix_affinity_masks[i])
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free_cpumask_var(vp_dev->msix_affinity_masks[i]);
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vp_remove_vqs(vdev);
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if (vp_dev->msix_enabled) {
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for (i = 0; i < vp_dev->msix_vectors; i++)
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free_cpumask_var(vp_dev->msix_affinity_masks[i]);
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/* Disable the vector used for configuration */
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vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR);
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pci_free_irq_vectors(vp_dev->pci_dev);
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vp_dev->msix_enabled = 0;
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kfree(vp_dev->msix_affinity_masks);
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kfree(vp_dev->msix_names);
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kfree(vp_dev->msix_vector_map);
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}
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vp_dev->msix_vectors = 0;
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vp_dev->msix_used_vectors = 0;
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kfree(vp_dev->msix_names);
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vp_dev->msix_names = NULL;
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kfree(vp_dev->msix_affinity_masks);
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vp_dev->msix_affinity_masks = NULL;
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kfree(vp_dev->msix_vector_map);
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vp_dev->msix_vector_map = NULL;
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free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev);
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pci_free_irq_vectors(vp_dev->pci_dev);
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}
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static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
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@ -219,79 +148,122 @@ static int vp_find_vqs_msix(struct virtio_device *vdev, unsigned nvqs,
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bool per_vq_vectors)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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const char *name = dev_name(&vp_dev->vdev.dev);
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int i, err = -ENOMEM, allocated_vectors, nvectors;
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u16 msix_vec;
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int i, err, nvectors, allocated_vectors;
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nvectors = 1;
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for (i = 0; i < nvqs; i++)
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if (callbacks[i])
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nvectors++;
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if (per_vq_vectors) {
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/* Best option: one for change interrupt, one per vq. */
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nvectors = 1;
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for (i = 0; i < nvqs; ++i)
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if (callbacks[i])
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++nvectors;
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err = pci_alloc_irq_vectors(vp_dev->pci_dev, nvectors, nvectors,
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PCI_IRQ_MSIX);
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} else {
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/* Second best: one for change, shared for all vqs. */
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nvectors = 2;
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err = pci_alloc_irq_vectors(vp_dev->pci_dev, 2, 2,
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PCI_IRQ_MSIX);
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}
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if (err < 0)
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return err;
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vp_dev->msix_vectors = nvectors;
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vp_dev->msix_names = kmalloc_array(nvectors,
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sizeof(*vp_dev->msix_names), GFP_KERNEL);
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if (!vp_dev->msix_names)
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goto out_free_irq_vectors;
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vp_dev->msix_affinity_masks = kcalloc(nvectors,
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sizeof(*vp_dev->msix_affinity_masks), GFP_KERNEL);
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if (!vp_dev->msix_affinity_masks)
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goto out_free_msix_names;
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for (i = 0; i < nvectors; ++i) {
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if (!alloc_cpumask_var(&vp_dev->msix_affinity_masks[i],
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GFP_KERNEL))
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goto out_free_msix_affinity_masks;
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}
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err = vp_request_msix_vectors(vdev, nvectors, per_vq_vectors);
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/* Set the vector used for configuration */
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snprintf(vp_dev->msix_names[0], sizeof(*vp_dev->msix_names),
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"%s-config", name);
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err = request_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_config_changed,
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0, vp_dev->msix_names[0], vp_dev);
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if (err)
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goto error_find;
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goto out_free_irq_vectors;
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if (per_vq_vectors) {
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vp_dev->msix_vector_map = kmalloc_array(nvqs,
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sizeof(*vp_dev->msix_vector_map), GFP_KERNEL);
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if (!vp_dev->msix_vector_map)
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goto error_find;
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/* Verify we had enough resources to assign the vector */
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if (vp_dev->config_vector(vp_dev, 0) == VIRTIO_MSI_NO_VECTOR) {
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err = -EBUSY;
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goto out_free_config_irq;
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}
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allocated_vectors = vp_dev->msix_used_vectors;
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vp_dev->msix_vector_map = kmalloc_array(nvqs,
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sizeof(*vp_dev->msix_vector_map), GFP_KERNEL);
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if (!vp_dev->msix_vector_map)
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goto out_disable_config_irq;
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allocated_vectors = 1; /* vector 0 is the config interrupt */
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for (i = 0; i < nvqs; ++i) {
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if (!names[i]) {
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vqs[i] = NULL;
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continue;
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}
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if (!callbacks[i])
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msix_vec = VIRTIO_MSI_NO_VECTOR;
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else if (per_vq_vectors)
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msix_vec = allocated_vectors++;
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if (callbacks[i])
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msix_vec = allocated_vectors;
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else
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msix_vec = VP_MSIX_VQ_VECTOR;
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msix_vec = VIRTIO_MSI_NO_VECTOR;
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vqs[i] = vp_dev->setup_vq(vp_dev, i, callbacks[i], names[i],
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msix_vec);
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if (IS_ERR(vqs[i])) {
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err = PTR_ERR(vqs[i]);
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goto error_find;
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goto out_remove_vqs;
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}
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if (!per_vq_vectors)
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continue;
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if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
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vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR;
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continue;
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}
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/* allocate per-vq irq if available and necessary */
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snprintf(vp_dev->msix_names[msix_vec],
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sizeof *vp_dev->msix_names,
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"%s-%s",
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snprintf(vp_dev->msix_names[i + 1],
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sizeof(*vp_dev->msix_names), "%s-%s",
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dev_name(&vp_dev->vdev.dev), names[i]);
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err = request_irq(pci_irq_vector(vp_dev->pci_dev, msix_vec),
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vring_interrupt, 0,
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vp_dev->msix_names[msix_vec],
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vqs[i]);
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vring_interrupt, IRQF_SHARED,
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vp_dev->msix_names[i + 1], vqs[i]);
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if (err) {
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/* don't free this irq on error */
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vp_dev->msix_vector_map[i] = VIRTIO_MSI_NO_VECTOR;
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goto error_find;
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goto out_remove_vqs;
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}
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vp_dev->msix_vector_map[i] = msix_vec;
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if (per_vq_vectors)
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allocated_vectors++;
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}
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vp_dev->msix_enabled = 1;
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return 0;
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error_find:
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vp_del_vqs(vdev);
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out_remove_vqs:
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vp_remove_vqs(vdev);
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kfree(vp_dev->msix_vector_map);
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out_disable_config_irq:
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vp_dev->config_vector(vp_dev, VIRTIO_MSI_NO_VECTOR);
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out_free_config_irq:
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free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev);
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out_free_msix_affinity_masks:
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for (i = 0; i < nvectors; i++) {
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if (vp_dev->msix_affinity_masks[i])
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free_cpumask_var(vp_dev->msix_affinity_masks[i]);
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}
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kfree(vp_dev->msix_affinity_masks);
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out_free_msix_names:
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kfree(vp_dev->msix_names);
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out_free_irq_vectors:
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pci_free_irq_vectors(vp_dev->pci_dev);
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return err;
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}
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@ -305,9 +277,8 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
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err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
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dev_name(&vdev->dev), vp_dev);
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if (err)
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goto out_del_vqs;
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return err;
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vp_dev->intx_enabled = 1;
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for (i = 0; i < nvqs; ++i) {
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if (!names[i]) {
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vqs[i] = NULL;
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@ -317,13 +288,15 @@ static int vp_find_vqs_intx(struct virtio_device *vdev, unsigned nvqs,
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VIRTIO_MSI_NO_VECTOR);
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if (IS_ERR(vqs[i])) {
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err = PTR_ERR(vqs[i]);
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goto out_del_vqs;
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goto out_remove_vqs;
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}
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}
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return 0;
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out_del_vqs:
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vp_del_vqs(vdev);
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out_remove_vqs:
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vp_remove_vqs(vdev);
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free_irq(pci_irq_vector(vp_dev->pci_dev, 0), vp_dev);
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return err;
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}
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@ -66,16 +66,12 @@ struct virtio_pci_device {
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/* MSI-X support */
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int msix_enabled;
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int intx_enabled;
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cpumask_var_t *msix_affinity_masks;
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/* Name strings for interrupts. This size should be enough,
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* and I'm too lazy to allocate each name separately. */
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char (*msix_names)[256];
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/* Number of available vectors */
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unsigned msix_vectors;
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/* Vectors allocated, excluding per-vq vectors if any */
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unsigned msix_used_vectors;
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/* Total Number of MSI-X vectors (including per-VQ ones). */
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int msix_vectors;
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/* Map of per-VQ MSI-X vectors, may be NULL */
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unsigned *msix_vector_map;
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@ -89,14 +85,6 @@ struct virtio_pci_device {
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u16 (*config_vector)(struct virtio_pci_device *vp_dev, u16 vector);
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};
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/* Constants for MSI-X */
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/* Use first vector for configuration changes, second and the rest for
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* virtqueues Thus, we need at least 2 vectors for MSI. */
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enum {
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VP_MSIX_CONFIG_VECTOR = 0,
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VP_MSIX_VQ_VECTOR = 1,
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};
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/* Convert a generic virtio device to our structure */
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static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
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{
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