forked from Minki/linux
virtio: refactor find_vqs
This refactors find_vqs, making it more readable and robust, and fixing two regressions from 2.6.30: - double free_irq causing BUG_ON on device removal - probe failure when vq can't be assigned to msi-x vector (reported on old host kernels) Tested-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Michael S. Tsirkin
Rusty Russell
parent
f6c8250703
commit
e969fed542
@ -52,8 +52,10 @@ struct virtio_pci_device
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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 */
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/* Vectors allocated, excluding per-vq vectors if any */
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unsigned msix_used_vectors;
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/* Whether we have vector per vq */
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bool per_vq_vectors;
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};
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/* Constants for MSI-X */
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@ -278,27 +280,24 @@ static void vp_free_vectors(struct virtio_device *vdev)
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vp_dev->msix_entries = NULL;
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}
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static int vp_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
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int *options, int noptions)
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{
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int i;
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for (i = 0; i < noptions; ++i)
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if (!pci_enable_msix(dev, entries, options[i]))
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return options[i];
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return -EBUSY;
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}
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static int vp_request_vectors(struct virtio_device *vdev, unsigned max_vqs)
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static int vp_request_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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/* We want at most one vector per queue and one for config changes.
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* Fallback to separate vectors for config and a shared for queues.
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* Finally fall back to regular interrupts. */
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int options[] = { max_vqs + 1, 2 };
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int nvectors = max(options[0], options[1]);
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if (!nvectors) {
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/* Can't allocate MSI-X vectors, use regular interrupt */
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vp_dev->msix_vectors = 0;
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err = request_irq(vp_dev->pci_dev->irq, vp_interrupt,
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IRQF_SHARED, name, vp_dev);
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if (err)
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return err;
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vp_dev->intx_enabled = 1;
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return 0;
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}
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vp_dev->msix_entries = kmalloc(nvectors * sizeof *vp_dev->msix_entries,
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GFP_KERNEL);
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@ -312,41 +311,34 @@ static int vp_request_vectors(struct virtio_device *vdev, unsigned max_vqs)
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for (i = 0; i < nvectors; ++i)
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vp_dev->msix_entries[i].entry = i;
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err = vp_enable_msix(vp_dev->pci_dev, vp_dev->msix_entries,
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options, ARRAY_SIZE(options));
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if (err < 0) {
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/* Can't allocate enough MSI-X vectors, use regular interrupt */
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vp_dev->msix_vectors = 0;
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err = request_irq(vp_dev->pci_dev->irq, vp_interrupt,
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IRQF_SHARED, name, vp_dev);
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if (err)
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goto error;
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vp_dev->intx_enabled = 1;
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} else {
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vp_dev->msix_vectors = err;
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vp_dev->msix_enabled = 1;
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err = pci_enable_msix(vp_dev->pci_dev, vp_dev->msix_entries, nvectors);
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if (err > 0)
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err = -ENOSPC;
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if (err)
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goto error;
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vp_dev->msix_vectors = nvectors;
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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(vp_dev->msix_entries[v].vector,
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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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/* 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(vp_dev->msix_entries[v].vector,
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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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iowrite16(v, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
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/* Verify we had enough resources to assign the vector */
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v = ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_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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iowrite16(v, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
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/* Verify we had enough resources to assign the vector */
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v = ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_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 (vp_dev->msix_vectors && vp_dev->msix_vectors != max_vqs + 1) {
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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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@ -366,13 +358,14 @@ error:
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static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
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void (*callback)(struct virtqueue *vq),
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const char *name)
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const char *name,
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u16 vector)
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{
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struct virtio_pci_device *vp_dev = to_vp_device(vdev);
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struct virtio_pci_vq_info *info;
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struct virtqueue *vq;
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unsigned long flags, size;
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u16 num, vector;
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u16 num;
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int err;
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/* Select the queue we're interested in */
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@ -391,7 +384,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
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info->queue_index = index;
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info->num = num;
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info->vector = VIRTIO_MSI_NO_VECTOR;
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info->vector = vector;
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size = PAGE_ALIGN(vring_size(num, VIRTIO_PCI_VRING_ALIGN));
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info->queue = alloc_pages_exact(size, GFP_KERNEL|__GFP_ZERO);
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@ -415,22 +408,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
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vq->priv = info;
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info->vq = vq;
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/* allocate per-vq vector if available and necessary */
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if (callback && vp_dev->msix_used_vectors < vp_dev->msix_vectors) {
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vector = vp_dev->msix_used_vectors;
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snprintf(vp_dev->msix_names[vector], sizeof *vp_dev->msix_names,
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"%s-%s", dev_name(&vp_dev->vdev.dev), name);
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err = request_irq(vp_dev->msix_entries[vector].vector,
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vring_interrupt, 0,
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vp_dev->msix_names[vector], vq);
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if (err)
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goto out_request_irq;
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info->vector = vector;
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++vp_dev->msix_used_vectors;
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} else
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vector = VP_MSIX_VQ_VECTOR;
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if (callback && vp_dev->msix_enabled) {
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if (vector != VIRTIO_MSI_NO_VECTOR) {
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iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
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vector = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
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if (vector == VIRTIO_MSI_NO_VECTOR) {
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@ -446,11 +424,6 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
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return vq;
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out_assign:
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if (info->vector != VIRTIO_MSI_NO_VECTOR) {
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free_irq(vp_dev->msix_entries[info->vector].vector, vq);
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--vp_dev->msix_used_vectors;
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}
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out_request_irq:
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vring_del_virtqueue(vq);
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out_activate_queue:
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iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
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@ -472,9 +445,6 @@ static void vp_del_vq(struct virtqueue *vq)
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iowrite16(info->queue_index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
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if (info->vector != VIRTIO_MSI_NO_VECTOR)
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free_irq(vp_dev->msix_entries[info->vector].vector, vq);
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if (vp_dev->msix_enabled) {
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iowrite16(VIRTIO_MSI_NO_VECTOR,
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vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
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@ -495,14 +465,72 @@ static void vp_del_vq(struct virtqueue *vq)
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/* the config->del_vqs() implementation */
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static 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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struct virtqueue *vq, *n;
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struct virtio_pci_vq_info *info;
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list_for_each_entry_safe(vq, n, &vdev->vqs, list)
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list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
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info = vq->priv;
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if (vp_dev->per_vq_vectors)
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free_irq(vp_dev->msix_entries[info->vector].vector, vq);
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vp_del_vq(vq);
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}
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vp_dev->per_vq_vectors = false;
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vp_free_vectors(vdev);
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}
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static int vp_try_to_find_vqs(struct virtio_device *vdev, unsigned nvqs,
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struct virtqueue *vqs[],
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vq_callback_t *callbacks[],
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const char *names[],
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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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u16 vector;
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int i, err, allocated_vectors;
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err = vp_request_vectors(vdev, nvectors, per_vq_vectors);
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if (err)
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goto error_request;
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vp_dev->per_vq_vectors = per_vq_vectors;
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allocated_vectors = vp_dev->msix_used_vectors;
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for (i = 0; i < nvqs; ++i) {
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if (!callbacks[i] || !vp_dev->msix_enabled)
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vector = VIRTIO_MSI_NO_VECTOR;
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else if (vp_dev->per_vq_vectors)
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vector = allocated_vectors++;
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else
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vector = VP_MSIX_VQ_VECTOR;
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vqs[i] = vp_find_vq(vdev, i, callbacks[i], names[i], vector);
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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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}
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/* allocate per-vq irq if available and necessary */
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if (vp_dev->per_vq_vectors && vector != VIRTIO_MSI_NO_VECTOR) {
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snprintf(vp_dev->msix_names[vector], sizeof *vp_dev->msix_names,
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"%s-%s", dev_name(&vp_dev->vdev.dev), names[i]);
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err = request_irq(vp_dev->msix_entries[vector].vector,
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vring_interrupt, 0,
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vp_dev->msix_names[vector], vqs[i]);
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if (err) {
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vp_del_vq(vqs[i]);
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goto error_find;
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}
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}
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}
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return 0;
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error_find:
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vp_del_vqs(vdev);
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error_request:
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return err;
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}
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/* the config->find_vqs() implementation */
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static int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
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struct virtqueue *vqs[],
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@ -510,29 +538,27 @@ static int vp_find_vqs(struct virtio_device *vdev, unsigned nvqs,
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const char *names[])
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{
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int vectors = 0;
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int i, err;
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int i, uninitialized_var(err);
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/* How many vectors would we like? */
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for (i = 0; i < nvqs; ++i)
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if (callbacks[i])
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++vectors;
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err = vp_request_vectors(vdev, vectors);
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if (err)
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goto error_request;
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for (i = 0; i < nvqs; ++i) {
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vqs[i] = vp_find_vq(vdev, i, callbacks[i], names[i]);
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if (IS_ERR(vqs[i]))
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goto error_find;
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}
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return 0;
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error_find:
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vp_del_vqs(vdev);
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error_request:
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return PTR_ERR(vqs[i]);
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/* We want at most one vector per queue and one for config changes. */
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err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
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vectors + 1, true);
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if (!err)
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return 0;
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/* Fallback to separate vectors for config and a shared for queues. */
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err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
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2, false);
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if (!err)
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return 0;
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/* Finally fall back to regular interrupts. */
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err = vp_try_to_find_vqs(vdev, nvqs, vqs, callbacks, names,
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0, false);
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return err;
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}
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static struct virtio_config_ops virtio_pci_config_ops = {
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